Protective activity of geraniol against acetic acid and Helicobacter pylori- induced gastric ulcers in rats

Geraniol, an active constituent of rose and palmarosa essential oils, possesses several pharmacological properties, including antioxidant, antibacterial and antiulcer activity. Geraniol was therefore investigated for its antiulcer and anti-Helicobacter pylori activity in rats. Ulcers were induced by injecting acetic acid into the sub-serosal layer of the stomach followed by orogastric inoculation of H. pylori for 7 days. Geraniol (15 and 30 mg/kg), vehicle and a standard drug combination (amoxicillin, 50 mg/kg; clarithromycin, 25 mg/kg and omeprazole, 20 mg/kg) were administered twice daily for 14 days. All the parameters were measured at the end of treatment. The ulcer index was significantly (P < 0.05) lowered in geraniol and standard drug-treated rats as compared to the H. pylori control group (4.13 ± 0.43). Treatment with geraniol (30 mg/kg) significantly (P < 0.01) increased the gastric pH along with a reduction in total acidity and gastric juice volume. Geraniol significantly (P < 0.05) attenuated the myeloperoxidase activity and augmented the total glutathione level in gastric mucosa. The extent of damage in the stomach was measured using a histopathological score. The score in H. pylori control, geraniol (30 mg/kg) and standard drugs was 9, 3.5 and 2.0 respectively. In the rapid urease test, treatment with geraniol (30 mg/kg) and the standard drugs produced a 33% and 67% cure respectively from H. pylori infection. Further, the reduction in bacterial load in the gastric mucosa was confirmed using modified Giemsa staining. Geraniol was observed to exhibit significant antiulcer and anti-H. pylori activity in a rodent model.