Investigation of Bolivian plant extracts for their radical scavenging activity and antioxidant activity Irene Parejo a , Francesc Viladomat a , Jaume Bastida a , Alfredo Rosas-Romero b , Gloria Saavedra c , M. Antonia Murcia d , Antonia M. Jime ´nez d , Carles Codina a, * a Departament de Productes Naturals, Biologia Vegetal i Edafologia, Facultat de Farma `cia, Universitat de Barcelona, Avda. Joan XXIII s/n, 08028 Barcelona, Spain b Departamento de Quı ´mica, Universidad Simo ´n Bolı ´var, Apartado 89000, Caracas 1080A, Venezuela c Centro de Tecnologı ´a Agroindustrial, Facultad de Ciencias y Tecnologı ´a, Universidad Mayor de San Simo ´n, Cochabamba, Bolivia d Area de Nutricio ´n y Bromatologı ´a, Facultad de Veterinaria y Ciencia y Tecnologı ´a de Alimentos, Campus de Espinardo, 30100 Murcia, Spain Received 6 January 2003; accepted 11 March 2003 Abstract Fifty-four different extracts of nine Bolivian plants belonging to the family Asteraceae were evaluated for their radical scavenging activity by the DPPH Á , NBT/hypoxanthine superoxide, and Á OH/luminol chemiluminescence methods, and for their antioxidant activity by the h-carotene bleaching test. The total phenolic content was also determined by the Folin-Ciocalteu method, and the oxidative stability by the Rancimat test. Both remarkably high phenolic content and radical scavenging and antioxidant activities were found mainly in the ethyl acetate fractions among the different plant extracts. Some ethyl acetate and even some defatted crude extracts exhibited activities comparable to those of commercial extracts/compounds, thus making it possible to consider some of the studied plants as a potential source of antioxidants of natural origin. D 2003 Elsevier Inc. All rights reserved. Keywords: Antioxidant activity; Asteraceae; Bolivia; Oxidative stability; Plant extracts; Radical scavenging activity; Rancimat; Total phenolic content 0024-3205/03/$ - see front matter D 2003 Elsevier Inc. All rights reserved. doi:10.1016/S0024-3205(03)00488-0