Chemical composition and in vitro potential activity on glucose metabolism and cytotoxicity of leaves of Erythroxylum monogynum Roxb.

Abstract

The aim of this study was to screen extracts from the leaves and stems of Erythroxylum monogynum for in vitro antidiabetic activity by assessing the α-amylase and α-glucosidase inhibition activities. The bioassay guided fractionation of the petroleum ether extracts of leaves followed by AgNO3-TLC, GC-MS, NMR and Mass spectrometry led to the identification of two new sterols, 4-methyl ergosta-7, 23-dien-3β-ol and 4-methyl ergosta-7, 24 (28)-dien-3β-ol. The 4methyl ergosta-7, 23-dien-3β-ol and 4-methyl ergosta-7, 24 (28)-dien-3β-ol showed marked α-amylase and α-glucosidase inhibitory activities with IC50 of 41.52 & 56.42 and 45.47 & 61.71 mg/ml respectively. The essential oils from leaves and stems were obtained by hydrodistillation and the chemical composition was determined by GC and GC-MS. The three monoterpene alcohols, isofenchol, isopulegol and isothujanol were isolated by preparative GC and their enzymes inhibition was evaluated. Both the oils and monoterpene alcohols demonstrated excellent inhibition of α-amylase and α-glucosidase activities with IC50 < 100 mg/ml. Subsequently all the isolated compounds and essential oils were subjected to cytotoxicity using MTT assay wherein, all the compounds presented low level of toxicity at all concentrations tested. The results showed remarkable α-amylase and α-glucosidase inhibitory activity of oils and all the compounds with low toxicity suggesting for exploration as an alternative to the conventional hypoglycemic agents.