The study sought to determine the phytochemical components, antioxidant and antimicrobial activities of n-hexane, ethyl acetate and methanolic extracts of Amaranthus hybridus L. leaf. Three extracts of A. hybridus were examined for antimicrobial activity using disc diffusion assay. The different extracts demonstrated varied concentration-dependent antimicrobial activities against the test organisms. All extracts studied in this work were active against E. coli, S. aureus, B. cereus, T. mentagrophyte and A. niger. The methanol extract showedpotent inhibitory activity against T. mentagrophyte when compared to a standard antifungal agent, fluconazole. In vitro antioxidant activities were studied spectrophotometrically using vitamin C as standard. There were significant correlations between the methanolic extract and vitamin C for 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging, reducing ability, hydroxyl radical inhibitory and phosphomolybdate scavenging. The results of this study have shown that leaves of A. hybridus possess bioactive compounds which contributed to its antimicrobial and antioxidant properties.
Key words: Maceration; Amaranthus hybridus; phytochemical constituents; antimicrobial; antioxidant; stigmasterol; quinaz‾ capsaicin; methyl commate B.