In vitro antifungal activity of cat's claw (Dolichandra unguis-cati L.) on fungal contaminants of grapes

APUD, G.R.; AREDES FERNANDEZ, P.A.; SAMPIETRO, D. A.; VATTUONE, M.A.; CATALAN,C.A.N.

Washington

Congreso; 68th ASEV National Conference; 2017

ASEV

Black rotis a disease caused by Aspergillus species, mainly Aspergillus niger and A.carbonarius. These fungi reduce the yield and the quality of grapes. Wine madewith rot fruit spoil its chemical and sensory properties. Synthetic fungicidesare commonly used for control of the Aspergillus species. They have severaladverse effects that do inappropriate their use. The aim of this work was toevaluate the in vitro antifungal activity of plant parts of Dolichandraunguis-cati on growth of Aspergillus niger and A. carbonarius. Fractions wereobtained from the plant leaves or stems by sequential extraction withdichloromethane (fCh2Cl2), ethyl acetate (fAcet) and methanol (fMeOH). Theywere assayed on conidial suspensions of A. niger and A. carbonarius by the microdilutionmethod in YES semiliquid medium (2500-2.4 ppm). The concentration of thefractions required to inhibit 50% of the fungal growth (IC50) were calculatedby probit analysis. Dot-blot bioautographies were carried out to establish theminimum inhibitory dose of fungal growth (MID). The composition of theinhibitoriest fraction was preliminarly investigated by TLC and the antifungalconstituents were detected by TLC bioautography. The fCh2Cl2 fraction from thestems showed the highest antifungal activity with IC50 values of 1025 and 1066ppm and DIM values of 625 and 1250 ìg on A. carbonarius and A. niger,respectively. TLC bioautographies indicated an inhibitory activity associatedto bands observed at Rf=0.70 and Rf=0.63 in the chromatograms observed underUV254nm. Further research is needed in order to separate and identified theseantifungal compounds.