Synthesis of andrographolide derivatives: A new family of α-glucosidase inhibitors Original Research Article

Andrographolide (1), the cytotoxic agent of the plant Andrographis paniculata, was subjected to semi-synthetic studies leading to a series of new derivatives, a novel family of glucosidase inhibitors. Nicotination of 3,19-hydroxyls in 15-alkylidene andrographolide derivatives (9) was favorable to α-glucosidase inhibition activity. Among them, 15-p-chlorobenzylidene-14-deoxy-11,12-didehydro-3,19-dinicotinateandrographolide (11c) was a very potent inhibitor against α-glucosidase with an IC50 value of 6 μM. However, all compounds concerned for β-glucosidase showed no inhibition. All compounds synthesized were characterized by the analysis of NMR, IR, HRMS spectra and the stereochemistry of 2 was confirmed by X-ray analysis.