New bioactive steroids from the soft coral Klyxum flaccidum†
Abstract
Six new steroids, klyflaccisteroids A–E (1–5) and a new 9,11-secogorgosteroid klyflaccisteroid F (6), along with two known steroids 9,11-secosteroid 3β,11-dihydroxy-9,11-secogorgost-5-en-9-one (7) and gorgost-5-ene-3β,9α,11α-triol (8), and a known eunicellin-based diterpenoid cladiellisin (9), were discovered from the soft coral K. flaccidum. Compound 6 is the first 9,11-secogorgosteroid 11-carboxylic acid isolated from natural sources. Cytotoxicity of these compounds and anti-inflammatory activities of 1–4 and 6–9 were also evaluated. Some compounds were shown to exhibit attractive bioactivities.