Beneficial effects of Trigonella foenum graecum and sodium orthovanadate on metabolic parameters in experimental diabetes Pardeep Kumar 1 , Asia Taha 1† , R. K. Kale 1 , P. McLean 2 and Najma Zaheer Baquer 1 * 1 School of Life Sciences, Jawaharlal Nehru University, New Delhi-110067, India 2 Faculty of Life Sciences, Division of Biosciences, University College London Medical School, London, W1T 4JF, UK Oxidative stress in diabetic tissues is accompanied by high-level of free radicals with simultaneously declined antioxidant enzymes status lead- ing to cell membrane damage. The present study was carried out to observe the effect of sodium orthovanadate (SOV) and Trigonella foenum graecum seed powder (TSP) administration on blood glucose and insulin levels, antioxidant enzymes, lipid peroxidation, pyruvate kinase, lactate dehydrogenase and protein kinase C in heart, muscle and brain of the alloxan-induced diabetic rats to see whether the treatment with SOV and TSP was capable of reversing the diabetic effects. Diabetes was induced by administration of alloxan monohydrate (15 mg/100 g body weight), and rats were treated with 2 IU insulin, 0.6 mg/ml SOV, 5% TSP in the diet and a combination of 0.2 mg/ml SOV and 5% TSP separately for 21 days. Blood glucose levels increased markedly in diabetic rats, animals treated with a combined dose of SOV and TSP had glucose levels almost comparable with controls, similar results were obtained in the activities of pyruvate kinase, lactate dehydrogenase, antioxidant enzymes and protein kinase C in diabetic animals. Our results showed that lower doses of SOV (0.2mg/ml) could be used in combination with TSP to effectively reverse diabetic alterations in experimental diabetes. Copyright © 2012 John Wiley & Sons, Ltd. key words—type 1 diabetes; lipid peroxidation; protein kinase C; antioxidant enzymes; Trigonella foenum graecum (fenugreek) seed powder abbreviations—CAT, Catalase; DAG, Diacylglycerol; GPx, Glutathione peroxidase; GR, Glutathione reductase; LDH, Lactate dehydrogenase; SOD, Superoxide dismutase; SOV, Sodium orthovanadate; TSP, Trigonella foenum graecum seed powder INTRODUCTION Diabetes is characterized by hyperglycemia and metabolic abnormalities resulting from decreased insulin levels caus- ing metabolic and other physiological changes in various organs. 1–6 Many antidiabetic compounds such as vanadium and plant extracts have been explored as an alternative to insulin therapy in various diabetic models. The most remark- able insulinomimetic effect of vanadium salts is their ability to normalize blood glucose in type 1 animal models of diabetes mellitus. 7 Vanadium also improves the altered glucose and lipid homeostasis through the reversal of key glycolytic, gluconeogenic and lipogenic enzymes. 8 The common toxic effects of vanadium are diarrhoea, dehydra- tion, decreased fluid and food intake and loss of weight. 9,10 Vanadium shows less toxicity when given in low doses. 11,6 Vanadium acts as a cofactor for the enzyme activity. 12 Trigonella foenum graecum Linn. (Leguminosae), com- monly known as fenugreek, is an annual herb widely grown in India, Egypt and Middle Eastern countries. 13,14 The seeds of fenugreek constitute chemical compounds such as saponins, coumarin, fenugreekine, nicotinic acid, sapogenins, phytic acid, scopoletin, trigonelline and mucilaginous fibre, which may inhibit cholesterol absorption and help lower sugar levels. 15,16,12 It also contains disogenin, gitogenin, neogitogenin, homorientin saponaretin and trigogenin. The chemical constituents of Trigonella foenum graecum seed powder (TSP) include volatile oils, alkaloids, saponins, sapogenins, flavonoids and mucilage. 17,18 Petit et al. 19 and Yoshikawa et al. 20 reported the isolation of furostanol saponins called trigoneoside Ia, Ib, IIa, IIb,IIIa and IIIb; glycoside and trifoenoside A in TSP. 21,14 Various reports have demonstrated that the TSP have hypoglycemic, hypocholesterolemic and hyperinsulinomic effects on type 1 and type 2 diabetes mellitus patients and experimental diabetic animals. 22–24,4,5,25 Furastanol saponins increase food consumption and induce hypocholesterolemia in streptozotocin diabetic rats. 19,26 Diasgenin (saponin) and trigonelline (alkaloid) inhibit glucose uptake in vitro. 27 4-Hydroxyisoleucine, an amino acid extracted and purified from TSP, displays a hypoglycemic and insulinotropic property in vitro and in vivo in diabetic rat model. 15,28–31 Oxidative stress is suggested to be a potential contributor to the development of complications in diabetes. 32,33 Superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and gluathione peroxidase (GPx) are some of the biological *Correspondence to: Najma Zaheer Baquer, School of Life Sciences, Jawaharlal Nehru University, New Delhi-110067, India. E-mail: nzbaquer@mail.jnu.ac.in † Current address: Department of Biomedical Sciences, College of Clinical Pharmacy, King Faisal University- Al-Ahsa, 31982, Kingdom of Saudi Arabia. Received 19 November 2011 Revised 2 February 2012 Accepted 6 February 2012 Copyright © 2012 John Wiley & Sons, Ltd. cell biochemistry and function Cell Biochem Funct 2012; 30: 464–473. Published online 16 April 2012 in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/cbf.2819