title: Study of the Gastroprotective Effect of Extracts and Semipurified Fractions of Chresta martii DC. and Identification of Its Principal Compounds.
abstract: Chresta martii (Asteraceae) is a species widely used by the population of the Xingu region of Sergipe, Brazil, in the form of a decoction (aerial parts) for the treatment of gastrointestinal diseases. The study aims to assess the gastroprotective activity of organic extracts and semipurified fractions and identify the principal compounds present in C. martii responsible for such activity. The organic extracts (cyclohexane: ECCm, ethyl acetate: EACm, and ethanol: EECm) were obtained from the dried aerial parts (500 g) of C. martii. For evaluation of the gastroprotective activity of extracts (50, 100, or 200 mg/kg; p.o.), male Swiss Webster mice (25-30 g) were used which had gastric ulcers induced by indomethacin (40 mg/kg, s.c.) or ethanol (0.2 mL/animal; p.o.). Among the extracts evaluated, EACm exhibited significant (P < 0.05) gastroprotective activity in the models used. The fractionation of EACm was performed in a silica gel column 60 eluted with the following compounds: [chloroform-F1 yield (10%)], [chloroform/ethyl acetate (1/1)-F2 yield (6%)], [ethyl acetate-F3 yield (8%)], and [ethyl/methanol acetate (1/1)-F4 yield (5%)]. Of the fractions described above, the F1 (25 mg/kg; p.o.) had greater gastroprotective activity (P < 0.05) than that displayed by ranitidine (80 mg/kg; p.o.) in the ethanol-induced ulcer model. The refractionation of F1 produced 23 subfractions and from these two yellow amorphous compounds were obtained by recrystallization, Rf: 0.46 and 0.31 (ethyl acetate : chloroform 5 : 5). The compounds isolated were characterized by nuclear magnetic resonance spectroscopy ((1)H-NMR and (13)C-NMR) and identified as flavones: chrysoeriol (yield: 0.43%) and 3',4'-dimethoxyluteolin (yield: 0.58%). Conclusion. Flavone 3',4'-dimethoxyluteolin is the principal compound present in the species C. martii and is probably responsible for gastroprotective activity observed in this species.
authors: Department of Physiology and Pharmacology, Laboratory of Pharmacology of Bioactive Products, Federal University of Pernambuco (UFPE), Recife, PE, Brazil.
authors: E S
authors: ES
authors: Franco
authors: Department of Parasitology, Laboratory of Mutagenesis and Research Center Aggeu Magalhães, Fiocruz Recife, PE, Brazil.
authors: M E B
authors: ME
authors: Mélo
authors: Department of Physiology and Pharmacology, Laboratory of Pharmacology of Bioactive Products, Federal University of Pernambuco (UFPE), Recife, PE, Brazil.
authors: B J A
authors: BJ
authors: Jatobá
authors: Department of Antibiotics, Laboratory of Chemistry of Natural Products, UFPE, Recife, PE, Brazil.
authors: A L B D
authors: AL
authors: Santana
authors: Sobral Laboratory of Pharmacology, Federal University of Ceará (UFC), CE, Brazil.
authors: A A R
authors: AA
authors: Silva
authors: Department of Antibiotics, Laboratory of Bioassays for Research on Drugs, UFPE, Recife, PE, Brazil.
authors: T G
authors: TG
authors: Silva
authors: Department of Antibiotics, Laboratory of Chemistry of Natural Products, UFPE, Recife, PE, Brazil.
authors: M S
authors: MS
authors: Nascimento
authors: Department of Physiology and Pharmacology, Laboratory of Pharmacology of Bioactive Products, Federal University of Pernambuco (UFPE), Recife, PE, Brazil.
authors: M B S
authors: MB
authors: Maia