Bottom-up and top-down effects in a pre-dispersal seed predation system: are non-predated seeds damaged?

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Stem protective tissue in Erythroxylum tortuosum (Erythroxylaceae), a fire tolerant species from cerrado

The origin and structure are described of the secondary protective tissue in the stem of Erythorxylum tortuosum Mart., a fire tolerant shrubby species common in Brazilian cerrado. The highly tortuous stems are covered with thick bark which is more developed at the base of the stem. After fire in the cerrado, rhytidome fragments of the burned stem flake off, revealing newly formed cork. The first periderm appears near of the terminal buds and is iniated by periclinal divisions in subepidermal cells giving rise to radial rows of cells. The first phellogen is discernible only after the differentiation of the several radial rows of cork cells. Other phellogens have their origin in successively deeper layers of the cortex. The sucessive periderms are discontinuous around the circumference. The collapsed cells with phenolic substances and the accumulated dead cells cause the formation of discontinuous blackish lines, which delimit the sucessive periderms in the rhytidome. The rhytidome contains large quantities of sclereids developed from cell wall thickening of cortex cells. The occurrence of periderm, in the young parts of the stem and of rhytidome in the older parts represents pyrophytic characteristics and may explain, in part, the fire tolerance of this species.

Preparative droplet counter-current chromatography for the separation of the new nor-seco-triterpene and pentacyclic triterpenoids from Qualea parviflora

The methanolic extract of the bark of the medicinal plant Qualea parviflora (Vochysiaceae) contains new nor-seco-triterpene and pentacyclic triterpenoids. They were separated in a preparative scale using droplet counter-current chromatography. The optimum solvent used was composed of a mixture of CHCl3/MeOH/H2O (43:37:20, v/v) in the descending mode and led to a successful separation of the new compound 28-nor-17, 22-seco-2 alpha, 3 beta, 19, 22, 23-pentahydroxy-Delta(12)-olecinane, besides the known triterpenoids bellericagenin B, bellericaside B and arjunglucoside I. Identification was performed by ESI-MS, H-1 NMR and C-13 NMR analyses.

Hymenaea stigonocarpa Mart. ex Hayne: A Brazilian medicinal plant with gastric and duodenal anti-ulcer and antidiarrheal effects in experimental rodent models

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Qualea parviflora Mart.: An integrative study to validate the gastroprotective, antidiarrheal, antihemorragic and mutagenic action

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The anti-ulcerogenic effects of Curatella americana L.

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Mechanisms of the Gastric Antiulcerogenic Activity of Anacardium humile St. Hil on Ethanol-Induced Acute Gastric Mucosal Injury in Rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Can a Strychnos species be used as antiulcer agent? Ulcer healing action from alkaloid fraction of Strychnos pseudoquina St. Hil. (Loganiaceae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Antiulcerogenic activity of Alchornea castaneaefolia: Effects on sornatostatin, gastrin and prostaglandin

The hydroethanolic extract of the leaves (HEL) and bark (HEB) obtained from Alchornea castaneaefolia (Euphorbiaceae) were investigated for their ability to prevent ulceration of the gastric mucosa in animal models. HEL (500 and 1000 mg/kg) and HEB (1000 mg/kg) significantly reduced the gastric injuries induced by the combination of HCl/ethanol and lowered the severity of gastric damage formation induced by indomethacin/bethanechol in mice. Further investigation showed that HEL also inhibited formation of ulcers in mice submitted to stress and pylorus ligature, but HEL did not modify gastric juice parameters in Shay mice. HEL was also effective in promoting the healing process in chronic gastric ulcer induced by acetic acid in rats. An enriched flavonoidic fraction (EFF at dose of 100 mg/kg) obtained from HEL reduced gastric lesions induced by HCl/ethanol and indomethacin/bethanechol in mice. Although EFF did not modify the amount of free mucus production by gastric mucosa, it was able to increase prostaglandin production. When administered to rats submitted to ethanol-induced gastric lesions, EFF increased the somatostatin serum levels, while the gastrin serum levels were proportionally decreased. Phytochemical investigation on HEL and EFF led to the isolation of flavonoids glycosides as the main compounds, thus suggesting that these substances may be involved in the observed antiulcer activity. (c) 2005 Elsevier B.V.. All rights reserved.

Antiulcerogenic effect and cytotoxic activity of semi-synthetic crotonin obtained from Croton cajucara Benth.

Trans-dehydrocrotonin, the major diterpene isolated from the bark of Croton cajucara, has good antiulcerogenic activity which, however, is accompanied by toxic effects. on the basis of these results, a semi-synthetic crotonin, named 4SRC, was prepared to determine whether this substance has similar antiulcerogenic activity with lower or no toxicity. The natural crotonin was also isolated from the bark of C. cajucara but was not used due to the small amount obtained. The cytotoxic effect of semi-synthetic crotonin, expressed as cell viability, was assessed in (a) lung fibroblast cell line (V79) derived from Chinese hamsters, a system commonly used for cytotoxicity studies, and (b) rat hepatocytes isolated from male Wistar rats. After treatment, cell viability was determined by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide reduction (MTT reduction), total acid content and neutral red uptake assays. To evaluate V79 cell viability, different concentrations of semi-synthetic crotonin were incubated with the cells. To evaluate the antiulcerogenic effects of semi-synthetic crotonin (50, 100 and 200 mg/kg), we used the models of gastric ulcer induced by ethanol/HCl, stress, indomethacin/bethanechol, and ethanol in male Swiss mice and male Wistar rats. The substance had an IC50 = 500 muM in the neutral red uptake and MTT reduction tests and an IC50 = 200 muM in the nucleic acid content test. With regard to hepatocyte viability after treatment with semi-synthetic crotonin at different concentrations, semi-synthetic crotonin had an IC50 = 10-500 muM in the nucleic acid content and MTT reduction tests and an IC50 = 120 muM in the neutral red uptake test. In another experiment, V79 cells were incubated with the metabolites produced by hepatocytes treated with different concentrations of semi-synthetic crotonin. After a 4-h incubation, semi-synthetic crotonin had an IC50 = 500 muM in the MTT reduction and neutral red uptake tests and an IC50 = 370 muM in nucleic acid content test. The substance had significant antiulcerogenic activity in all models studied, suggesting the presence of a possible antisecretory effect combined with a cytoprotective effect. For this reason, the effect of semi-synthetic crotonin was also evaluated on biochemical parameters of gastric juice and gastric wall mucus, both obtained from pylorus-ligated mice. No significant differences were observed in these parameters between semi-synthetic crotonin-treated and control animals. The results obtained with semi-synthetic crotonin are promising, with a significant preventive effect against gastric ulcer induced by different agents. Our data also show that semi-synthetic crotonin was less toxic than dehydrocrotonin and that the cytotoxic effects decreases with the time that isolated hepatocytes were in culture. (C) 2003 Elsevier B.V. B.V. All rights reserved.

Qualea grandiflora, a Brazilian Cerrado medicinal plant presents an important antiulcer activity

Qualea grandiflora is one of the species widely used in folk medicine to treat gastric ulcers in Cerrado of the central region of Brazil. The hydroalcoholic extract of bark (HE) of Qualea grandiflora was investigated for their ability to prevent and heal lesions in the gastric mucosa. The oral administration of HE exhibited antiulcer activity decreasing the ulcerative index induced by HCl/ethanol solution, indomethacin/bethanechol and stress. In the Shay model, results showed that HE (p.o.) only reduced the severity of gastric lesions without effects on pH, gastric acidity or volume. When given by intraduodenal route, HE changed the pH, but did not modify the other parameters of the gastric juice. These data were in accordance with those obtained when HE was administered orally for 14 days after gastric ulcers were induced by acetic acid in rats. HE presented healing process in subacute gastric ulcer induced by acetic acid in rats. Moreover, histological examinations showed the simple columnar epithelium, lamina propria with simple branched tubular glandules with dilated lumen and large amounts of mucus secretion. Phytochemical investigation of HE led to the detection of terpenes, steroids, saponins, phenolic compounds and tannins in this extract, which may be involved in the observed activity. (c) 2005 Elsevier B.V.. All rights reserved.

Effect of essential oil obtained from Croton cajucara Benth. on gastric ulcer healing and protective factors of the gastric mucosa

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The gastroprotective effect of the essential oil of Croton cajucara is different in normal rats than in malnourished rats

It has been shown previously that malnourished rats are resistant to acute gastric lesions but not to subchronic gastric ulceration. It also has been demonstrated that the essential oil obtained from the bark of Croton cajucara (Sacaca) has antiulcer properties. In the present study, the ability of this essential oil to prevent the formation of gastric ulcers in rats fed a diet with 17 % protein (normoproteic rats) or 6 % protein (malnourished rats) was investigated. At a dose of 100 mg/kg body weight, orally, the essential oil significantly reduced the gastric injury caused by indomethacin (25 % after 2 h and 70 % after 4 h) only in normoproteic rats. In the pylorus ligature model, the essential oil increased the pH and gastric volume, but decreased the total acid concentration in both groups when compared to the respective control group. The essential oil significantly increased prostaglandin E2 production in glandular cells by 50 % compared to the controls in both groups of rats. In addition, the amount of gastric mucus was two-fold higher in malnourished rats than in normoproteic rats. The present results show that the enhanced protective effect of essential oil in malnourished rats involved an increase in prostaglandin E2 production and mucus secretion, which are both factors that protect the gastric mucosa against damage. In agreement with this, malnourished rats always had a lower number of acute gastric ulcers.

Gastroprotective mechanisms of Citrus lemon (Rutaceae) essential oil and its majority compounds limonene and beta-pinene: Involvement of heat-shock protein-70, vasoactive intestinal peptide, glutathione, sulfhydryl compounds, nitric oxide and prostaglandin E-2

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Hancornia speciosa: Indications of gastroprotective, healing and anti-Helicobacter pylori actions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)