Trichostigma octandrum (L.) (hoopvine) is a plant native to tropical and subtropical regions that is traditionally valued for its medicinal and nutritional properties. This study was conducted to investigate the nutritional composition and biological activities of hoopvine leaf powder. Therefore, the proximate analysis, secondary metabolites, antimicrobial activity, antioxidant activity, and total polyphenol and flavonoid contents of aqueous and ethanolic leaf extracts were evaluated. Hoopvine leaf powder contained high levels of crude protein (24.46%), ether extract (3.66%), ash (21.74%), crude fiber (10.69%), and energy content (3365.50 kcal/kg), along with essential vitamins and minerals. The amino acid profile was dominated by glutamic acid (2.46%) followed by aspartic acid (1.86%), and lysine and methionine contents were 1.09% and 0.26%, respectively. Gas chromatography‒mass spectrometry analysis revealed fifteen bioactive constituents in the methanolic extract, among which Ethylamine, bis-N-(trimethylsilyl) (86% similarity) was the predominant compound, contributing 46.65% of the total chromatographic area. Stock concentrations of hoopvine (250 mg/mL for the aqueous extract and 50 mg/mL for the ethanolic extract) demonstrated antimicrobial activity against Staphylococcus aureus. Antimicrobial activity and the polyphenol and flavonoid contents of both aqueous and ethanolic hoopvine extracts increased in a concentration-dependent manner (p≤0.05). Comparative analysis of the two solvent extracts revealed that at concentrations of 0.5 and 1.0 mg/mL, the aqueous extract exhibited stronger antioxidant activity than the ethanolic extract (p≤0.05). In addition, at 0.5 mg/mL, the flavonoid content of the aqueous extract was significantly higher than that of the ethanolic extract (p≤0.05). These findings suggest that hoopvine leaf powder has potential applications as a functional ingredient in animal feed and human food owing to its high protein content, rich mineral composition, energy value, and antioxidant properties.