Sinulariaone A: A novel diterpenoid with a 13-membered carbocyclic skeleton from an octocoral Sinularia species

Chemical composition screening of an octocoral identified as Sinularia species led to the isolation of a novel diterpenoid, sinulariaone A (1), featuring an unprecedented 13-membered carbocyclic skeleton. The structure of 1 was established by spectroscopic elucidation, computed calculation and X-ray diffraction analysis. It is to note that diterpenoid 1, involving an uncommon 13-membered carbocyclic carbon system, with suggested biosynthesis from the common 14-membered carbocyclic cembrane analogues by ring contraction, is one of a kind. This is the first time to obtain a 13-membered carbocyclic cembranolide analogue featuring an acetyl group at C-3. Moreover, a single-crystal X-ray diffraction analysis of chlorofurancembranoid B (2), obtained in our previous study from the same octocoral species, was reported for the first time to demonstrate the absolute configuration. Diterpenoid 1 showed cytotoxicity towards human promyelocytic leukemia HL-60 cells, with an IC₅₀ value of 38.01 μM ([Fig. 1]).

Fig. 1 Structures of Sinulariaone A (1) and Chlorofurancembranoid B (2)

Publication History

Article published online:
16 November 2023