Ulvapyrone, a pyrone-linked benzochromene from sea lettuce Ulva lactuca Linnaeus (family Ulvaceae): newly described anti-inflammatory agent attenuates arachidonate 5-lipoxygenase.

Green marine macroalgae, particularly Ulva lactuca, is an essential constituent of the cuisines in many Asian countries. The present work aims to separate a bioactive pyrone attached benzochromene analogue, named as ulvapyrone from the organic extract of U. lactuca, followed by its structural characterisation as 2-{(6a'-hydroxyethyl-4'-methyltetrahydro-2H-pyran-2'-one)-6'-yl}-4-methyl-7-ethylacetate-8-hydroxy-7, 8-dihydrobenzo [de]chromene. Ulvapyrone exhibited prospective inhibition property against arachidonate 5-lipoxygenase (IC50 ∼1 mg mL-1) comparable to that demonstrated by ibuprofen (IC50 0.9 mg mL-1), which connoted its anti-inflammatory activity. The studied benzochromene exhibited promising antioxidant potential (IC50 0.5-0.6 mg mL-1), which further reinforced its attenuation property against 5-lipoxygenase. Bioactivities of ulvapyrone were linearly correlated with electronic parameter (topological polar surface area ∼102) along with less binding energy (-8.22 kcal mol-1) with the allosteric site of 5-lipoxygenase. In silico predictions of physicochemical parameters along with absorption, distribution, metabolism and excretion could recognise the acceptable oral bioavailability of ulvapyrone.