Antihyperglycemic effect of Cephalotaxus sinensis leaves and GLUT-4 translocation facilitating activity of its flavonoid constituents.
The objectives of this study were to investigate the antihyperglycemic effect of Cephalotaxus sinensis leaves and to identify the active components. The antihyperglycemic effect of various fractions (FA, FB, FC, FD) of the 80% ethanol extract of the leaves was evaluated in streptozotocin (STZ)-induced diabetic rats. Among the tested fractions, FC was the most active. FC (0.48 g/kg) given orally for 10 d reduced significantly (p<0.001) the blood glucose of STZ-induced diabetic rats. The food and water intakes of FC (0.48 g/kg)-treated diabetic rats were reduced significantly (p<0.001) when compared to the 0.5% carboxymethyl cellulose (CMC)-treated diabetic rats. The activity-guided fractionation of the ethanol extract of C. sinensis leaves furnished three flavonoid compounds, apigenin-5-O-[alpha-L-rhamnopyranosyl-(1-->4)-6-O-beta-D-acetylglucopyranoside] (1), apigenin (2), and apigenin-5-O-[alpha-L-rhamnopyranosyl-(1-->4)-6-O-beta-D-glucopyranoside] (3). The elevation of GLUT-4 protein level in membrane preparations from mice adipocytes was detected by Western blot analysis after adipocytes were pre-incubated with FC (0.1, 1, 10 mg/ml), apigenin (0.1, 2 mg/ml) and apigenin-5-O-[alpha-L-rhamnopyranosyl-(1-->4)-6-O-beta-D-acetylglucopyranoside] (0.1, 2 mg/ml), respectively. Phytochemical investigation and HPLC-DAD analysis of FC indicated that the flavonoids were the major constituents in this fraction. These results suggest that the fraction from C. sinensis leaves is a promising drug for the treatment of diabetes, and that the flavonoids from this plant are the active constituents.
Li
Wei
W
School of Life Science and Technology, Beijing Institute of Technology, PR China.
Dai
Rong-Ji
RJ
Yu
Yu-Hong
YH
Li
Liang
L
Wu
Chong-Ming
CM
Luan
Wei-Wei
WW
Meng
Wei-Wei
WW
Zhang
Xin-Sheng
XS
Deng
Yu-Lin
YL
D017667:Adipocytes / Q000166:cytology; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D015153:Blotting, Western; D002266:Carboxymethylcellulose Sodium / Q000494:pharmacology; D002462:Cell Membrane / Q000737:chemistry; D032483:Cephalotaxus / Q000033:anatomy & histology*; D002851:Chromatography, High Pressure Liquid; D003921:Diabetes Mellitus, Experimental; D004305:Dose-Response Relationship, Drug; D004326:Drinking / Q000187:drug effects; D004353:Drug Evaluation, Preclinical; D004435:Eating / Q000187:drug effects; D005419:Flavonoids / Q000737:chemistry* / Q000494:pharmacology; D005913:Glipizide / Q000494:pharmacology; D051275:Glucose Transporter Type 4 / Q000378:metabolism*; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology; D008297:Male; D008744:Methylamines / Q000494:pharmacology; D051379:Mice; D015394:Molecular Structure; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use; D018515:Plant Leaves / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar
D001786:Blood Glucose; D005419:Flavonoids; D051275:Glucose Transporter Type 4; D007004:Hypoglycemic Agents; D007328:Insulin; D008744:Methylamines; D010936:Plant Extracts; C495694:Slc2a4 protein, rat; C027451:methylamine; D002266:Carboxymethylcellulose Sodium; D005913:Glipizide