Evaluation of the hypoglycaemic activity of Petiveria alliacea (Guinea Hen Weed) extracts in normoglycaemic and diabetic rat models

Abstract

Objective: Petiveria alliacea (P alliacea) has ethno-traditional use as a hypoglycaemic agent in Jamaica and is yet to be scientifically validated as such. Therefore, extracts of aerial parts of the plant were evaluated for hypoglycaemic activity in normoglycaemic and diabetic rats. Methods: Aqueous and hexane extracts prepared from leaves of P alliacea were tested for hypoglycaemic activity. An acute administration of the extracts (200 and 400 mg/kg body weight) was evaluated in normoglycaemic rats. Additionally, the hypoglycaemic effect of sub-chronic administration was assessed in streptozotocin-induced diabetic rats. Blood glucose was recorded using a glucometer and test strips. Data were analysed using Student's t-test (p ≤ 0.05). Results: The aqueous and hexane extracts demonstrated no significant reduction of fasting blood glucose (FBG) and no significant improvement of glucose tolerance in normal rats. The aqueous extract (400 mg/kg body weight) increased FBG from 4.75 ± 0.28 mmol/L to 5.88 ± 0.46 when compared to control (p ≤ 0.001). In diabetic rats, the hexane extract (400 mg/kg body weight) caused reduction of FBG after two weeks of treatment (p ≤ 0.010), but this was not sustained. The aqueous extract showed no reduction of FBG in diabetic rats. Conclusion: The aqueous extract of P alliacea demonstrated a hyperglycaemic effect in normoglycaemic rats and showed no hypoglycaemic activity in diabetic rats. The hexane extract caused no hypoglycaemic action in normal rats and failed to sustain an initial hypoglycaemic action in diabetic rats. This study presents evidence that does not support significant hypoglycaemic activity of P alliacea; this could hold significant implications for its use in ethno-traditional medicine.