First report of anti-inflammatory chromenyl derivatives from the spineless cuttlefish Sepiella inermis

Abstract

The spineless cuttlefish Sepiella inermis encompasses a major share in the marine fisheries sector, and represents as a culinary delicacy in many cultures. Bioactivity-guided fractionation of methanol:ethyl acetate (MeOH:EtOAc, 1:1) extract of the edible parts of the species ensued in identification of two hexahydro chromenyl analogues namely, methyl 7-ethyl-hexahydro-8a-methyl-2H-chromene-4-carboxylate (1) and methyl 1-acetoxy-hexahydro-3-methyl-3-propyl-1H-isochromene-4-carboxylate (2). The isolated metabolites were checked for their radical scavenging and anti-inflammatory potentials by selective in vitro models. The isochromenyl derivative exhibited potential 2,2-diphenyl-1-picryl-hydrazil and 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (IC₅₀ < 0.45 mg mL⁻¹) radical-scavenging capacities along with pro-inflammatory cyclooxygenase-2 (COX-2) (IC₅₀ 0.75 mg mL⁻¹) and 5-lipoxygenase (5-LOX) (IC₅₀ 0.77 mg mL⁻¹) inhibitory activities. The titled compounds displayed the selectivity indices (IC₅₀ anti-COX-1/IC₅₀ anti-COX-2) greater than 1.25, in comparison with synthetic anti-inflammatory drug ibuprofen (0.44), which attributed to their greater selectivity towards inducible pro-inflammatory enzyme COX-2.

Graphical Abstract

Keywords:

• hexahydro chromenyls
• pro-inflammatory cyclooxygenase
• 5-lipoxygenase
• Spineless cuttlefish
• Sepiella inermis

Acknowledgements

The authors are thankful to Indian Council of Agricultural Research (ICAR) funded Consortium Research Platform (CRP) Project on “Health Food” (grant number ICAR/HF/2012-2017). The authors are grateful to the Director, Central Marine Fisheries Research Institute for support and guidance. Thanks are due to the Head, Marine Biotechnology Division for facilitating the research programmes.

Disclosure statement

The authors declare no competing financial interest.