Synergistic mutual potentiation of antifungal activity of Zuccagnia punctata Cav. and Larrea nitida Cav. extracts in clinical isolates of Candida albicans and Candida glabrata

BUTASSI, ESTEFANÍA; SVETAZ, LAURA; IVANCOVICH, JUAN JOSÉ; FERESIN, GABRIELA; TAPIA, ALEJANDRO; ZACCHINO, SUSANA

PHYTOMEDICINE

ELSEVIER GMBH

Año: 2015 vol. 22 p. 666 - 678

0944-7113

Background: Zuccagnia punctata Cav. (Fabaceae) and Larrea nitida Cav. (Zygophyllaceae) are indistinctly or jointly used in traditional medicine for the treatment of fungal-related infections. Although their dichloromethane (DCM) extract have demonstrated moderate antifungal activities when tested on their own, antifungal properties of combinations of both plants have not been assessed previously. Purpose: The aim of this study was to establish with statistical rigor whether Z. punctata (ZpE) and L. nitida DCM extract (LnE) interact synergistically against the clinically important fungi Candida albicans and Candida glabrata and to characterize the most synergistic combinations. Study design: For synergism assessment, the statistical-based Boik?s design was applied. Eight ZpE?LnEfixedratio mixtures were prepared from four different months of 1 year and tested against Candida strains.L (Loewe index) of each mixture at different fractions affected (φ) allowed for the finding of the most synergistic combinations, which were characterized by HPLC fingerprint and by the quantitation of the selected marker compounds. Methods: L and confidence intervals were determined in vitro with the MixLow method, once the estimated parameters from the dose?respon (four flavonoids for ZpE and three lignans for LnE) were quantified in each extract and their combinations, with a valid HPLC?UV method. The 3D-HPLC profiles of the most synergistic mixtures were obtained by HPLC?DAD. Results: ThreeoverfourICφ50ZpE/IC50 LnE fixed-ratio mixtures displayed synergistic interactions at effect levels = 0.62) mixture was 65.96 μg/ml (ZpE = 28%; LnE = 72%) containing 8 and 36% of flavonoids and lignans respectively. On the other hand, one over four ICφ > 0.5 against C. albicans. The dosis of the most synergistic (L50ZpE/IC50φ LnE mixtures displays synergistic interactions at φ > 0.5 against C. glabrata. The dosis of the most synergistic (L = 0.67) mixture was 168.23 μg/ml (ZpE = 27%; LnE = 73%) with 9.7 and 31.6% of flavonoids and lignans respectively. Conclusions : Studies with the statistical-based MixLow method, allowed for the finding of the most ZpE?LnE synergistic mixtures, giving support to a proper joint use of both antifungal herbs in traditional medicine.