A new polyhydroxysteroid glycoside, regulusoside D (1), and a new polyhydroxylated steroid, (24S)-cholestane-3β,5,6β,8,15α,24-hexol (2), together with seven known compounds were purified from the starfish Pentaceraster regulus collected near Con Co Islands, Vietnam. The structure elucidation was confirmed by extensive analysis of their NMR and HR-QTOF mass experiments. Among isolated compounds, regulusoside D (1), (24S)-cholestane-3β,5,6β,8,15α,24-hexol (2), granulatoside A (4), 5α-cholestane-3β,6β,7α,15α,16β,26-hexol (6), 5α-cholestane-3β,6β,7α,8β,15α,16β,26-heptol (7) and 5α-cholestane-3β,6α,8,15α,16β,26-hexol (8) exhibited strong inhibitory effects on LPS-induced NO production in RAW264.7 cells with IC50 values of 9.13 ± 1.17, 9.19 ± 0.77, 8.63 ± 3.31, 12.61 ± 0.51, 14.83 ± 3.02 and 10.98 ± 1.22 µM, respectively.
Keywords: NO production; Oreasteridae; Pentaceraster regulus; polyhydroxylated steroid.