Baoshu Liu

Antifungal triterpene glycosides from the sea cucumber Bohadschia marmorata.

Four new holostan-type triterpene glycosides, marmoratoside A ( 1), 17 alpha-hydroxy impatienside A ( 2), marmoratoside B ( 3), 25-acetoxy bivittoside D ( 4), together with two known triterpene glycosides, impatienside A ( 5) and bivittoside D ( 6), were isolated from the sea cucumber Bohadschia Marmorata Jaeger. On the basis of spectroscopic analyses, including two-dimensional NMR techniques, and chemical reactions, the structures of the new triterpene glycosides were elucidated. Compounds 1, 2, 5, and 6 exhibited significant antifungal activity against six strains (0.70 < or = MIC (80) < or = 2.81 microM).

Antifungal nortriterpene and triterpene glycosides from the sea cucumber Apostichopus japonicus Selenka

A nortriterpene glycoside, 26-nor-25-oxo-holotoxin A1 (1), four triterpene glycosides, including both holostane and non-holostane types analogues, holotoxins D-G (2-5), together with three known triterpene glycosides, holotoxins A1 and B (6, 7), and cladoloside B (8), were isolated from the warty sea cucumber Apostichopus japonicus Selenka, a traditional tonic with high economic value in China. The structures of the new compounds were elucidated by a combination of detailed spectroscopic analysis and chemical methods. This is the first report of a nortriterpene glycoside isolated from sea cucumbers. These compounds showed potent antifungal activities in the in vitro biotest. A preliminary structure-activity analysis suggests that the 18(20) lactone group and the Δ(25) terminal double bond may increase the activity. The component of the carbohydrate chain seems play an important role whereas the double bond transformation from Δ(9(11)) to Δ(7) in the aglycone moiety contributes little to the bioactivity.

Bioactive 11,20-Epoxy-3,5(16)-diene Briarane Diterpenoids from the South China Sea Gorgonian Dichotella gemmacea

Seven new briarane diterpenoids, gemmacolides G-M (1-7), were isolated together with two known analogues, juncin O and junceellolide C, from the South China Sea gorgonian Dichotella gemmacea. The structures of the new compounds were elucidated by detailed analysis of spectroscopic data and comparison with reported data. In an in vitro bioassay, these compounds exhibited different levels of growth inhibition activity against A549 and MG63 cells. In particular, compound 4 was more active than the positive control adriamycin against A549 cells. Compounds 4 and 7 also exhibited weak antimicrobial activity against the bacterium Bacillus megaterium and the fungus Septoria tritici, respectively.

Argusides D and E, Two New Cytotoxic Triterpene Glycosides from the Sea Cucumber Bohadschia argusJaeger

Two new triterpene glycosides, argusides D and E (1 and 2, resp.), have been isolated from the sea cucumber Bohadschia argus Jaeger collected in the South China Sea. Their structures have been established by spectral analysis (ESI‐MS, and 1D‐ and 2D‐NMR) and chemical evidence. Compounds 1 and 2 both possess an holostane‐type triterpene aglycone with a C(9)C(11) bond, an OH group at C(12), and tetrasaccharide moieties, but differ in the side chains. The two glycosides exhibited significant cytotoxicities against four human tumor cell lines, A549, HCT‐116, HepG2, and MCF‐7.

Bioactive polyoxygenated steroids from the South China sea soft coral, Sarcophyton sp.

Seven new polyoxygenated steroids (1–7) were isolated together with seven known analogues (8–14) from the South China Sea soft coral, Sarcophyton sp. The structures of the new compounds were identified on the basis of extensive spectroscopic analysis and comparison with reported data. All the steroids are characterized with 3β,5α,6β-hydroxy moiety, displaying carbon skeletons of cholestane, ergostane, gorgostane and 23,24-dimethyl cholestane. In the in vitro bioassay, metabolites exhibited different levels of antimicrobial activity against bacterial species Escherichia coli and Bacillus megaterium, and fungal species Microbotryum violaceum and Septoria tritici. No inhibition was detected towards microalga Chlorella fusca. Preliminary structure-activity analysis suggests that the 11α-acetoxy group may increase both antibacterial and antifungal activities. The terminal-double bond and the cyclopropane moiety at the side chain may also contribute to the bioactivity.

Bioactive (3Z,5E)-11,20-epoxybriara-3,5-dien-7,18-olide diterpenoids from the South China Sea gorgonian Dichotella gemmacea.

Six new (3Z,5E)-11,20-epoxybriara-3,5-dien-7,18-olide diterpenoids, gemmacolides N–S (1–6), were isolated together with four known analogues, juncenolide D, and juncins R, S and U (7–10), from the South China Sea gorgonian Dichotella gemmacea. The structures of the new compounds were elucidated by the detailed analysis of spectroscopic data in combination with the comparison with reported data. The absolute configuration of 1 was determined by a TDDFT calculation of its solution ECD spectrum, affording the determination of absolute configuration of other analogues by simply comparing their ECD spectra with that of 1. The cytotoxic and antimicrobial activities of these compounds were evaluated. In preliminary in vitro bioassays, compounds 4, 5, 6, 8 and 9 showed cytotoxicity against A549 and MG63, while compounds 1, 2, 4, 7–10 showed antimicrobial activity against the fungus Septoria tritici and the bacterium Escherichia coli.

A Novel Sulfated Holostane Glycoside from Sea Cucumber Holothuria leucospilota

A new sulfated holostane glycoside, leucospilotaside B (1), together with the two related structurally known compounds holothurin B2 (2) and holothurin B (3), was isolated from sea cucumber Holothuria leucospilota collected from the South China Sea. The structure of 1 was elucidated by spectral analysis (1H‐, 13C‐, and 2D‐NMR, ESI‐MS, and HR‐ESI‐MS) and chemical methods. The compounds 1–3 possess the same disaccharide moiety, but were different in the side chains of the triterpene aglycone. Compound 1 showed significant cytotoxicities against four human tumor cell lines, HL‐60, MOLT‐4, A‐549, and BEL‐7402.

Tumor cell growth inhibitory activity and structure–activity relationship of polyoxygenated steroids from the gorgonian Menella kanisa

Fourteen new polyoxygenated steroids (6, 9, 14-18, 20-23, 25-27) having carbon skeletons of cholestane, ergostane, and 24-norcholestane, were isolated together with thirteen known analogues (1-5, 7, 8, 10-13, 19, 24) from the South China Sea gorgonian Menella kanisa. The structures of the new compounds were elucidated by detailed analysis of spectroscopic data and comparisons with reported data. This is the first report of chemical investigation on the title gorgonian. Compounds 12 and 13 were reported for the first time from natural sources. These compounds exhibited different levels of growth inhibition activity against A549 and MG-63 cell lines in bioassay in vitro. Preliminary structure-activity analysis revealed an important role of side chain in the activity. A substitution of a 5α-hydroxy or an oxidation of 6β-hydroxy to a ketone carbonyl group may decrease the activity whereas the contribution of the 1-ketone group remains uncertain.

Chemistry and Tumor Cell Growth Inhibitory Activity of 11,20-Epoxy-3Z,5(6)E-diene Briaranes from the South China Sea Gorgonian Dichotella gemmacea

Eighteen new 11,20-epoxy-3Z,5E-dien briaranes, gemmacolides AA–AR (1–18), were isolated together with three known analogs, dichotellides F (19) and I (20), and juncenolide C (21), from the South China Sea gorgonian Dichotella gemmacea. The structures of the compounds were elucidated by detailed spectroscopic analysis and comparison with reported data. The absolute configuration was determined based on the ECD experiment. In the in vitro bioassay, compounds 1–3, 5, 6, 8–12, and 14–19 exhibited different levels of growth inhibition activity against A549 and MG63 cell lines. Preliminary structure-activity analysis suggests that 12-O-isovalerate may increase the activity whereas 13- or 14-O-isovalerate may decrease the activity. Contribution of substitutions at C-2 and C-16 remains uncertain.

Triterpene Glycosides from Sea Cucumber Holothuria leucospilota

Abstract Aim To find new bioactive triterpene glycosides from the sea cucumber Holothuria leucospilota . Methods Column chromatography on silica gel and ODS RP-C 18 and HPLC were used for the isolation and purification of triterpene glycosides, and their structures were elucidated on the basis of spectral data and chemical evidence. Results Seven triterpene glycosides were isolated from the sea cucumber H. leucospilota , and identified as leucospilotaside A ( 1 ), leucospilotaside B ( 2 ), leucospilotaside C ( 3 ), holothurin B ( 4 ), holothurin B 2 ( 5 ), echinoside B ( 6 ), and holothurin A ( 7 ). Conclusion Compound 2 is a new triterpene glycoside, and compounds 1, 3, 5 and 6 have been isolated from this sea cucumber for the first time.