Eunicidiol, an Anti-inflammatory Dilophol Diterpene from Eunicea fusca

Abstract

A new dilophol diterpene, eunicidiol (1), has been isolated from the crude extract of Eunicea fusca, a gorgonian coral collected from Hillsboro Ledge, Florida. This compound was purified, along with fuscol (2) and eunicol (3), using a combination of normal- and reversed-phase chromatography methods. The structure of eunicidiol (1) was elucidated by 1D and 2D NMR spectroscopic analysis, and the absolute configuration was assigned using Mosher's method. The anti-inflammatory activity of 1-3 was evaluated by measuring their ability to reduce phorbol myristate acetate (PMA)-induced edema in a mouse ear model. Topical application of a 100 μg/ear dose of diterpenes 1-3 significantly reduced edema by 44%, 46%, and 54%, respectively. This activity was superior to indomethacin, a known anti-inflammatory used as a control.

Marine natural products

“…776 Eunicidiol 1009 and known related diterpenes eunicol 777 and fuscol 777 were identied as potent topical anti-inammatory metabolites of Eunicea fusca (Hillsboro Ledge, Florida). 778 Extracts of Lobophytum pauciorum (Taketomijima Is., Okinawa) 779 provided cyclolobatriene 1010 and the related metabolites lobatriene, 780 eunicol 777 and fuscol. 777 A low temperature (7 C) NMR spectrum of 1010 identied three conformational isomers, while heating to 70 C induced a thermal Cope rearrangement to lobatriene (identical by NMR and sign of [a]).…”

Marine Pharmacology in 2012–2013: Marine Compounds with Antibacterial, Antidiabetic, Antifungal, Anti-Inflammatory, Antiprotozoal, Antituberculosis, and Antiviral Activities; Affecting the Immune and Nervous Systems, and Other Miscellaneous Mechanisms of Action

“…As shown in Table 2, and in contrast to the 20 marine compounds ( 115 – 134 ) with described anti-inflammatory mechanisms of action, for marine compounds ( 135 – 157 ), only anti-inflammatory activity, namely IC 50 , was reported, but the molecular mechanism of action remained undetermined: A. polyacanthus steroids ( 135 , 136 ) [137]; barettin ( 137 ) [138]; briarenolide F ( 138 ) [139]; diketopiperazine ( 139 ) [140]; 6- epi -cladieunicellin F ( 140 ) [141]; crassarosteroside A ( 141 ) [142]; cystodione A ( 142 ) [143]; densanins A and B ( 143 , 144 ) [144]; dissesterol ( 145 ) [145]; echinohalimane A ( 146 ) [146]; eunicidiol ( 147 ) [147]; flexibilisolide C ( 148 ) [148]; flexibilisquinone ( 149 ) [149]; lobocrassin F ( 150 ) [150]; perthamide J ( 151 ) [151]; pseudoalteromone A ( 152 ) [152]; sarcocrassocolide M ( 153 ) [153]; sclerosteroids K and M ( 154 , 155 ) [154]; seco-briarellinone ( 156 ) [155]; and sinularioside ( 157 ) [156]. …”

Diterpenoids of Gorgonian Corals: Chemistry and Bioactivity

“…In 2012, eunicidiol ( 223 ) , a new dilophol‐type diterpenoid possessed a cyclodecane ring as well as an C 8 side chain, was obtained from Florida specimen of the gorgonian coral E. fusca . The authors proposed the biosynthetic pathway shown in Scheme .…”