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Chemical composition screening of octocoral Briareum stechei , collected from Okinawan waters, led to the isolation of 10 briarane-type diterpenoids, including four previously-undescribed metabolites, briastecholides G–J (1 – 4), in addition to six known analogues, brianodin A (5), briarlides G (6) and P (7), and violides G, O, and P (8 – 10). The structures of 1 – 10 were elucidated by spectroscopic methods. Briastecholide D (1) was found to possess an unprecedented 10/6/5/5-fused tetracyclic scaffold. Furthermore, the stereochemistry of brianodin A (5) was elucidated directly by the single-crystal X-ray diffraction analysis for the first time in this study. Briaranes 2 and 5 – 8 reduced the release of iNOS to 17.01, 37.95, 28.76, 1.21 and 26.66%, respectively, at a concentration of 10 μM. [Display omitted] • Four new briaranes, briastecholides G–J (1 – 4) was isolated from an octocoral Briareum stechei. Briastecholide D (1) was found to possess a 10/6/5/5-fused tetracyclic scaffold. • The absolute configuration of brianodin A was confirmed by single-crystal X-ray diffraction analysis. • Briaranes reduced the release of iNOS. [ABSTRACT FROM AUTHOR]

[Display omitted] A novel cembranoid, (1 R ,7 R ,8 R ,11 R ,12 R)-7,8:11,12-bisepoxycembrene A (1), was isolated from an octocoral Sinularia sp. The structure of 1 was elucidated using spectroscopic methods, and its absolute configuration was confirmed by a single-crystal X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

During the chemical screening of the sea whip octocoral Junceella fragilis , five chlorine-containing briarane-type diterpenoids featuring with an s-cis -Δ3(E),5(16)-diene conjugated diene system, were discovered. Of these compounds, two are entirely novel entities: (−)-frajunolide H (1) and fragilide Y (2). Additionally, three known analogs were identified: fragilide P (3), junceellolide B (4), and junceellolide C (5). To determine the absolute structures of 1 and 3 , single-crystal X-ray diffraction analysis was utilized. On the other hand, 2D NMR experiments in combination with data from the literature enabled accurate verification of the structure of 2. Moreover, an evaluation of the conformations of previously-discovered briaranes such as frajunolide H and junceellolide B and C was carried out. Among these newly-discovered compounds, fragilide Y possessed anti-inflammatory activity that reduced the expression of cyclooxygenase-2 (COX-2) to 88.70% at a concentration of 10 μM. Altogether, this study yielded valuable information about the unique chemistry and promising pharmacological properties of chlorine-containing briarane diterpenoids from sea whip octocoral. [Display omitted] • Two new chlorine-containing briaranes, (−)-frajunolide H and fragilide Y, were isolated from Junceella fragilis. • The structures, including the absolute configurations, of (−)-frajunolide H and fragilide P, were determined by X-ray diffraction analysis. • The conformation of Δ3(E),5(16)-conjugated diene moiety in frajunolide H, junceellolides B and C, were revised. [ABSTRACT FROM AUTHOR]

Three new polyacetoxybriarane diterpenoids, briavioids A–C (1 – 3), as well as two known analogues, briaexcavatin M (4) and excavatolide F (5), were isolated from a cultured soft coral Briareum violaceum. The structures and relative stereochemistry of new metabolites 1 – 3 were assigned on the basis of NMR studies. Single-crystal X-ray diffraction analysis was performed to identify the structure of 1. Briaranes 1 – 5 were assessed in terms of their inflammation activity by screening their inhibition abilities against iNOS protein in LPS-stimulated RAW264.7 macrophage cells. [Display omitted] • Three previously-undescribed briaranes, briavioids A–C (1 – 3), were isolated from a cultured octocoral Briareum violaceum. • The structure of briavioid A was confirmed by a single-crystal X-ray diffraction analysis. • Excavatolide F reduced the release of iNOS. [ABSTRACT FROM AUTHOR]

[Display omitted] • An uncommon spiroketal steroid, 24-dehydrohippuristaol (1), was isolated from Isis hippuris. • 24-Dehydrohippuristaol is the first Δ24(28)-hippuristanol derivative. • 24-Dehydrohippuristaol showed cytotoxicity towards DLD-1 and LoVo cells. Chemical screening of a Formosan sea bamboo octocoral Isis hippuris have led to the isolation of nine spiroketal steroids, including a new metabolite, 24-dehydrohippuristanol (1), a new natural product, hippuristanol 11-one (2), as well as seven known analogs, hippuristanol (3), 22- epi -hippuristanol (4), hippurin-1 (5), 22- epi -hippurin-1 (6), 3-acetyl-22- epi -hippurin-1 (7), 3α-acetoxy-11β-hydroxy-24-methyl-22,25-epoxy-5α-furostan-18,20β-lactone (8) and (22 S)-3α-acetoxy-11β,18α-dihydroxy-24-methyl-18,20β;22,25-diepoxy-5α-furostane (9). The structures of steroids 1 – 9 were corroborated by 2D NMR experiments and comparison with literature data. The configurations of steroids 3 , 4 , 6 and 9 , obtained in previous studies, were reported for the first time in this study by single-crystal X-ray diffraction analysis. Steroid 1 exhibited cytotoxic effects against DLD-1 and LoVo cancer cells with IC 50 values of 5.54 and 6.89 μM, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • A rare 7β,8β-epoxybriarane, briavioid D (1), was isolated from Briareum violaceum. • The structure of briarane 1 was determined by a single-crystal X-ray diffraction analysis. • Briavioid D is the first example of briarane analog possessing a 7,8‑epoxy group in the γ-lactone moiety. A rare 7β,8β-epoxybriarane, briavioid D (1), has been isolated from a cultured octocoral Briareum violaceum. The structure of 1 was deduced by extensive 2D NMR studies. Single-crystal X-ray diffraction analysis was performed to identify the structure of 1 and this compound was found to reduce the release of iNOS to 85.77 %, at a concentration of 10 μM. [ABSTRACT FROM AUTHOR]

[Display omitted] • 17,20-epoxysteroids, hippuristeroketal B (1), hippuristerones A (2) and I (3), were isolated from octocoral Isis hippuris. • The absolute stereochemistry of steroids 1 – 3 was determined by single-crystal X-ray diffraction analysis. • Hippuristerone A (2) exhibited cytotoxic effect against HT-29 and DLD-1 cancer cells. Three 17,20-epoxysteroids, including a new metabolite, hippuristeroketal B (1), as well as two known compounds, hippuristerones A (2) and I (3), have been isolated from octocoral Isis hippuris collected off the waters of Taiwan. The structure of steroid 1 was deduced by extensive 1D and 2D NMR studies. The absolute stereochemistry of steroids 1 – 3 was determined by single-crystal X-ray diffraction analysis. Steroid 2 exhibited cytotoxic effect against HT-29 and DLD-1 cancer cells with IC 50 values of 11.39 and 12.86 μM, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two new 8,17-epoxybriaranes, briastecholides K and L, were obtained from octocoral Briareum stechei. • The absolute configuration of excavatolide E was confirmed by single-crystal X-ray diffraction analysis. Octocorals belonging to genus Briareum were proven to be rich sources of briarane-type diterpenoids. Three 8,17-epoxybriaranes, including a known metabolite, excavatolide M (1), as well as two new compounds, briastecholides K (2) and L (3), have been isolated from octocoral Briareum stechei collected off the waters of Taiwan. In this study, the absolute configuration of 1 was determined by single-crystal X-ray diffraction analysis for the first time. Moreover, the structures and stereochemistry of briaranes 2 and 3 were established based on spectroscopic analysis and comparison with those of 1. [ABSTRACT FROM AUTHOR]

Two novel chlorine-containing cembranoids, chlorofurancembranoids A (1) and B (2), were isolated from an octocoral identified as Sinularia sp. The structures of 1 and 2 were elucidated using spectroscopic methods, and the absolute configuration of 1 was further confirmed by single-crystal X-ray diffraction analysis. Cembranoid 2 showed cytotoxicity towards human promyelocytic leukemia HL-60 cells, with an IC 50 value of 3.67 μM. [Display omitted] [ABSTRACT FROM AUTHOR]