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

Ethnopharmacological relevance: Strychnos pseudoquina St. Hil. (Loganiaceae) is one Brazilian native medicinal species described in the first edition of the Brazilian Official Pharmacopoeia in 1929. This medicinal plant, popularly known as quina-quina, quina-branca or casca aromatica was very commonly used in folk medicine in tea form obtained from the bark and/or leaves as tonic, antipyretic, antimalarial and mainly against diseases of the liver, spleen and stomach.Aim of the study: Previous study already characterized the gastroprotective action of this species The aim of the present study is to elucidate the mechanism of the healing process mediated by the methanolic extract (ME) and their enriched alkaloid fraction (EAF) from Strychnos pseudoquina in chronic gastric ulceration induced by 5% acetic acid in rats, an experimental model that accurately reflects human gastrointestinal disease.Material and methods: The ME and EAF was administered orally in a single dose (based on previously study of dose-response curve) for 14 days after chronic ulceration was induced in rats. The healing effect of ME and EAF was evaluated by macroscopic and morphometric analyses, immunohistochemical assay (PCNA and SOD) and anti-Helicobacter pylori effect was evaluated by in vitro assay.Results: Our results demonstrated that EAF significantly reduced border internal (42%) and external (38%) lesion area (mm(2)) by macroscopic analyses (P <0.05). Animals treated with EAF stimulated some proliferative factors by increasing the height of epithelial regenerative area and the expression of PCNA-positive nuclei. The number of vessels in gastric mucosa of rats treated with EAF reveals an expressive increase (4 times more than vehicle treatment) of vessels that stimulate cells proliferation in the healing region. These results suggest that the recovery of vascularization of the ulcerated area is involved in the healing action of alkaloid fraction of Strychnos pseudo quina. The MIC (minimum inhibitory concentration) of 75 mu g/ml from EAF showed an effective in vitro anti-Helicobacter pylori action of this fraction. EAF also was quite effective in the process of SOD release that is an important protective factor against bacterial agents. The efficacy of EAF was accomplished safely without presenting any alteration of toxicological parameters during 14 day of treatment.Conclusions: The expressive gastric healing effect by increasing cellular proliferation together with expression of SOD activity and antibacterial action against Helicobacter pylori confirm the efficacy of this species in heal gastric mucosa and these results are a important contribution to the knowledge of a crude drug presents at the Brazilian Official Pharmacopoeia since 1929. (C) 2011 Elsevier B.V. All rights reserved

Indigofera suffruticosa Mill as new source of healing agent: Involvement of prostaglandin and mucus and heat shock proteins

Ethnopharmacological relevance: Indigofera suffruticosa is specie typical of the Cerrado or Brazilian savannah; it is a member of the Fabaceae family - in folkmedicine is used for gastric disorders, infection and inflammation.Aim of the study: Ethyl acetate fraction (AcF) and aqueous fraction (AqF) of the methanolic extract of I. suffruticosa leaves were evaluated against acute gastric ulcer. The AcF fraction was selected to assess its activity in ulcer healing and its gastroprotective effects via mucus and gastric secretion.Materials and methods: The gastroprotective action of AcF and AqF fractions were evaluated in a rodent experimental model. The action mechanisms, involvements of the antisecretory action, mucus and prostaglandin production, toxicological and healing activity of the AcF (100 mg/kg, p.o.) were evaluated. We also used histological analysis (HE and PAS) and immunohistochemical (PCNA and HSP-70) assays to evaluate the effects of I. suffruticosa.Results: AcF significantly inhibited the gastric mucosal damage caused by ethanol. This effect was statistically significant in 100 mg/kg group compared vehicle. AcF did not interfered with gastric secretion, significantly increased the PGE(2) and mucus production (validated in PAS technique). The gastroprotection was attenuated by pretreatment with N-ethylmaleimide, but not L-NAME. In acid-acetic-induced ulcer model AcF accelerated ulcer healing. Immunohistochemistry analysis showed induction of proliferating cell (PCNA) and heat shock protein (HSP 70).Conclusions: These results showed that AcF acted as gastroprotective agent stimulating prostaglandin, mucus and HSP70. (C) 2011 Elsevier B.V. All rights reserved

Mechanisms of action underlying the gastric antiulcer activity of the Rhizophora mangle L.

Ethnopharmacological relevance: Rhizophora mangle, the red mangrove, has long been known as a traditional antiulcer medicine. The present work evaluated the mechanisms of action involved in the anti-ulcer properties of the Rhizophora mangle bark extracts.Materials and methods: Gastroprotection of Rhizophora mangle was evaluated in rodent experimental models (ethanol). To elucidate the mechanisms of action the antisecretory action and involvement of NO, SH, mucus and PGE(2) were evaluated. The acetic acid-induced gastric ulcer model. Western blotting assay (COX-1, COX-2 and EGF) and immunohistochemical localization of HSP-70, PCNA and COX-2 were also used to evaluate the Rhizophora mangle healing properties.Results: Results showed that Rhizophora mangle bark crude extract (CE), as well as ethyl acetate (EtOAc) and butanolic fractions (BuOH) provided significant gastroprotection at all the tested doses. Thereby, the following protocols were performed using the lowest dose capable of producing the most effective gastroprotection, which was the BuOH 0.5 mg/kg (P<0.001). Several mechanisms are involved in the antiulcer activity of Rhizophora mangle, such as, participation of NO, SH and mucus. The enhancement of PGE2 levels and the upregulation of COX-2 and EGF seem to be directly linked to the antisecretory, cytoprotective and healing effects of BuOH. HSP-70 and PCNA are also involved in this cicatrisation process. No sign of toxicity was observed in this study, considering the analyzed parameters.Conclusion: Our study reinforces its traditional medicinal use. Considering that the current therapies are based on the use of antisecretory or cytoprotective drugs, the Rhizophora mangle arises as a promising alternative antiulcer therapy. (C) 2011 Elsevier B.V. All rights reserved