Procerolides A-B from Microcionidae marine sponge Clathria procera: Anti-inflammatory macrocylic lactones with selective cyclooxygenase-2 attenuation properties.

Cyclooxygenase-2 has been recognized to catalyze the formation of inflammatory prostaglandins from arachidonic acid. Attenuation potential against cyclooxygenase-2 coupled with greater anti-inflammatory selectivity index were contemplated to be vital indicators to assess anti-inflammatory activities of bioactive compounds. In the present study, two undescribed fourteen-membered macrocyclic lactones, procerolide A and B were isolated to homogeneity from the organic extract of the marine sponge Clathria procera (family: Microcionidae). Procerolide B exhibited greater attenuation potential against cyclooxygenase-2 (IC 0.89 mM) than that displayed by procerolide A, whereas 5-lipoxygenase inhibitory activity of procerolide B (IC 1.08 mM) was significantly greater than that displayed by procerolide A (IC 0.95 mM) and anti-inflammatory agent ibuprofen (IC 4.50 mM). Additionally, greater anti-inflammatory selectivity index of the procerolides (~1.3) than the synthetic agent (0.43) was accounted for the selective inhibition of the compounds towards cyclooxygenase-2. Higher electronic properties (topological polar surface area of > 100) along with lesser steric properties (molar volume < 300 cm) of the compounds compared to the standard supported their significant anti-inflammatory potential. Additionally, procerolide B exhibited comparatively lesser binding energy with aminoacyl residues of cyclooxygenase-2 (-9.82 kcal/mol) thereby recognizing its prospective therapeutic use against inflammatory pathogenesis.