ISOLATION of ANTIFUNGAL QUINOID DERIVATIVES from LEAVES of Pentacalia desiderabilis (Vell.) Cuatre. (Asteraceae) USING IONIC LIQUID in the MICROWAVE ASSISTED EXTRACTION

Abstract

In the present work, leaves of Pentacalia desiderabilis (Asteraceae) were subjected to extraction using aqueous 1-butyl-3-methylimidazolium bromide (BMImBr) in the microwave assisted extraction (MAE). The obtained extract was partitioned using CH2Cl2 and antifungal activity against Cladosporium cladosporioides and C. sphaerospermum of the organic phase was evaluated. Sequentially, this material was subjected to several chromatographic procedures to afford four quinoid derivatives identified as jacaranone (1), methyl-jacaranone (2), quinolacetic acid (3), and methyl 1-hydroxy-4-oxo-cyclohexaneacetate (4), being the first occurrence of compounds 2 – 4 in P. desiderabilis. Isolated quinoid derivatives were submitted to bioautography assay and the obtained results indicated that compounds 1 – 3 are active against Cladosporium cladosporioides (0.78, 12.5 and 12.5 μg, respectively) and C. sphaerospermum (3.13, 12.5 and 12.5 μg, respectively).