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 pseudoquina. The MIC (minimum inhibitory concentration) of 75 μg/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.

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

ETHNOPHARMACOLOGICAL RELEVANCE

Qualea parviflora Mart. is a medicinal species commonly found in the Brazilian Cerrado biome.

AIM OF THE STUDY

Based on ethnopharmacological data, methanolic extract from Qualea parviflora (QP) bark was evaluated for its antiulcer, analgesic, anti-hemorrhagic, mutagenic and anti-Helicobacter pylori activities.

MATERIAL AND METHODS

The gastroprotective action of the extract was evaluated in rodent experimental models (HCl/ethanol, ethanol or NSAID). We also evaluated mutagenic effect (Ames assay), anti-Helicobacter pylori, anti-hemorrhagic action, analgesic and inflammatory effects (hot-plate test and carrageenin-induced hind paw edema) of methanolic extract from Qualea parviflora.

RESULTS

QP (500 mg/kg, p.o.) was able to protect gastric mucosa against HCl/ethanol solution (77%), absolute ethanol (97%), and also against injurious effect of NSAID (36%). When QP was challenged with sulfhydryl depletor compound, the gastroprotective action of extract was abolished. QP treatment was able to maintain the GSH level and show a concentration-dependent inhibition effect on the lipid peroxidation. QP present anti-Helicobacter pylori effect (MIC=75 microg/mL), anti-hemorrhagic and antidiarrheal action but not present analgesic or anti-inflammatory effect.

CONCLUSION

methanolic extract from Qualea parviflora had gastroprotective effect related to the increase of gastric mucosa defensive factors such PGE(2) levels and maintain the basal gastric glutathione levels. The methanolic extract also showed anti-Helicobacter pylori activity, anti-hemorrhagic effect and antioxidant action, but absence of analgesic, mutagenic and toxic effects, a profile that adds safety to its use.

The anti-ulcerogenic effects of Curatella americana L

ETHNOPHARMACOLOGICAL RELEVANCE

Curatella americana L. (Dilleneaceae) is a medicinal plant very frequently cited as acting against gastrointestinal disorders in ethnopharmacological inventories of the Cerrado region of Brazil.

AIM OF THE STUDY

The ethanolic extract (CEB) and infusion (BI) of Curatella americana bark were investigated for their ability to prevent and heal ulceration of the gastric mucosa.

MATERIALS AND METHODS

The preventive and healing actions of Curatella americana were evaluated in experimental in vivo models in rodents that simulated this disease in human gastric mucosa.

RESULTS

CEB significantly decreased the severity of gastric damage formation induced by the combination of several gastroprotective models (HCl/ethanol, indomethacin/bethanecol, absolute ethanol, stress and pylorus ligature). But, unlike CEB, the BI did not exert gastroprotective effect. The gastroprotective action of CEB involved antisecretory action, augmentation of gastric mucus (48%) and participation of endogenous sulfhydryl compounds that increase efficacy of barrier mucosa against injurious agents. CEB also presents effective healing action in chronic gastric disease (1.90+/-0.55 vs. 6.86+/-0.46 mm2)in the control) and its action mechanisms consisted of increasing the PGE2 (40%) and somatostatin levels (269%) while decreasing the gastrin level in rat plasma (79%).

CONCLUSIONS

The gastroprotective effect and healing action of Curatella americana involved modulation of PGE2, somatostatin and gastrin levels, probably due to the presence of oligomeric and polymeric proanthocyanidins in the bark.