New Bicyclic Cembranoids from the South China Sea Soft Coral Sarcophyton trocheliophorum

Lin-Fu Liang,He-Yao Wang,Yue-Wei Guo,Xu-Wen Li,Wen-Ting Chen

doi:10.1038/srep46584

Abstract

Nine new bicyclic cembranoids, sarcophytrols M–U(1–9), were isolated from the South China Sea soft coral Sarcophyton trocheliophorum as minor components, along with one known related cembranoid 10. Their structures were elucidated by detailed spectroscopic analysis and chemical conversion. The chemical structures of these metabolites are characterized by the different patterns of the additional cyclization within the 14-member skeleton, which leading to the formation of furan, pyran, oxepane, and peroxyl rings, respectively. Among them, sarcophytrols R and S(6 and 7) share a rare decaryiol skeleton with an unusual C12/C15 cyclization. In addition, the absolute configurations of sarcophytrols M and T(1 and 8) were determined by the modified Mosher’s method. The research of these new secondary metabolites provided a further understanding of the diversity of cyclized cembranoids from the title species.

Highlights

Cyclization is an extraordinary artistry that nature turn the simple cembranoids to a prodigious variety of structurally novel compounds, and it often links to a network of oxygenation process1, which lead to the formation of epoxyl2–5, furan4,6–8, pyran5,7,8, and oxepane5,9,10
We have focused our attentions on the cembrane-type metabolites with diverse kinds of cyclizations from the latter collection to find more chemically interesting and biologically active compounds
The characteristic chemical features of them are the diverse types of cyclized rings: furan rings possessed by sarcophytrols M–P [1,2,3,4], pyran rings formed at different positions in sarcophytrols Q–S [5,6,7], while oxepane and peroxyl rings appeared in sarcophytrols T [8] and U [9], respectively

Summary

OPEN New Bicyclic Cembranoids from the South China Sea Soft Coral

Sarcophyton trocheliophorum received: 13 February 2017 accepted: March 2017 Published: April 2017. A previous study we conducted on a collection of the title animal from Hainan had resulted in the isolation of a series of new cembranoids and cembranoid derivatives3,4,9,16 Many of these new secondary metabolites with different patterns of cyclizations showed significant inhibitory activity against human protein tyrosine phosphatase 1B (PTP1B) enzyme, a promising drug target for the treatment of type 2 diabetes and obesity. We have focused our attentions on the cembrane-type metabolites with diverse kinds of cyclizations from the latter collection to find more chemically interesting and biologically active compounds This continuous investigation has resulted in the isolation of nine new cembranoids [1,2,3,4,5,6,7,8,9], together with one known related cembranoid 10 (Fig. 1). We report the isolation and structure elucidation of these new cembranoids

Results and Discussion

OMe OAc

Methods

Additional Information