Phytochemical Profiling, Proximate Composition, And Biological Activity Screening of Hydrocotyle Bonariensis Crude Extracts

Abstract

Hydrocotyle bonariensis Lam. (Araliaceae), commonly known as largeleaf pennywort, is widely used in traditional medicine across Africa and South America for the management of inflammatory conditions, infections, and metabolic disorders. Despite these ethnobotanical applications, systematic phytochemical and biological activity data for Nigerian populations of this species remain lacking. This study characterised the qualitative and proximate chemical composition of crude extracts prepared from the leaves and roots of H. bonariensis collected in Zaria, Nigeria, and evaluated these extracts for antimicrobial and cytotoxic activities. Qualitative phytochemical screening revealed the consistent presence of alkaloids, phenolic compounds, tannins, saponins, and flavonoids across polarity-graded solvent extracts (n-hexane, chloroform, ethyl acetate, and methanol). Proximate analysis (AOAC, 2016) indicated that leaves contained higher carbohydrate content (22.03%), while roots contained higher moisture (24.53%), crude protein (15.03%), and crude fibre (18.91%). Agar well diffusion assays demonstrated dose-dependent antimicrobial activity against both Gram-positive and Gram-negative bacteria and fungal strains, with the methanolic root extract yielding the broadest inhibitory spectrum (zones of inhibition: 2–30 mm at 400–700 µg/cm³). The methanol leaf extract recorded the lowest minimum inhibitory concentration (MIC) against Salmonella typhi and E.coli(<0.12 mg/cm³). Brine shrimp lethality testing (BSLT) yielded LC₅₀ values of 20.98–76.35 µg/cm³ for leaf extracts and 65.78–91.27 µg/cm³ for root extracts, all well below the 1000 µg/cm³ cytotoxicity threshold (Meyer et al., 1982). These findings provide scientific support for the ethnomedicinal use of H. bonariensis and justify further bioassay-guided fractionation and structural characterisation of its bioactive constituents.