Journal of Ethnopharmacology 107 (2006) 285–290 Effect of aqueous bark extract of Garuga pinnata Roxb. in streptozotocin-nicotinamide induced type-II diabetes mellitus Annie Shirwaikar ∗ , K. Rajendran, Rakesh Barik Department of Pharmacognosy, Manipal College of Pharmaceutical Sciences, Manipal, Karnataka, India Received 27 July 2005; received in revised form 8 March 2006; accepted 15 March 2006 Available online 24 March 2006 Abstract A study was undertaken to evaluate the antihyperglycemic activity of aqueous extract of bark of Garuga pinnata Roxb. (Burseraceae). The various parameters studied included fasting blood sugar levels, serum lipid levels, liver glycogen content, serum insulin level and glycated hemoglobin in diabetic and normal rats. Streptozotocin-nicotinamide was used to induce type-II diabetes mellitus. Treatment with the extract at two dose levels showed a significant increase in the liver glycogen and serum insulin level and a significant decrease in fasting blood glucose and glycated hemoglobin levels. The total cholesterol and serum triglycerides levels were also significantly reduced and the HDL cholesterol levels were significantly increased upon treatment with the extract thus proving the potent antidiabetic property of the plant. © 2006 Elsevier Ireland Ltd. All rights reserved. Keywords: Antidiabetic effect; Streptozotocin-nicotinamide induced diabetes mellitus; Garuga pinnata 1. Introduction Garuga pinnata Roxb. (Burseraceae) is a medium sized tree, up to 50 ft high, distributed almost throughout India. It occurs sporadically in mixed deciduous forests and is a com- mon associate of teak and sal trees (The Wealth of India, 1950). It has been reported that the leaves of this tree are used in the treatment of opacities in conjunctivitis. The fruits are used as stomachic and cooling agent (Nadkarni, 1954). The leaf juice mixed with honey is used in the treatment of asthma (Kirtikar and Basu, 1991). Cytotoxic activity of this tree has been reported (Wongsinkongman et al., 2002). The Kol, Kondh and the Saora communities of tribal Orissa take the bark of this tree with pepper for about 15 days twice daily for treat- ment of diabetes (Jain et al., 1991). Though there is no sci- entific evidence to support the antidiabetic effect of Garuga pinnata (GP), tribals continue to use it in the management of diabetes. The objective of this study was to ascertain the scientific basis for the use of this plant in the management of dia- betes using streptozotocin-nicotinamide induced type-II diabetic rats. ∗ Corresponding author. Tel.: +91 820 2571201x2; fax: +91 820 2571998. E-mail address: annieshirwaikar@yahoo.com (A. Shirwaikar). 2. Materials and methods 2.1. Collection of plant material The bark of GP was collected during November 2003 from the Chattisgarh forests, Madhya Pradesh, India. The bark was identified by Dr. S.C. Jena, Director, Chattisgarh Rajya Van Vikas Nigam Limited, Madhya Pradesh, India and Mr. A.K. Murthy, Medicinal Plants Survey, Central Ayurvedic Research Institute, Bhubaneswar, Orissa, India. A voucher specimen (PP 530) has been deposited in herbarium of Department of Pharma- cognosy, Manipal College of Pharmaceutical Sciences, Manipal, Karnataka, India. 2.2. Preliminary phytochemical screening Preliminary phytochemical screening (Kokate, 1994; Harborne, 1998) revealed the presence of steroids, terpenes, saponins, carbohydrates, tannins and mucilage in the bark. 2.3. Preparation of GP aqueous bark extract The aqueous extract was prepared by cold maceration of 150 g of the shade dried bark powder in 500 ml of drinking water for 7 days. The extract was filtered, concentrated, dried in vacuo 0378-8741/$ – see front matter © 2006 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.jep.2006.03.012