Aloe barbadensis Miller leaf exudate is a potential treatment for bovine mastitis

Background: Aloe barbadensis Miller, also known as Aloe vera is a well-known phytotherapeutic, and parts of its leaves are used for a wide range of medicinal purposes. This study seeks to assess the in vitro antimicrobial and cytotoxic effects of leaf exudate (LE) from A. barbadensis leaves against Staphylococcus aureus and MAC-T bovine mammary epithelial cells. Methods: : Seasonal LE samples were collected, and the effect on total phenolic and aloin contents was determined. Antimicrobial activity of LE was evaluated using the broth microdilution method, and toxicity to MAC-T cells was determined by MTT assay. Results: : Samples collected during different seasons of the year showed a seasonal effect on the chemical profile of LE (P<0.05). However, despite these chemical variations, we found no differences in antimicrobial activity against S. aureus. For all studied samples, the minimum inhibitory concentration (MIC) was 1,000 µg/mL. Furthermore, we found an elevated cytotoxic effect of LE on MAC-T cells with a significant reduction in cellular viability at 7.8 µg/mL (P<0.05) and an IC50 of 91.89 µg/mL. Conclusions: : Despite the antimicrobial effects of LE, the high toxicity for MAC-T cells suggests that it is unsuitable for intramammary use, but does have potential as a topical antimicrobial.