THE ETHANOL–WATER EXTRACT OF RAMALINA CAPITATA HAS GASTROPROTECTIVE AND ANTIOXIDATIVE PROPERTIES: AN EXPERIMENTAL STUDY IN RATS WITH INDOMETHACIN-INDUCED GASTRIC INJURIES

ABSTRACT Ethanol : water (1:1) (EWRC), ethanol (ERC), methanol (MRC) and water (WRC) extracts of Ramalina capitata (Ach.) Nyl. (R. capitata) significantly reduced the gastric lesions induced by indomethacin (IND). The highest gastroprotective effect (66.6%) was shown by EWRC at a 200 mg/kg dose. IND caused significant decreases in the levels of glutathione peroxidase (GPx), glutathione S-transferase (GST), superoxide dismutase (SOD) and reduced glutathione (GSH). However, EWRC exhibited a significant antioxidant activity against oxidative damage in stomach tissues, increasing the levels of GPx, GST, SOD and GSH. However, catalase and myeloperoxidase levels increased by the administration of IND were found to be lower in EWRC administrated groups. Furthermore, all extracts tested exhibited significant in vitro antioxidant activity. These results indicate that the extracts of R. capitata have gastroprotective effects against IND-induced gastric ulcer, which could be attributed to its reducing effect of oxidative damage and of neutrophil infiltration into gastric tissues. PRACTICAL APPLICATIONS Lichens are complex plants, living in symbiotic relationships with fungi and algae, and the pertinent partners are defined as mycobiont and phycobiont, respectively. Lichens have been reported to show a wide variety of biological activities, including antibiotic, antimycobacterial, antiviral, anti-ulcerogenic, anti-inflammatory, analgesic, antipyretic and antiproliferative. However, the usage of R. capitata (Ach.) Nyl., a lichen species, in folk medicine has not been elucidated yet; although, in some countries, it has been used as a spice mixture usually added to foods. In the present study, we aimed to determine the in vivo gastroprotective effect on indomethacin-induced gastric ulcer model in rats and the in vitro antioxidant activity of some extracts of Ramalina capitata, and to expose the possible relationship between anti-ulcer and antioxidant activities. In addition, some antioxidant parameters in rat stomach tissues were evaluated to determine the effects of these parameters on the ulceration process.