Pharmacological Evaluation of (Piliostigma thonningi) Root Extract: Antioxidant and Anti-inflammatory Properties

Abstract

Medicinal plants have been widely explored for their therapeutic potential due to their rich phytochemical composition. Piliostigma thonningii, a widely used plant in traditional medicine, is known for its diverse bioactive compounds with potential health benefits. This study aims to evaluate the phytochemical composition, antioxidant activity, and anti-inflammatory properties of the methanol root extract of Piliostigma thonningii. Standard qualitative methods revealed the presence of anthraquinones, alkaloids, phenols, tannins, phytosterols, and saponins, while cardiac glycosides, glycosides, flavonoids, and steroids were absent. Antioxidant potential was assessed using DPPH radical-scavenging, ferric reducing antioxidant potential (FRAP), and hydrogen peroxide scavenging assays, revealing dose-dependent radical inhibition. The root crude extract of Piliostigma thonningii exhibits dose-dependent antioxidant activity across DPPH, FRAP, and hydrogen peroxide scavenging assays, with higher concentrations showing increased efficacy. The presence of bioactive phytochemicals, including flavonoids and phenolic compounds, contributes to its ability to reduce oxidative stress and inhibit free radicals. Anti-inflammatory activity was evaluated in vitro via albumin denaturation inhibition and in vivo using the carrageenan-induced paw edema model in rats. At 100 mg/kg, the extract exhibited moderate anti-inflammatory effects, with paw edema peaking at 4 hours (9.093 ± 0.071) and declining at 5 hours (7.362 ± 0.089). However, higher concentrations (200 and 400 mg/kg) showed increased inflammation, peaking at 4 hours (19.621 ± 0.033) and 5 hours (20.001 ± 0.056), respectively. Diclofenac (negative control) demonstrated controlled inflammatory responses, with edema peaking at 4 hours (10.585 ± 0.066) and declining by 5 hours (9.207 ± 0.022). These findings suggest that while the extract has notable anti-inflammatory effects at lower doses, higher doses may exhibit pro-inflammatory tendencies. This study highlights the potential of Piliostigma thonningii root extract as a natural source of anti-inflammatory agents, warranting further investigation for therapeutic applications.