Estudo químico dos metabólitos especiais de caule e folhas de Dulacia egleri (Rangel) Sleumer (Olacaceae) e atividade antifúngica

Abstract

The species Dulacia egleri belongs to the genus Dulacia, one of the representatives of the family Olacaceae, with about 13 species found only in South America. The species under study is endemic to Brazil, being popularly known as "rat-dick" and has as its main characteristic the strong odor of rotten onion coming from its leaves. This work describes the isolation and identification of the special metabolites of D. egleri, as well as its activity against fungal strains. The aromatic sesquiterpene eglerisine (I) and the nucleoside ribavirin (II) were isolated from the stem. The nucleosides ribavirin (II) and adenosine (V), the flavonoid 3-methoxy-6,7-methylenedioxy4'-hydroxyflavone (III) and the p-hydroxybenzoic acid (IV) were isolated from the leaves. In the evaluation of the antifungal potential the stem hexane residue (RHC) showed to be active against all the fungal strains tested (MIC: 31.5 to 125 μg/mL). The residues dichloromethane from the stem (RDC) and ethyl acetate from the stem (RAC) showed significant inhibition against C. albicans, C. krusei, C. tropicalis and C. neoformans with MIC ranging from 62.5 to 250 μg/mL and 31,5 to 125 μg/mL, respectively. The leaves ethyl acetate residue (RAF) was shown to be active against C. albicans (MIC: 62.5 μg/mL). The residues dichloromethane from the leaves (RDF) and hydromethanolic from the leaves (RHMF) were moderately active against all fungal strains tested with MIC ranging from 62.5 to 500 μg/mL. This study contributed significantly to the chemical and biological knowledge of the species under study.