EVALUATION OF THE ANTIOXIDANT AND Α-AMYLASE INHIBITORY ACTIVITIES OF Mitragyna inermis (WILLD) O. KUNTZE AND Tamarindus indica LINN.

Abstract

The current study was conducted to explore the antioxidant and anti-diabetic potential of Tamarindus (T.) indica and Mitragyna(M.) inermis aqueous leaves extracts. Along with this, the estimation of available total phenolics and total flavonoids contents was also carried out to establish the scientific background of the antioxidant and anti-diabetic potential of used plants. For estimation of total phenolics and total flavonoids contents, Folin-ciocalteu and Aluminium chloride (AlCl3) colorimetric method was used respectively. Antioxidant activity of prepared aqueous extracts was determined by various in vitro assays such as DPPH•, ABTS•+, FRAP assay while for the determining anti-diabetic potential of two used aqueous extracts plants, α-amylase inhibition assay was performed using the 3,5- dinitrosalicylic acid method. The results of the current study suggested that the aqueous extracts of both species have similar polyphenol content while in the case of flavonoid content, it was reported higher in T. indica leaves (9.90 mg QE/100 mg extract) and this is significantly different (p˂0.001) from the aqueous leaves extract of M. inermis. The results revealed that both plant extracts effectively scavenged DPPH and ABTS radical which suggested the strong antioxidant potential of used extracts. Besides, plant extracts also exhibited higher Fe (III) reducing activities. When these results were compared with standard treatment, highly significant difference was reported at 10 mg/ml extract doses (p˂0.001). Both leaf extracts exhibit remarkable α-amylases inhibitory activity, this was reported 89.55% with T. indica while 75.65% with M. inermis at 10 mg/mL extract. Hence leaves extracts of selected plants have significant antioxidant and anti-diabetic potential which justify the use of these two plants in traditional remedies. Further works are necessary for the isolation, characterization, and identification of active antioxidant and anti-diabetic molecules from the aqueous extracts of T. indica and M. inermis, which may serve as a potential natural source of antioxidant and anti-diabetes.