Title : Effects of an aqueous Morinda citrifolia fruit extract on indomethacin induced gastric ulcer in rats
Non-steroidal anti-inflammatory drugs (NSAIDs) have been accepted as a major cause of GU (80% of the cases) that results in impaired quality of life, work loss, and high–cost medical care. The tissue inflammatory response seems to be related to an excess release of a number of inflammatory mediators especially inflammatory prostaglandins (PGs) derived from cyclooxygenase-2 (COX-2) and nitric oxide (NO) derived from inducible nitric oxide synthase (iNOS). Nowadays, the use of herbal or traditional medicines is becoming popular in GU due to the potent antioxidant and anti-inflammatory activities of their biologically active compounds. The mature unripe fruit of Morinda citrifolia (Linn.) or noni (Rubiaceae), is one of a tropical medicinal plant that has been used in Thai folk medicine as a reliever of heartburn or stomachache. Previous studies in vitro and in vivo systems had shown that an aqueous M. citrifolia fruit extract (AMFE) possessed potent anti-inflammatory property in suppressing iNOS and COX-2 activities including antiulcer property against ethanol-, serotonin- and acetic acid-induced gastric ulcer (GU) in rats. Therefore, the efficacy of AMFE in treatment of GU induced by an oral administration of indomethacin (NSAID) (30 mg/kg) for 5 h schedule in rats was further evaluated. The sum of the area (mm2) of all haemorrhagic ulcerations for each stomach was used as ulcer index. The expression of COX-1, COX-2 and iNOS expression in the gastric ulcerated tissue was also evaluated using quantitative real-time polymerase chain reaction (qRT-PCR) analysis. The obtained results showed that an oral administration of AMFE at the dose of 1.25 g/kg [equivalent to 0.806 mg of scopoletin (a biomarker)] for 3 days significantly decreased ulcer index with a comparable ulcer healing efficacy to that of lansoprazole (a standard antiulcer agent). The qRT-PCR resullts also showed that AMFE exerted a comparable potency to lansoprazole in down-regulation of iNOS and COX–2 gene expression and in up-regulation of COX-1 gene expression. The finding indicated that AMFE may be beneficial as a potential therapeutic agent for NSAIDs-induced GU mainly through its anti-inflammatory and gastroprotective activities.