Gastroprotective effect of alpha-pinene and its correlation with antiulcerogenic activity of essential oils obtained from Hyptis species

Abstract

Background: Alpha-pinene (α-pinene) is a monoterpene commonly found in essential oils with gastroprotective activity obtained from diverse medicinal plants, including Hyptis species. The genus Hyptis (lamiaceae) consists of almost 400 species widespread in tropical and temperate regions of America. In the north and northeastern Brazil, some Hyptis species are used in traditional medicine to treat gastrointestinal disturbances.

Objective: The present study has investigated the gastoprotective effect of purified α-pinene in experimental gastric ulcer induced by ethanol and indomethacin in mice.

Materials and methods: Gastric ulcers were induced in male Swiss mice (20-30 g) by oral administration of absolute ethanol or indomethacin 45 min after oral pretreatment with vehicle, standard control drugs or α-pinene (10, 30, and 100 mg/kg). One hour after the ulcerative challenges, the stomach were removed, and gastric lesions areas measured. The effects of α-pinene on the gastric juice acidity were determined by pylorus ligation model. The gastrointestinal motility and mucus depletion were determined by measuring the gastric levels of phenol red and alcian blue, respectively. Hematoxylin and eosin stained sections of gastric mucosa of the experimental groups were used for histology analysis.

Results: α-pinene pretreatment inhibited ethanol-induced gastric lesions, reduced volume and acidity of the gastric juice and increased gastric wall mucus (P < 0.05). Furthermore, we showed an interesting correlation between concentration of α-pinene and gastroprotective effect of Hyptis species (P Pearson = 0.98).

Conclusion: Our data showed that the α-pinene exhibited significant antiulcerogenic activity and a great correlation between concentration of α-pinene and gastroprotective effect of Hyptis species was also observed.

Keywords: Alpha-pinene; Hyptis; antiulcerogenic; essential oil; gastric ulcer; terpenes.

Figure 1

Effect of oral administration of the α-pinene (100 mg/kg) on gastric volume (a), total acidity (b), pH (c) and mucus production (d). In the graph, the ordinates express the ulcer area (mm²) 45 min after ingestion of the ethanol The results are expressed as the mean ± standard error of the mean n = 6 animals for each group. *Significantly different from the vehicle group (analysis of variance followed by Bonferroni's multiple comparison test, P < 0.05

Figure 2

Hematoxilyn and eosin – stained sections of the gastric tissue in mice (20×). (a) normal and (b) vehicle-pretreated mice. Large reduction in the gastric epithelium (black line) accompanied by intense edema in the submucosal layer (red line) and leukocyte infiltration (red arrow). (c) mice pretreated with ranitidine (40 mg/kg). Mild disruption of the surface epithelium mucosa, with no leukocyte infiltration and mucosal damage. (d-f) mice pretreated with 10, 30 and 100 mg/kg α-pinene, respectively. Gastric structure approached of normal control group (a)

Figure 3

Correlation between concentration of alpha-pinene and gastroprotective effect (%/%) of essential oils obtained from four Hyptis species (Hyptis martiussim, Hyptis suaveolens, Hyptis crenata and Hyptis spicigera). Pearson correlation (P = 0.98) and linear regression (R² = 0.95) were performed to assed the significant correlation (P < 0.05)