Ameliorative effects of Hydrolea zeylanica in streptozotocin-induced oxidative stress and metabolic changes in diabetic rats.

Hydrolea zeylanica (L.) Vahl (Hydroleaceae) is an aquatic edible herb used to treat diabetes. However, appropriate experimental models are not available for validating its ethnomedicinal claim.With this aim in mind, we examined the bioactivity of hydroalcohol fraction of leaves of H. zeylanica (HAHZ) in streptozotocin-induced oxidative stress in diabetic rats.In vitro antidiabetic and free radical scavenging activities of different fractions of H. zeylanica were performed. The most effective bioactive fraction e.g. HAHZ was considered for kinetic studies to understand the mode of inhibition of α-glucosidase and α-amylase. To understand the chemical composition, GC-MS/MS and LC-MS/MS analysis of HAHZ were performed. To find out the molecular mechanism of action of HAHZ, streptozotocin-induced oxidative stress and metabolic changes in diabetic rats were studied.

HAHZ demonstrated significantly higher radical scavenging and antidiabetic activities. Kinetic analysis revealed that HAHZ inhibited α-glucosidase competitively, and α-amylase mixed competitively. To understand the chemical composition, GC-MS/MS and LC-MS/MS analysis of HAHZ identified 32 compounds and among which R-limonene (0.52%), perillartine (0.41%), N-formyl-L-lysine (1.49%), limonen-6-ol, pivalate (1.43%), lidocaine (1.70%) and gamolenic acid (2.80%) were reported to have antioxidant and antidiabetic activities. HAHZ-400 mg/kg showed significant (^cp < 0.001) improvement in serum markers (SGOT, SGPT, ALP, total bilirubin, total protein, triglycerides, total cholesterol, HDL-C, LDL-C) and oxidative markers (MDA, SOD, CAT, GSH) in serum, liver and pancreas in a dose dependent manner. In histopathological observation, HAHZ-400 mg/kg showed marked improvement in restoring cellular architecture of liver and pancreas.

Antidiabetic property of HAHZ was due to presence of R-limonene, perillartine, N-formyl-L-lysine, limonen-6-ol, pivalate, lidocaine and gamolenic acid which may improve glycemic control mechanism by stimulating insulin secretion in diabetic rats.