Abstract:The objective of this research was to extract phenolic compounds from Makiang (Cleistocalyx nervosum) seeds waste obtained from the elaboration of makiang beverages using the microwave assisted extraction method. The optimal conditions of microwave assisted extraction of total phenolics from makiang seeds were determined using response surface method. The variables of microwave power, extraction time and ethanol proportion on effect of total phenolic were designed the experiment by Box Behnken design. The estimation of the mathematical model indicated that the second-order polynomial model was appropriate to determine optimal conditions of microwave assisted extraction of total phenolics from makiang seeds. The highest yield of total phenolic from makiang seed and antioxidant activity were obtained when the extraction process was set at a microwave power, 450 W, an extraction time of 213 second and an ethanol proportion of 51%(v/v). Under these optimal conditions, the predicted and experimental values of total phenolic from makiang seeds were the 75.659 mgGAE/gDW and 75.132±0.576 mgGAE/gDW, respectively. The research showed that total phenolics from makiang seeds by microwave assisted extraction have the high efficiency in terms of high yield and antioxidant activity within short time extraction which can apply to use in cosmetic product, health food and pharmaceutical industry.