Hop is an important source of secondary metabolites, like flavonoids. Some of these are pharmacologically active. Often, their concentration in wild type plants is rather low.

Soft corals of the genus Lobophytum, a marine invertebrate, have shown diverse biological activities as antiinflammatory, cytotoxic, and antibacterial. Our research is concerning with biological screening and discovering bioactive substances from the Red Sea soft coral Lobophytum pauciflorum. In vitro cyclooxygenase inhibitory activity using COX-1 and COX-2 kits and antimicrobial screening were carried out for n-hexane, dichloromethane, ethyl acetate and methanol fractions. The isolated compounds were elucidated using different spectroscopic methods including nuclear magnetic resonance and mass spectrometry. Also n-hexane fraction was subjected to GC/MS analysis. Bioassay guided fractionation resulted in isolation and characterization of two bio-active metabolites nephthenol (2) and gorgost-5-ene-3β-ol (3) with significant in vitro antiinflammatory activity against COX-1 and COX-2 compared to Indomethacin and Celecoxib. Four other compounds were also isolated: Heptadecan-1-ol (1), palmitic acid (4), stearic acid (5) and batilol (6). The isolated compounds showed antimicrobial activity ranging from 25 μg/ml to 50 μg/ml against the tested microorganisms. The fatty acid constituents of the n-hexane fraction were identified by GC/MS analysis; results revealed the presence of hexadecanoic acid, methyl ester as major saturated fatty acid and 7,10-hexadecadienoic acid, methyl ester as major unsaturated fatty acid.
Keywords: Lobophytum pauciflorum, gorgost-5-ene-3β-ol, nephthenol, COX-1, COX-2 and GC/MS.