Optimization of ultrasound-assisted extraction of antioxidant compounds from Mucuna pruriens pods using response surface methodology: a waste-to-value approach

Abstract

Mucuna pruriens, a leguminous plant known for the rich bioactive content of its seeds, also exhibitssignificant antioxidant potential in its pods, an underutilized agricultural by-product. This study aimed tooptimize ultrasound-assisted extraction (UAE) conditions to maximize the recovery of phenoliccompounds with antioxidant capacity (AOC) from M. pruriens pods. Optimization was conducted usingresponse surface methodology (RSM), evaluating the effects of extraction time (10–20 min), ethanolconcentration (0–100%), and ultrasound amplitude (0–80%). Ethanol concentration was identified as themost influential variable affecting both total phenolic content (TPC) and AOC. Optimal UAE conditions(10 min, 30% ethanol, 80% amplitude) yielded significantly higher TPC (274.21 ± 1.43 mg GAE per g) andAOC (DPPH: 2.41 ± 0.11, ABTS: 1.87 ± 0.09 and FRAP: 3.67 ± 0.08 mmol TEAC per g) compared to thetraditional decoction method. HPLC-MS-based metabolite profiling tentatively identified 22 bioactivecompounds in the pod and seed extracts. Furthermore, a notable L-Dopa content (5.8%) was quantifiedin the optimized pod extract, highlighting its potential as a valuable bioresource. These findingsdemonstrate the efficiency and sustainability of UAE in valorizing M. pruriens pods and support theirpotential application in food, nutraceutical, and pharmaceutical formulations.