RESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Bergenia himalaica Boriss is mainly distributed in the temperate Himalayas between altitudes of 900 and 3000m ranging from the southeastern regions in central Asia and northern regions in South Asia. The plant has a long history of its use in traditional medicine for the treatment of various diseases such as diabetes, urinary complaints, kidney stones, hemorrhagic diseases and epilepsy. The aim of this study is to isolate pure compounds from Bergenia himalaica Boriss, elucidate their structures and determine their blood glucose lowering activity to obtain additional scientific evidence for its usage in traditional medicine for the management of diabetes. MATERIALS AND METHODS: The crude methanolic extract from the aerial parts of Bergenia himalaica Boriss was separated into EtOAc and water sub-extracts and the EtOAc sub-extract was further divided into petroleum ether soluble and insoluble fractions. The pet-ether insoluble fraction was subjected to fractionation through column chromatography followed by prep. TLC. The blood glucose lowering activity of the 2 new compounds was evaluated in streptozotocin-nicotinamide induced diabetic rats. Additionally, glucose-stimulated insulin secretion was measured on isolated mice islets. RESULTS: Two new compounds bergenicin and bergelin were isolated and their structures determined on the basis of spectral analysis. Significant decrease of blood glucose was observed at 1-h (1.0mg/kg) and 2-h (0.5mg/kg), after bergenicin administration to the diabetic rats and at 2-h (1.0mg/kg) and 3-h (0.5mg/kg), after bergelin administration. Bergenicin, but not bergelin, enhanced glucose-stimulated insulin secretion in isolated pancreatic islets. CONCLUSIONS: In the present studies two new compounds, bergenicin and bergelin were isolated from Bergenia himalaica Boriss and their structures were elucidated. Both the compounds showed anti-hyperglycemic effects in streptozotocin-nicotinamide induced diabetic rats. Bergenicin showed insulinotropic effect; suggesting that the anti-hyperglycemic effect is mostly due to enhancement of insulin secretion from pancreatic ß-cells.
