Pharmacological Research 47 (2003) 323–329 Anti-diabetic effects of Gymnema yunnanense extract Jing-Tian Xie a,c , Anbao Wang a,c , Sangeeta Mehendale a,c , Jian Wu a,c , Han H. Aung a,c , Lucy Dey a,c , Shengxiang Qiu d , Chun-Su Yuan a,b,c,∗ a Tang Center for Herbal Medicine Research, The Pritzker School of Medicine, The University of Chicago Medical Center, 5841 S. Maryland Avenue, MC 4028, Chicago, IL 60637, USA b Committee on Clinical Pharmacology and Pharmacogenomics, The Pritzker School of Medicine, The University of Chicago Medical Center, 5841 S. Maryland Avenue, MC 4028, Chicago, IL 60637, USA c Department of Anesthesia and Critical Care, The Pritzker School of Medicine, The University of Chicago Medical Center, 5841 S. Maryland Avenue, MC 4028, Chicago, IL 60637, USA d Herbstandard, Inc., 1743 Canyon View Court, Chesterfield, MO, USA Accepted 21 November 2002 Abstract In this study, we evaluated anti-hyperglycemic effect and body weight reduction activity of Gymnema yunnanense extract in obese ob/ob and diabetic db/db mice. Animals received daily intraperitoneal injections of the extract 100 mg/kg for 12 days. On Day 5, the extract-treated ob/ob mice had significantly lower fasting blood glucose levels compared to vehicle-treated mice (161 ± 14.5 mg/dl versus 238 ± 21.5 mg/dl, P< 0.01). On Day 12, the extract-treated ob/ob mice had normal fasting blood glucose levels, compared with vehicle-treated mice (119 ±3.3 mg/dl versus 240 ±12.9 mg/dl, P< 0.01). Glucose tolerance improved significantly. This was demonstrated by overall glucose excursion calculated as area under the curve (AUC) during the 2 h intraperitoneal glucose tolerance test (IPGTT), which decreased by approximately 22% (P< 0.01) compared to vehicle-treated ob/ob mice. In addition, extract-treated ob/ob mice lost weight significantly from 51.7 ± 1.9g on Day 0 to 45.7 ± 1.2 g on Day 12 (P< 0.05 compared to vehicle-treated mice). In db/db mice, after treatment with same dose of the extract, fasting blood glucose levels also decreased significantly from Day 0 of 247 ± 13.9 mg/dl to Day 5 of 172 ± 7.5 mg/dl and to Day 12 of 190 ± 2.7 mg/dl (both P< 0.01 compared to vehicle-treated group from Day 0 of 239 ± 12.1 mg/dl to Day 5 of 230 ± 8.5 mg/dl and Day 12 of 247 ± 18.9 mg/dl, respectively). After 12 days of extract treatment, body weight in db/db mice reduced from 61.8 ± 1.4 g on Day 0 to 59.8 ± 1.1 g on Day 12 (P< 0.05). Our results support an in vivo anti-hyperglycemic and body weight reduction activity of G. yunnanense extract that may prove to be of clinical importance in improving the management of type 2 diabetes. © 2003 Elsevier Science Ltd. All rights reserved. Keywords: Gymnema yunnanense Tsiang; Herbal medicine; Diabetes; Anti-hyperglycemia; Body weight change; ob/ob mice; db/db mice 1. Introduction Diabetes mellitus is a chronic metabolic disease that has a significant impact on the health, quality of life, and life expectancy of patients, as well as on the health care system. Diabetes mellitus is divided into two major categories: type 1 diabetes (formerly known as insulin-dependent diabetes mellitus, or IDDM), and type 2 diabetes (formerly known as non-insulin dependent diabetes mellitus, or NIDDM). The prevalence of diabetes is approximately 6% in the US and 3% world-wide, of which 90% is type 2 diabetes [1]. The two types of diabetes have distinct pathogeneses, but hyper- glycemia and various life-threatening complications result- ∗ Corresponding author. Tel.: +1-773-702-1916; fax: +1-773-834-0601. E-mail address: cyuan@airway.uchicago.edu (C.-S. Yuan). ing from long-term hyperglycemia are the most common features [2,3]. Effective control of the blood glucose level is a key step in preventing or reversing diabetic complications and improving the quality of life in both types 1 and 2 dia- betic patients [4,5]. Sustained reductions in hyperglycemia will decrease the risk of developing microvascular compli- cations, and most likely reduce the risk of macrovascular complications [6]. Currently available drugs for type 2 diabetes have a num- ber of limitations, such as adverse effects and high rates of secondary failure. As a complementary/alternative approach, medicinal herbs with anti-hyperglycemic activities are in- creasingly sought after by diabetic patients and healthcare professionals. For example, Gymnema sylvestre, a plant na- tive to the tropical forests of India, has long been used as a treatment for diabetes [7,8]. Data have been shown that 1043-6618/03/$ – see front matter © 2003 Elsevier Science Ltd. All rights reserved. doi:10.1016/S1043-6618(02)00322-5