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.

Tamarindus indica and Mitragyna inermis are widely used by herbalists to cure diabetes mellitus. The aim of this study is to investigate the inhibitory potential of aqueous and various organic solvent fractions from both plants and some isolated compounds against advanced glycation end-products (AGEs). For this purpose, an in vitro BSA–fructose glycation model was used to evaluate the inhibition of AGE formation. Furthermore, the effects of the fractions on mouse fibroblast (NIH-3T3) and human hepatocyte (HepG2) survival were evaluated. The leaf, stem, and root fractions of both plants exhibited significant inhibition of AGEs formation. The IC₅₀ values appeared to be less than 250 µg/mL; however, all fractions presented no adverse effects on NIH-3T3 up to 500 µg/mL. Otherwise, our phytochemical investigation afforded the isolation of a secoiridoid from the Mitragyna genus named secoiridoid glucoside sweroside (1), along with three known quinovic acid glycosides: quinovic acid-3β-O-β-d-glucopyranoside (2), quinovic acid-3-O-β-d-6-deoxy-glucopyranoside, 28-O-β-d-glucopyranosyl ester (3), and quinovic acid 3-O-α-l-rhamnopyranosyl-(4→1)-β-d-glucopyranoside (4). In particular, 1–3 are compounds which have not previously been described in Mitragyna inermis roots. However, the isolated compounds did not exhibit AGE inhibitory activity. Further investigation on these potent antiglycation fractions may allow for the isolation of new antidiabetic drug candidates.

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.

Introduction: Antioxidants and glucosidases inhibitors are interesting in diabetes mellitus prevention and its management. However, conventional drugs have a multitude of unenviable side effects. Thus, research is turning towards herbal remedies, hence this study that was interested in two plants used in the traditional treatment of diabetes in Bobo-Dioulasso. Objective: The aim was to evaluate Chamaecrista (C.) nigricans and Pseudocedrela (P.) kotschyi roots water extracts effect on sorghum α-amylase activity. Methodology: Total phenolic and flavonoid contents were quantified using Folin-Ciocalteu reagent and aluminum trichloride, respectively. FRAP, DPPH and ABTS methods were used to estimate the extracts antioxidant activity. The α-amylase inhibition tests were carried out using the glucose assay method with dinitrosalicylic acid. Results: The C. nigricans and P. kotschyi extracts have shown strong antioxidant activities, 7031.52±15 and 8762.35±51 µmol AAE.g-1E respectively, referring to trolox using ABTS method. These extracts have also shown an inhibitory effect of 98.57% and 97.67% respectively on α-amylase activity. Conclusion/perspectives: These plants have in vitro an interesting anti-amylasic potential. Further investigations will be necessary using a pure enzyme and a wider range of concentration of the extracts in order to determine the kinetic parameters and the fractionation by chromatography to determine the most effective fraction(s). Finally, an in vivo evaluation of the anti-diabetic effect of the extracts could be considered. Keywords: anti α-amylase, antioxidant, Chamaecrista nigricans, Pseudocedrela kotschyi.