Screening de plantas de la flora Argentina en busca de extractos con actividad antifúngica en combinación con antifúngicos comerciales.

CORDISCO, E.; SORTINO, M.; SVETAZ, L.

Rosario

Congreso; 4ta Reunión Internacional de Ciencias Farmacéuticas (RICiFa); 2016

Fungal infections have increased dramatically in recent years. The number of antifungal drugs is limited and has several disadvantages. For these reasons, it is necessary to find alternative treatments. The aim of this work was to perform a screening of plant extracts from the Argentinean flora, which in combination with commercial antifungals, enhance their activity. Fifteen ethanol extracts were prepared from: Mikania periplocifolia Hook. & Arn., leaves, flowers and stems; Zanthoxylum coco Gillies ex Hook. f. & Arn., leaves, calices, fruits and stems; Ruprechtia laxiflora Meins., leaves; Muehlenbeckia sagittifolia (Ortega) Meisn., leaves; Gochnatia glutinosa (D. Don) Hook. & Arn., flowers, leaves and stems; Acacia caven (Molina) Molina, pods, leaves and stems. The antifungal activity of each extract alone was assessed using the broth microdilution method, against a panel of fungal species with clinical importance: five Candida spp., three Aspergillus spp., Cryptococcus neoformans and three species of dermatophytes. Extracts with MIC  1000 µg/mL were considered active. The extracts of Z. coco (leaves, calices and stems) and G. glutinosa (leaves and stems) were active against C. neoformans and dermatophytes, whereas no activity was observed against Candida and Aspergillus spp. To allow the rapid screening of the antifungal activity of extracts in combination with antifungals, the agar diffusion method was chosen. Extracts solutions were poured into the culture medium (final concentration MIC/2) and antifungals (caspofungin, voriconazole, itraconazole, fluconazole, posaconazole and amphotericin B at the concentration recommended by CLSI M44-A2 standard document), into paper disks. All combinations with voriconazole, except those of A. caven, showed a significant increase in activity. The inhibition zone diameter was increased between 6-21 mm according to the control extracts. These results constitute the starting point for the development of combinations useful for the treatment of human fungal infections. The selected combinations will be evaluated employing the checkerboard method to quantify the activity enhancement.