In vivo and in vitro antidiabetic effect of Cistus laurifolius L. and detection of major phenolic compounds by UPLC-TOF-MS analysis

Ethnopharmacological relevance: In Turkish folk medicine, various parts of Cistus laurifolius L. are used to treat gastric ulcer and various types of pains. Additionally the tea prepared from the leaves is used to decrease symptoms of diabetes. Materials and methods: In the present study, the hypoglycemic effects of aqueous and ethanol extracts of Cistus laurifolius were investigated in normal, glucose loaded hyperglycemic and streptozocin (STZ)-induced diabetic rats. alpha-Glucosidase and alpha-amylase enzyme inhibitory effects were determined to evaluate the mechanism of action. Total phenolic content of the extracts were determined by using Folin-Ciocalteu reagent and Ultra Performance Liquid Chromatography-Time of Flight Mass Spectrometer (UPLC-TOF-MS) was used to detect the major phenolic compounds in the extract. Results: Results indicated that blood glucose levels of the STZ-induced diabetic rats were decreased by ethanol extract at of 250 and 500 mg/kg doses as compared to control group (16%-34%). In glucose loaded animals, extracts have shown a weak hypoglycemic effect (11%-20%). Additionally, the ethanol extract of Cistus laurifolius is found to be a potent inhibitor of alpha-glucosidase and alpha-amylase, possibly due to several polyphenolic compounds present within the extract. Twelve major flavonoids (apigenin, quercetin, kaempferol, naringenin, quercitrin and their derivatives), gallic, ellagic and chlorogenic acid in chromatographic fingerprint were analyzed by the on-line UPLC-TOF-MS system. Conclusions: Due to having inhibitory effect on blood glucose level and carbohydrate digesting enzymes (alpha-glucosidase and alpha-amylase), Cistus laurifolius leaves might be beneficial for diabetic patients. (C) 2013 Elsevier Ireland Ltd. All rights reserved.