Abstract
The ethanol extract of B. javanica seed was fractionated with solvents of different polarities and tested for antioxidant activities by several assays including DPPH radical scavenging activity, ferric reducing antioxidant power (FRAP), ferrous ion chelating activity (FCA), and nitric oxide radical scavenging activity (NORSA) along with their polyphenolic contents. Antidiabetic activity was evaluated both in vitro and in vivo using a glycogen phosphorylase α (GPα) inhibition assay and oral glucose tolerance test (OGTT) in nondiabetic rats. The ethyl acetate fraction (EAF), rich in tannin, exhibited the strongest antioxidant activities to DPPH, FRAP, and NORSA, except for FCA. The EAF also exerted a dose-depended inhibition of GPα (IC50 = 0.75 mg/ml). Further evaluation of hypoglycemic effect on OGGT indicated that rats treated with EAF (125 mg/kg bw) showed a 39.91% decrease (P < 0.05) in blood glucose levels at 30 min, and continuous fall (P < 0.05) of 28.89% and 20.29% was observed in the following hours (60 and 90 min) compared to the normal control during OGTT. The EAF was applied to polyamide column chromatography, and the resulting tannin-free fraction was tested for both GPα inhibition and antioxidant (DPPH only) activity. The GPα inhibitory activity was retained, while antioxidant activity was lost (4.6-fold) after tannin removal. These results concluded that the GPα inhibitory activity initially detected was primarily due to the compounds other than tannins, whereas antioxidant activity was mainly due to the tannins.
Highlights
Diabetes is one of the most common chronic diseases characterized by hyperglycemia as a result of impaired insulin secretion by pancreatic β cells and by cellular resistance to insulin [1]
The results from the current experiment showed that fractions of B. javanica seed contained various amounts of Total flavonoid contents (TFC), Total phenol content (TPC), Total extractable tannins (TET), and phenol (NPP) and greatly influenced their antioxidant properties
Most polyphenolic compounds were extracted with ethyl acetate and exhibited the highest activities to DPPH, Ferric Reducing Antioxidant Power (FRAP), and nitric oxide radical scavenging activity (NORSA), except for ferrous ion chelating activity (FCA) (Table 2), suggesting that polyphenol is the main contributor for antioxidant activities of the extracts
Summary
Diabetes is one of the most common chronic diseases characterized by hyperglycemia as a result of impaired insulin secretion by pancreatic β cells and by cellular resistance to insulin [1]. The current pharmacological treatment of diabetes is aimed at maintaining strict control of glycemia using oral hypoglycemic agent and insulin or combination of both. Currently available oral antihyperglycemic agents, even when used intensively, are often unable to control the hyperglycemia and the disease progressively worsens with time. The ethnopharmacological evidence has proven that the use of herbal medicine is a viable alternative for the control of diabetes and other diseases. Many plant species have been reported to have hypoglycemic effect, which may act through different mechanisms, including inhibition of α-glucosidase [8], inhibition of DPP-IV [9], and inhibition of glycogen phosphorylase and/or enhancement of insulin secretion, The Scientific World Journal stimulation of glucose uptake [10]. The wide diversity of plant species has led scientists to make great efforts to bioprospect plants that may contribute to the control of diabetes
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
