ENHANCING THE EXTRACTION OF POLYPHENOLS FROM ACACIA LEUCOPHLOEA BARK BY MICROWAVE-ASSISTED ENZYMATIC EXTRACTION METHOD AND IN-VITRO STUDY OF ITS ANTIOXIDANT AND ANTIBACTERIAL ACTIVITY

This study aims to identify the suitable method for extraction of polyphenols from Acacia leucophloea bark using enzymes and to optimize the processing condition for extraction using Response Surface Methodology. A microwave-assisted enzymatic extraction (MAEE) method was developed and optimized to augment the polyphenol yield. The optimal extraction conditions were as follows: the amount of cellulase 1%, agitation speed 108 rpm, incubation time 1.5 h, and irradiation time 6 min. Under these conditions, polyphenol yield could reach 6.31%, which was higher than other extraction methods studied. The antioxidant activity of the crude extract and the encapsulated extract was evaluated by DPPH radical and reducing power assay. The antibacterial activities of crude extract and the encapsulated extract were studied using the disc diffusion technique. Among the tested bacteria, Klebsiella pneumoniae was most susceptible to polyphenol extract with the highest inhibition zone of 18.6 ± 0.5 mm at the concentration of 8 mg/mL. The outcome of the study indicates that the MAEE method was efficient and eco-friendly, and the polyphenols have remarkable antioxidant and antibacterial activities.