Protective Effect of Hydroalcoholic Olive Leaf Extract on Experimental Model of Colitis in Rat: Involvement of Nitrergic and Opioidergic Systems

• Published in: Phytotherapy research 2014-09, Vol.28 (9), p.1367-1373
• Main Authors: Fakhraei, Nahid, Abdolghaffari, Amir Hossein, Delfan, Bahram, Abbasi, Ata, Rahimi, Nastaran, Khansari, Azadeh, Rahimian, Reza, Dehpour, Ahmad Reza
• Format: Article
• Language: English
• Subjects: acetic acid-induced colitis; Animals; Anti-Inflammatory Agents - pharmacology; colitis; Colitis, Ulcerative - chemically induced; Colitis, Ulcerative - drug therapy; Colon - drug effects; Colon - pathology; disease models; inflammation; inflammatory bowel disease (IBD); Interleukin-2 - metabolism; interlukin-2 (IL-2); leaf extracts; Male; nitrergic and opioidergic systems; nitric oxide; Olea - chemistry; olive leaf extract (OLE); olives; Plant Extracts - pharmacology; Plant Leaves - chemistry; protective effect; Rats; Rats, Wistar; tumor necrosis factor-alpha; Tumor Necrosis Factor-alpha - metabolism; tumour necrosis factor-α (TNF-α)
• ISSN: 0951-418X; 1099-1573
• DOI: 10.1002/ptr.5139

The aim of the present study is to investigate the possible protective effect of dry olive leaf extract (OLE) against acetic acid‐induced ulcerative colitis in rats, as well as the probable modulatory effect of nitrergic and opioidergic systems on this protective impact. Olive leaf extract was administered (250, 500 and 750 mg/kg) orally for two successive days, starting from the colitis induction. To assess the involvement of nitrergic and opioidergic systems in the possible protective effect of OLE, L‐NG‐Nitroarginine Methyl Ester (10 mg/kg) and naltrexone (5 mg/kg) intraperitoneal (i.p.) were applied 30 min before administration of the extract for two successive days, respectively. Colonic status was investigated 48 h following induction through macroscopic, histological and biochemical analyses. Olive leaf extract dose‐dependently attenuated acetic acid‐provoked chronic intestinal inflammation. The extract significantly reduces the severity of the ulcerative lesions and ameliorated macroscopic and microscopic scores. These observations were accompanied by a significant reduction in the elevated amounts of TNF‐α and interlukin‐2 markers. Moreover, both systems blockage reversed protective effects of OLE in the rat inflammatory bowel disease model. These finding demonstrated, for the first time, a possible role for nitrergic and opioidergic systems in the aforementioned protective effect, and the extract probably exerted its impact increasing nitric oxide and opioid tones. Copyright © 2014 John Wiley & Sons, Ltd.