Herbal medicines are considered to offer gentle means of managing chronic diseases at a lower cost. Pterocarpus marsupium Roxb. (PM) (Gammalu in Sinhala) heartwood and bark have been used as anti diabetic remedies in many cultures for thousands of years. The aim of this review is to share the existing evidence on anti diabetic effects of the P. marsupium. The hypoglycemic effects, antidyslipidaemic effects, anti oxidative effects and the safety of the PM heartwood and the bark have been scientifically validated using multitude of in vitro and in vivo studies.
Multiple mechanisms responsible for hypoglycemic effects of PM including -cell regeneration, insulin release and insulin like actions of some compounds isolated were identified. Epicatechin, a flavonoid isolated from the bark has shown insulin-like effects on cell regeneration and insulin release.
Several compounds including pterostilbene and marsupsin isolated from the PM heartwood were identified as compounds with hypoglycemic effects. The latex (gum) of the tree is a popular remedy used for diabetes even though the literature on PM does not discuss about the anti diabetic effects of the latex.
Few investigations focused on the anti diabetic effects of PM latex have demonstrated strong inhibitory effects of latex on α-amylase and ά-glucosidase activities and on protein glaciation. Investigations focusing on the anti diabetic effects and possible toxicity of the PM latex are essential to validate its efficacy and safety