title: Beneficial impact of Zingiber zerumbet on insulin sensitivity in fructose-fed rats.
abstract: Zingiber zerumbet (L) Smith (Zingiberaceae), commonly known as the pinecone or shampoo ginger, is distributed in many parts of Asia. It has been demonstrated that the aqueous extract of Z. zerumbet exerted a potential blood glucose lowering effect in normoglycemic and streptozotocin-induced hyperglycemic rats. The present study was undertaken to clarify whether the ethanol extract of Zingiber zerumbet (EEZZ) is effective in improving insulin resistance. Insulin resistance was induced in rats by feeding a high-fructose diet for six weeks. Thereafter, rats were maintained on the same diet and treated with oral EEZZ or pioglitazone once daily for eight weeks. At the end of treatment, the degree of basal insulin resistance was measured by homeostasis model assessment (HOMA-IR). Insulin sensitivity was calculated using the composite whole body insulin sensitivity index (ISIcomp). Protein expression was evaluated by immunoblotting. Phytochemicals in EEZZ were determined through liquid chromatography-tandem mass. Not only curcumin but also quercetin and kaempferol were abundant in EEZZ. EEZZ (300 mg/kg/day) displayed similar characteristics to pioglitazone (20 mg/kg/day) in reducing HOMA-IR and elevating ISIcomp as well as enhancing hepatic glycogen accumulation. Elevated glycosylated hemoglobin levels and hyperinsulinemia were ameliorated by EEZZ. Further, EEZZ enhanced the action of insulin on muscle glucose transporter subtype 4 translocation and attenuated hepatic phosphoenolpyruvate carboxykinase expression. This study suggests that EEZZ may be an ethnomedicine for improving insulin sensitivity.
authors.affiliation: School of Chinese Pharmaceutical Sciences and Chinese Medicine Resources, China Medical University, Taichung, Taiwan, ROC.
authors.forename: Chia Ju
authors.initials: CJ
authors.lastname: Chang
authors.forename: Thing-Fong
authors.initials: TF
authors.lastname: Tzeng
authors.forename: Yuan-Shiun
authors.initials: YS
authors.lastname: Chang
authors.forename: I-Min
authors.initials: IM
authors.lastname: Liu
mesh_terms: D000818:Animals; D005632:Fructose / Q000008:administration & dosage; D007004:Hypoglycemic Agents / Q000494:pharmacology; D007333:Insulin Resistance; D008297:Male; D000077205:Pioglitazone; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D045162:Thiazolidinediones / Q000494:pharmacology; D030521:Zingiberaceae / Q000737:chemistry*
chemical_list: D007004:Hypoglycemic Agents; D010936:Plant Extracts; D045162:Thiazolidinediones; D005632:Fructose; D000077205:Pioglitazone