Polyhydroxylated steroid derivatives from the starfish Pentaceraster regulus

Area of Science:

• Marine Natural Products Chemistry
• Pharmacology
• Organic Chemistry

Background:

• Starfish are a rich source of bioactive marine natural products.
• Marine organisms, including starfish, are increasingly investigated for novel therapeutic compounds.
• Inflammation is a complex biological response implicated in various diseases.

Purpose of the Study:

• To isolate and characterize new polyhydroxysteroid glycosides and polyhydroxylated steroids from the starfish Pentaceraster regulus.
• To evaluate the inhibitory effects of isolated compounds on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 cells.

Main Methods:

• Chemical investigation of the starfish Pentaceraster regulus using chromatographic techniques.
• Structure elucidation of isolated compounds through extensive Nuclear Magnetic Resonance (NMR) and High-Resolution Quadrupole Time-of-Flight (HR-QTOF) mass spectrometry.
• In vitro bioassay to assess the inhibitory activity against LPS-induced NO production in RAW264.7 macrophage cells.

Main Results:

• Two new compounds, regulusoside D (1) and (24S)-cholestane-3β,5,6β,8,15α,24-hexol (2), were identified.
• Seven known compounds were also isolated and characterized.
• Reguloside D (1), (24S)-cholestane-3β,5,6β,8,15α,24-hexol (2), and four other known compounds demonstrated significant inhibitory effects on NO production with IC50 values ranging from 8.63 to 14.83 µM.

Conclusions:

• The study successfully isolated and identified novel polyhydroxysteroid glycosides and polyhydroxylated steroids from Pentaceraster regulus.
• Several isolated compounds, including the new entities, possess potent anti-inflammatory properties by inhibiting nitric oxide production.
• These findings highlight the potential of starfish-derived compounds as leads for developing new anti-inflammatory agents.