J Ethnopharmacol. 2001 Aug; 76(3): 269-77.

Effect of an antidiabetic extract of Catharanthus roseus on enzymic activities in streptozotocin induced diabetic rats.

Singh SN, Vats P, Suri S, Shyam R, Kumria MM, Ranganathan S, Sridharan K.

Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi 110054, India. shoba72@yahoo.com

Hypoglycemic activity was detected in dichloromethane:methanol extract (1:1) of leaves and twigs of Catharanthus roseus (family Apocynaceae), a traditionally used medicinal plant, using streptozotocin (STZ) induced diabetic rat model. Extract at dose 500 mg/kg given orally for 7 and 15 days showed 48.6 and 57.6% hypoglycemic activity, respectively. Prior treatment at the same dose for 30 days provided complete protection against STZ challenge (75 mg/kg/i.p.x1). Enzymic activities of glycogen synthase, glucose 6-phosphate-dehydrogenase, succinate dehydrogenase and malate dehydrogenase were decreased in liver of diabetic animals in comparison to normal and were significantly improved after treatment with extract at dose 500 mg/kg p.o. for 7 days. Results indicate increased metabolization of glucose in treated rats. Increased levels of lipid peroxidation measured as 2-thiobarbituric acid reactive substances (TBARS) indicative of oxidative stress in diabetic rats were also normalized by treatment with the extract.