Xiao-Jian Liao

Oryzamides A–E, Cyclodepsipeptides from the Sponge-Derived Fungus Nigrospora oryzae PF18

Three new cyclohexadepsipeptides, oryzamides A-C (1-3), two isolation artifacts, oryzamides D (4) and E (5), and the known congener scopularide A (6), all possessing a rare 3-hydroxy-4-methyldecanoic acid (HMDA) substructure, were isolated from the mycelial extract of the sponge-derived fungus Nigrospora oryzae PF18. Their planar structures were elucidated by spectroscopic analysis and comparison with the literature data. The absolute configurations were determined using the advanced Marfeys method and single-crystal X-ray diffraction analysis. Among them, oryzamides D (4) and E (5) were a pair of diastereomers at the sulfur atom of the l-methionine sulfoxide residue, which showcased the possible separation of a pair of methionine sulfoxide diastereomers. The X-ray crystal structure of scopularide A (6) was obtained for the first time, thereby establishing its relative and absolute configuration at C-4 of the HMDA residue. Oryzamides A-C (1-3) did not display cytotoxic, antibacterial, antiparasitic, and NF-κB inhibitory activities.

New Furan and Cyclopentenone Derivatives from the Sponge-Associated Fungus Hypocrea Koningii PF04

Two new furan derivatives, hypofurans A and B (1 and 2), and three new cyclopentenone derivatives, hypocrenones A–C (3–5), along with seven known compounds (6–12), were isolated from a marine fungus Hypocrea koningii PF04 associated with the sponge Phakellia fusca. Among them, compounds 10 and 11 were obtained for the first time as natural products. The planar structures of compounds 1–5 were elucidated by analysis of their spectroscopic data. Meanwhile, the absolute configuration of 1 was determined as 2R,3R by the comparison of the experimental and calculated electronic circular dichroism (ECD) spectra. All the isolates were evaluated for their antibacterial and antioxidant activity. Compounds 1, 10, and 12 all showed modest antibacterial activity against Staphylococcus aureus ATCC25923 (MIC, 32 μg/mL). In addition, compounds 1, 10 and 11 exhibited moderate DPPH radical scavenging capacity with IC50 values of 27.4, 16.8, and 61.7 µg/mL, respectively.

New Pentahydroxylated Steroids from the South China Sea Gorgonian Subergorgia suberosa

Two new pentahydroxylated steroids, (3β,12β,16β,23E)‐cholesta‐5,23‐diene‐3,12,16,20,25‐pentaol (1) and (3β,12β,16β)‐cholesta‐5,25(26)‐diene‐3,12,16,20,24‐pentaol (2), were isolated from the EtOH extract of the South China Sea gorgonian Subergorgia suberosa. In addition, four known steroids were detected. The structures of these compounds were established by spectroscopic methods and comparison of their data with those of the related known compounds. In addition, the cyctotoxicities of the compounds were evaluated against selected cancer cell lines.

Gliomasolides A–E, unusual macrolides from a sponge-derived fungus Gliomastix sp. ZSDS1-F7-2

Five unusual macrolides, gliomasolides A–E (1–5), were isolated from a sponge-derived fungus Gliomastix sp. ZSDS1-F7-2. Their structures were established by extensive spectroscopic analyses and single-crystal X-ray diffraction studies. Structurally in common, these compounds feature a very rare 14-membered macrocyclic backbone lacking of methyl group. Cytotoxic effect of these metabolites against the growth of HeLa cell lines was evaluated, revealing that 1 exhibited moderate inhibitory effect with an IC50 value of 10.1 μM.

Structurally diverse secondary metabolites from a deep-sea-derived fungus Penicillium chrysogenum SCSIO 41001 and their biological evaluation

Five new compounds, including a cytotoxic dimeric isocoumarin, bipenicilisorin (1), a merosesquiterpenoid, yaminterritrem C (2), a citrinin dimer, penicitrinone F (3), a alkaloid, terremide D (4), and a δ-valerolacton, (E)-4-(propen-1-yl)-5,6-dihydro-2H-pyran-2-one (5), along with ten known compounds (6-15) were isolated from a deep-sea-derived fungus Penicillium chrysogenum SCSIO 41001. Their structures and absolute configurations were elucidated by NMR spectra, MS, CD, optical rotation, X-ray crystallography, and compared with literature data. Biological evaluation results revealed that 1 exhibited significant cytotoxic activities against K562, A549, and Huh-7 cell lines with IC50 values of 6.78, 6.94, and 2.59μM, respectively. Compound 3 exhibited moderate inhibitory activity against EV71 with IC50 value of 14.50μM. In addition, 13 and 14 showed specific COX-2 inhibitory activities with IC50 values of 1.09 and 1.97μM, respectively.

9,11-Secosteroids with cytotoxic activity from the South China Sea gorgonian coral Subergorgia suberosa

Nine new 9,11-secosterols (1-9), containing the same 3β,6α,11-trihydroxy-9,11-seco-5α-cholest-7-en-9-one steroidal nucleus, whereas possessing an array of structurally diverse side chains, along with fourteen known 9,11-secosterol compounds (10-23), were isolated from the South China Sea gorgonian coral Subergorgia suberosa, of which 3/4, 5/6, 7/8, and the known compounds 11/12, 20/21 were five pairs of inseparable C-24 epimers. Their structures were established by the extensive analyses of 1D and 2D NMR spectra, high-resolution chemical ionization mass spectrometry (HRCIMS), and by the comparison with literature data. Cytotoxic effect of these metabolites against the growth of HeLa cell lines was evaluated. The result showed that the inhibitory effect of compounds 1-23 varied considerably depending on the nature of the side chain in spite of sharing the same steroidal nucleus. Compound 19, featuring both the absence of hydroxyl group and the presence of double bond in the stigmasterol side chain, exhibited the most potent cytotoxicity with IC50 being 15.1 μM. The preliminary structure activity relationship studies identified some important structural features considerably influencing the biological effect deserved, providing valuable information for chemists and pharmacologists to design and synthesize more effective antitumor agents bearing the 9,11-secosteroid framework.

Isolation of a new cytotoxic polyhydroxysterol from the South China Sea soft coral Sinularia sp.

Abstract A new polyhydroxysterol, (22E)-24-methylenecholestane-22-ene-3β,5α,6β-triol (1), together with four known analogues (2–5) were isolated from the South China Sea soft coral Sinularia sp. Their structures were elucidated by spectroscopic analyses and comparison with previously reported data. All these compounds exhibited cytotoxic effect against both HepG2 and HeLa cell lines with IC50 values ranging from 8.36 to 37.30 μM. Preliminary structure–activity relationship study identified that the presence of double bonds in the side chains of these polyhydroxysterols significantly reduced the biological effect obtained.

A new α-pyrone from the deep-sea actinomycete Nocardiopsis dassonvillei subsp. dassonvillei DSM 43111(T)

Abstract A new α-pyrone, nocapyrone S (1), together with five known compounds (2-6), were isolated from the deep-sea actinomycete Nocardiopsis dassonvillei subsp. dassonvillei DSM 43111(T). Their structures were determined by spectroscopic analyses. The absolute configuration of 1 was established by quantum approaches. Cytotoxic activity of 1 was evaluated against K562, MCF-7, SGC7901, A375, Hela, and HepG2 cell lines.

Aspergchromones A and B, two new polyketides from the marine sponge-associated fungus Aspergillus sp SCSIO XWS03F03

Abstract Two new polyketides, aspergchromones A (1) and B (2), together with five known compounds, secalonic acid D (3), noreugenin (4), (3S)-5-hydroxymellein (5), (4S)-6-hydroxyisosclerone (6), and (-)-regiolone (7), were isolated from the ethyl acetate extract of marine sponge-derived fungus Aspergillus sp. SCSIO XWS03F03. Their structures were elucidated by means of spectroscopic techniques (1D and 2D NMR, MS, UV, and IR). The absolute configurations of the new compounds were established by ECD calculations. Compound 3 showed moderate antimicrobial activity.

A new sesquiterpene from the gorgonian coral Menella sp.

Abstract A new sesquiterpene named menecubebane B (1) and a known analogue (2) were isolated from the gorgonian coral Menella sp. Their structures were elucidated by the extensive analyses of spectroscopic data and by the comparison with related literature. Cytotoxic effect against both Eca9706 and HeLa cell lines was evaluated, revealing 1 exhibited moderate cytotoxicity against the two cell lines involved with IC50 values being 20.8 and 30.6 μM, respectively.