Isolation of aureol from Smenospongia sp and cytotoxic activity of some aureol derivatives

The sesquiterpene aureol ( 1) was isolated by chromatographic fractionation of a non-polar extract from Smenospongia sp. Methylation of aureol yielded 5'-O-methyl-aureol ( 2) while the prepared acylation products of aureol were 5'-O-acetyl-aureol ( 3), 5'-O-benzoyl-aureol ( 4), 5'-O-(4-fluoro-benzoyl)-aureol ( 5), 5'-O-(4-chlorobenzoyl)-aureol ( 6), 5'-O-( 4- methylbenzoyl)aureol ( 7), 5'-O- nicotinoyl- aureol ( 8), aureol-N,N-dimethylthiocarbamate ( 9), 5'-O-( 2-furoylcarbonyl)aureol ( 10), 5'-O-(2-thienoylcarbonyl- aureol ( 11). The structures of aureol as well as its ten derivatives were established through spectral analysis. The in vitro cytotoxic activities of the eleven compounds were evaluated against Hepa59T/VGH, KB and Hela tumor cell lines.