Abstract

MADJITOLOUM BETOLOUM Salomon , TALLA Emmanuel , NGASSOUM Martin Benoît , TSATSOP TSAGUE Roli Karole , NYEMB Jean Noël , MAHMOUT Yaya

The optimal conditions of Microwave-Assisted Extraction (MAE) of total phenol content and total flavonoids content from A. occidentale L. 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 (mL/g) 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 620 W, solvent-to-solids ratio of 33.4 mL/g and methanol concentration of 63.17% according to the analysis of response surface. These optimum conditions yielded total phenolic contents (TPC) of 674.58 mg Gallic Acid Equivalent (GAE)/ 100g DM and total flavonoid content (TFC) of 85.38 mg Quercetin Equivalent (QE)/100g DM. Close agreement between experimental and predicted values was found.