METHODS: F. deltoidea and vitexin was administrated orally to six-weeks STZ-induced diabetic rats over 8 weeks period. The glucose and insulin tolerances were assessed by intraperitoneal glucose (2 g/kg) tolerance test (IPGTT) and intraperitoneal insulin (0.65 U/kg) tolerance test (IPITT), respectively. Subsequently, insulin resistance was assessed by homeostasis assessment model of insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI) and the insulin/triglyceride-derived McAuley index. The histological changes in the pancreas were then observed by hematoxylin-eosin (H&E) staining. Further, the pattern of fatty acid composition and infrared (IR) spectra of the serum and pancreas were monitored by gas chromatography (GC) method and Fourier Transform Infrared (FT-IR) spectroscopy.

RESULTS: F. deltoidea and vitexin increased pancreatic antioxidant enzymes and promoted islet regeneration. However, a significant increase in insulin secretion was observed only in rats treated with F. deltoidea. More importantly, reduction of fasting blood glucose is consistent with reduced FT-IR peaks at 1200-1000 cm-1.

METHODS: The petroleum ether, chloroform and methanol extracts of F. deltoidea were prepared and subjected to standardization using preliminary phytochemical and HPLC analysis. Dose selection was made on the basis of acute oral toxicity study (50-5000 mg/kg b. w.) as per OECD guidelines. Diabetes mellitus was induced with streptozotocin and rats found diabetic were orally administered with the extract (250, 500 and 1000 mg/kg) for 14 days. Levels of blood glucose and insulin were measured in control as well as diabetic rats on 0, 7 and 14th day. In addition, glucose metabolism regulating gene expression was assessed using RT-PCR.