Optimization Of Microwave-Assisted Extraction Of Bioactive Compounds From Anogeissus Leiocarpus Guill. 26 Perr. Stem Bark Using Response Surface Methodology

The optimal conditions of Microwave-Assisted Extraction MAE of antioxidants from Anogeissus leiocarpus Guill. 26 Perr stem bark were determined. A second-order regression for central composite design CCD was used to investigate the effects of four independent variables namely extraction time s irradiation power W solvent-to-solids ratio mlg and methanol concentration on the responses. The second-order regression for CCD consisted of 24 experimental points and 4 replications at the central point. Data were analyzed using Statgraphics software. The optimal conditions based on combination responses were extraction time of 83 s irradiation power of 538 W solvent-to-solids ratio of 16.3 mlg and methanol concentration of 51.84 according to the analysis of response surface. These optimum conditions yielded total phenolic contents TPC and total flavonoid content TFC of 498 mg Gallic Acid Equivalent GAE gDM and 3068 g Quercetin Equivalent QEgDM respectively with DPPHsc of 53.21 and total antioxidant activity TAA of 96206 g Vitamin C Equivalent VCEgDM. Close agreement between experimental and predicted values was found.