Sinusiaetone A, an Anti-inflammatory Norditerpenoid with a Bicyclo[11.3.0]hexadecane Nucleus from the Hainan Soft Coral Sinularia siaesensis

Abstract

A novel norditerpenoid, sinusiaetone A (1), featuring an uncommon bicyclo[11.3.0]­hexadecane carbon skeleton, and four polyoxygenated cembranoids (2–5) were isolated from the Hainan soft coral Sinularia siaesensis. Their structures were established by spectroscopic analysis, X-ray diffraction, quantum chemical computational approaches, and/or a modified Mosher’s method. A plausible biosynthetic pathway of 1 and its biogenetic relationship with 2–5 were proposed. New compounds 1–3 displayed an interesting inhibitory activity against lipopolysaccharide-induced inflammation in BV-2 microglial cells.

Structural and Biological Insights into the Hot‐Spot Marine Natural Products Reported from 2012 to 2021

“…The biosynthetic pathway involving a [2+2]‐cyclization has been proposed. [ 152 ] Sinunanolobatone A ( 166 ), isolated from a soft coral Sinularia nanolobata , is a novel diterpenoid featuring an unprecedented bicyclo[13.1.0]pentadecane skeleton. It exhibits strong inhibitory activity against lipopolysaccharide‐induced inflammation in BV‐2 microglial cells.…”

Dolabellane Diterpenoids from the Xisha Soft Coral Clavularia viridis

“…In the course of our ongoing search for bioactive metabolites from the South China Sea Cnidarians, − the soft coral Clavularia viridis was collected from the Xisha Islands, Hainan Province, China. A systematic chemical investigation of the title animals led to the isolation of 12 new dolabellanes ( 1 – 12 ) and three known related analogues ( 13 – 15 ). , Structurally, clavuperoxylides A ( 3 ) and B ( 4 ) represent the first examples of dolabellanes containing peroxyl groups, especially the novel peroxide bridge in 4 , and clavufuranolides A–C ( 9 – 11 ) are the first example of dolabellane diterpenoids comprising a tetrahydrofuran ring.…”

Sinuscalide A: An Antiviral Norcembranoid with an 8/8-Fused Carbon Scaffold from the South China Sea Soft Coral Sinularia scabra

“…Soft corals of the genus Sinularia − (phylum Cnidaria, class Anthozoa, subclass Octocorallia, order Alcyonacea, family Alcyoniidae) are one of the most widely distributed soft coral genera over the oceans. To date, it has yielded a wealth of diverse and complex structures, especially various types of terpenoids, which possess a broad range of biological properties, such as cytotoxic, anti-inflammatory, immunosuppression, and antimalarial activities. , Among all of the species of Sinularia , Sinularia scabra has been mainly chemically investigated by Sheu’s group and Guo’s group from the soft coral samples in the Taiwan and the South China Sea, of which they obtained sesquiterpenoids, norditerpenoids, and cembranoids. − …”