Heterolactone and Heterolactams A–M, Verticillane Diterpenoids with Anti-Inflammatory and Hepatoprotective Activities from the Soft Coral Heteroxenia ghardaqensis

Abstract

Fourteen new verticillane diterpenoids, heterolactone (1) and heterolactams A−M (2−14), were isolated from the soft coral Heteroxenia ghardaqensis. They structurally share the same 6/12 bicyclic carbon skeleton that is not commonly encountered in marine organisms. The structures, including the absolute configurations, were determined by extensive spectroscopic analysis, singlecrystal X-ray diffraction analysis, calculated ECD spectra, and DP4+ probability analyses. Compounds 5, 8, and 9 showed anti-inflammatory activities, and 2, 8, and 12 displayed hepatoprotective activities in zebrafish assays.

Tagpyrrollins A and B and Tagpyrrollidone A: Three Pyrrole Steroid Analogues with AKR1B1-Targeting Inhibitory Activity from the Sponges Stylissa massa and Pseudospongosorites suberitoides

“…Marine alkaloids containing pyrrole/imidazole ring systems are a group of naturally occurring compounds marked by their structural variability and biological activity. , Sponges are important sources for producing pyrrole/imidazole alkaloids, , as well as some soft corals. , Our group has had a long-standing interest in discovering alkaloids from invertebrates, especially those collected from Xisha islands of the South China Sea. − During the past decade, some interesting pyrrole/imidazole alkaloids were reported by our group; for example, (±)-spiroreticulatine, a pair of unusual spiro quinoline-imidazole alkaloids, was acquired from the sponge Fascaplysinopsis reticulata in 2015 (Figure A) . Then, a series of highly rearranged nardosinane sesquiterpenoids were obtained from the soft corals Clavularia koellikeri , which represented a first case in which pyrrole units exist in this sesquiterpene family .…”

“…1,2 Sponges are important sources for producing pyrrole/ imidazole alkaloids, 3,4 as well as some soft corals. 5,6 Our group has had a long-standing interest in discovering alkaloids from invertebrates, especially those collected from Xisha islands of the South China Sea. 7−9 During the past decade, some interesting pyrrole/imidazole alkaloids were reported by our group; for example, (±)-spiroreticulatine, a pair of unusual spiro quinoline-imidazole alkaloids, was acquired from the sponge Fascaplysinopsis reticulata in 2015 (Figure 1A).…”