Cytotoxic compounds from invasive giant salvinia (Salvinia molesta) against human tumor cells.

Giant salvinia (Salvinia molesta) is one of the most noxious invasive species in the world. Our bioactivity-guided fractionation of ethanol extract of giant salvinia led to the isolation of 50 compounds. Of the six new compounds (1-6), salviniol (1) is a rare abietane diterpene with a new ferruginol-menthol coupled skeleton and both salviniside I (2) and salviniside II (3) are novel benzofuran glucose conjugates with unique 10-membered macrodiolide structures. Sixteen abietane diterpenes (1, 7-17, and 19-22) demonstrated in vitro activities against human tumor cells, and 7 and 8 showed selective cytotoxicity to tumor cells over normal cells.