ABSTRACT
Objective To investigate the secondary metabolites of fungus Engyodontium. album (E. album) associated with the South China Sea cucumber Holothuria nobilis (H. nobilis) Selenka. Methods The EtOAc extract of E. album was purified by repeated column chromatography on silica gel, Sephadex LH-20, and high-performance liquid chromatography (HPLC). Structures of the obtainedcompounds were determined by spectroscopic analysis and comparison with previously reported data. Results Five compounds were isolated and their structures were determined as: (22E, 2AR)-5a, 8«-epidioxy- ergosta-6, 22-dien-3β-ol (1), (22E, 24iR)-ergosta-5,7, 22-trien-3β-ol (2), (22E, 24iR)-ergosta-7, 22-dien-3β, 5α, 6β-triol (3), 3β, 5«-dihydroxy-(22E, 24iR)-ergosta-7, 22-dien-6-one (4), 3β, 5α-dihydroxy-6β-methoxy-ergosta-7, 22-dien (5). Conclusion This is the first report on the secondary metabolites of E. album associated with the sea cucumber H. nobilis Selenka, and the five compounds have been reported for the first time from the fungus E. album.
ABSTRACT
Objective: To study the constituents from the sea cucumber Holothuria nobilis. Methods: The compounds of the sea cucumber were separated by multi-chromatography and their structures were elucidated by physico-chemical and spectral analyses. Results: Two new triterpene glycosides were isolated and their structures have been deduced by extensive spectral analysis (IR, 2D-NMR, and ESI-MS) and chemical structures as 3-O-{3″″-O-methyl-β-D- glucopyranosyl-(1→3)-β-D-glucopyranosyl-(1→4)-β-D- quinovopyranosyl-(1→2)-4′-O-sulfate-β-D-xylopyranosyl} -holosta-22, 25-epoxy-9-ene-3β, 12α, 17α, 25β-tetraol- sodium salt (nobiliside I, 1) and 3-O-{β-D-quinovopyranosyl-(1→2) 4′-O-sulfate-β-D-xylopyranosyl}-holoshillaside 18 (16)-lactone-22, 25-epoxy-9-ene-3β, 12α, 17α-triol sodium (nobiliside II, 2). Conclusion: Two aglycons are both new compounds named nobiliside I and nobiliside II.
ABSTRACT
Objective Triterpene glycosides were expected to be isolated from the sea cucumber Holothuria nobilis.Methods The crude saponins of sea cucumber were desulfated with pyridine-dioxane(1∶1),the desulfated products were separated by multi-chromatography to afford two compounds.Results On the basis of chemical methods and spectral evidences,especially 2D NMR and ESI-MS technologies,these two compounds were identified as 3-O-(3-O-methyl-?-D-glucopyranosyl(1→3)-?-D-quinovopyranosyl(1→4)-?-D-quinovopyranosyl(1→2)-?-D-xylopyranosyl)-holosta-9-ene-3?,12?,17?,25?-tetraol(Ⅰ),named as nobiliside 1a;3-O-(3-O-methyl-?-D-glucopyranosyl(1→3)-?-D-xylopyranosyl(1→4)-?-D-quinovopyranosyl(1→2)-4′-O-sulfate-?-D-xylopyranosyl)-holosta-22,25-epoxy-9-ene-3?,12?,17?,25?-triol(Ⅱ),named as nobiliside 2a.Conclusion Two compounds are new triterpene glycosides.