Anti-aging effect is a stimulating topic that attracting serious consideration from many researchers. Medicinal plants with anti-aging properties thereby have become common research subjects in various fields of science. This study aims to determine phytochemical constituents, specifically the total of phenolic and flavonoid contents and evaluate the anti-aging activity of ethanolic extracts from the stem of Lasia spinosa L. The DPPH and ABTS assays were applied to investigate the in vitro antioxidant and free radical scavenging properties. Drosophila melanogaster Canton-S was used as the model organism to evaluate in vivo antioxidant activity, lifespan extension, climbing, and reproduction abilities. The results indicated that Lasia spinosa L. extract presented the phenolic and flavonoid contents, which were 271.65 mg GAE/g and 579.57 mg QE/g, respectively. The EC50 values of antioxidant activity was 23.80 µg/mL in DPPH assay and was 3.56 µg/mL for the assay of ABTS. The result also showed that the lifespan of adult fruit flies fed on extracts from Lasia spinosa L. was increased in oxidative stress conditions induced by H2O2. In lifespan assays, Drosophila melanogaster fed on the ethanolic extract from Lasia spinosa L. stem at 0.5 mg/mL of
concentration in combination with standard food showed their mean lifespan increased to 22.9%, 50% survival increased to 22.2%, and the maximum lifespan of last flies increased to 20.7% compared with the control. The research results demonstrated a potential property among its natural compounds of Lasia spinosa L, which is capable of anti-aging through antioxidant activity in vitro and in vivo conditions.