ABSTRACT Peptic ulcers are an important pathology, and the search for safer and more effective treatment methods is of paramount importance. In this study, we assess the gastroprotective effects of the hydroethanolic extract (HE) and ethyl acetate fraction (EAF) from Kalanchoe pinnata leaves against an ethanol/HCl-induced ulcer model in rats. The HE reduced gastric lesions by approximately 47% (400 mg/kg). A significant inhibition of the gastric lesions by 50% was observed after pretreatment with the EAF (200 mg/kg). Quercetrin and quercetin 3-O-α-L-arabinopyranosyl-(1→2)-α-L-rhamnopyranoside were isolated and identified in the flavonoid fraction (EAF) by HPLC and NMR analyses because this fraction showed the highest gastroprotective effect. This fraction demonstrated high antioxidant activities (CE50=41.91 µg/mL) by DPPH in comparison with Trolox(r) and 11.33 mmol Trolox(r) equivalent by ORAC. In conclusion, the HE and FAE from K. pinnata displayed gastroprotective activity in rats, most likely due to the presence of flavonoids.

A "carqueja", Baccharis trimera (Less) DC (Asteraceae), é uma espécie vegetal característica de regiões tropicais, muito utilizada na medicina popular como antiinflamatória, hipoglicemiante e em tratamento de problemas digestivos. A avaliação da atividade antiúlcera do extrato bruto liofilizado e do extrato liofilizado da "resina" (porção que durante a concentração dos extratos ficava depositada no fundo do recipiente com aspecto viscoso e pegajoso) foi realizada através de indução aguda por etanol acidificado. O extrato bruto liofilizado, na dose de 400 mg/ kg, reduziu a área de lesão em 90%, 200 mg/kg, 87%, 100 mg/kg, 66% e o fármaco controle (lansoprazol), 66%. O extrato liofilizado da "resina", administrado na dose de 400 mg/kg, reduziu a área de lesão em 82%, 200 mg/kg, 82%, 100 mg/kg, 53% e o fármaco controle (lansoprazol), 70%. A atividade antioxidante foi ensaiada com extrato bruto liofilizado, extrato liofilizado da "resina", pó da droga e frações clorofórmica, acetato de etila, etanol e etanol 50% através do método que reduz o radical 2,2'-difenil-1-picril-hidrazil (DPPH), permitindo após o equilíbrio da reação, calcular a quantidade de antioxidante gasta para reduzir 50% do DPPH, apresentando resultado evidente, comparado à vitamina E. Não foram verificados sinais de alteração aparente no ensaio de toxicidade na dose única de 5g/kg, em camundongos.

Baccharis trimera (Less) DC (Asteraceae) is a medicinal Brazilian plant well-known by "carqueja". Natural from tropical regions, used as home-made medicine as anti-inflammatory, hypoglycemiant and for the treatment of digestive problems. The evaluation of the antiulcer activity of the extract and the "resin" (portion which during the extracts concentration was settled at the bottom of the recipient, showing a viscous and clammy aspect), was accomplished through the acute induction by acidified ethanol. The lyophilized extract, at a dose of 400 mg/kg, reduced the lesion area at 90%; 200 mg/kg, at 87%; 100 mg/kg, at 66%; and the control (lansoprazol) at 66%. The "resin" administered at the 400 mg/kg dose reduced the lesion area at 82%; 200 mg/kg, at 82%, 100 mg/kg, at 53% and the control (lansoprazol), at 70%. The antioxidant activity of the lyophilized extract, of the "resin" of the powdered drug, of the chloroform, ethyl acetate, ethanol and 50% ethanol fractions was tested following the method which reduces the 2,2-dipheny l-1 -picrylhydrazyl (DPPH) radical, permitting after the reaction balance, to calculate the amount of antioxidant spent to reduce 50% of the DPPH. The result was meaningful, when compared with the vitamin E result. The acute toxicity test performed in mice showed no apparent alteration.