Bioactive Eunicellin-Based Diterpenoids from the Soft Coral Cladiella krempfi

Abstract

Four new eunicellin-based diterpenoids, krempfielins A–D (1–4), along with two known compounds (5 and 6) have been isolated from a soft coral Cladiella krempfi. The structures of the new metabolites were elucidated by extensive spectroscopic analysis and by comparison with spectroscopic data of related known compounds. Compounds 5 and 6 were shown to exhibit cytotoxicity against a limited panel of cancer cell lines. Furthermore, compounds 2, 3, 5 and 6 were shown to exert significant in vitro anti-inflammatory activity against LPS-stimulated RAW264.7 macrophage cells.

Krempfielins Q and R, Two New Eunicellin-Based Diterpenoids from the Soft Coral Cladiella krempfi

“…Many cytotoxic and anti-inflammatory eunicellin-based compounds have been discovered from soft corals [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. Recently, we isolated several eunicellins with anti-inflammatory activity by significantly inhibiting superoxide anion generation and elastase release in human neutrophiles induced by FMLP/CB [ 17 , 18 ].…”

“…Soft corals of the genus Cladiella have been known to be rich sources of eunicellin-type metabolites and several bioactivities of these compounds have been studied [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. Our previous studies on the soft coral Cladiella krempfi have resulted in the isolation of a series of new eunicellin-based diterpenoids, krempfielins A–P [ 15 , 16 , 17 , 18 ]. Our contineous investigation on the chemical constituents of soft coral C .…”

The marine-derived pachycladin diterpenoids as novel inhibitors of wild-type and mutant EGFR

“…The eunicellin-based diterpenoids displayed a wide range of bioactivities including anti-inflammatory and antitumor activities [14, 15]. Examples of these are the potent microtubule disruptors, sarcodictyins and eleutherobin, which were found to be among the most cytotoxic natural products [16].…”

Cytotoxic and Anti-Inflammatory Eunicellin-Based Diterpenoids from the Soft Coral Cladiella krempfi

“…The soft coral Cladiella krempfi has been found to generate several types of metabolites including eunicellin-type diterpenoids [15] and pregnane-type steroids [16,17,18]. Our previous chemical investigation of C. krempfi had led to the isolation of four new eunicellin-based diterpenoids, krempfielins A–D [19]. In this paper, we further report the isolation of five new eunicellin-based diterpenoids, krempfielins E–I ( 1 – 5 ) (Chart 1) and known compounds 6-methyl ether of litophynol B ( 6 ) [13], sclerophytin A ( 7 ) [20], sclerophytin B ( 8 ) [20], litophynin I monoacetate ( 9 ) [21], 6-acetoxy litophynin E ( 10 ) [22], (1 R* , 2 R* , 3 R* , 6 S* , 9 R* , 10 R* , 14 R* )-3-acetoxycladiell-7(16),11(17)-dien-6-ol ( 11 ) [23] and litophynin F ( 12 ) [24].…”