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.

Background: The purpose of this study was to evaluate α-amylase inhibitory effects of hydroethanolic extracts of bark from Daniella oliveri, Sclerocarya birrea, Maranthes polyandra, and Pteleopsis suberosa to fight type-II diabetes. Methods: Compound extractions were performed by hydroethanol maceration followed by liquid-liquid fractionation with solvents. TLC profiling was carried out with different fractions. The inhibitory effects of plant extracts on α-amylase activity were determined using rice starch as a substrate. Results: TLC profiling of different fractions showed different phytochemical compounds. The hydroethanolic plant extracts exhibited dose-dependent inhibition of α-amylase. D. oliveri displayed competitive inhibition, M. polyandra and S. birrea showed uncompetitive inhibition and Pteleopsis suberosa exerted mixed-inhibition. M. polyandra extract exerted the highest inhibitory effect (IC50 = 0.5 mg/mL). Conclusions: The barks of M. polyandra exhibit a remarkable α-amylase inhibitory effect which can be a novel source of antidiabetic molecules.

The aim of the present study was to investigate the polyphenolic profile and the anti-inflammatory and anti-nociceptive activities of four traditionally used medicinal plants from Burkina Faso: Parkia biglobosa, Detarium microcarpum, Vitellaria paradoxa and Sclerocarya birrea. The analysis of the main phenolic compounds was performed by the HPLC-UV-MS method. The anti-inflammatory effect of the aqueous bark extracts was investigated by the λ-carrageenan-induced rat paw edema test. The anti-nociceptive activity was evaluated by the Randall–Selitto test under inflammatory conditions. Seven phenolic acids (gallic, protocatechuic, gentisic, vanillic, p-coumaric, ferulic, and syringic acids), and three flavonoids (catechin, epicatechin, and quercitrin) were identified in the plant samples. High contents of gallic acid were determined in the D. microcarpum, P. biglobosa and S. birrea extracts (190–300 mg/100 g), and V. paradoxa extract was the richest in epicatechin (173.86 mg/100 g). The λ-carrageenan-induced inflammation was significantly reduced (p < 0.001) by the P. biglobosa and D. microcarpum extracts (400 mg/kg p.o.). Under the inflammatory conditions, a significant anti-nociceptive activity (p < 0.001) was obtained after 2–3 h from the induction of inflammation. The effects of the tested extracts could be related to the presence of polyphenols and could be useful in the management of certain inflammatory diseases.

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