title: Antioxidant activities and triterpenoids isolated from Alternanthera brasiliana (L.) Kuntze leaves.
abstract: The species Alternanthera brasiliana (L.) Kuntze (Amaranthaceae) is a perennial herbaceous plant widely distributed in Brazil's eastern beaches and certain Amazonian regions. Crude ethanolic (70%) extract, fractions (dichloromethane, ethyl acetate and n-butanolic) and the mixture isolated were investigated regarding their content of total phenolic compounds by Folin-Ciocalteau assay. Total phenolic contents varied from 29.0 to 56.6 mg/g (dry fraction). The scavenging capacity of the extract, fractions and mixture isolated was characterised by the 1,1-diphenyl-2-picrylhydrazyl method. Only ethyl acetate fraction exhibited a modest scavenging capacity (SC50 = 163.00 μg/mL and SC% = 64.29% at 250 μg/mL) in a dose-dependent manner. Crude extract, dichloromethane and butanolic fractions presented a very weak scavenging capacity (SC% ≤ 40% at 250 μg/mL). A correlation between the antioxidant activity and the total phenolic contents could not be observed. The fractionation and purification of dichloromethane fraction evidenced the presence of a mixture of β-sitosterol, stigmasterol and spinasterol, which was identified by NMR methods and compared with literature data. Results of this study demonstrated for the first time the antioxidant activity of A. brasiliana.
authors.affiliation: a Phytochemical Research Laboratory, Department of Industrial Pharmacy , Federal University of Santa Maria , Build 26, Room 1115 , Santa Maria , RS , 97105-900 , Brazil.
authors.forename: D F
authors.initials: DF
authors.lastname: Pereira
authors.forename: R B
authors.initials: RB
authors.lastname: Zanon
authors.forename: M
authors.initials: M
authors.lastname: Dos Santos
authors.forename: A A
authors.initials: AA
authors.lastname: Boligon
authors.forename: M L
authors.initials: ML
authors.lastname: Athayde
mesh_terms: D027703:Amaranthaceae / Q000737:chemistry*; D000975:Antioxidants / Q000737:chemistry; D010636:Phenols / Q000737:chemistry; D018515:Plant Leaves / Q000737:chemistry*; D014315:Triterpenes / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D010636:Phenols; D014315:Triterpenes