Cespitulones A and B, Cytotoxic Diterpenoids of a New Structure Class from the Soft Coral Cespitularia taeniata

Abstract

Two novel diterpenoids, cespitulones A (1) and B (2), were isolated from extracts of the soft coral Cespitularia taeniata. Both compounds possess an unprecedented bicyclo [10.3.1] ring system with C-C bond connections between C-10 and C-20, and between C-20 and C-11. Their structures were elucidated on the basis of extensive spectroscopic analyses. Compound 1 exhibited significant cytotoxicity against human medulloblastoma and colon adenocarcinoma cancer cells.

Coral and Coral-Associated Microorganisms: A Prolific Source of Potential Bioactive Natural Products

“…Interestingly, only 156 exhibited cytotoxicity against the P-388 cell line, with an ED 50 of 6.9 μM [126]. In another study, Lin et al [127] isolated two novel diterpenoids, cespitulones A and B, which possess an unprecedented bicyclo ring system with C-C bond connections between C-10 and C-20 and between C-20 and C-11, from the coral Cespitularia taeniata . However, only the compound cespitulone A ( 157 ) (Figure 20) exhibited significant cytotoxicity against the Daoy and WiDr cancer cell lines, with IC 50 values of 8.7 and 6.7 µM, respectively.…”

Chemical and biological profile of Cespitularia species: A mini review

“…Recently, Lin et al [15] stated that the isolated diterpenoid from CH 2 Cl 2 /EtOH extract of C. taeniata, cespitulon A ( 74 ), exhibited significant cytotoxicity against human medulloblastoma and colon adenocarcinoma cancer cells with IC 50 values of 8.7 and 6.7 μM, respectively by a comparison with a positive control with IC 50 at 0.3 μM [15] .…”

“…Soft corals of the genus Cespitularia are rich in novel and diverse chemical structures with interesting biological activities. This genus elaborates varied diterpenoids of cembrane, neodolabellane, cespitularane, and verticillane skeleton [9] , [10] , [11] , [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] . Few numbers of sesquiterpenes were also reported [23] .…”

“…The Cespitularia species are characterized with a special type of diterpenoids such as cespitularia, cespihypotin, cespitulactam, cespitularin, and cespitulons. The biogenetic pathways of these diterpenoids were described in few reports [15] , [16] . The biogenetic pathways of Cespitularia diterpenoids, as shown in Fig.…”

“…Reports related metabolites chemistry of the genus Cespitularia is scarce. Earlier studies of the genus Cespitularia led to the isolation of a diverse array of diterpenoids including alcyonolides, caryophyllanoids, cembranolides, cespitularanoids, dolabellanoids, norverticillanoids, verticillanoids, and xenicanoids [3] , [9] , [10] , [11] , [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] , [24] , [25] , [26] , [27] , [28] , [29] , [30] .…”