An anti-inflammatory salmachroman from the sea urchin Salmacis bicolor: a prospective duel inhibitor of cyclooxygenase-2 and 5-lipoxygenase

Abstract

An isochroman derived polyketide, salmachroman characterized as methyl 15³(11-(10-hydroxy-12-oxo-6-pent-6³-en-6¹-yl)isochroman-10-yl)-13-oxotetrahydrofuran-15-yl was isolated from the organic extract of the Echinodermata sea urchin Salmacis bicolor (family Temnopleuridae) through chromatographic fractionation. The structure of the compound was identified by detailed spectroscopic techniques. Salmachroman demonstrated significant duel inhibition potential against pro-inflammatory enzymes, cyclooxygense-2 (IC₅₀ 1.29 mM) and 5-lipoxygenase (IC₅₀ 1.39 mM). The compound exhibited significantly greater anti-inflammatory selectivity index (1.03) than that displayed by the anti-inflammatory agent ibuprofen (0.43). The isochroman analogue exhibited greater antioxidant activities against 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (IC₅₀ 1.19 mM) and 2,2-diphenyl-1-picrylhydrazyl (IC₅₀ 1.24 mM) than the standard antioxidative agent α-tocopherol (IC₅₀ > 1.50 mM). The binding properties of the compound with the active site of cyclooxygense-2 and 5-lipoxygenase enzymes, combined with its higher electronic parameters as attributed by the structure-activity relationship accounted for its significant anti-inflammatory properties.

Graphical Abstract

Keywords:

• Salmacis bicolor
• Temnopleuridae
• salmachroman
• isochroman derived polyketide
• anti-inflammatory and antioxidant activity
• selectivity index

Acknowledgements

The authors thank the Director, ICAR-CMFRI, and Head, Marine Biotechnology Division of ICAR-CMFRI for guidance and support.

Disclosure statement

The authors declare no competing financial interest.

Additional information

Funding

This work was supported by the Indian Council of Agricultural Research-Central Marine Fisheries Research Institute (ICAR-CMFRI), India under the project titled as ‘Development of Bioactive Pharmacophores from Marine Organisms’ (grant number MBT/HLT/SUB23).