CONICET | Buscador de Institutos y Recursos Humanos

Larrea divaricata Cav. (Zygophyllaceae) is a South American plant widely distributed in Argentina. In popular medicine it is used for treatment of tumors, inflammatory diseases, rheuma and fever. The aqueous extract of the plant present antitumoral, immunomodulatory, antimicrobial activities and antioxidant action on rat peroxidase of subamxilary glands. In this work the antioxidant activity "per se" of the aqueous extract and of the majority compound in the plant, nordihydroguaiaretic acid (NDGA) was determined using different spectrophotometry assays. It was evaluated the catalase (CAT), superoxide dismutase (SOD) activities and the inhibitory capacity of linoleic acid peroxidation (FTC) and the scavenger activity of the free radical dyphenylpicrilhydrazil (DPPH). NDGA content was determined by HPLC. Results were expressed as antioxidant medium effective concentration (EC50) for FTC and DPPH (NDGA content) or as Activity (U/ml) (Mean ± SEM) of three experiments made by triplicate. The NDGA content was 0.119 ± 0.018 g % of the dried weight of the plant (0.43 % W/W of dry extract). Antioxidant activity FTC: Extract EC50 : 26.3 ± 1.8 µg/ml (0.1 µg/ml) ; NDGA EC50:1± 0.08 µg/ml DPPH: Extract EC50: 13.18 ± 1 µg/ml (0.057 µg/ml); NDGA EC50 : 0.81± 0.05 µg/ml. CAT: extract: 0.1 µg/ml: 0.50 ± 0.01 10 µg/ml: 0.65 ± 0.02 ; 100 µg/ml: 1 ± 0.1; NDGA: 0.001 µg/ml: without activity; 0.01 µg/ml: 0.15 ± 0.01; 0.1 µg/ml: 2.26 ± 0,20; 0.5 µg/ml: 5.16 ± 0.5;. SOD: Extract: 0.1 µg/ml: 0.11 ± 0.05; 10 µg/ml: 0.90 ± 0.04; 100 µg/ml: 1.37 ± 0.08; 1000 µg/ml: 2±0.2; NDGA: 0.001 µg/ml: -3.8± 0.30; 0.01 µg/ml:-1.10± 0.01; 0.1 µg/ml: -0.5 ± 0.05; 1 µg/ml: 0.52±.0.05. The aqueous extract and the NDGA present antioxidant activity, nevertheless others compounds different from NDGA could be implicated in some antioxidant activities exerted by the extract