Gastric ulcers are among the most important diseases in the world. The gastric mucosa is continuously exposed to potentially injurious agents such as acid, pepsin, bile acids, food ingredients, bacterial products, and drugs. 1) These agents have been implicated in the pathogeneses of gastric ulcer, such as an increase in gastric acid and pepsin secretion, a decrease in gastric blood flow, the suppression of endogenous generation of prostaglandins, inhibition of mucosal growth and cell proliferation, and alteration of gastric mobility.2)The current therapy for this disease continues to have, as one of its major goals, the control of Helicobacter pylori as well as H ϩ /K ϩ -ATPase, acid secretion and a subsequent reversal of mucosal damage and inflammation. 3)Many pharmaceutical products have been employed for the treatment of gastroduodenal ulcer and peptic disease, and for decreasing mortality and morbidity rates, but they are not completely effective and produce many adverse effects. Moreover, these pharmaceutical products are too expensive. 4)Plant extracts are some of the most attractive sources of new drugs and have been shown to produce promising results for the treatment of gastric ulcer. 5)Simaroubaceae is a large botanical family with pantropical distribution; only a few representatives occur in temperate regions. Quassia amara L., a representative of this family, is a neotropical forest shrub or small tree reputed in traditional medicine to have good effect on stomach diseases, especially gastric ulcers. In Brazil, this species is found in a region from the border with Guiana to the state of Maranhão. It is popularly known in Latin American as "Amargo", "Hombre Grande", "Simaruba", "Pau Quassia", "Murubá", "Murupá" and "Quina de Caiena". 6)This plant is a source of several compounds which include both b-carbonile and cantin-6 alkaloids, as well as, primarily, the bitter components known as quassinoids, a group of substances belonging to the terpens class. Antimalarial, antifeedant and antifertility pharmacological activities are atributted to these quassinoids. 7)In considering the use of this plant in Brazilian folk medicine and the several chemical substances isolated and identified from Quassia amara bark, we have performed a study of the antiulcerogenic effects for four different extracts of this species using standard rodent models of induced gastric ulcer. Quassia amara L., a neotropical forest shrub of the Simaroubaceae family, is widely used in Caribbean folk medicine and in some northern states of Brazil for the treatment of gastric ulcers. This plant is a source of numerous compounds including both b b-carbonile and cantin-6 alkaloids as well as, primarily, the bitter compounds known as quassinoids. We analyzed the possible antiulcerogenic activities of four extracts of different polarities: 70% ethanol (70% EtOH), 100% EtOH, 100% dichloromethane (DCM), and 100% hexane (HEX) obtained from Quassia amara bark. All extracts, administered at doses of 5000 mg/kg orally and 1000 mg/kg intraperitonea...
Croton cajucara BENTH. (Euphorbiaceae), commonly known as "sacaca," is widely used as an aromatic and bitter tea made from the bark and leaves of a plant in Amazonian folk medicine for the treatment of a wide range of gastrointestinal symptoms. 1,2) We also reported the antiulcerogenic activity of DHC (trans-dehydrocrotonin), the principal furano diterpene isolated from C. cajucara bark, on indomethacin-, hypothermic restraint-stress-, ethanol-and pylorus ligature-induced gastric ulcers in mice and rats.3) We also studied possible antiulcerogenic mechanisms involved in the action of DHC.4) The acute and subchronic toxicity of this compound was also studied by our group through both in vivo and in vitro assays showing oral toxicity when administered for a short period of time (35 d).3,5) Besides DHC, we also studied the antiulcerogenic activity of other diterpenes with a clerodane skeleton such as cordatin and aparisthman with excellent results. 6,7)We describe here the isolation of the second most important nor-clerodane diterpene from the bark of this plant, crotonin, and our study of its antiulcerogenic activity on indomethacin/bethanechol-, hypothermic restraint-stress-and pylorus ligature-induced gastric ulcer in mice. In the HCl/ethanol model, we studied whether the effect of crotonin was dose-dependent compared with that of cimetidine. The parameters of gastric-acid secretion such as gastric acidity and gastric-juice volume were analyzed in animals submitted to the Shay method and treated with crotonin by the oral and intraduodenal route. Moreover, the effects of crotonin on free mucus production were also determined. Data for DHC was also included for comparison in all experiments. Regarding the structure activity relationship, by comparing the antiulcerogenic activity of DHC and crotonin, we can evaluate the importance of parts of both molecules for the bioactivity tested.
Flavonoids (or bioflavonoids) are a group of about 4000 naturally occurring compounds that are ubiquitous in vascular plants. These compounds are responsible for the autumnal burst of hues and the many shades of yellow, orange, and red in flowers. They are also important for the normal growth, development, and defense of plants. 1) Flavonoids occur in several medicinal plants, and herbal remedies containing flavonoids have been indicated in folk medicine around the world.2) Thus these compounds are important for plants, animals, and humans.The relationship between flavonoids and humans has stimulated the study of the biochemical, physiologic, and pharmacologic activities of these compounds. Flavonoids have antiinflammatory activity 3) and protect the gastric mucosa against a variety of ulcerogenic agents in different mammalian species. As a result, many studies have examined the antiulcerogenic activities of plants containing flavonoids using either naturally derived or synthetic compounds.2) Despite some promising results obtained with this class of molecules, there are currently few flavonoid related to antiulcerogenic properties.Turnera ulmifolia L., a plant popularly known in Brazil and South America as chanana, belongs to the family Turneraceae. This species is a small herb with a wide geographic distribution, ranging from Guyana to southeastern Brazil, including São Paulo state, where it is considered a weed. 4)Some species of Turnera are used in folk medicine for the treatment of several diseases. Recently, Antonio and Souza Brito 5) demonstrated in rats that organic extracts from T. ulmifolia inhibited gastric lesions induced by ligature of the pylorus, and by indomethacin and ethanol. Those authors also detected flavonoids in these preparations.Since the tea of this species is used in folk medicine to treat gastric ulcers in Brazil and other South American countries, we investigated the antiulcerogenic properties of a lyophilized infusion obtained from the aerial parts of T. ulmifolia, in different models of gastric ulcer in mice. We also screened the extract for the presence of different classes of natural products to determine whether there was a correlation between the chemical composition of the infusion and the biological activity of the tea. MATERIAL AND METHODSAnimals Fasted male Swiss albino mice (30-40 g) or male Wistar rats (200-220 g) from the Central Animal House of the State University of Campinas (CEMIB/UNI-CAMP) were used. The animals were fed a certified Nuvilab CR-a diet with free access to tap water, and were housed under standard conditions of illumination (12 h light/dark), humidity (60Ϯ1%), and temperature (21.5Ϯ2°C). All of the experimental protocols were approved by the local Committee for Ethics in Animal Experimentation at UNICAMP.Drugs All reagents were of the highest purity. The following drugs were used: absolute ethanol, acetic acid, bethanechol chloride, cimetidine, cysteamine, indomethacin, lansoprazole, sodium bicarbonate, (Sigma Chemical, St. Louis, MO, U.S.A.). The AqF ...
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