Polyketides from Eleutherine bulbosa.

Four new polyketides, (R)-4-hydroxyeleutherin, eleuthone, eleutherinol-8-O-β-D-glucoside and isoeleuthoside C (dihydroisoeleutherin-5-O-β-D-gentiobioside) were isolated from the bulbs of Eleutherine bulbosa, to join eleutherin, isoeleutherin, eleutherinol, eleutherol, eleuthoside B (eleutherol-4-O-β-D-gentiobioside), eleuthoside C (dihydroeleutherin-5-O-β-D-gentiobioside), hongconin (4-oxodihydroisoeleutherin) and elecanacin, which have already been isolated from the same plant. The structures of the new polyketides, based on oxydated cyclic systems, have been elucidated by chemical and spectroscopic methods.