Introduction. Antioxidants have shown chemopreventive potential in degenerative, inflammatory, autoimmune, oncology and respiratory distress associated pathologies. Objective. To assess the phytochemical and antioxidant properties in vitro by DPPH and ABTS method. Design. Observational analytical. Location. Laboratory of Experimental Pharmacology, Faculty of Medicine, Universidad Nacional Mayor de San Marcos, Lima, Peru. Biological/Chemical Material. Aloe vera leaves, Plukenetia volubilis seeds, Caiophora carduifolia leaves-stalks, Cecropia membranacea leaves. Interventions. Observation and analysis of the antioxidant capacity by DPPH-method mean effective concentration (EC50) of the extracts and trolox equivalent antioxidant capacity by the ABTS method. Main outcome measures. Phytochemical preliminary march, antioxidant percent uptake inhibition by DPPH radical, determination of equival...