Veerapur V P, Prabhakar K R, Thippeswamy B S, Bansal Punit, Srinivasan K K, Unnikrishnan M K
Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal 576 104, India.
Indian J Exp Biol. 2010 Aug;48(8):800-10.
To study the effect and mode of action of water extract (DVW) and polar fraction of ethanol extract (DVE-4) of D. viscosa in high-fructose diet induced insulin resistance in male Wistar rats. D. viscosa's effects were evaluated on a battery of targets involved in glucose homeostasis (in vitro studies). Rats were rendered insulin resistant by feeding 66% (w/w) fructose and 1.1% (v/w) coconut oil mixed with normal pellet diet (NPD) for six weeks. DVW and DVE4 at different doses were administered simultaneously. At the end of the study, blood glucose, oral glucose tolerance test, lipid profile and insulin were estimated and homeostatic model assessment (HOMA) levels were calculated. In addition, enzymatic and nonenzymatic liver antioxidant levels were also estimated. Quantification of biomarker quercetin was done using HPLC. Fructose diet with DVW, DVE-4 significantly reduced blood glucose, serum insulin, HOMA, lipid profiles and significantly improved glucose tolerance and HDL-c levels. In addition, these extract and fraction also decreased oxidative stress by improving endogenous antioxidants. In different bioassays, DVW and DVE-4 inhibited protein tyrosine phosphatase-1B with IC50 65.8 and 54.9 microg/ml respectively and showed partial inhibition of dipeptidyl peptidase-IV. Moreover, DVW and DVE-4, at 10 microg/ml showed 60 and 54.2% binding to peroxisome proliferator-activated receptor-gamma. Further, 2.1% (w/w) of quercetin was quantified in bioactive-DVE-4 using HPLC method. The results provide pharmacological evidence of D. viscosa in treatment of prediabetic conditions and these effects may be mediated by interacting with multiple targets operating in diabetes mellitus.
研究粘毛地锦水提取物（DVW）和乙醇提取物的极性部分（DVE - 4）对高果糖饮食诱导的雄性Wistar大鼠胰岛素抵抗的作用及作用方式。通过在正常颗粒饲料（NPD）中混合66%（w/w）果糖和1.1%（v/w）椰子油喂养大鼠六周，使其产生胰岛素抵抗。同时给予不同剂量的DVW和DVE4。在研究结束时，测定血糖、口服葡萄糖耐量试验、血脂谱和胰岛素水平，并计算稳态模型评估（HOMA）水平。此外，还测定了肝脏的酶促和非酶促抗氧化剂水平。使用高效液相色谱法对生物标志物槲皮素进行定量。含DVW、DVE - 4的果糖饮食显著降低了血糖、血清胰岛素、HOMA、血脂谱，并显著改善了葡萄糖耐量和高密度脂蛋白胆固醇（HDL - c）水平。此外，这些提取物和馏分还通过改善内源性抗氧化剂降低了氧化应激。在不同的生物测定中，DVW和DVE - 4分别以65.8和54.9微克/毫升的IC50抑制蛋白酪氨酸磷酸酶 - 1B，并对二肽基肽酶 - IV表现出部分抑制作用。此外，DVW和DVE - 4在10微克/毫升时与过氧化物酶体增殖物激活受体 - γ的结合率分别为60%和54.2%。此外，使用高效液相色谱法在生物活性DVE - 4中定量出2.1%（w/w）的槲皮素。这些结果为粘毛地锦治疗糖尿病前期状况提供了药理学证据，这些作用可能是通过与糖尿病中起作用的多个靶点相互作用来介导的。
