Chemical Study and Biological Activity Evaluation of Two Azorean Macroalgae:Ulva rigida and Gelidium microdon

The green macroalga Ulva rigida C. Agardh (Chlorophyta) and the red macroalga Gelidium microdon Kützing(Rhodophyta), collected from the Azorean archipelago, were investigated for their secondary metabolites and their invitro growth inhibitory effect on three human tumor cell lines: MCF-7 (breast adenocarcinoma), NCI-H460 (non-small celllung cancer) and A375-C5 (melanoma), as well as for their antifungal and antibacterial activities. The methanol extractof U. rigida furnished isofucosterol (1), 7(E)-3β-hydroxy-5α,6α-epoxymegastigmane (2) and (+)-dehydrovomifoliol (3)while the methanol extract of G. microdon yielded cholesterol (4) and lumichrome (5). The crude extracts of bothmacroalgae were found to be moderately active against the three cell lines whereas compound 1 showed a weak effectand compound 2 was inactive. The crude extracts of the two macroalgae were found to be moderately active againstsome fungi and bacteria while compounds 1 and 2 were inactive against all microorganisms tested