The Effects of Methanolic Extract of Melissa officinalis on Experimental Gastric Ulcers in Rats

BACKGROUND

Melissa officinalis (MO) has potent antioxidant activity. Recent research has demonstrated the anti-ulcer properties of some medicinal plants through their antioxidant properties.

OBJECTIVES

The aim of this study was to evaluate the effects of methanolic extracts of MO on experimental gastric ulcers in rats.

MATERIALS AND METHODS

Male Wistar rats (200 - 250 g) were starved for 24 hours prior to the induction of gastric ulceration by either indomethacin (48 mg/kg/oral) or water immersion restraint (WIR) stress. Experimental rats received either ranitidine (25 mg/kg) or MO extract (150, 300 and 450mg/kg) orally 2 hours prior to WIR stress or indomethacin treatment, for the evaluation of their gastroprotective effects. The control group received the same volume of saline. Gastric lesions were scored according to the surface of lesions on the ulcer index. Superoxide dismutase (SOD) and glutathione peroxidase (GPX) were determined as measures of antioxidant defense, and malondialdehyde (MDA) was determined to measure tissue oxidation.

RESULTS

MO extract (150 and 300 mg/kg) significantly decreased the ulcer index in both the indomethacin (1.3 ± 0.09 and 1.5 ± 0.19, respectively) and WIR stress groups (1.5 ± 0.17 and 1.5 ± 0.22, respectively), as compared to the control rats (2.5 ± 0.28) (P < 0.01). MO extract (450 mg/kg) significantly reduced ulcer index readings in WIR stress rats (1.8 ± 0.31 vs. 2.4 ± 0.15 in the WIR group), however, MO extract at a dose of 450 mg/kg did not prevent indomethacin-induced gastric ulceration (2.4 ± 0.26). There was no significant difference in the ulcer index for MO extract- (150 and 300 mg/kg) and ranitidine-treated rats (P > 0.05). Also, MO extract (150 and 300 mg/kg) significantly reduced MDA serum levels (0.69 ± 0.6 µmol/L and 0.85 ± 0.24 µmol/L, respectively, vs. 4.5 ± 1.9 µmol/L in the saline group) and significantly increased antioxidants' SOD activities (296.3 ± 146.4 U/mL and 561.4 ± 120 U/mL, respectively, vs. 190.2 ± 63.8U/mL in the control group) and GPX levels (8273 ± 3049 U/mL and 14574 ± 5012 U/mL, respectively), compared to the control (3236 ± 1699 U/mL).

CONCLUSIONS

Our results showed that MO extract may have a gastroprotective effect against experimental gastric ulcers in rats. The exact mechanism has not yet been determined, but it may be due to enhancing enzymatic antioxidant defenses and inhibiting lipid peroxidation.

Multiplex-PCR-Based Screening and Computational Modeling of Virulence Factors and T-Cell Mediated Immunity in Helicobacter pylori Infections for Accurate Clinical Diagnosis

The outcome of H. pylori infection is closely related with bacteria's virulence factors and host immune response. The association between T cells and H. pylori infection has been identified, but the effects of the nine major H. pylori specific virulence factors; cagA, vacA, oipA, babA, hpaA, napA, dupA, ureA, ureB on T cell response in H. pylori infected patients have not been fully elucidated. We developed a multiplex- PCR assay to detect nine H. pylori virulence genes with in a three PCR reactions. Also, the expression levels of Th1, Th17 and Treg cell specific cytokines and transcription factors were detected by using qRT-PCR assays. Furthermore, a novel expert derived model is developed to identify set of factors and rules that can distinguish the ulcer patients from gastritis patients. Within all virulence factors that we tested, we identified a correlation between the presence of napA virulence gene and ulcer disease as a first data. Additionally, a positive correlation between the H. pylori dupA virulence factor and IFN-γ, and H. pylori babA virulence factor and IL-17 was detected in gastritis and ulcer patients respectively. By using computer-based models, clinical outcomes of a patients infected with H. pylori can be predicted by screening the patient's H. pylori vacA m1/m2, ureA and cagA status and IFN-γ (Th1), IL-17 (Th17), and FOXP3 (Treg) expression levels. Herein, we report, for the first time, the relationship between H. pylori virulence factors and host immune responses for diagnostic prediction of gastric diseases using computer-based models.