Journal of Ethnopharmacology 104 (2006) 356–361 Action of Hygrophila auriculata against streptozotocin-induced oxidative stress M. Vijayakumar a , R. Govindarajan a , G.M.M. Rao a , Ch.V. Rao a , A. Shirwaikar b , S. Mehrotra a , P. Pushpangadan a,∗ a Pharmacognosy and Ethnopharmacology Division, National Botanical Research Institute, Lucknow 226 001, Uttar Pradesh, India b Pharmaceutics Department, College of Pharmaceutical Sciences, MAHE, Manipal 576119, India Received 1 November 2004; received in revised form 23 August 2005; accepted 24 September 2005 Available online 9 November 2005 Abstract Hygrophila auriculata (K. Schum.) Heine (Family: Acanthaceae) is a wild herb widely used in ‘Ayurveda’ as ‘Rasayana’ drug for treatment of various disorders. Treatment of diabetic rats with aerial parts of Hygrophila auriculata extract (HAEt, 100 and 250 mg/kg body weight) for 3 weeks showed significant reduction in blood glucose, thiobarbituric acid reactive substances (TBARS) and hydroperoxide in both liver and kidney. The treatment with HAEt significantly increased the glutathione (GSH), glutathione peroxidase (GPx), glutathione S-transferase (GST) and catalase (CAT) in the drug-treated group, which is comparable to the control group. HAEt and glibenclamide-treated rats also showed decreased lipid peroxidation that is associated with increased activity of superoxide dismutase (SOD) and catalase. The ability of HAEt on tissue lipid peroxidation and antioxidant status in diabetic animals has not been studied before. The result of this study thus shows that HAEt possesses significant antidiabetic activity along with potent antioxidant potential in diabetic conditions. © 2005 Elsevier Ireland Ltd. All rights reserved. Keywords: Hygrophila auriculata; Diabetes; Antioxidant enzymes; Photochemiluminescence 1. Introduction Oxidative stress, defined as an imbalance between oxidants and antioxidants leads to many biochemical changes and is an important causative factor in several human chronic diseases, such as atherosclerosis and cardiovascular diseases, mutagene- sis and cancer, several neurodegenerative disorders and the aging process (Frei, 1999). Diabetes mellitus is one such disease and it is estimated that the number of diabetic patients will continue to increase in the future (Furusho et al., 2002). It has been postu- lated that the etiology of the complications of diabetes involves oxidative stress perhaps as a result of hyperglycemia (Hunt et al., 1990). The elevated levels of blood glucose in diabetes produce oxygen-free radicals (OFR), which cause membrane damage Abbreviations: CAT, catalase; GPx, glutathione peroxidase; GSH, glu- tathione; GST, glutathione S-transferase; HAEt, Hygrophila auriculata extract; LPO, lipid peroxidation; ROS, reactive oxygen species; SOD, superoxide dis- mutase; STZ, streptozotocin; TBARS, thiobarbituric acid reactive substances ∗ Corresponding author. Tel.: +91 522 2205848; fax: +91 522 2205836. E-mail address: pushpangadan@satyam.net.in (P. Pushpangadan). due to peroxidation of membrane lipids and protein glycation (Sato et al., 1979). Baynes (1991) reported that plasma thio- barbituric acid reactive substance (TBARS) levels increased in diabetic patients due to vascular lesions induced by hyper- glycemia. Diabetic patients thus have an increased incidence of vascular diseases and it has been suggested that free radical activ- ity increased in diabetes (Oberly, 1988). It has also been shown that glucose under physiological conditions produces oxidants that possesses reactivity similar to the hydroxyl-free radicals. Recent years have witnessed a renewed interest in plants as pharmaceuticals because they synthesize a variety of secondary metabolites with antioxidant potential which can play a major role in protection against molecular damage induced by reac- tive oxygen species (ROS) (Cao et al., 1997; Vaya et al., 1997). Many traditional plant treatments for diabetes mellitus are used throughout the world. Few of the medicinal plant treatments for diabetes have received scientific scrutiny, for which World Health Organization (WHO) has also recommended attention (WHO, 1980). Hygrophila auriculata (K. Schum.) Heine Syn. Asteracantha longifolia Nees. (Acanthaceae), is a wild herb commonly found 0378-8741/$ – see front matter © 2005 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.jep.2005.09.030