Larrea divaricata Cav. enhances the innate immune response during the systemic infection by Candida albicans

Larrea divaricata Cav. is a plant used in Argentinean folk medicine. The aim of this work was to evaluate the effect of a purified fraction (F1) obtained from an extract of the plant on murine macrophages (MO) against a systemic infection by Candida albicans. Mice were divided in four groups: 1) healthy without treatment; 2) healthy with F1 treatment; 3) infected, without treatment; and 4) infected with F1 treatment. Peritoneal MO were harvested and the following tests were performed: Apoptosis, phagocytosis, hydrogen peroxide (H2O2) production, nitric oxide (NO) production, determination of seric TNF- aand IL-10 and toxicity of F1. Results showed that F1 increased phagocytosis, H2O2production, superoxide anion and NO levels in presence of C. albicans. These effects are probably due to a modulate mechanism of diverse receptors, such as TLR-2, Dectin-1, mannose receptor and CRs. Apoptosis and TNF-a levels were also increased by F1. The use of this fraction did not induce toxicity on mice. In conclusion, F1 induces a state of pre- activation of MOs, which is enhanced by the presence of C. albicans. The lack of toxicity in addition with the immunomodulatory action becomes F1 a potential safe treatment of disseminated candidiasis.   Key words: Larrea divaricata, fraction, macrophages, disseminated candidiasis, immunomodulatory activity.