{"paper_id":"45188b0d-1139-4ce9-a7df-c7510f066bfa","body_text":"Correlation between Antioxidant Capacity and Phenolic Compounds of Korean Red Pine (Pinus densiflora Sieb. et Zucc.) Bark Fractions under In Vitro Gastrointestinal Digestive Conditions | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Correlation between Antioxidant Capacity and Phenolic Compounds of Korean Red Pine (Pinus densiflora Sieb. et Zucc.) Bark Fractions under In Vitro Gastrointestinal Digestive Conditions Seung-Su Choi, Young Sung Jung, Gyo-Ha Hwang, Sanggil Lee, Nam Soo Han, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4852257/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 17 You are reading this latest preprint version Abstract This study investigates the correlation between phenolic compounds and antioxidant capacities of Korean red pine ( Pinus densiflora Sieb. et Zucc.) bark (RPB) fractions under in vitro gastrointestinal digestion. RPB extracts were obtained using 70% ( v/v ) aqueous ethanol and further fractionated with n -hexane, ethyl acetate, and water. Their antioxidant capacities were evaluated using three antioxidant assays. Phenolic compounds were quantified using a liquid chromatography system to assess their stability. The antioxidant capacity of RPB extract and its fractions were found to be significantly influenced by the digestive process. Gastric digestion increased the contents of procyanidin B1 and catechin, whereas intestinal digestion degraded most of the phenolic compounds except protocatechuic acid. Principal component analysis results showed that taxifolin had the greatest impact on data variability, indicating that this polyphenol plays an important role in the antioxidant capacity of RPB. This study provides insights into the stability and bioaccessibility of phenolic compounds in RPB under simulated gastrointestinal conditions, supporting its potential use as a source of natural antioxidants in dietary supplements. Bioaccessibility Digestion stability Polyphenol Principal component analysis Simulated digestion Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Pinus densiflora Sieb. et Zucc. (Korean red pine) is a native coniferous tree found in Korea, Japan, northeastern China, and the southeastern regions of Russia [ 1 ]. In Korea, red pine trees have the largest forest area, accounting for approximately 22% of the total forest land as of 2015 [ 2 ]. Pine bark is typically considered a byproduct and discarded, but it can also be upcycled as high-value material through specific manufacturing processes [ 3 , 4 ]. Pine bark has been developed as dietary supplements because it contains various bioactive compounds, including protocatechuic acid, procyanidin B1, catechin, caffeic acid, vanillin, and taxifolin [ 5 , 6 ]. Bioactive compounds present in Korean red pine bark (RPB) are known to have potent antioxidant capacity as well as effects in improving cardiovascular health, enhancing the immune system, improving glycemic control, and enhancing cognitive function [ 4 , 7 ]. The bioactive compounds of RPB are absorbed and metabolized in the human digestive system [ 4 ]. Bioactive phenolic compounds with small molecular weights are readily absorbed in the small intestine, whereas relatively larger phenolic molecules, such as procyanidins, reach the large intestine and are metabolized by gut microbiota [ 4 , 7 ]. This indicates that the major phenolic compounds of RPB must remain stable during the digestive process to be bioactive. In vitro simulated digestion offers an alternative to animal and clinical trials due to its reduced ethical concerns, lower costs, and fewer side effects [ 8 , 9 ]. This method can provide information on the stability and antioxidant capacity of high-molecular-weight compounds such as procyanidins in RPB. Simulated digestion in vitro also allows the identification of metabolites, catechin and epicatechin monomers, derived from RPB during digestion [ 10 , 11 ]. The objective of this study is to comparatively evaluate the phenolic compound content and antioxidant capacity before and after simulated human digestion of RPB extract and its fractions. The RPB fractions were investigated for antioxidant capacity, total phenolic content (TPC), and total flavonoid content (TFC), and individual phenolic compounds. Principal component analysis (PCA) was utilized to determine the impact of digestion on antioxidant capacity and phenolic content. This study may contribute the better understanding of the bioavailability of upcycled bioactive materials from natural resources-derived byproducts. Materials and methods The Materials and methods section is presented as Supplementary Material. Results and Discussion Extraction and fractionation of RPB First, in this study, RPB extracts were obtained by extracting RPB at various ethanol concentrations. An aqueous solvent with a high concentration of ethanol can effectively extract bioactive compounds from RPB [ 12 ]. Ethanol aids in forming hydrogen bonds with the abundant hydroxyl groups of phenolic compounds [ 13 ]. Among those five extracts obtaining by varying ethanol concentrations, the optimal extract was determined by measuring the antioxidant capacity using two radical chromogens 2,2′-azobis(2-methylpropionamidine) dihydrochloride (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) (Table S1 ). The phosphate-buffered saline-based ABTS assay is suitable for determining water-soluble antioxidants, whereas the methanol-based DPPH assay can measure the antioxidant capacity of non-polar antioxidants [ 14 ]. Among the various RPB extracts, RPB extracted with 70% ( v/v ) aqueous ethanol showed significantly ( p < 0.05) the highest antioxidant capacity (Table S1 ) and was used in subsequent experiments. TPC, TFC, and antioxidant capacity of RPB fractions The RPB extract obtained by extraction with 70% ( v/v ) aqueous ethanol was concentrated in vacuum and sequentially fractionated using n -hexane, ethyl acetate, and water (Fig. S1 ). The bioactives of RPB have different solubilities depending on the polarity of the fractionating solvent [ 15 ]. The antioxidant capacity (ABTS, DPPH, ferric reducing antioxidant power [FRAP]), TPC, and TFC of the RPB extract and its fractions are shown in Table 1 . The antioxidant capacity, TPC, and TFC of the three fractions decreased in the following order: water fraction > ethyl acetate fraction > n -hexane fraction. Among the fractions, the water fraction with the highest antioxidant capacity was 21- to 50-fold higher than the n -hexane fraction with the lowest antioxidant capacity. The TPC and TFC of the water fraction were approximately 11 and 7 times higher, respectively, than those of the n -hexane fraction. These indicate that the bioactive compounds in the RPB extract are relatively polar substances. Here in, the results are also supported by a previous report showing that the extraction efficiency of bioactive compounds from RPB increased under solvent conditions with the addition of ionic additives [ 13 ]. Table 1 Antioxidant capacity, total phenolic content (TPC), and total flavonoid content (TFC) of red pine bark (RPB) extract and its fractions Extract and fraction Antioxidant capacity TPC (mg GAE e /g) TFC (mg CE f /g) ABTS a (mg VCE b /g) DPPH c (mg VCE/g) FRAP d (mg VCE/g) RPB extract 1055.0 ± 47.6 A 825.4 ± 6.4 B 573.4 ± 15.7 A 697.1 ± 10.4 A 419.9 ± 3.6 A n -Hexane fraction 47.9 ± 1.1 C 16.8 ± 2.5 C 25.0 ± 0.5 D 57.5 ± 6.0 D 50.9 ± 12.3 C Ethyl acetate fraction 933.6 ± 43.1 B 686.5 ± 25.7 B 446.2 ± 11.7 C 586.3 ± 5.0 C 370.9 ± 5.4 B Water fraction 997.9 ± 16.5 AB 832.8 ± 23.1 A 514.8 ± 4.5 B 641.3 ± 12.5 B 375.1 ± 13.0 B a ABTS, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt. b VCE, vitamin C equivalent. c DPPH, 2,2-diphenyl-1-picrylhydrazyl. d FRAP, ferric reducing antioxidant power. e GAE, garlic acid equivalent. f CE, catechin equivalent. Different superscripts in the same column indicated significant differences among extract and fractions as determined by Tukey’s honestly significant difference test ( p < 0.05). Antioxidant capacity, TPC and TFC of in vitro digested RPB fractions Antioxidant capacity, TPC, and TFC of the RPB extract and its three fractions after in vitro simulated digestion are shown in Fig. 1 as a percentage of the control (gray bars). In vitro digestion can provide information on the stability of the antioxidant components contained in the RPB extract and fractions. Moreover, in vitro digestion indirectly contributes to the antioxidant capacity of metabolites derived during the digestive process [ 4 ]. RPB extract (Fig. 1 a) and water fraction (Fig. 1 d) showed similar patterns of changes in antioxidant capacity under digestive conditions. In contrast, the ethyl acetate fraction (Fig. 1 c) showed lower antioxidant capacity and TFC in the intestinal digestion phase than in the gastric digestion phase. Polyphenolic compounds become less stable during intestinal digestion process due to enzymes and pH changes, which reduces their antioxidant capacity [ 16 , 17 ]. The n -hexane fraction showed either no detectable antioxidant capacity or a very large deviation after digestion, which is thought to be due to the low initial antioxidant capacity of the n -hexane fraction (Table 1 ). Liquid chromatography (LC) profile of RPB extract and its fractions The major phenolic compounds in RPB were analyzed using LC. Peaks 1–6 were identified as protocatechuic acid, procyanidin B1, catechin, epicatechin, taxifolin, and quercetin, respectively (Fig. 2 ). The information (slope and intercept) of the calibration curves for the quantification of these phenolic compounds is shown in Table S4. The limit of quantification for six phenolic compounds ranged from 2.0 to 14.0 µg/mL. The ethyl acetate fraction contained the highest amounts of phenolic compounds. The relative content of phenolic compounds in the ethyl acetate fraction (Fig. 2 c) was more than twice that of the 70% ( v/v ) aqueous ethanol extract (Fig. 2 a). In contrast, the major phenolic compounds of RPB were not detected in the n -hexane and water fractions, indicating that the major phenolic compounds of RPB have the highest solubility in ethyl acetate [ 5 , 18 ]. Additionally, this suggests that the fractionation process can remove the matrix contained in the RPB extract, thereby generating an enriched fraction with major phenolic compounds. Stability of major phenolic compounds in RPB fractions The digestive stability of phenolic compounds was evaluated for the RPB extract (Fig. 3 a) and the ethyl acetate fraction (Fig. 3 b). After intestinal digestion, no phenolic compounds were detected in either the RPB extract or the ethyl acetate fraction except for protocatechuic acid and taxifolin. These results are consistent with previous reports that phenolic compounds are degraded under intestinal digestive conditions [ 17 , 19 ]. Gastric digestion significantly ( p < 0.05) increased the contents of procyanidin B1 and catechin compared to the control group (Fig. 3 ), which is partly due to the breakdown of high-molecular-weight compounds such as procyanidin. A condensed tannin procyanidin is broken down under the acidic conditions (pH 3.0) of gastric digestion to produce its fragment catechin monomer [ 16 ]. Correlation study The correlation between the antioxidant capacity, TPC, TFC, and digestive stability of phenolic compounds in RPB extract and its ethyl acetate fraction was evaluated using principal component analysis (PCA; Fig. 4 ). For the RPB extract, approximately 70.7% of the data variability was explained by principal component 1, whereas for the ethyl acetate fraction, approximately 64.9% of the data variability was explained by principal component 1. Taxifolin exhibited the highest values in both principal component 1 and principal component 2 in both RPB extract and ethyl acetate fraction, which is partly due to the high content of taxifolin (Fig. 2 ). Antioxidant capacity, TPC, and TFC were highly clustered with epicatechin and quercetin in both RPB extract and ethyl acetate fraction (Fig. 4 a, c). The gastric digestion conditions are primarily explained by principal component 1 and show a pattern similar to that before digestion (Fig. 4 b, d). In contrast, the intestinal digestion conditions are mainly explained by principal component 2 and show a different pattern from the gastric digestion (Fig. 4 b, d). These PCA results (Fig. 4 b, d) visually indicate that phenolic compounds are less stable under intestinal digestion conditions compared to gastric digestion (Fig. 3 ). Conclusion In this study, the correlation between phenolic compounds and antioxidant capacity of RPB extract and its fractions under in vitro gastrointestinal digestion conditions was investigated. The antioxidant capacity of RPB extract and its three fractions were significantly affected by the in vitro simulated digestion. Gastric digestion increased the content of certain phenolic compounds such as procyanidin and catechin. Intestinal digestion, on the other hand, led to the degradation of most phenolic compounds, except for protocatechuic acid. This highlights how important the stability of bioactive compounds during digestion is for their bioavailability and effectiveness. PCA results showed that taxifolin had the greatest influence on the variability of the data, indicating that taxifolin plays an important role in the antioxidant capacity of RPB extract and its fraction. These findings support the potential use of RPB as a source of natural antioxidants in dietary supplements. Further studies are needed to improve the stability and bioavailability of its bioactive compounds during digestion. Abbreviations ABTS 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt CE catechin equivalents DPPH 2,2-diphenyl-1-picrylhydrazyl GAE gallic acid equivalents FRAP ferric reducing antioxidant power LC liquid chromatography PCA principal component analysis RPB red pine bark TFC total flavonoid content TPC total phenolic content VCE vitamin C equivalents. Declarations Author Contributions Conceptualization: Seung-Su Choi, Dae-Ok Kim; Methodology: Young Sung Jung, Nam Soo Han; Formal analysis and investigation: Seung-Su Choi, Gyo-Ha Hwang; Writing - original draft preparation, Young Sung Jung, Sanggil Lee, Dae-Ok Kim; Writing - review and editing: Dae-Ok Kim; Funding acquisition: Dae-Ok Kim; Resources: Sanggil Lee, Nam Soo Han, Dae-Ok Kim; Supervision: Dae-Ok Kim. Funding This work was supported by the Ministry of Education of the Republic of Korea and the National Research Foundation of Korea (NRF-2020R1F1A1060767), Republic of Korea. Data Availability All data generated or analyzed during this study are included in this published article. Financial Interests The authors declare no competing interests and no financial interests. Conflict of interest The authors declare no conflict of interest. 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Supplementary Files 2024PFHNSupplementary.docx Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 18 Aug, 2024 Reviews received at journal 17 Aug, 2024 Reviews received at journal 17 Aug, 2024 Reviews received at journal 15 Aug, 2024 Reviewers agreed at journal 12 Aug, 2024 Reviews received at journal 12 Aug, 2024 Reviewers agreed at journal 10 Aug, 2024 Reviewers agreed at journal 09 Aug, 2024 Reviewers agreed at journal 08 Aug, 2024 Reviewers agreed at journal 07 Aug, 2024 Reviewers agreed at journal 06 Aug, 2024 Reviewers agreed at journal 06 Aug, 2024 Reviewers agreed at journal 06 Aug, 2024 Reviewers invited by journal 06 Aug, 2024 Editor assigned by journal 05 Aug, 2024 Submission checks completed at journal 05 Aug, 2024 First submitted to journal 03 Aug, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {\"props\":{\"pageProps\":{\"initialData\":{\"identity\":\"rs-4852257\",\"acceptedTermsAndConditions\":true,\"allowDirectSubmit\":false,\"archivedVersions\":[],\"articleType\":\"Research Article\",\"associatedPublications\":[],\"authors\":[{\"id\":341748232,\"identity\":\"3eb1ce80-787e-4fae-9167-8a4211254349\",\"order_by\":0,\"name\":\"Seung-Su Choi\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Kyung Hee University\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Seung-Su\",\"middleName\":\"\",\"lastName\":\"Choi\",\"suffix\":\"\"},{\"id\":341748233,\"identity\":\"bbe3fcc2-5b66-4af9-8edc-8c4955771e44\",\"order_by\":1,\"name\":\"Young Sung Jung\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Kyung Hee University\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Young\",\"middleName\":\"Sung\",\"lastName\":\"Jung\",\"suffix\":\"\"},{\"id\":341748234,\"identity\":\"7ea92cc5-57f4-4a9d-951f-bf5387718bc4\",\"order_by\":2,\"name\":\"Gyo-Ha Hwang\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Kyung Hee University\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Gyo-Ha\",\"middleName\":\"\",\"lastName\":\"Hwang\",\"suffix\":\"\"},{\"id\":341748235,\"identity\":\"30497c65-88d4-43e8-9708-7a56f71b20d7\",\"order_by\":3,\"name\":\"Sanggil Lee\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Pukyong National University\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Sanggil\",\"middleName\":\"\",\"lastName\":\"Lee\",\"suffix\":\"\"},{\"id\":341748236,\"identity\":\"3034d507-4dfc-48f8-861b-6bb163475e39\",\"order_by\":4,\"name\":\"Nam Soo Han\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Chungbuk National University\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Nam\",\"middleName\":\"Soo\",\"lastName\":\"Han\",\"suffix\":\"\"},{\"id\":341748237,\"identity\":\"88047546-b168-4631-bb71-2b117e4d65f2\",\"order_by\":5,\"name\":\"Dae-Ok Kim\",\"email\":\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAwElEQVRIiWNgGAWjYBACe/Ye4888Bv/kJCQgAgYEtRj2nEk4PKfigDHxWgxu5Bw4/OfMgcQZJGjJbTic23YnfebsHgOGHzUMxuYNBLXkMwC1PMudLXPGgLHnGIOZzAHitDDnzpPIMWDgbWCwkSDKYbxtzOlyQC2Mf4nTAvQ+z5nDCdJALcxAW8wIagEHMk9FmuHMGWkFh2WOSRgT1AKNSht5iRvJGx++qbExnEFICwo4wMBA0I5RMApGwSgYBcQAANZJRK8swojLAAAAAElFTkSuQmCC\",\"orcid\":\"\",\"institution\":\"Kyung Hee University\",\"correspondingAuthor\":true,\"prefix\":\"\",\"firstName\":\"Dae-Ok\",\"middleName\":\"\",\"lastName\":\"Kim\",\"suffix\":\"\"}],\"badges\":[],\"createdAt\":\"2024-08-03 08:25:56\",\"currentVersionCode\":1,\"declarations\":\"\",\"doi\":\"10.21203/rs.3.rs-4852257/v1\",\"doiUrl\":\"https://doi.org/10.21203/rs.3.rs-4852257/v1\",\"draftVersion\":[],\"editorialEvents\":[],\"editorialNote\":\"\",\"failedWorkflow\":false,\"files\":[{\"id\":63660749,\"identity\":\"1ba3f290-aeca-4daa-9bf5-ef14bb4be5e1\",\"added_by\":\"auto\",\"created_at\":\"2024-08-30 17:44:23\",\"extension\":\"png\",\"order_by\":1,\"title\":\"Figure 1\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":59772,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eAntioxidant capacity (ABTS, DPPH, and FRAP), total phenolic content (TPC), and total flavonoid content (TFC) of red pine bark (RPB) extract and its fractions after simulated human digestion. (a) RPB extract; (b) \\u003cem\\u003en\\u003c/em\\u003e-hexane fraction; (c) ethyl acetate fraction; (d) water fraction. Gray bar (■), control; red bar (■), gastric phase; blue bar (■), intestinal phase. The letters on the bars indicate significant differences among each assay as determined by Tukey’s honestly significant difference test (\\u003cem\\u003ep\\u003c/em\\u003e \\u0026lt; 0.05)\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"floatimage1.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4852257/v1/7f73bd28204fd2e7f8cab70d.png\"},{\"id\":63660349,\"identity\":\"6a958eab-8912-4467-9daa-159f475c1b01\",\"added_by\":\"auto\",\"created_at\":\"2024-08-30 17:36:23\",\"extension\":\"png\",\"order_by\":2,\"title\":\"Figure 2\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":99659,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003ePhenolic compound profiles of RPB extract and its fractions using liquid chromatography at 280 nm. (a) RPB extract; (b) \\u003cem\\u003en\\u003c/em\\u003e-hexane fraction; (c) ethyl acetate fraction; (d) water fraction. Peak 1, protocatechuic acid; peak 2, procyanidin B1; peak 3, catechin; peak 4, epicatechin; peak 5, taxifolin; peak 6, quercetin\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"floatimage2.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4852257/v1/686fb8f711224c71b3896b45.png\"},{\"id\":63660351,\"identity\":\"7b55b678-c4c8-4b1b-a199-dd9dd6c15a7e\",\"added_by\":\"auto\",\"created_at\":\"2024-08-30 17:36:23\",\"extension\":\"png\",\"order_by\":3,\"title\":\"Figure 3\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":38847,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003ePhenolic compounds of RPB extract and its fractions after simulated human digestion. (a) RPB extract; (b) ethyl acetate fraction. Gray bar (■), control; red bar (■), gastric phase; blue bar (■), intestinal phase. The letters on the bars indicate significant differences among each compound as determined by Tukey’s honestly significant difference test (\\u003cem\\u003ep\\u003c/em\\u003e \\u0026lt; 0.05)\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"floatimage3.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4852257/v1/55887031692e1119cdc016b0.png\"},{\"id\":63660750,\"identity\":\"42af387b-ba9e-4a2a-ac87-f1473d383835\",\"added_by\":\"auto\",\"created_at\":\"2024-08-30 17:44:23\",\"extension\":\"png\",\"order_by\":4,\"title\":\"Figure 4\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":123563,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003ePrincipal component analysis of phenolic compounds, antioxidant capacity (ABTS, DPPH, and FRAP), TPC, and TFC of RPB extract and its ethyl acetate fraction after simulated human digestion. (a and b) RPB ethanol extract; (c and d) ethyl acetate fraction\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"floatimage4.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4852257/v1/875bf79103fbf6dfd800b909.png\"},{\"id\":63660751,\"identity\":\"3a6114b9-9af6-4adc-a9e6-4d51c069c565\",\"added_by\":\"auto\",\"created_at\":\"2024-08-30 17:44:28\",\"extension\":\"pdf\",\"order_by\":0,\"title\":\"\",\"display\":\"\",\"copyAsset\":false,\"role\":\"manuscript-pdf\",\"size\":710558,\"visible\":true,\"origin\":\"\",\"legend\":\"\",\"description\":\"\",\"filename\":\"manuscript.pdf\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4852257/v1/5e51ff88-680d-415b-845d-b93b5d7234d2.pdf\"},{\"id\":63660352,\"identity\":\"e9909816-8374-4101-8de4-b1ce485cd62d\",\"added_by\":\"auto\",\"created_at\":\"2024-08-30 17:36:23\",\"extension\":\"docx\",\"order_by\":2,\"title\":\"\",\"display\":\"\",\"copyAsset\":false,\"role\":\"supplement\",\"size\":100936,\"visible\":true,\"origin\":\"\",\"legend\":\"\",\"description\":\"\",\"filename\":\"2024PFHNSupplementary.docx\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-4852257/v1/02258a018641e1723b6b0958.docx\"}],\"financialInterests\":\"No competing interests reported.\",\"formattedTitle\":\"Correlation between Antioxidant Capacity and Phenolic Compounds of Korean Red Pine (Pinus densiflora Sieb. et Zucc.) Bark Fractions under In Vitro Gastrointestinal Digestive Conditions\",\"fulltext\":[{\"header\":\"Introduction\",\"content\":\"\\u003cp\\u003e \\u003cem\\u003ePinus densiflora\\u003c/em\\u003e Sieb. et Zucc. (Korean red pine) is a native coniferous tree found in Korea, Japan, northeastern China, and the southeastern regions of Russia [\\u003cspan citationid=\\\"CR1\\\" class=\\\"CitationRef\\\"\\u003e1\\u003c/span\\u003e]. In Korea, red pine trees have the largest forest area, accounting for approximately 22% of the total forest land as of 2015 [\\u003cspan citationid=\\\"CR2\\\" class=\\\"CitationRef\\\"\\u003e2\\u003c/span\\u003e]. Pine bark is typically considered a byproduct and discarded, but it can also be upcycled as high-value material through specific manufacturing processes [\\u003cspan citationid=\\\"CR3\\\" class=\\\"CitationRef\\\"\\u003e3\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR4\\\" class=\\\"CitationRef\\\"\\u003e4\\u003c/span\\u003e]. Pine bark has been developed as dietary supplements because it contains various bioactive compounds, including protocatechuic acid, procyanidin B1, catechin, caffeic acid, vanillin, and taxifolin [\\u003cspan citationid=\\\"CR5\\\" class=\\\"CitationRef\\\"\\u003e5\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR6\\\" class=\\\"CitationRef\\\"\\u003e6\\u003c/span\\u003e].\\u003c/p\\u003e \\u003cp\\u003eBioactive compounds present in Korean red pine bark (RPB) are known to have potent antioxidant capacity as well as effects in improving cardiovascular health, enhancing the immune system, improving glycemic control, and enhancing cognitive function [\\u003cspan citationid=\\\"CR4\\\" class=\\\"CitationRef\\\"\\u003e4\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR7\\\" class=\\\"CitationRef\\\"\\u003e7\\u003c/span\\u003e]. The bioactive compounds of RPB are absorbed and metabolized in the human digestive system [\\u003cspan citationid=\\\"CR4\\\" class=\\\"CitationRef\\\"\\u003e4\\u003c/span\\u003e]. Bioactive phenolic compounds with small molecular weights are readily absorbed in the small intestine, whereas relatively larger phenolic molecules, such as procyanidins, reach the large intestine and are metabolized by gut microbiota [\\u003cspan citationid=\\\"CR4\\\" class=\\\"CitationRef\\\"\\u003e4\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR7\\\" class=\\\"CitationRef\\\"\\u003e7\\u003c/span\\u003e]. This indicates that the major phenolic compounds of RPB must remain stable during the digestive process to be bioactive.\\u003c/p\\u003e \\u003cp\\u003e \\u003cem\\u003eIn vitro\\u003c/em\\u003e simulated digestion offers an alternative to animal and clinical trials due to its reduced ethical concerns, lower costs, and fewer side effects [\\u003cspan citationid=\\\"CR8\\\" class=\\\"CitationRef\\\"\\u003e8\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR9\\\" class=\\\"CitationRef\\\"\\u003e9\\u003c/span\\u003e]. This method can provide information on the stability and antioxidant capacity of high-molecular-weight compounds such as procyanidins in RPB. Simulated digestion \\u003cem\\u003ein vitro\\u003c/em\\u003e also allows the identification of metabolites, catechin and epicatechin monomers, derived from RPB during digestion [\\u003cspan citationid=\\\"CR10\\\" class=\\\"CitationRef\\\"\\u003e10\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR11\\\" class=\\\"CitationRef\\\"\\u003e11\\u003c/span\\u003e].\\u003cdiv class=\\\"BlockQuote\\\"\\u003e\\u003cp\\u003eThe objective of this study is to comparatively evaluate the phenolic compound content and antioxidant capacity before and after simulated human digestion of RPB extract and its fractions. The RPB fractions were investigated for antioxidant capacity, total phenolic content (TPC), and total flavonoid content (TFC), and individual phenolic compounds. Principal component analysis (PCA) was utilized to determine the impact of digestion on antioxidant capacity and phenolic content. This study may contribute the better understanding of the bioavailability of upcycled bioactive materials from natural resources-derived byproducts.\\u003c/p\\u003e\\u003c/div\\u003e\\u003c/p\\u003e\"},{\"header\":\"Materials and methods\",\"content\":\"\\u003cp\\u003eThe \\u003cspan refid=\\\"Sec2\\\" class=\\\"InternalRef\\\"\\u003eMaterials and methods\\u003c/span\\u003e section is presented as Supplementary Material.\\u003c/p\\u003e\"},{\"header\":\"Results and Discussion\",\"content\":\"\\u003cdiv id=\\\"Sec4\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003eExtraction and fractionation of RPB\\u003c/h2\\u003e \\u003cp\\u003eFirst, in this study, RPB extracts were obtained by extracting RPB at various ethanol concentrations. An aqueous solvent with a high concentration of ethanol can effectively extract bioactive compounds from RPB [\\u003cspan citationid=\\\"CR12\\\" class=\\\"CitationRef\\\"\\u003e12\\u003c/span\\u003e]. Ethanol aids in forming hydrogen bonds with the abundant hydroxyl groups of phenolic compounds [\\u003cspan citationid=\\\"CR13\\\" class=\\\"CitationRef\\\"\\u003e13\\u003c/span\\u003e]. Among those five extracts obtaining by varying ethanol concentrations, the optimal extract was determined by measuring the antioxidant capacity using two radical chromogens 2,2\\u0026prime;-azobis(2-methylpropionamidine) dihydrochloride (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) (Table \\u003cspan refid=\\\"MOESM1\\\" class=\\\"InternalRef\\\"\\u003eS1\\u003c/span\\u003e). The phosphate-buffered saline-based ABTS assay is suitable for determining water-soluble antioxidants, whereas the methanol-based DPPH assay can measure the antioxidant capacity of non-polar antioxidants [\\u003cspan citationid=\\\"CR14\\\" class=\\\"CitationRef\\\"\\u003e14\\u003c/span\\u003e]. Among the various RPB extracts, RPB extracted with 70% (\\u003cem\\u003ev/v\\u003c/em\\u003e) aqueous ethanol showed significantly (\\u003cem\\u003ep\\u003c/em\\u003e\\u0026thinsp;\\u0026lt;\\u0026thinsp;0.05) the highest antioxidant capacity (Table \\u003cspan refid=\\\"MOESM1\\\" class=\\\"InternalRef\\\"\\u003eS1\\u003c/span\\u003e) and was used in subsequent experiments.\\u003c/p\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec5\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003eTPC, TFC, and antioxidant capacity of RPB fractions\\u003c/h2\\u003e \\u003cp\\u003eThe RPB extract obtained by extraction with 70% (\\u003cem\\u003ev/v\\u003c/em\\u003e) aqueous ethanol was concentrated in vacuum and sequentially fractionated using \\u003cem\\u003en\\u003c/em\\u003e-hexane, ethyl acetate, and water (Fig. \\u003cspan refid=\\\"MOESM1\\\" class=\\\"InternalRef\\\"\\u003eS1\\u003c/span\\u003e). The bioactives of RPB have different solubilities depending on the polarity of the fractionating solvent [\\u003cspan citationid=\\\"CR15\\\" class=\\\"CitationRef\\\"\\u003e15\\u003c/span\\u003e]. The antioxidant capacity (ABTS, DPPH, ferric reducing antioxidant power [FRAP]), TPC, and TFC of the RPB extract and its fractions are shown in Table\\u0026nbsp;\\u003cspan refid=\\\"Tab1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003e. The antioxidant capacity, TPC, and TFC of the three fractions decreased in the following order: water fraction\\u0026thinsp;\\u0026gt;\\u0026thinsp;ethyl acetate fraction\\u0026thinsp;\\u0026gt;\\u0026thinsp;\\u003cem\\u003en\\u003c/em\\u003e-hexane fraction. Among the fractions, the water fraction with the highest antioxidant capacity was 21- to 50-fold higher than the \\u003cem\\u003en\\u003c/em\\u003e-hexane fraction with the lowest antioxidant capacity. The TPC and TFC of the water fraction were approximately 11 and 7 times higher, respectively, than those of the \\u003cem\\u003en\\u003c/em\\u003e-hexane fraction. These indicate that the bioactive compounds in the RPB extract are relatively polar substances. Here in, the results are also supported by a previous report showing that the extraction efficiency of bioactive compounds from RPB increased under solvent conditions with the addition of ionic additives [\\u003cspan citationid=\\\"CR13\\\" class=\\\"CitationRef\\\"\\u003e13\\u003c/span\\u003e].\\u003c/p\\u003e \\u003cp\\u003e \\u003cdiv class=\\\"gridtable\\\"\\u003e\\u003ctable float=\\\"Yes\\\" id=\\\"Tab1\\\" border=\\\"1\\\"\\u003e \\u003ccaption language=\\\"En\\\"\\u003e \\u003cdiv class=\\\"CaptionNumber\\\"\\u003eTable 1\\u003c/div\\u003e \\u003cdiv class=\\\"CaptionContent\\\"\\u003e \\u003cp\\u003eAntioxidant capacity, total phenolic content (TPC), and total flavonoid content (TFC) of red pine bark (RPB) extract and its fractions\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/caption\\u003e \\u003ccolgroup cols=\\\"6\\\"\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c1\\\" colnum=\\\"1\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c2\\\" colnum=\\\"2\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c3\\\" colnum=\\\"3\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c4\\\" colnum=\\\"4\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c5\\\" colnum=\\\"5\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c6\\\" colnum=\\\"6\\\"\\u003e\\u003c/div\\u003e \\u003cthead\\u003e \\u003ctr\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c1\\\" morerows=\\\"1\\\" rowspan=\\\"2\\\"\\u003e \\u003cp\\u003eExtract and fraction\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colspan=\\\"3\\\" nameend=\\\"c4\\\" namest=\\\"c2\\\"\\u003e \\u003cp\\u003eAntioxidant capacity\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c5\\\" morerows=\\\"1\\\" rowspan=\\\"2\\\"\\u003e \\u003cp\\u003eTPC\\u003c/p\\u003e \\u003cp\\u003e(mg GAE\\u003csup\\u003ee\\u003c/sup\\u003e/g)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c6\\\" morerows=\\\"1\\\" rowspan=\\\"2\\\"\\u003e \\u003cp\\u003eTFC\\u003c/p\\u003e \\u003cp\\u003e(mg CE\\u003csup\\u003ef\\u003c/sup\\u003e/g)\\u003c/p\\u003e \\u003c/th\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eABTS\\u003csup\\u003ea\\u003c/sup\\u003e\\u003c/p\\u003e \\u003cp\\u003e(mg VCE\\u003csup\\u003eb\\u003c/sup\\u003e/g)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eDPPH\\u003csup\\u003ec\\u003c/sup\\u003e\\u003c/p\\u003e \\u003cp\\u003e(mg VCE/g)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eFRAP\\u003csup\\u003ed\\u003c/sup\\u003e\\u003c/p\\u003e \\u003cp\\u003e(mg VCE/g)\\u003c/p\\u003e \\u003c/th\\u003e \\u003c/tr\\u003e \\u003c/thead\\u003e \\u003ctbody\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eRPB extract\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e1055.0\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;47.6\\u003csup\\u003eA\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e825.4\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;6.4\\u003csup\\u003eB\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e573.4\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;15.7\\u003csup\\u003eA\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e697.1\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;10.4\\u003csup\\u003eA\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e419.9\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;3.6\\u003csup\\u003eA\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e\\u003cem\\u003en\\u003c/em\\u003e-Hexane fraction\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e47.9\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;1.1\\u003csup\\u003eC\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e16.8\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;2.5\\u003csup\\u003eC\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e25.0\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;0.5\\u003csup\\u003eD\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e57.5\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;6.0\\u003csup\\u003eD\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e50.9\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;12.3\\u003csup\\u003eC\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eEthyl acetate fraction\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e933.6\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;43.1\\u003csup\\u003eB\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e686.5\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;25.7\\u003csup\\u003eB\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e446.2\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;11.7\\u003csup\\u003eC\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e586.3\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;5.0\\u003csup\\u003eC\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e370.9\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;5.4\\u003csup\\u003eB\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eWater fraction\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e997.9\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;16.5\\u003csup\\u003eAB\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e832.8\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;23.1\\u003csup\\u003eA\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e514.8\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;4.5\\u003csup\\u003eB\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e641.3\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;12.5\\u003csup\\u003eB\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e375.1\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;13.0\\u003csup\\u003eB\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003c/tbody\\u003e \\u003c/colgroup\\u003e \\u003ctfoot\\u003e \\u003ctr\\u003e\\u003ctd colspan=\\\"6\\\"\\u003e\\u003csup\\u003ea\\u003c/sup\\u003eABTS, 2,2\\u0026prime;-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt.\\u003c/td\\u003e\\u003c/tr\\u003e \\u003ctr\\u003e\\u003ctd colspan=\\\"6\\\"\\u003e\\u003csup\\u003eb\\u003c/sup\\u003eVCE, vitamin C equivalent.\\u003c/td\\u003e\\u003c/tr\\u003e \\u003ctr\\u003e\\u003ctd colspan=\\\"6\\\"\\u003e\\u003csup\\u003ec\\u003c/sup\\u003eDPPH, 2,2-diphenyl-1-picrylhydrazyl.\\u003c/td\\u003e\\u003c/tr\\u003e \\u003ctr\\u003e\\u003ctd colspan=\\\"6\\\"\\u003e\\u003csup\\u003ed\\u003c/sup\\u003eFRAP, ferric reducing antioxidant power.\\u003c/td\\u003e\\u003c/tr\\u003e \\u003ctr\\u003e\\u003ctd colspan=\\\"6\\\"\\u003e\\u003csup\\u003ee\\u003c/sup\\u003eGAE, garlic acid equivalent.\\u003c/td\\u003e\\u003c/tr\\u003e \\u003ctr\\u003e\\u003ctd colspan=\\\"6\\\"\\u003e\\u003csup\\u003ef\\u003c/sup\\u003eCE, catechin equivalent.\\u003c/td\\u003e\\u003c/tr\\u003e \\u003ctr\\u003e\\u003ctd colspan=\\\"6\\\"\\u003eDifferent superscripts in the same column indicated significant differences among extract and fractions as determined by Tukey\\u0026rsquo;s honestly significant difference test (\\u003cem\\u003ep\\u003c/em\\u003e\\u0026thinsp;\\u0026lt;\\u0026thinsp;0.05).\\u003c/td\\u003e\\u003c/tr\\u003e \\u003c/tfoot\\u003e \\u003c/table\\u003e\\u003c/div\\u003e \\u003c/p\\u003e \\u003cp\\u003e \\u003cb\\u003eAntioxidant capacity, TPC and TFC of\\u003c/b\\u003e \\u003cb\\u003ein vitro\\u003c/b\\u003e \\u003cb\\u003edigested RPB fractions\\u003c/b\\u003e\\u003c/p\\u003e \\u003cp\\u003eAntioxidant capacity, TPC, and TFC of the RPB extract and its three fractions after \\u003cem\\u003ein vitro\\u003c/em\\u003e simulated digestion are shown in Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003e as a percentage of the control (gray bars). \\u003cem\\u003eIn vitro\\u003c/em\\u003e digestion can provide information on the stability of the antioxidant components contained in the RPB extract and fractions. Moreover, \\u003cem\\u003ein vitro\\u003c/em\\u003e digestion indirectly contributes to the antioxidant capacity of metabolites derived during the digestive process [\\u003cspan citationid=\\\"CR4\\\" class=\\\"CitationRef\\\"\\u003e4\\u003c/span\\u003e]. RPB extract (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003ea) and water fraction (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003ed) showed similar patterns of changes in antioxidant capacity under digestive conditions. In contrast, the ethyl acetate fraction (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003ec) showed lower antioxidant capacity and TFC in the intestinal digestion phase than in the gastric digestion phase. Polyphenolic compounds become less stable during intestinal digestion process due to enzymes and pH changes, which reduces their antioxidant capacity [\\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR17\\\" class=\\\"CitationRef\\\"\\u003e17\\u003c/span\\u003e]. The \\u003cem\\u003en\\u003c/em\\u003e-hexane fraction showed either no detectable antioxidant capacity or a very large deviation after digestion, which is thought to be due to the low initial antioxidant capacity of the \\u003cem\\u003en\\u003c/em\\u003e-hexane fraction (Table\\u0026nbsp;\\u003cspan refid=\\\"Tab1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003e).\\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec6\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003eLiquid chromatography (LC) profile of RPB extract and its fractions\\u003c/h2\\u003e \\u003cp\\u003eThe major phenolic compounds in RPB were analyzed using LC. Peaks 1\\u0026ndash;6 were identified as protocatechuic acid, procyanidin B1, catechin, epicatechin, taxifolin, and quercetin, respectively (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig2\\\" class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003e). The information (slope and intercept) of the calibration curves for the quantification of these phenolic compounds is shown in Table S4. The limit of quantification for six phenolic compounds ranged from 2.0 to 14.0 \\u0026micro;g/mL. The ethyl acetate fraction contained the highest amounts of phenolic compounds. The relative content of phenolic compounds in the ethyl acetate fraction (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig2\\\" class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003ec) was more than twice that of the 70% (\\u003cem\\u003ev/v\\u003c/em\\u003e) aqueous ethanol extract (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig2\\\" class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003ea). In contrast, the major phenolic compounds of RPB were not detected in the \\u003cem\\u003en\\u003c/em\\u003e-hexane and water fractions, indicating that the major phenolic compounds of RPB have the highest solubility in ethyl acetate [\\u003cspan citationid=\\\"CR5\\\" class=\\\"CitationRef\\\"\\u003e5\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR18\\\" class=\\\"CitationRef\\\"\\u003e18\\u003c/span\\u003e]. Additionally, this suggests that the fractionation process can remove the matrix contained in the RPB extract, thereby generating an enriched fraction with major phenolic compounds.\\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec7\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003eStability of major phenolic compounds in RPB fractions\\u003c/h2\\u003e \\u003cp\\u003eThe digestive stability of phenolic compounds was evaluated for the RPB extract (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig3\\\" class=\\\"InternalRef\\\"\\u003e3\\u003c/span\\u003ea) and the ethyl acetate fraction (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig3\\\" class=\\\"InternalRef\\\"\\u003e3\\u003c/span\\u003eb). After intestinal digestion, no phenolic compounds were detected in either the RPB extract or the ethyl acetate fraction except for protocatechuic acid and taxifolin. These results are consistent with previous reports that phenolic compounds are degraded under intestinal digestive conditions [\\u003cspan citationid=\\\"CR17\\\" class=\\\"CitationRef\\\"\\u003e17\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR19\\\" class=\\\"CitationRef\\\"\\u003e19\\u003c/span\\u003e]. Gastric digestion significantly (\\u003cem\\u003ep\\u003c/em\\u003e\\u0026thinsp;\\u0026lt;\\u0026thinsp;0.05) increased the contents of procyanidin B1 and catechin compared to the control group (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig3\\\" class=\\\"InternalRef\\\"\\u003e3\\u003c/span\\u003e), which is partly due to the breakdown of high-molecular-weight compounds such as procyanidin. A condensed tannin procyanidin is broken down under the acidic conditions (pH 3.0) of gastric digestion to produce its fragment catechin monomer [\\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e].\\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec8\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003eCorrelation study\\u003c/h2\\u003e \\u003cp\\u003eThe correlation between the antioxidant capacity, TPC, TFC, and digestive stability of phenolic compounds in RPB extract and its ethyl acetate fraction was evaluated using principal component analysis (PCA; Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig4\\\" class=\\\"InternalRef\\\"\\u003e4\\u003c/span\\u003e). For the RPB extract, approximately 70.7% of the data variability was explained by principal component 1, whereas for the ethyl acetate fraction, approximately 64.9% of the data variability was explained by principal component 1. Taxifolin exhibited the highest values in both principal component 1 and principal component 2 in both RPB extract and ethyl acetate fraction, which is partly due to the high content of taxifolin (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig2\\\" class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003e). Antioxidant capacity, TPC, and TFC were highly clustered with epicatechin and quercetin in both RPB extract and ethyl acetate fraction (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig4\\\" class=\\\"InternalRef\\\"\\u003e4\\u003c/span\\u003ea, c). The gastric digestion conditions are primarily explained by principal component 1 and show a pattern similar to that before digestion (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig4\\\" class=\\\"InternalRef\\\"\\u003e4\\u003c/span\\u003eb, d). In contrast, the intestinal digestion conditions are mainly explained by principal component 2 and show a different pattern from the gastric digestion (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig4\\\" class=\\\"InternalRef\\\"\\u003e4\\u003c/span\\u003eb, d). These PCA results (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig4\\\" class=\\\"InternalRef\\\"\\u003e4\\u003c/span\\u003eb, d) visually indicate that phenolic compounds are less stable under intestinal digestion conditions compared to gastric digestion (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig3\\\" class=\\\"InternalRef\\\"\\u003e3\\u003c/span\\u003e).\\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003c/div\\u003e\"},{\"header\":\"Conclusion\",\"content\":\"\\u003cp\\u003eIn this study, the correlation between phenolic compounds and antioxidant capacity of RPB extract and its fractions under \\u003cem\\u003ein vitro\\u003c/em\\u003e gastrointestinal digestion conditions was investigated. The antioxidant capacity of RPB extract and its three fractions were significantly affected by the \\u003cem\\u003ein vitro\\u003c/em\\u003e simulated digestion. Gastric digestion increased the content of certain phenolic compounds such as procyanidin and catechin. Intestinal digestion, on the other hand, led to the degradation of most phenolic compounds, except for protocatechuic acid. This highlights how important the stability of bioactive compounds during digestion is for their bioavailability and effectiveness. PCA results showed that taxifolin had the greatest influence on the variability of the data, indicating that taxifolin plays an important role in the antioxidant capacity of RPB extract and its fraction. These findings support the potential use of RPB as a source of natural antioxidants in dietary supplements. Further studies are needed to improve the stability and bioavailability of its bioactive compounds during digestion.\\u003c/p\\u003e\"},{\"header\":\"Abbreviations\",\"content\":\"\\u003cdiv class=\\\"DefinitionList\\\"\\u003e \\u003cdiv class=\\\"DefinitionListEntry\\\"\\u003e \\u003cdiv class=\\\"Term\\\"\\u003eABTS\\u003c/div\\u003e \\u003cdiv class=\\\"Description\\\"\\u003e \\u003cp\\u003e2,2\\u0026prime;-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/div\\u003e \\u003cdiv class=\\\"DefinitionListEntry\\\"\\u003e \\u003cdiv class=\\\"Term\\\"\\u003eCE\\u003c/div\\u003e \\u003cdiv class=\\\"Description\\\"\\u003e \\u003cp\\u003ecatechin equivalents\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/div\\u003e \\u003cdiv class=\\\"DefinitionListEntry\\\"\\u003e \\u003cdiv class=\\\"Term\\\"\\u003eDPPH\\u003c/div\\u003e \\u003cdiv class=\\\"Description\\\"\\u003e \\u003cp\\u003e2,2-diphenyl-1-picrylhydrazyl\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/div\\u003e \\u003cdiv class=\\\"DefinitionListEntry\\\"\\u003e \\u003cdiv class=\\\"Term\\\"\\u003eGAE\\u003c/div\\u003e \\u003cdiv class=\\\"Description\\\"\\u003e \\u003cp\\u003egallic acid equivalents\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/div\\u003e \\u003cdiv class=\\\"DefinitionListEntry\\\"\\u003e \\u003cdiv class=\\\"Term\\\"\\u003eFRAP\\u003c/div\\u003e \\u003cdiv class=\\\"Description\\\"\\u003e \\u003cp\\u003eferric reducing antioxidant power\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/div\\u003e \\u003cdiv class=\\\"DefinitionListEntry\\\"\\u003e \\u003cdiv class=\\\"Term\\\"\\u003eLC\\u003c/div\\u003e \\u003cdiv class=\\\"Description\\\"\\u003e \\u003cp\\u003eliquid chromatography\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/div\\u003e \\u003cdiv class=\\\"DefinitionListEntry\\\"\\u003e \\u003cdiv class=\\\"Term\\\"\\u003ePCA\\u003c/div\\u003e \\u003cdiv class=\\\"Description\\\"\\u003e \\u003cp\\u003eprincipal component analysis\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/div\\u003e \\u003cdiv class=\\\"DefinitionListEntry\\\"\\u003e \\u003cdiv class=\\\"Term\\\"\\u003eRPB\\u003c/div\\u003e \\u003cdiv class=\\\"Description\\\"\\u003e \\u003cp\\u003ered pine bark\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/div\\u003e \\u003cdiv class=\\\"DefinitionListEntry\\\"\\u003e \\u003cdiv class=\\\"Term\\\"\\u003eTFC\\u003c/div\\u003e \\u003cdiv class=\\\"Description\\\"\\u003e \\u003cp\\u003etotal flavonoid content\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/div\\u003e \\u003cdiv class=\\\"DefinitionListEntry\\\"\\u003e \\u003cdiv class=\\\"Term\\\"\\u003eTPC\\u003c/div\\u003e \\u003cdiv class=\\\"Description\\\"\\u003e \\u003cp\\u003etotal phenolic content\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/div\\u003e \\u003cdiv class=\\\"DefinitionListEntry\\\"\\u003e \\u003cdiv class=\\\"Term\\\"\\u003eVCE\\u003c/div\\u003e \\u003cdiv class=\\\"Description\\\"\\u003e \\u003cp\\u003evitamin C equivalents.\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/div\\u003e \\u003c/div\\u003e\"},{\"header\":\"Declarations\",\"content\":\"\\u003cp\\u003e\\u003cstrong\\u003eAuthor Contributions\\u003c/strong\\u003e\\u0026nbsp; \\u0026nbsp; \\u0026nbsp; \\u0026nbsp; \\u0026nbsp; \\u0026nbsp;\\u003c/p\\u003e\\n\\u003cp\\u003eConceptualization: Seung-Su Choi,\\u0026nbsp;Dae-Ok Kim; Methodology: Young Sung Jung, Nam Soo Han; Formal analysis and investigation: Seung-Su Choi, Gyo-Ha Hwang; Writing - original draft preparation, Young Sung Jung,\\u0026nbsp;Sanggil Lee,\\u0026nbsp;Dae-Ok Kim; Writing - review and editing:\\u0026nbsp;Dae-Ok Kim; Funding acquisition:\\u0026nbsp;Dae-Ok Kim; Resources:\\u0026nbsp;Sanggil Lee,\\u0026nbsp;Nam Soo Han,\\u0026nbsp;Dae-Ok Kim; Supervision:\\u0026nbsp;Dae-Ok Kim.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eFunding \\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eThis work was supported by the Ministry of Education of the Republic of Korea and the National Research Foundation of Korea (NRF-2020R1F1A1060767), Republic of Korea.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eData Availability \\u0026nbsp; \\u0026nbsp; \\u0026nbsp; \\u0026nbsp;\\u003c/strong\\u003e\\u0026nbsp;\\u003c/p\\u003e\\n\\u003cp\\u003eAll data generated or analyzed during this study are included in this published article.\\u0026nbsp;\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eFinancial Interests\\u003c/strong\\u003e\\u0026nbsp;\\u003c/p\\u003e\\n\\u003cp\\u003eThe authors declare no competing interests and no financial interests.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eConflict of interest \\u0026nbsp; \\u0026nbsp;\\u0026nbsp;\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eThe authors declare no conflict of interest.\\u003c/p\\u003e\"},{\"header\":\"References\",\"content\":\"\\u003col\\u003e\\u003cli\\u003e\\u003cspan\\u003eZhao W, Gao J, Hall D, Andersson BA, Bruxaux J, Tomlinson KW, Drouzas AD, Suyama Y, Wang X-R (2024) Evolutionary radiation of the Eurasian \\u003cem\\u003ePinus\\u003c/em\\u003e species under pervasive gene flow. 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J Korean Wood Sci Technol 47:498\\u0026ndash;508. \\u003cspan class=\\\"ExternalRef\\\"\\u003e\\u003cspan class=\\\"RefSource\\\"\\u003ehttps://doi.org/10.5658/WOOD.2019.47.4.498\\u003c/span\\u003e\\u003cspan address=\\\"10.5658/WOOD.2019.47.4.498\\\" targettype=\\\"DOI\\\" class=\\\"RefTarget\\\"\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eGonzales GB, Smagghe G, Grootaert C, Zotti M, Raes K, Camp JV (2015) Flavonoid interactions during digestion, absorption, distribution and metabolism: a sequential structure\\u0026ndash;activity/property relationship-based approach in the study of bioavailability and bioactivity. Drug Metab Rev 47:175\\u0026ndash;190. \\u003cspan class=\\\"ExternalRef\\\"\\u003e\\u003cspan class=\\\"RefSource\\\"\\u003ehttps://doi.org/10.3109/03602532.2014.1003649\\u003c/span\\u003e\\u003cspan address=\\\"10.3109/03602532.2014.1003649\\\" targettype=\\\"DOI\\\" class=\\\"RefTarget\\\"\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/li\\u003e\\u003c/ol\\u003e\"}],\"fulltextSource\":\"\",\"fullText\":\"\",\"funders\":[],\"hasAdminPriorityOnWorkflow\":false,\"hasManuscriptDocX\":true,\"hasOptedInToPreprint\":true,\"hasPassedJournalQc\":\"\",\"hasAnyPriority\":false,\"hideJournal\":false,\"highlight\":\"\",\"institution\":\"\",\"isAcceptedByJournal\":true,\"isAuthorSuppliedPdf\":false,\"isDeskRejected\":\"\",\"isHiddenFromSearch\":false,\"isInQc\":false,\"isInWorkflow\":false,\"isPdf\":false,\"isPdfUpToDate\":true,\"isWithdrawnOrRetracted\":false,\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"plant-foods-for-human-nutrition\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":false,\"externalIdentity\":\"\",\"sideBox\":\"Learn more about [Plant Foods for Human Nutrition](https://www.springer.com/journal/11130)\",\"snPcode\":\"11130\",\"submissionUrl\":\"https://submission.nature.com/new-submission/11130/3\",\"title\":\"Plant Foods for Human Nutrition\",\"twitterHandle\":\"\",\"acdcEnabled\":true,\"dfaEnabled\":true,\"editorialSystem\":\"stoa\",\"reportingPortfolio\":\"Springer Hybrid\",\"inReviewEnabled\":true,\"inReviewRevisionsEnabled\":false},\"keywords\":\"Bioaccessibility, Digestion stability, Polyphenol, Principal component analysis, Simulated digestion\",\"lastPublishedDoi\":\"10.21203/rs.3.rs-4852257/v1\",\"lastPublishedDoiUrl\":\"https://doi.org/10.21203/rs.3.rs-4852257/v1\",\"license\":{\"name\":\"CC BY 4.0\",\"url\":\"https://creativecommons.org/licenses/by/4.0/\"},\"manuscriptAbstract\":\"\\u003cp\\u003eThis study investigates the correlation between phenolic compounds and antioxidant capacities of Korean red pine (\\u003cem\\u003ePinus densiflora\\u003c/em\\u003e Sieb. et Zucc.) bark (RPB) fractions under \\u003cem\\u003ein vitro\\u003c/em\\u003e gastrointestinal digestion. RPB extracts were obtained using 70% (\\u003cem\\u003ev/v\\u003c/em\\u003e) aqueous ethanol and further fractionated with \\u003cem\\u003en\\u003c/em\\u003e-hexane, ethyl acetate, and water. Their antioxidant capacities were evaluated using three antioxidant assays. Phenolic compounds were quantified using a liquid chromatography system to assess their stability. The antioxidant capacity of RPB extract and its fractions were found to be significantly influenced by the digestive process. Gastric digestion increased the contents of procyanidin B1 and catechin, whereas intestinal digestion degraded most of the phenolic compounds except protocatechuic acid. Principal component analysis results showed that taxifolin had the greatest impact on data variability, indicating that this polyphenol plays an important role in the antioxidant capacity of RPB. This study provides insights into the stability and bioaccessibility of phenolic compounds in RPB under simulated gastrointestinal conditions, supporting its potential use as a source of natural antioxidants in dietary supplements.\\u003c/p\\u003e\",\"manuscriptTitle\":\"Correlation between Antioxidant Capacity and Phenolic Compounds of Korean Red Pine (Pinus densiflora Sieb. et Zucc.) Bark Fractions under In Vitro Gastrointestinal Digestive Conditions\",\"msid\":\"\",\"msnumber\":\"\",\"nonDraftVersions\":[{\"code\":1,\"date\":\"2024-08-30 17:36:18\",\"doi\":\"10.21203/rs.3.rs-4852257/v1\",\"editorialEvents\":[{\"type\":\"communityComments\",\"content\":0},{\"type\":\"decision\",\"content\":\"Revision requested\",\"date\":\"2024-08-18T16:13:52+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"editorInvitedReview\",\"content\":\"\",\"date\":\"2024-08-18T02:23:33+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"editorInvitedReview\",\"content\":\"\",\"date\":\"2024-08-17T12:24:00+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"editorInvitedReview\",\"content\":\"\",\"date\":\"2024-08-15T19:24:06+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"37996274129667860680058256032593588753\",\"date\":\"2024-08-12T20:02:18+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"editorInvitedReview\",\"content\":\"\",\"date\":\"2024-08-12T11:29:23+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"63335956803121013296704542512504299122\",\"date\":\"2024-08-10T06:44:22+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"130863698373542151067622797989788635492\",\"date\":\"2024-08-09T14:58:18+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"196931543282050054894457051429554688313\",\"date\":\"2024-08-09T01:13:42+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"280493475241451115481362237159623154539\",\"date\":\"2024-08-07T16:20:02+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"69805252507978104453531890359759382288\",\"date\":\"2024-08-07T01:55:47+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"338713213693923691710756249347793881674\",\"date\":\"2024-08-07T01:53:08+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"323348436645469652601246728621390584758\",\"date\":\"2024-08-07T01:13:23+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewersInvited\",\"content\":\"\",\"date\":\"2024-08-07T00:15:00+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"editorAssigned\",\"content\":\"\",\"date\":\"2024-08-05T07:20:42+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"checksComplete\",\"content\":\"\",\"date\":\"2024-08-05T07:18:30+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"submitted\",\"content\":\"Plant Foods for Human Nutrition\",\"date\":\"2024-08-03T08:24:34+00:00\",\"index\":\"\",\"fulltext\":\"\"}],\"status\":\"published\",\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"plant-foods-for-human-nutrition\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":false,\"externalIdentity\":\"\",\"sideBox\":\"Learn more about [Plant Foods for Human Nutrition](https://www.springer.com/journal/11130)\",\"snPcode\":\"11130\",\"submissionUrl\":\"https://submission.nature.com/new-submission/11130/3\",\"title\":\"Plant Foods for Human Nutrition\",\"twitterHandle\":\"\",\"acdcEnabled\":true,\"dfaEnabled\":true,\"editorialSystem\":\"stoa\",\"reportingPortfolio\":\"Springer Hybrid\",\"inReviewEnabled\":true,\"inReviewRevisionsEnabled\":false}}],\"origin\":\"\",\"ownerIdentity\":\"f3f1f768-b956-4ea2-9304-1d76adac525d\",\"owner\":[],\"postedDate\":\"August 30th, 2024\",\"published\":true,\"recentEditorialEvents\":[],\"rejectedJournal\":[],\"revision\":\"\",\"amendment\":\"\",\"status\":\"under-review\",\"subjectAreas\":[],\"tags\":[],\"updatedAt\":\"2024-09-26T10:38:34+00:00\",\"versionOfRecord\":[],\"versionCreatedAt\":\"2024-08-30 17:36:18\",\"video\":\"\",\"vorDoi\":\"\",\"vorDoiUrl\":\"\",\"workflowStages\":[]},\"version\":\"v1\",\"identity\":\"rs-4852257\",\"journalConfig\":\"researchsquare\"},\"__N_SSP\":true},\"page\":\"/article/[identity]/[[...version]]\",\"query\":{\"redirect\":\"/article/rs-4852257\",\"identity\":\"rs-4852257\",\"version\":[\"v1\"]},\"buildId\":\"qtupq5eGEP_6zYnWcrvyt\",\"isFallback\":false,\"isExperimentalCompile\":false,\"dynamicIds\":[84888],\"gssp\":true,\"scriptLoader\":[]}","source_license":"CC-BY-4.0","license_restricted":false}