Blood glucose‐lowering effect of Tectona grandis flowers in type 2 diabetic rats: A study on identification of active constituents and mechanisms for antidiabetic action 柚木花对2型糖尿病大鼠的降糖作用：一项鉴定其活性成份与降糖作用机制的研究. (3rd March 2014)

• Record Type: Journal Article
• Authors: Ramachandran, Subramaniam; Rajasekaran, Aiyalu
• Is Part Of: Journal of diabetes. Volume 6:Number 5(2014)
• Page Start: 427
• Page End: 437
• Publication Date: 2014-03-03
• Subjects: Diabetes -- Periodicals; 618.3646005
• DOI: 10.1111/1753-0407.12121
• Languages: English
• ISSNs: 1753-0393

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <sec id="jdb12121-sec-0001" sec-type="section"> <title>Background</title> <p>Ayurveda documents antidiabetic activity of <italic>Tectona grandis</italic> flowers. However, until now, the effects of <italic>T. grandis</italic> flowers in preclinical models of type 2 diabetes (T2D) have been unknown. Hence, the aim of the present study was to evaluate the blood glucose‐lowering effect of methanol extract of <italic>T. grandis</italic> flowers (METGF) in T2D rats and to identify possible active constituents as well as the mechanisms for the antidiabetic action.</p> </sec> <sec id="jdb12121-sec-0002" sec-type="section"> <title>Methods</title> <p>Rats were rendered diabetic by administration of streptozotocin–nicotinamide (65 mg/kg–110 mg/kg, i.p.). After the induction of diabetes, Groups 3 and 4 received METGF (100 and 200 mg/kg respectively) while Group 5 received glibenclamide (5 mg/kg) orally for 4 weeks. Blood glucose and body weight were determined at the end of Weeks 2 and 4. Hemoglobin, HbA1c, total protein, urea, creatinine, insulin, and lipid levels were determined in Week 4. Active constituents in METGF were identified using HPLC analysis. Antidiabetic mechanisms of METGF were evaluated by investigating the insulin sensitizing action and inhibition of α‐amylase and α‐glucosidase activity.</p> </sec> <sec id="jdb12121-sec-0003" sec-type="section"> <title>Results</title> <p>Both METGF and glibenclamide significantly improved body weight, reduced blood glucose, and normalized altered biochemical parameters (<italic>P</italic> < 0.001) in T2D rats. The presence of polyphenolic active constituents, such as gallic acid, quercetin, rutin, ellagic acid, ferulic acid, and kaempferol, in METGF was confirmed by HPLC. In vitro, METGF, gallic acid, quercetin, and rutin exhibited significant (<italic>P</italic> < 0.001) insulin sensitizing action and inhibition of α‐amylase and α‐glucosidase activity.</p> </sec> <sec id="jdb12121-sec-0004" sec-type="section"> <title>Conclusions</title> <p>Polyphenolic active constituents present in METGF are possibly responsible for the blood glucose‐lowering effect in T2D rats via an insulin‐sensitizing action, as well as inhibition of α‐amylase and α‐glucosidase activity.</p> </sec> </abstract>