Glucose adsorption capacity and inhibitory potential of Pseudocedrela kotschyi (Schweinf.) Harms (Meliaceae) leaf extracts against α-amylase: a comparative study over three months

Objective(s): The aim of this study was to evaluate the antidiabetic potential of Pseudocedrela kotschyi leaf decoction by making a comparison between extracts harvested over three months. Design: This study is done through a few experiences. After the quantification of total polyphenols by folin-Ciocalteu reagent method, the antioxidant activities were tested with ABTS, DPPH and FRAP essays. Then, the glucose oxidase kit was used to determine the glucose adsorption capacity of the extracts. At last, dinitrosalicylic acid method served to evaluate the α-amylase inhibitory activity of the extracts. Results: As results the leaves extracts of Pseudocedrela kotschyi showed a polyphenol content of 39,97 ± 3,63 mg EAG/g DE for October, 74,2 ± 11,64 for November and 59,45 ± 7,024 for December. For total flavonoids, the content was 4,86 ± 0,29 mg QE/g DE (October) 5,68 ± 0,39 mg QE/g DE (November) and 5,548 ± 0,19 mg QE/g DE (December). In addition, the antioxidant activity was correlated with the phenolic content (r = -0.65 for DPPH IC50, r = -0.84 for ABTS IC50 and r = 0.97 for FRAP). Besides, the extracts exhibited a strong α-amylase inhibitory activity (IC50 = 0,272 mg DE/mL for October, 0,097 mg DE/mL for November and 0,101 mg DE/mL for December) and had a high capacity to adsorb glucose (over 219,98 ±2,54mmol/g DE for a 30mM glucose solution for November). Conclusion: Pseudocedrela kotschyi leaf decoction has the ability to inhibit α-amylase activity and adsorb glucose in glucose concentrated solution. So it possess a high antidiabetic potential. Keywords: Glucose adsorption, α-amylase, Pseudocedrela kotschyi, antioxidant activity.