Briarenolides F and G, New Briarane Diterpenoids from a Briareum sp. Octocoral

Abstract

Two new briarane diterpenoids, briarenolides, F (1) and G (2), were isolated from an octocoral identified as Briareum sp. The structures of briaranes 1 and 2 were established by spectroscopic methods and by comparison of the spectroscopic data with those of known briarane analogues. Briarenolide F was proven to be the first 6-hydroperoxybriarane derivative and this compound displayed a significant inhibitory effect on the generation of superoxide anion by human neutrophils.

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]. …”

Overview of the genus Briareum (Cnidaria, Octocorallia, Briareidae) in the Indo-Pacific, with the description of a new species

“…This uncertainty in identification becomes obvious in the biochemistry and pharmacological studies in which the identification of source organisms is of great interest. It has been proven that Briareum offers extensive bioactive chemical compounds with antiviral, and antimicrobial properties (Chen et al 2006; Wang et al 2012; Yeh et al 2012), and it is the most important source of briarane-type metabolites among the diterpenoids isolated from octocorals (Sung et al 2002; Hong et al 2012). In spite of Briareum being a valuable and an important source of biochemical compounds, the identifications of these species usually remains unsatisfactory and uncertain.…”

Hydroperoxyditerpenoids from Octocorals

“…[8] 12 was found to display an inhibitory effect on the generation of superoxide anions by human neutrophils (inhibition rate IC 50 = 6.73 μM). [9]…”

“…The structures of cembranoids 6-9 were determined by spectroscopic methods and cembranoids 6, 8, and 9 were found to reduce the level of iNOS to 43, 61, and 46 %, respectively, at a concentration of 10 μM. [6] In continuing studies of the constituents of octocorals identified as Briareum sp., collected from the waters off Southern Taiwan, three hydroperoxybriaranes, briarenolides B (10), [7] D (11), [8] and F (12), [9] were obtained ( Figure 6), and their structures were determined based on analysis of spectroscopic data; 12 was the first 6-hydroperoxybriarane analogue. In cytotoxicity testing, 11 showed cytotoxicity towards DLD-1 and CCRF-CEM tumor cells (ED 50 = 2.0, 14.4 μM, respectively).…”