Gastroprotective effects of the essential oil of Hyptis crenata Pohl ex Benth. on gastric ulcer models

Abstract

Ethnopharmacological relevance: Hyptis crenata Pohl ex Benth (Lamiaceae), popularly known as "hortelã-brava" or "hortelã do campo", is widely distributed in the northeast of Brazil. In Brazil, the leaves of this plant have been used in traditional medicine for the treatment of gastrointestinal disturbances, including gastric ulcers. In an attempt to experimentally validate this claimed antiulcerogenic activity, the gastroprotective effects of the essential oil extracted from the leaves of the Hyptis crenata Pohl ex Benth (EOHc) were evaluated in recognized gastric ulcer models in mice.

Materials and methods: EOHc was obtained by hydrodistillation and analyzed using gas chromatography-mass spectrometry (GC-MS). Swiss male mice (25-30g) were used for the studies. The gastric ulcers were induced by oral administration of absolute ethanol or indomethacin 45min after oral pretreatment with EOHc, vehicle and positive control drugs. One hour after the ulcerative challenges, the stomachs were removed and the area of the lesions was measured. The volume, pH and total acidity of the gastric secretions were determined using the pylorus ligature model. The gastrointestinal motility was measured using gastric emptying and intestinal transit. The ethanol-induced gastric mucus depletion and lipid peroxidation were also analyzed.

Results: Our findings are as follows: A significant inhibition of gastric lesions induced by absolute ethanol was observed in the mice pre-treated with EOHc, at a dose of 30 and 100 and 300mg/kg (5.56±1.51, 2.88±0.82 and 1.71±0.54mm(2), respectively) compared to control group (118.03±35.4mm(2)). Also, EOHc (300mg/kg) produced a gastroprotective effect against the gastric lesions induced by indomethacin (16.07±4.68mm(2)) compared to control group (38.64±6.1mm(2)). EOHc pretreatment produced a reduction in the ethanol-induced lipid peroxidation from 3.9±0.22 to 2.4±0.1μmol/mg tissue (EOHc-300mg/kg and control group, respectively). We also observed that EOHc pretreatment decreased the gastric emptying, but did not alter the intestinal transit ratio, ethanol-induced depletion of the gastric wall mucus or secretion parameters (volume, pH and [H(+)]).

Conclusion: Our data indicate that EOHc exerts a gastroprotective effect, indicated by its significant inhibition of gastric lesions in ethanol- and indomethacin-induced ulcer models, which may be associated with its accelerating effect on gastric emptying and reduction in oxidative damages. Our data suggest a potential therapeutic application for EOHc in the treatment of gastric ulcers.

Keywords: Essential oil; Gastric ulcer; Gastroprotective effect; Hyptis crenata Pohl ex Benth.