Hypoglycemic activities and biochemical parameters modulation of herbal formulations of Allium cepa L. in alloxanized diabetic rats

The aim of this work was to formulate and evaluate the herbal tablets of Allium cepa L. for in vitro tablet properties, hypoglycemic effects and for their effects on some biochemical parameters in diabetic rats. Aqueous extract of A. cepa L. was obtained by cold maceration and freeze dried. A. cepa L. extract compatibility with some tablet excipients was assessed using Fourier transform infrared spectroscopy. A. cepa L. tablets consisted of the extract, gelatin, polyvinyl pyrrolidone (PVP), carboxymethyl cellulose (CMC), Primogel®, Ac-Di-Sol®, Avicel® PH102, anhydrous lactose, talc and stearic acid. Tablets were prepared according to standard physical properties using wet granulation method. The tablets were evaluated for antidiabetic properties and for their effects on some biochemical parameters in alloxan induced diabetic rats with glibenclamide and distilled water as positive and negative controls respectively. The extract-excipient compatibility test indicated compatibility of the extract with gelatin, PVP, CMC, Primogel®, Ac-Di-Sol®, Avicel® PH102, and anhydrous lactose. The prepared tablets maintained adequate mechanical integrity and dissolution profiles after storage for six months. There was significant reduction in blood glucose level upon daily administration of the tablets compared to the negative control (p = 0.05). Maximum reduction of blood glucose levels ranging from 20 to 70% were achieved within 21 days of daily administration of the tablets. The plasma levels of liver enzymes such as alanine transaminase, aspartate transaminase and alkaline phosphatase were significantly reduced together with total cholesterol and triglycerides. There were also reduced activities of catalase, glutathione reductase and malondialdehyde. Key words: Allium cepa, hypoglycemic effects, biochemical parameters, alloxan, wet granulation.