Study Of Gastric Antiulcer Effects On Experimental Rats And Antibacterial Activity Of Extracts Of Rhizophora Apiculata

Objectives: To study the effects of the active fraction of stem aqueous extracts derived from the oceanic mangrove plant, Rhizophora apiculata, on experimental gastric ulcer in rats and antibacterial activity of different parts of the plant in order to provide theoretical and experimental evidence for further exploitation of the medicinal value of the oceanic mangrove plant.Methods: Rhizophora apiculata is a typical mangrove plant in Hainan province. Aqueous extracts of its stem were further fractionated on macroreticular resin with distilled water and different ethanol concentrations.The B fraction of stem aqueous extracts of the plant was found to show antiulcer effect by active screening.â‘ The safety of the active fraction was evaluated elementarily by acute toxicity test in mice.â‘¡Rats were divided randomly into six groups, namely, normal control group, model control group, groups with tested drug(setting three groups which were administrated respectively the B fraction of stem aqueous extracts of Rhizophora apiculata at a dose of 480, 240, 60mg/kg.) and Cimitidine group. All rats were separately administered at 10ml/kg to each group every day for three days. Except normal control group, pylorus ligated gastric ulcer was induced for 17h or water immersion restraint stressed gastric ulcer was induced for 18h on the rest rats after the last administration. After collecting blood, rats were killed to observe gastric mucosa lesions of rats in every group. Ulcer index was determined. Percentage inhibition of ulcer was calculated. Furthermore, gastric juice volume, free acidity, total acidity, peptic activity, levels of nitric oxide(NO), malonaldehyde(MDA) and superoxide dismutase(SOD) in blood serum and gastric tissue and endothelin(ET) in plasma were examined.In addition, by routine dilution method, antibacterial activity in vitro against 10 clinical isolation strains was respectively observed on aqueous and ethanol extracts of follicle, leaf, root and stem of Rhizophora apiculata. The same observation was also made on the A and B fractions of stem aqueous extracts of the plant. Antibacterial activity of all parts was indicated with minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC).Result:â‘ Maximum tolerable dose(MTD) of the B fraction of stem aqueous extracts of Rhizophora apiculata for mice by intragastric administration was 4.0g/kg, which suggests median lethal dose(LD50) of the fraction is more than 4.0g/kg.â‘¡The B fraction of stem aqueous extracts of Rhizophora apiculata relieved gastric mucosa lesions significantly in pylorus-ligated rats. The percentage inhibition of ulcer of all tested groups was less than that of model group,...