Lobophytones H-N, Biscembranoids from the Chinese Soft Coral Lobophytum pauciflorum

Abstract

Chemical examination of a Chinese soft coral Lobophytum pauciflorum resulted in the isolation of seven new biscembranoids, named lobophytones H-N (1-7). Their structures were determined by interpretation of 1D-and 2D-NMR (correlation spectroscopy (COSY), heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond connectivity (HMBC), and nuclear Overhauser effect spectroscopy (NOESY)) spectroscopic data in association with MS and IR data. All compounds were tested for the inhibition of lipopolysaccharide (LPS)-induced nitric oxide (NO) production, cytotoxicity of mouse peritoneal macrophage, and antibacterial activities.

Four New 7,8-Epoxycembranoids from a Chinese Soft Coral <i>Lobophytum</i> sp.

“…[1][2][3][4][5][6][7][8] All these findings indicate that natural cembranoids of marine origin still merit continuous attention for biomedical research. As part of an ongoing project to search for bioactive natural products from Lobophytum corals inhabited in South China Sea, [13][14][15][16][17] a Hainan soft coral, Lobophytum sp., has been chemically investigated based on the EtOAc extract containing high amounts of terpenoids as detected by 1 resulted in the isolation and characterization of four new 7,8-epoxycembranoids, namely (2S*,7S*,8S*,12R*,1Z,3E,10E)-7,8:2,16-diepoxycembra-1(15),3,10-trien-12-ol (1), (2S*,7S*, 8S*,11R*,1Z,3E)-7,8:2,16-diepoxycembra-1(15), 3,12(20)-trien-11-ol (2), (4S*,7S*,8S*,1Z,2E,11E)-16-acetoxy-7,8-epoxycembra-1(15),2,11-trien-4-ol (3), and (7S*,8S*,15S*,1E,3E,1 1E)-7,8-epoxycembra-1,3,11-trien-15,16-diol (4), along with eleven known analogues 5-15. The structures of known compounds were identified by comparison of their 1 H-and 13 C-NMR spectroscopic data and optical rotations with those reported in the literature.…”

“…The structures of known compounds were identified by comparison of their 1 H-and 13 C-NMR spectroscopic data and optical rotations with those reported in the literature. They were identified as (7S*,8S*,15R*,1E,3E,11E)-7,8-epoxycembra-1,3,11-trien-15,16-diol (5), 18) sarcophytoxide (6), 19) sarcophine (7), 20) (+)-7β,8β-dihydroxydeepoxysarcophytoxide (8), 21) 4-epiisocembrol (9), 22) isocembrol (10), 22) methyl (7S*,8S*,1E,3E,11E)-7,8-epoxycembra-1,3,11-trien-16-carboxylate (11), 23) (7S*,8S*,1E,3E,11E)-7,8-epoxycembra-1,3,11-trien-15-ol (12), 24) sarcophytolide (13), 25) (7R*,8S*,1E,3E,11Z)-7-hydroxycembra-1,3,11-trien-20,8-olide (14), 25) and (7S*,8S*,1E,3Z,11Z)-7-hydroxycembra-1,3,11-trien-20,8-olide (15), 25) respectively. It's worthy pointing out that (7S*,8S*,15R*,1E,3E,11E)-7,8-epoxycembra-1,3,11-trien-15,16-diol (5), previously obtained as a semi-synthetic product of sarcophine, 18) is reported herein of its natural occurrence for the first time.…”

Cembrane Diterpenes Chemistry and Biological Properties

“…The plausible biogenetic pathway of biscembrane analogs was assumed to be derived by a Diels-Alder cycloaddition of two "mono" cembranoids, representing cembranoid-diene and cembranoid-dienophile. This depiction was late on supported by the natural occurring monomeric cembranoids, such as dienophiles methyl sarcoate and methyl tetrahydrosarcoate (methyl tortuosoate), which were regarded to be the precursors to form left part of biscembranoids [166].…”

“…Compounds 163, and 165 showed significant antimicrobial activity against bacterial isolates, and also showed excellent anti-QS inhibition activity measured by means of bioluminescence inhibition with biosensor model systems [63]. named cleospinols A-D (166)(167)(168)(169), and the 3 -hydroxy-iso-pentan-10-oate ester of cleospinol A (170) [64].…”

“…Biscembranoid diterpenoids were discovered in two species of the genus Lobophytum pauciflorum yielded lobophytones A-S (566-584) [166][167][168], while Sarcophyton producted other analogs, ximaolides A-G (585-591) [169,170], methyl neosartortuate acetate (592) [58], methyl tortuoate A (593), methyl tortuoate B (594) [7], nyalolide (595) [8], bisglaucumlides A-K (596-606) [171,172]. in vitro cytotoxicity against the human nasophyringeal carcinoma CNE-2 cell line, with IC 50 values of 22.7 and 24.7 μg/mL, and the murine P-388 tumor cell line, with IC 50 values of 3.5 and 5.0 μg/mL, respectively [7].…”