Gastroprophylactic Effects of p-Cymene in Ethanol-Induced Gastric Ulcer in Rats

The prevalence of gastric ulcers has increased in recent years, mainly because of non-steroidal anti-inflammatory drug utilization. Therefore, the current study investigates the gastroprotective effect of p-Cymene on absolute ethanol-induced acute gastric mucosal hemorrhagic lesions in rats. Thirty Sprague Dawley rats were randomly separated into five groups: normal control, ulcer control, reference, and two experimental groups. The normal and ulcer control groups were orally fed with 0.5% carboxymethylcellulose (CMC). The reference group was fed orally with 20 mg/kg omeprazole. The experimental groups were fed with 30 mg/kg and 60 mg/kg p-Cymene, respectively. After one hour, the normal group was fed with 0.5% CMC, and groups 2-5 were given absolute alcohol. After another hour all rats were sacrificed. The ulcer control group showed severe superficial hemorrhagic gastric mucosal lesions with decreased gastric mucus secretion and pH of gastric content. p-Cymene significantly reduced ethanol-induced gastric lesions, as evidenced by increased mucus and pH of gastric content, decreased ulcer area, reduced or absence of edema, and leucocyte infiltration of the subcutaneous layer. In gastric mucosal homogenate, p-Cymene displayed a significant increase in superoxide dismutase (SOD), catalase (CAT) activities, prostaglandin E2 (PGE2), and significantly reduced the malondialdehyde (MDA) level. In addition, p-Cymene increased the intensity of periodic acid-Schiff (PAS) stain of the gastric epithelium, and produced up-regulation of the HSP 70 protein and down-regulation of the Bax protein of the stomach epithelium, as well as a reduction in the levels of tumor necrotic factor-alpha and interleukin-6, while the level of interleukin-10 was increased. p-Cymene decreased the level of TNF-a and IL-6, and increased the level of IL-10. Acute toxicity with a higher dose of 500 mg/kg p-Cymene did not manifest any toxicological signs in rats and could enhance defensive mechanisms against gastric mucosal lesions. p-Cymene showed gastroprotective effects that could be attributed to its antioxidant nature, or its ability to increase mucus secretion, increase endogenous enzymes (SOD, CAT, PGE2), reduce MDA level, up-regulate HSP 70 protein, down-regulate Bax protein, and modulate inflammatory cytokines.