Flavonoid Composition of Finger Millet (Eleusine coracana (L.) Gaertn.) and Its Anti-aging Effect on Caenorhabditis elegans

In this study, the total flavonoid composition and bioactivity of finger millet was analyzed. Eleusine coracana flavonoids (ECFs) were obtained through sequential 70% ethanol extraction, ethyl acetate extraction, and purification with D101 macroporous resin. The total flavonoid content was determined using the NaNO₂-Al(NO₃)₃-NaOH colorimetric method, and the flavonoid composition using ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS). The in vitro antioxidant activity of ECFs was evaluated using chemical assays, and the anti-aging activity using C. elegans as a model organism. The results demonstrated that the total flavonoid content of ECFs was 82.6%, with 16 major components being identified, including flavonoid glycosides and catechin. In vitro antioxidant tests showed that ECFs exhibited half-maximal inhibitory concentrations (IC₅₀) of 45.34 and 22.75 μg/mL against 1, 1-diphenyl-2-picrylhydrazyl(DPPH) and 2, 2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radicals, respectively, with the IC₅₀ against ABTS cation radicals being lower than that of the positive control vitamin E (29.25 μg/mL). At a concentration of 200 μg/mL, ECFs increased catalase activity in C. elegans by 53.98%, superoxide dismutase activity by 30.64%, and glutathione levels by 51.06%, while decreasing malondialdehyde (MDA) content by 11.82%. ECFs extended the lifespan of C. elegans by 17.86%, and improved its mobility compared to the control group, indicating improved vitality. ECFs had no significant effect on C. elegans fecundity suggesting no promoting effect on its reproductive function. Additionally, ECFs reduced the level of lipofuscin by 53.91%. These findings demonstrated that ECFs had significant antioxidant effects both in vitro and in vivo as well as remarkable anti-aging activity in C. elegans, which could provide a foundation for the functional application of finger millet.