The present invention provides novel .alpha.-glucosidase inhibitory compound (-)-mesquitol and its analogs isolated in significant yield from traditional medicinal plant Dichrostachys cinerea and further modification of (-)-mesquitol to enhance the .alpha.-glucosidase inhibitory potential; the invention also identifies the usage of (-)-mesquitol and its analogues, based on their .alpha.-glucosidase inhibitory activity, as broad based potential therapeutics as antihyperglycernic, antidiabatic, antiobesity, antiviral, anticancer, immunestimulants and the like.
