Prunolides A, B, and C:  Novel Tetraphenolic Bis-Spiroketals from the Australian Ascidian Synoicum prunum

Abstract

Three novel tetraphenolic bis-spiroketals, prunolides A-C (1, 3, and 4) have been isolated from the Australian ascidian Synoicum prunum. The structures were determined from NMR spectroscopic data and from an X-ray analysis of prunolide A. The prunolides contain a unique 1,6,8-trioxadispiro[4.1.4.2]trideca-3,10,12-triene-2,9-dione carbon skeleton. The known compound rubrolide A (5) was also isolated.

Progress of Bromophenols in Marine Algae from 2011 to 2020: Structure, Bioactivities, and Applications

“…Over the past few decades, a great number of BPs were isolated from various marine algae species including red algae [ 4 , 5 , 6 , 7 , 8 , 9 ], green algae [ 10 , 11 , 12 , 13 , 14 ], and brown algae [ 15 , 16 , 17 , 18 , 19 ]. Some BPs are also found in other marine organisms such as sponges [ 18 , 20 , 21 , 22 , 23 , 24 ], ascidians [ 25 , 26 , 27 ], mussels [ 28 ], polychaetes [ 29 ], and marine proteobacteria [ 30 ]. However, BPs from microalgae have not yet been reported.…”

Bromophenols in Marine Algae and Their Bioactivities

“…Some, but not all, species of red algae have a relative higher content of certain BPs [49], which may possibly explain why so many BPs have been reported from red algae. The BPs were also found to exist in other lower marine organisms such as ascidians [50–52] and sponges [53–62]. BPs are common marine secondary metabolites, and biosynthesized in the presence of bromoperoxidases, hydrogen peroxide, and bromide [63,64].…”

Ten-Year Research Update Review: Antiviral Activities from Marine Organisms

“…The crude extract and a furanone metabolite, rubrolide R, isolated from the ascidian Synoicum , together with the known compounds rubrolide A, cadiolide B and prunolide A ( Figure 6 B), were tested against the Japanese encephalitis virus (JEV). Among these compounds, prunolide A and cadiolide B, previously isolated from Synoicum prunum [ 240 ] and Botryllus sp. [ 241 ], showed antiviral properties in Vero cells against the JEV at 1.7 and 1.4 μM respectively [ 194 ].…”