Multi-instrumental analysis of bioactive compounds and antioxidant properties in Rauvolfia vomitoria Afzel. leaves extract

Abstract

This research investigated the phytochemical components and antioxidant properties of the ethanol leaves extract fraction (C5), which was obtained by macerating the leaves in 80% ethanol, fractionating the extract via column chromatography, and further purifying it using TLC. The resulting purified fraction was characterized through UV–Vis, FTIR, and GC–MS analyses. Qualitative phytochemical screening of fraction C5 confirmed the presence of flavonoids, alkaloids, terpenoids, saponins, and cardiac glycosides. UV-Vis spectroscopy revealed an absorption maximum at 406 nm, suggesting extended conjugated systems such as oxidized polyphenolics or carotenoid derivatives. FTIR analysis showed characteristic bands, including O-H stretching at 3200–3600 cm⁻¹ (indicative of phenolic and hydroxyl groups), aromatic C=C stretching at 1450–1600 cm⁻¹, aliphatic C-H stretching at 2850–2950 cm⁻¹, and C-O stretching at 1000–1300 cm⁻¹ (related to ethers, alcohols, or ester linkages). GC-MS profiling identified 14 constituents, including terpenoids, methoxylated phenylpropanoids, phytosterols, fatty acids, and the therapeutically significant indole alkaloid reserpine. In-vitro antioxidant assays showed clear, concentration dependent activity in all three methods: at 2.0 mg/mL, fraction C5 produced 71.4% DPPH inhibition, 76.8% ABTS inhibition, and 72.5% ferric reducing activity, whereas gallic acid was significantly more potent at every concentration (p < 0.001), both exhibited a similar linear dose–response. These findings offer scientific support for the traditional medicinal use of Rauvolfia vomitoria Afzel. leaves and highlight its potential as a natural source of antioxidants for managing oxidative stress-related conditions.