Comparative Phytochemical Composition and In-Vitro Antioxidant Properties of Hydroethanolic Extract of Acanthus montanus, Alafia barteri, Aspilia africana, and Boerhavia diffusa Leaves

Abstract

Growing worries about the limitations of synthetic antioxidants and high cost have heightened the search for natural alternatives from medicinal plants. The investigation examined the phytochemical makeup and in vitro antioxidant effects of hydroethanolic extracts of Acanthus montanus, Alafia barteri, Aspilia africana, and Boerhavia diffusa leaves, four species extensively employed in traditional medicine in North Central Nigeria.  Qualitative phytochemical analysis showed that all extracts contained flavonoids, phenols, tannins, cardiac glycosides, alkaloids, and saponins. Quantitative results demonstrated that tannins and cardiac glycosides were the predominant compounds, especially in B. diffusa and A. montanus, whereas flavonoid concentrations were relatively lower.   Antioxidant activity was evaluated with DPPH, ABTS, and ferric reducing antioxidant power (FRAP) assays. Alafia barteri, with an IC₅₀ of 44.36µg/ml, 7.5 µg/ml for ABTS and DPPH radical scavenging activity, and 1.6 mMol/ Fe^2+/g ferric reducing capacity, was the lowest among all tested extracts, translating to the best antioxidant capacity.  All extracts displayed concentration‑dependent radical‑scavenging and reducing actions, with B. diffusa showing the greatest potency in all tests, followed by A. montanus; A. barteri presented moderate activity, while A. africana exhibited the lowest antioxidant potential. The robust antioxidant performance of B. diffusa was linked to its elevated phenolic and flavonoid levels, highlighting the pivotal role of these phytochemicals in redox modulation. These results offer scientific support for the ethnomedical applications of the examined plants.   Additional research encompassing compound isolation, toxicity profiling, and in vivo assessments is recommended to further develop them into therapeutic or nutraceutical agents for diseases linked to oxidative stress.