Indian Journal of Experimental Biology Vol. 44, April 2006, pp. 292-299 Effect of plantain banana on gastric ulceration in NIDDM rats: Role of gastric mucosal glycoproteins, cell proliferation, antioxidants and free radicals M Mohan Kumar, M C Joshi, T Prabha, M Dorababu & R K Goel * Department of Pharmacology, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221 005, India Received 20 September 2005; revised 19 December 2005 Methanolic extract of Musa sapientum var. Paradisiaca (MSE, 100 mg/kg) was studied for its antiulcer and mucosal defensive factors in normal and non-insulin dependent diabetes mellitus (NIDDM) rats. NIDDM was induced by administering streptozotocin (STZ, 70 mg/kg, ip) to 5 days old rat pups. The animals showing blood glucose level >140mg/dL after 12 weeks of STZ administration were considered as NIDDM positive. Effects of MSE were compared with known ulcer protective drug, sucralfate (SFT, 500 mg/kg) and anti-diabetic drug glibenclamide (GLC, 0.6 mg/kg) when administered orally, once daily for 6 days against gastric ulcers (GU) induced by cold-restraint stress (CRS) and ethanol and subsequent changes in gastric mucosal glycoproteins, cell proliferation, free radicals (lipid peroxidation and nitric oxide) and anti-oxidants enzymes (super oxide dismutase and catalase) and glutathione (GSH) levels. MSE showed better ulcer protective effect in NIDDM rats compared with SFT and GLC in CRS-induced GU. NIDDM caused a significant decrease in gastric mucosal glycoprotein level without having any effect on cell proliferation. However, all the test drugs reversed the decrease in glycoprotein level in NIDDM rats, but cell proliferation was enhanced in case of MSE alone. Both CRS or NIDDM as such enhanced gastric mucosal LPO, NO and SOD, but decreased CAT levels while CRS plus NIDDM rats caused further increase in LPO and NO level without causing any further changes in SOD and CAT level. MSE pretreatment showed reversal in the levels of all the above parameters better than GLC. Ethanol caused a decrease in glutathione level which was further reduced in NIDDM-ethanol rats. MSE reversed the above changes significantly in both normal as well as in NIDDM rats, while GLC reversed it only in NIDDM rats. However, SFT was ineffective in reversing the changes induced by CRS or ethanol or when given in NIDDM-CRS or NIDDM-ethanol rats. The results indicated that the ulcer protective effect of MSE could be due to its predominant effect on mucosal glycoprotein, cell proliferation, free radicals and antioxidant systems. Keywords: Antioxidants, Cell proliferation, Free radicals, Glycoproteins, Musa sapientum, NIDDM Oxidative stress is believed to initiate and aggravate many diseases including peptic ulcers and diabetes mellitus (DM) 1,2 . Persistent hyperglycemic status in diabetes causes increased oxidative stress. Mecha- nisms that contribute to increased oxidative stress in diabetes may include not only increased non- enzymatic and oxidative glycosylation (glycation) but also due to change in energy metabolism, alteration in sorbitol pathway activity and the status of antioxidant defense system and localized tissue damage resulting from hypoxia and ischemic reperfusion injury 2 . Marked increase in oxidative stress in DM is indicated by elevated concentrations of lipid peroxidation products 3 . Transient changes in activities of antioxidant enzymes like superoxide dismutase, catalase and glutathione peroxidase have been found in conjunction with increases in plasma glucose levels in case where control of diabetes is poor 4 . The superoxide dismutase (SOD) activity and glutathione (GSH) levels have been reported to decrease in various organs of diabetic animals, such as kidney, intestine and stomach 5 . These reports are indicative that the increase in reactive oxygen species may have a role in the aggravation of gastric mucosal damage in diabetes. Plantain banana (Musa sapientum var. paradisiaca, MS) was reported to possess ulcer protective and healing activity through its predominant action on mucosal defensive factors 6,7 . Methanolic extract of MS has shown antioxidant activity in gastric mucosal homogenates, where it reverses the increase in lipid peroxidation (LPO) and SOD induced by stress in normal rats 8 . A natural flavonoid, leucocyanidin isolated from MS has been reported to have anti-ulcer ________________ *Correspondent author: Phone: +91-542-2307522; Fax : +91-542-2367568 E-mail: rkgoel_bhu@yahoo.co.in