Eleutherinone, a novel fungitoxic naphthoquinone from Eleutherine bulbosa (Iridaceae).
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  g/spot, while eleutherol was inactive.
Alves
Tânia Maria Almeida
TM
Laboratório de Química de Produtos Naturais, Centro de Pesquisas René Rachou-Fiocruz, Belo Horizonte, MG, Brasil.
Kloos
Helmut
H
Zani
Carlos Leomar
CL
D000935:Antifungal Agents / Q000737:chemistry / Q000494:pharmacology*; D002963:Cladosporium / Q000187:drug effects*; D027621:Iridaceae / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D009285:Naphthoquinones / Q000737:chemistry / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology
D000935:Antifungal Agents; D009285:Naphthoquinones; D010936:Plant Extracts; C478365:eleutherinone