Chemico-Biological Interactions 167 (2007) 71–83 Gastroprotective effect of Terminalia arjuna bark on diclofenac sodium induced gastric ulcer Rethinam Sundaresan Devi, Shoba Narayan, Ganapathy Vani, Chennam Srinivasulu Shyamala Devi ∗ Department of Biochemistry, University of Madras, Guindy Campus, Chennai 600025, Tamil Nadu, India Received 23 November 2006; received in revised form 21 January 2007; accepted 22 January 2007 Available online 2 February 2007 Abstract Aim: The present study was aimed to evaluate the effect of methanolic extract of Terminalia arjuna (TA) on diclofenac sodium induced gastric ulcer in experimental rats. Methods: Animals were induced for gastric ulcer with diclofenac sodium (DIC) (80 mg/kg bodyweight in water, orally) and treated orally with TA in various doses ranging from 100 mg/kg bodyweight to 500 mg/kg bodyweight. The effective dose was 400 mg/kg bodyweight, since this dose elicited a maximum reduction in lesion index. The gastroprotective effect of TA was assessed from volume of gastric juice, pH, free and total acidity, pepsin concentration, acid output in gastric juice, the levels of non-protein sulfhydryls (NP-SH), lipid peroxide (LPO), reduced glutathione (GSH), and activities of enzymic antioxidants—super oxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and myeloperoxidase (MPO) in gastric mucosa. The levels of DNA, protein bound carbohydrate complexes—hexose, hexoseamine, sialic acid, fucose in gastric mucosa and gastric juice and the levels of RNA in gastric mucosa were assessed. The stomach tissues were used for adherent mucus content and also for the histological examination. Results: A significant reduction in lesion index was observed in ulcer induced animals treated with TA (DIC+TA) compared to ulcerated rats (DIC). A significant increase was observed in pH, NP-SH, GSH, enzymic antioxidants, protein bound carbohydrate complexes, adherent mucus content, nucleic acids with a significant decrease in volume of gastric juice, free and total acidity, pepsin concentration, acid output, LPO levels and MPO activities in DIC + TA rats compared to DIC rats. Histological studies confirmed the gastroprotective activity of TA. Conclusion: From the data presented in this study it could be concluded that T. arjuna acts as an gastroprotective agent probably due to its free radical scavenging activity and cytoprotective nature. © 2007 Elsevier Ireland Ltd. All rights reserved. Keywords: Gastric ulcer; Diclofenac sodium; Terminalia arjuna; Gastroprotective activity ∗ Corresponding author at: Old No. 62, New No. 66, II Main Road, Gandhi Nagar, Adyar, Chennai 600020, India. Tel.: +91 44 24412575; fax: +91 44 22352494. E-mail addresses: devibiochem@gmail.com, rs devi6@yahoo.co.in (C.S. Shyamala Devi). 1. Introduction Gastric ulcer is a common disorder where disconti- nuity in the gastric mucosa is observed [1]. It is caused by many factors like stress, drugs, alcohol, etc., [2] and is reported to be due to an imbalance between offensive acid-pepsin secretion and defensive mucosal factors like mucin secretion and cell shedding [3]. Non-steroidal 0009-2797/$ – see front matter © 2007 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.cbi.2007.01.011