Optimization of the Aqueous Decoction Process of Combretum micranthum Leaves

This work proposes to compare the extraction of total polyphenols and the coloring obtained after several series of decoction at 100°C/20min, of whole or crushed leaves of Combretum micranthum. The total phenolic content of the extracts obtained after decoction was determined by Folin’s method. The color parameters were measured using a colorimeter based on the CIELAB system. The analysis of variance (ANOVA) shows significant differences (p < 0.05) on different parameters evaluated. The Minitab 19 software was used to classify the extracts according to the color parameters (L, A, and B). The results showed that the maximum of polyphenols (21.67%) was extracted in the crushed leaves after three series of decoctions while with the whole leaves the maximum of 16.17% is obtained after six series of decoctions. The concentration of total polyphenols becomes low from four series of decoctions with 0.146 g·AG·100 g^-1 MS. The red and yellow coloring drops respectively by 85 and 69% with crushed leaves and 64 and 21% with whole leaves. The conductivity and the brix of the extracts fall according to the series of decoctions. These results show that for optimal use of C. micranthum leaves in traditional medicine, crushed leaves and three series of decoctions are indicated and sufficient.