Antioxidant Activity and DAF-16-Associated Lifespan-Promoting Effects of Essential Oil from Melastoma sanguineum Sims in Caenorhabditis elegans

Melastoma sanguineum Sims is a traditional medicinal plant with edible fruits, but little is known about the biological activities of its essential oil. In this study, Caenorhabditis elegans was used as an animal model to investigate the antioxidant and lifespan-promoting effects of M. sanguineum essential oil, designated EO-2141. EO-2141 showed in vitro antioxidant activity. In C. elegans, EO-2141 significantly extended mean lifespan and reduced lipofuscin accumulation. It also enhanced resistance to oxidative and thermal stress and reduced DCF fluorescence. In addition, EO-2141 reduced MDA levels and increased SOD and GSH-PX activities. Gene-expression analysis showed that EO-2141 upregulated daf-16 and the stress-responsive genes sod-3, ctl-2, and hsp-16.2, while reducing akt-1 expression. DAF-16::GFP analysis further showed that EO-2141 increased the proportion of worms exhibiting nuclear DAF-16 localization. Moreover, EO-2141 failed to produce a significant lifespan extension in daf-16(mgDf50) mutants, further implicating DAF-16 in the longevity response to EO-2141. These findings demonstrate the antioxidant and lifespan-promoting effects of EO-2141 in C. elegans and provide transcriptional, subcellular-localization, and genetic evidence supporting the involvement of DAF-16 in its longevity response.