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Abstract The α-glycosidase inhibition assay is used to examine the inhibition activity of traditional Chinese medicines through extraction with methanol. The α-glycosidase inhibition activity of the isolated compounds is measured by α-glycosidase inhibition assay and compared with Acarbose. Molecular docking is implemented to study the interaction between isolated compounds and CtMGAM (maltase–glucoamylase-C) or NtMGAM (maltase–glucoamylase-N). Compared with those of Acarbose, the methanol extract of Gardenia jasminoides Ellis has a higher activity to inhibit α-glycosidase among the 74 traditional Chinese medicines. Geniposide and Gardenoside, isolated compounds from Gardenia jasminoides Ellis , have better inhibition activity (IC 50 values of 0.35 and 0.46 mg/ml, respectively) than Acarbose (IC 50 values of 0.75 mg/ml). The molecular docking results show that Geniposide and Gardenoside have specific binding affinities with CtMGAM and can be considered comparable to those of Acarbose. Our findings illuminate the possible anti-diabetic mechanism of Gardenia jasminoides Ellis and support its use for the treatment of diabetes. Highlights • We illuminate the anti-diabetic mechanism for supporting the use of Geniposide and Gardenoside in the near future. [ABSTRACT FROM AUTHOR]

Introduction Cassia grandis Lf fruits are ethnobotanically used for digestive disorders, anemia, and for reducing blood glucose. However, there are no studies about the antidiabetic activity nor the oral toxicity of the plant fruit-extracts. This paper aims to evaluate the hypoglycemic effect of C. grandis fruits extract in vivo, and assess the acute oral toxicity, and sub-acute oral toxicity. The antioxidant activity and the α-glycosidase inhibitor effect were also evaluated. Methods The extract was obtained by maceration of the fruit pulp with 70% hydroalcoholic solution (1:2, m:v). The extractive solution was concentrated in a vacuum rotary evaporator, up to a drug: solvent ratio of 2:1 (g/ml). Soluble solids, relative density, refractive index, pH, total phenolics, and flavonoids were determined. A preliminary phytochemical screening was made, followed by the quantitation of volatiles by GC/MS. The acute and sub-acute oral toxicity was evaluated in Sprague Dawley rats, by using biochemical and hematological parameters. The radical scavenging activity (DPPH , ABTS ) and α-glycosidase inhibitory effect were tested. The hypoglycemic effect was assessed in alloxan-induced diabetic rats. Results The extract of C. grandis contains alkaloids, coumarins, flavonoids, free amino acids, amines, phenols, tannins, reduced sugars, resins, saponins, steroids, and triterpenes, plus 38 volatile compounds, being linalool the most abundant (1,66%). The extract exhibited an LD 50  > 2000 mg/kg, and after a continuous administration (1000 mg/kg, 28-days), the hematological and biochemical parameters were normal. The extract showed hypoglycemic effect, being the dose 200 mg/kg no statistically different from glibenclamide at 25 mg/kg. Good antioxidant activity and a potent α-glycosidase inhibitory effect were also observed. Conclusion C. grandis extract is an excellent hypoglycemic and non-toxic plant product. The hypoglycemic mechanism could be associated with the antioxidant effect and with the α-glycosidase inhibition. Up to the best of our knowledge, this is the first report on the hypoglycemic effect in vivo of C. grandis fruits extract. [ABSTRACT FROM AUTHOR]

Abstract: The effect of a methanol extract of Rosa damascena Mill. flowers was studied, in comparison to the α-glucosidase inhibitor acarbose, in normal and diabetic rats. The inhibition mode of this extract was examined by measuring enzyme activity in different concentrations of substrate for Lineweaver–Burk plot analysis. The results show that Rosa damascena extract has an intensive inhibitory effect on α-glucosidase. Its inhibition was found to be noncompetitive. Oral administration of this plant extract (100 to 1000mg/kg body wt.) significantly decreased blood glucose after maltose loading in normal and diabetic rats in a dose-dependent manner. These results suggest that Rosa damascena might exert an anti-diabetic effect by suppressing carbohydrate absorption from the intestine and can reduce the postprandial glucose level. [Copyright &y& Elsevier]