In vitro Antioxidant Activities of Hydroethanolic Extract of Defatted Wonderful Kola (Buchholzia coriacea) Seeds and Its Safety Evaluation in Murine Models

Introduction: Buccholzia coriaceaseed possesses a vast number of therapeutic applications in African traditional medicine. However, there are still limited information on its bioactive constituents, pharmacological actions and safety profile. This study was designed to prepare hydroethanolic extract of (defatted) Buccholzia coriacea seeds (HEBCS), evaluate its total phenols and flavonoids, in vitro antioxidant activity and its safety in rats and mice.

Methods: Seeds were defatted with hexane and the residue extracted with 80% ethanol (EtOH). The total phenols and flavonoid content of the lyophilised HEBCS was determined followed by in vitro antioxidant activity against stable free radicals (DPPH, ABTS+) and reactive oxygen species (OH, NO and H2O2). Limit test (at 5000 mg/ kg body weight (bw) and acute toxicity test (at doses of 62.5, 125, 250 and 500 mg/kg bw) was carried out in rats followed by sub chronic toxicity study (at doses of 125 and 250 mg/ kg bw) in mice. Biomarkers of hepatic function (ALT, AST, ALP and total bilirubin) and renal function (urea and creatinine) were assessed.

Results: The total phenols and flavonoids content of HEBCS was found to be 31.76 μg GAE/ mg and 22.82 μg QE/ mg respectively. The half-maximal inhibitory concentration (IC50) value for HEBCS when tested against DPPH, ABTS+, OH, H2O2 and NO were found to be 257.85, 496.73, 883.68, 475.68 and 1786.42 μg/mL respectively. The Median Lethality Dose (LD50) for HEBCS in rat was greater than 5000 mg/ kg body weight. HEBCS did not show any significant (P = .05) hepatic or renal toxicity.

Conclusion: Data obtained from the present study highlight the safety of HEBCS and its potential role as a source of natural antioxidants.