Evaluation of the Antioxidant Profile of the Ethanolic Seed Extract of Mucuna pruriens Using Four Complementary in vitro Antioxidant Assays

Abstract

Background: Oxidative stress results from an imbalance between reactive oxygen species and antioxidant defence mechanisms and is implicated in the development of several chronic and degenerative conditions. Medicinal plants containing bioactive phytochemicals are increasingly investigated as potential natural sources of antioxidants. Mucuna pruriens seeds contain several phytochemical constituents associated with antioxidant activity; however, their antioxidant profile has not been comprehensively evaluated using multiple complementary in vitro assays. Aims: To evaluate the antioxidant profile of the ethanolic seed extract of Mucuna pruriens collected from Enyiogugu Mbaise, Imo State, Nigeria, using four complementary in vitro antioxidant assays (DPPH radical scavenging, FRAP, ABTS radical cation decolourisation, and hydrogen peroxide scavenging), with ascorbic acid as the reference standard. Study Design: Experimental laboratory-based in vitro antioxidant evaluation. Place and Duration of Study: Department of Chemistry, Imo State University, Owerri, Imo State, Nigeria. Seeds were collected from Enyiogugu Mbaise, Imo State. Methodology: Fresh mature seeds of Mucuna pruriens were authenticated, air-dried, pulverised and extracted by cold maceration in 95% ethanol. Antioxidant activity of the extract (40–120 mg/mL) was assessed in triplicate using DPPH radical scavenging, ferric reducing antioxidant power (FRAP), ABTS radical scavenging and hydrogen peroxide scavenging assays. Ascorbic acid served as the positive control. Results: Both the extract and ascorbic acid showed concentration-dependent antioxidant activity across 40–120 mg/mL. DPPH inhibition by the extract increased from 93.02% to 96.12%, comparable to ascorbic acid (76.95–96.10%). FRAP activity rose from 0.564 to 0.840 for the extract versus 0.769–0.961 for the standard. ABTS inhibition ranged from 53.07% to 72.09% (extract) and 74.21–82.03% (ascorbic acid). H₂O₂ scavenging by the extract was 50.95–58.99%, lower than the standard (74.21–83.09%). The strongest activity was observed in the DPPH assay. Conclusion: The ethanolic seed extract of Mucuna pruriens from this locality possesses appreciable antioxidant potential through multiple mechanisms (radical scavenging and electron transfer) and may serve as a natural source of antioxidants for food, nutraceutical and pharmaceutical applications.