Different chemotypes of Sinularia flexibilis exist in the Hainan island. Thus, a collection of this soft coral from a location different from the one of our previous study afforded three novel cembranoid esters featuring a n-butyl alcohol moiety, a structural element rare in natural products of both terrestrial and marine origin. The structures of the new compounds were elucidated by detailed spectroscopic analysis and by the comparison of their spectroscopic data with those reported in the literature. In addition, the absolute stereochemistry of the previously reported diepoxycembrene (9) was first time determined by the X-ray diffraction analysis. In bioassays, compounds 6–8 exhibited strong anti-inflammatory effect with IC₅₀ values of 2.7, 4.7, and 4.2 μM, respectively, whereas compound 5 displayed cytotoxicity against several cancer cells with IC₅₀ values ranging from 8.9 to 27.4 μM. A preliminary structural-activity relationship (SAR) was also described.

海南岛存在不同的柔韧性奇异菌（Sinularia flexibilis）化学型。因此，从与我们先前的研究不同的位置收集了这种软珊瑚，得到了三种具有正丁醇部分的新型斜柏酸酯，正丁醇部分是陆地和海洋天然产物中罕见的结构元素。通过详细的光谱分析以及通过将其光谱数据与文献报道的数据进行比较，阐明了新化合物的结构。此外，先前报道的二环氧聚乙稀（9）的绝对立体化学是首次通过X射线衍射分析确定。在生物测定中，化合物6 – 8化合物具有较强的抗炎作用，IC ₅₀值分别为2.7、4.7和4.2μM，而化合物5对几种癌细胞的细胞毒性显示，IC ₅₀值为8.9至27.4μM。还描述了初步的结构活性关系（SAR）。