The Composition of Essential Oils from Different Parts of Gilia capitata Sims

Bluehead gilia or bluefield gilia (Gilia capitata Sims) from the family Polemoniaceae is an annual herbaceous plant widely distributed in the western regions of North America, but cultivated as an ornamental flower in various regions to support pollinators. The chemical composition of the plant has not been studied before. For the first time, essential oil (EO) was obtained by hydrodistillation from the different parts of gilia, harvested in Estonia. The yield of EOs was from 0.42 to 1.97 mL/kg, with the greatest yields from seeds, flowers, fruits, and leaves. Its component composition was studied using the GC-MS method. 118 compounds have been identified. The EO of flowers was dominated by the hexahydrofarnesyl acetone (19.1%), followed by palmitic acid (12.2%), γ-decalactone (7.1%), (Z)-2-p-menthen-1-ol (3.6%). Hexahydrofarnesyl acetone was also dominant in most parts of the G. capitata. The predominant compounds in the EO of leaves were diterpene alcohols: phytol (23.3%), isomanool (12.1%) and sclareol (4.5%), apocarotenoids, C13-norisoprenoid (E)-β-ionone (4.5%). The most dominant compounds in EO of stems are isomanool (8.3 %), sclareol (6.7%) and (E,E)-2,4-decadienal (5.3%). The dominant in the fruits were hexahydrofarnesyl acetone (18.2%), palmitic acid (8.0%), heptacosane (5.3%) and γ-decalactone (4.6 %). The dominant in the shell were (+)-epi-bicyclosesquiphellandrene (15.4%), β-elemene (8.5%) and pentadecanal (6.3%). The dominant in the seeds were hexahydrofarnesyl acetone (15.2%), palmitic acid (11.1%), 1,3-d’dimethylbenzene (10.3%) and heptacosane (5.0%). The dominant in the root were (-)-myrtenol (25.7%), (E)-myrtanol (16.4%), palmitic acid (8.1%) and 2-pentylfuran (2.9%). The results hint at further study options on the antimicrobial and anti-inflammatory effects of G. capitata.