Seasonal variation of anticandidal activity of Zuccagnia punctata Cav. (Fabaceae) DCM exudate and quantification of active and analytical markers in each period of the year.

BUTASSI, E.; SVETAZ, L.; FERESIN, G.; TAPIA, A.; ZACCHINO, S.

Puerto Varas

Congreso; XIV International Congress of Ethnopharmacology, VIII Simposio Internacional de Química de Productos Naturales y sus Aplicaciones.; 2014

The DCM of Zuccagnia punctata Cav. (Fabaceae), a monotypic species found in arid and semiarid areas of Argentina at 900-2200m osl [1]traditionally used for wound healing purposes [2] showed in previous studies antiCandida albicans activity, being 2(,4(-dihydroxychalcone (1) the active marker and 2(,4(-dihydroxy-3-methoxy chalcone (2) the analytical marker [3,4]. Studies on mechanism of action showed that Z. punctata exudate and its most active component have a different mode of action than the polyene and azole class existing drugs, since they did not disrupt membranes at concentrations as amphotericin B does and are fungicide and not fungistatic, an important difference with azoles [5]. In this work, we report the antifungal activity of Z. punctata exudate in the four seasons of a year against the clinically important C. albicans (Ca) and C. glabrata (Cg) strains by determining the minimum concentrations that inhibit 50, 80, 95 and 95 % growth (MIC50, MIC 80, MIC 90 and MIC 95). The different MICs were obtained from non-linear regression doseresponse curves of mixed-effects constructed for each extract with MixLow software from properly designed plates (in triplicate) in which 10 different extract concentrations (in sextuplicate = 60 wells) were mixed with inoculum along with 36 control wells [5]. Results showed that the best effects were observed in the end of Spring (MIC50-MIC95 ranges 27.33- 38.01 9g/mL) and of Summer (28.63-39.96 9g/mL) for Ca. In turn, Cg was less sensitive with higher values of MIC ranging between 58.73 and 100.09 %, being the activities slightly higher in Summer. From the HPLC quantification of the two markers named above, it could be seen that the statistical differences in activity is not correlated with the active marker which maintain a statistical similar concentration in all seasons of the year. Synergism studies of the different principal compounds are in progress and will allow to determine the best proportion of them that could be correlated to the seasonal variation of the antifungal activity.