Memórias do Instituto Oswaldo Cruz
Print version ISSN 0074-0276
ALVES, Tânia Maria Almeida; KLOOS, Helmut and ZANI, Carlos Leomar. Eleutherinone, a novel fungitoxic naphthoquinone from Eleutherine bulbosa (Iridaceae). Mem. Inst. Oswaldo Cruz [online]. 2003, vol.98, n.5, pp. 709-712. ISSN 0074-0276. http://dx.doi.org/10.1590/S0074-02762003000500021.
The dichloromethane extract prepared from the underground parts of Eleutherine bulbosa (Miller) Urban (Iridaceae) showed strong activity in the direct bioautography assay with the phytopathogenic fungus Cladosporium sphaerospermum. This assay was used to guide the fractionation of this extract and allowed the isolation of four compounds: the new naphthoquinone eleutherinone[8-methoxy-1-methyl-1,3-dihydro-naphtho(2,3-c)furan-4,9 -dione] and the known compounds, previously isolated from this species, eleutherin [9-methoxy-1(R),3(S)-dimethyl-3,4-dihydro-1H-benzo(g)isochromene-5,10-dione], isoeleutherin [9-methoxy-1(R),3(R)-dimethyl-3,4-dihydro-1H-benzo(g)isochromene-5,10-dione], and eleutherol [4-hydroxy-5-methoxy-3(R)-methyl-3H-naphtho(2,3-c)furan-1 -one]. All quinonoid compounds showed strong antifungal activity in the bioautography assay at 100 µg/spot, while eleutherol was inactive.
Keywords : naphthoquinone; Eleutherine bulbosa; fungicide; medicinal plant; Cladosporium sphaerospermum.