Amtul Z. Ali

New Labdane diterpenes as intestinal α-glucosidase inhibitor from antihyperglycemic extract of Hedychium spicatum (Ham. Ex Smith) rhizomes

Phytochemical investigation of antihyperglycemic extract of rhizomes of Hedychium spicatum led to the isolation of two new labdane type diterpenes 2, 3 along with seven known compounds (1, 4-9). Their structures were established on the basis of NMR (1D and 2D) and mass spectroscopic analysis. The new compound 2 displayed strong intestinal alpha-glucosidase inhibitory activity. Other compounds also displayed varying degree of intestinal alpha-glucosidase inhibitory potential.

New furanoflavanoids, intestinal α-glucosidase inhibitory and free-radical (DPPH) scavenging, activity from antihyperglycemic root extract of Derris indica (Lam.)

A bioassay-guided fractionation and chemical examination of antihyperglycemic root extract of Derris indica resulted in isolation and characterization of two new furanoflavanoids (1, 2) along with thirteen known compounds (3-15). Their structures were determined on the basis of extensive spectroscopic (IR, MS, 1D and 2D NMR) data analysis and by comparison with the literature data. All the compounds were tested in vitro for intestinal alpha-glucosidase inhibitory and DPPH radical activity. New compounds (1, 2) displayed moderate intestinal alpha-glucosidase inhibitory as well as free radical scavenging activity. Other compounds also displayed varying degrees of moderate intestinal alpha-glucosidase inhibitory activity. Pongamol (6) displayed potent intestinal alpha-glucosidase inhibition.

Reduction in post-prandial hyperglycemic excursion through α-glucosidase inhibition by β-acetamido carbonyl compounds

A series of beta-acetamido carbonyl compounds (S(1)-S(7)) were prepared using Dakin-West reaction from different substituted aldehyde and acetophenone in the presence of lanthanum triflate as a solid catalyst. All the compounds were tested for their alpha-glucosidase inhibitory potential against rat intestinal alpha-glucosidase. The most potent rat intestinal alpha-glucosidase inhibitors S(5) and S(7) were tested for their antihyperglycemic activity following carbohydrate tolerance test. Both the compounds displayed antihyperglycemic activity equivalent to the standard drug acarbose.

Synthesis and biological evaluation of novel 8-aminomethylated oroxylin A analogues as α-glucosidase inhibitors

A series of 8-aminomethylated derivatives (1a-1j) were prepared by Mannich reaction of oroxylin A (1) with appropriate primary or secondary amines and para-formaldehyde. All the compounds were tested for their alpha-glucosidase inhibition activity against both yeast and rat intestinal alpha-glucosidase. Some of the compounds demonstrated significantly better alpha-glucosidase inhibitory activity than the parent compound (oroxylin A).

New antihyperglycemic, α-glucosidase inhibitory, and cytotoxic derivatives of benzimidazoles

Glycosidases play an important role in a wide range of physiological and pathological conditions, and have become potential targets for the discovery and development of agents useful for the treatment of diseases such as diabetes, cancer, influenza, and even AIDS. In this study, several benzimidazole derivatives were prepared from o-phenylenediamine and aromatic and heteroaromatic carboxaldehydes in very good yields, using PdCl2(CH3CN)2 as the most efficient catalyst. Synthesized compounds were assayed for their activity on yeast and rat intestinal α-glucosidase inhibition and cytotoxic activity against colon carcinoma cell line HT-29. Compound 3e exhibited 95.6% and 75.3% inhibition of yeast and rat intestinal α-glucosidase enzyme, while showing 74.8% cytotoxic activity against the HT-29 cell line at primary screening concentrations of 2.1 mM for yeast and rat intestinal α-glucosidase enzyme and 0.2 mM for cytotoxic activity against the HT-29 cell line, respectively. Compound 3c displayed 76% and 34.4% inhibition of yeast and rat intestinal α-glucosidase enzyme, and 80.4% cytotoxic activity against the HT-29 cell line at similar primary screening concentrations. The IC50 value for the most potent intestinal α-glucosidase inhibitor compound 3e was found to be 99.4 μM. The IC50 values for the most active cytotoxic compounds 3c and 3e were 82 μM and 98.8 μM, respectively. Both compounds displayed significant antihyperglycemic activity in starch-induced postprandial hyperglycemia in rats. This is the first report assigning yeast and rat intestinal α-glucosidase enzyme inhibition, cytotoxic activity against the HT-29 cell line, and antihyperglycemic activity to benzimidazole compounds 3c and 3e.

A new prenylated isoflavone from Derris scandens Benth

The phytochemical study of the whole plant of Derris scandens (Leguminosae) has resulted in the isolation of a new isoflavone derivative, scandinone A (11), together with 11 known compounds (1–10, 12). Structural elucidations of these compounds were performed using spectroscopic methods especially 1D, 2D NMR, and mass spectral analyses. The α-glucosidase-inhibitory activity of the isolates was also evaluated.