Gastroprotective Effect of Geopropolis from Melipona scutellaris Is Dependent on Production of Nitric Oxide and Prostaglandin

Abstract

The aim of this study was to evaluate the gastroprotective activity of ethanolic extract of geopropolis (EEGP) from Melipona scutellaris and to investigate the possible mechanisms of action. The gastroprotective activity of the EEGP was evaluated using model ulcer induced by ethanol. To elucidate the possible mechanisms of action, we investigated the involvement of the nonprotein sulfhydryl (NP-SH) groups, nitric oxide and prostaglandins. In addition, the antisecretory activity of EEGP was also evaluated by pylorus ligated model. The EEGP orally administrated (300 mg/kg) reduced the ulcerative lesions induced by the ethanol (P < 0.05). Regarding the mechanism of action, the prior administration of nitric oxide and prostaglandins antagonists suppressed the activity of gastroprotective EEGP (P < 0.05). On the other hand the gastroprotective activity of EEGP was kept in the group pretreated with the antagonist of the NP-SH groups; furthermore the antisecretory activity was not significant (P > 0.05). These results support the alternative medicine use of geopropolis as gastroprotective and the activities observed show to be related to nitric oxide and prostaglandins production.

Figure 1

Effect of the p.o. administration of ethanolic extract of geopropolis (EEGP) on the ethanol induced ulcers. Control (C) treated with vehicle, omeprazole 30 mg/kg (Omep 30), and EEGP with doses of 100, 200, and 300 mg/kg. The results are expressed as means ± SEM, n = 5. Symbols indicate statistical difference (ANOVA followed by Dunnett test, P < 0.05). ∗ compared to the control group.

Figure 2

Effect of the p.o. administration of ethanolic extract of geopropolis (EEGP) on the ethanol induced ulcers. Rats pretreated subcutaneous (s.c.) with the N-ethylmaleimide 10 mg/kg (NEM). After 30 min, the rats were treated with vehicle (C and NEM) and with 300 mg/kg doses of EEGP. The results are expressed as means ± SEM, n = 5. Symbols indicate statistical difference (ANOVA followed by Tukey test, P < 0.05). # compared to control (C) group and ∗ compared to control group.

Figure 3

Effect of the p.o. administration of ethanolic extract of geopropolis (EEGP) on the ethanol induced ulcers. Rats pretreated with 5 mg/kg of the L-NAME (i.p.). After 30 min, the rats were treated with vehicle (C and L-NAME) and 300 mg/kg doses of EEGP. The results are expressed as means ± SEM, n = 5. Symbols indicate statistical difference (ANOVA followed by Tukey test, P < 0.05). # compared to control group; ∗ compared to control (C) group; ∗∗ compared to EEGP group.

Figure 4

Effect of the p.o. administration of ethanolic extract of geopropolis (EEGP) on the ethanol induced ulcers. Rats pretreated with 5 mg/kg of the indomethacin-INDO (i.p.). After 30 min, the rats were treated with vehicle (C and Indo) and 300 mg/kg doses of EEGP. The results are expressed as means ± SEM, n = 5. Symbols indicate statistical difference (ANOVA followed by Tukey test, P < 0.05). # compared to control group; ∗ compared to control (C) group; ∗∗ compared to EEGP group.