Study on Antioxidant Activity and Immune-Enhanced Activity of Basil Crude Extract and its Solvent Fractions

Objective: Basil has various biological activities, and sufficient research on its extracts can help to clarify the main components that exert biological activity. Methods: Solvents with different polarities were used to extract the basil crude extract (CE), and the total polyphenol (TP) and total flavonoid (TF) contents of extracts were measured. The compounds of extracts were identified using high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). Their antioxidant and immune-enhanced activities were evaluated. Results: The CE and its four solvent fractions were obtained including petroleum ether extract (PE), ethyl acetate extract (EE), n-butanol extract (BE), and water extract (WE). Among them, BE had the highest TP and TF contents, followed by EE, and all five extracts contained maltol and arbutin. The BE and EE have better 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities, while CE with less TP and TF contents showed better 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity than that of BE and EE. Besides, BE and EE also exert a better effect on relevant indicators of immunosuppressive mice than other extracts. Conclusion: The basil extracts (BE and EE), which have higher TP and TF contents, demonstrate better in vitro antioxidant activities and immune-enhancing effects on immunosuppressed mice. This provides a theoretical basis for the application of basil.