Identification and in vitro anti-esophageal cancer activity of a series of halogenated monoterpenes isolated from the South African seaweeds Plocamium suhrii and Plocamium cornutum.

Five known (1, 2, 4, 6 and 7) halogenated monoterpenes together with 1Z,3R∗,4S∗,5E,7Z)-1-bromo-3,4,8-trichloro-7-(dichloromethyl)-3-methylocta-1,5,7-triene (3) and (3R∗,4S∗)-3,4,6,7-tetrachloro-3,7-dimethyl-octen-1-ene (5) were isolated from the red macroalga Plocamium suhrii and their structures deduced from their spectroscopic data. The seven compounds from P. suhrii together with five related compounds from Plocamium cornutum have been evaluated for their cytotoxic effects on an esophageal cancer cell line (WHCO1).

Antiplasmodial halogenated monoterpenes from the marine red alga Plocamium cornutum.

In our continuing search for antimalarial leads from South African marine organisms we have examined the antiplasmodial organic extracts of the endemic marine red alga Plocamium cornutum (Turner) Harvey. Two new and three known halogenated monoterpenes were isolated and their structures determined by standard spectroscopic techniques. The 3,7-dimethyl-3,4-dichloro-octa-1,5,7-triene skeleton is common to all five compounds.

Fucoxanthin, tetraprenylated toluquinone and toluhydroquinone metabolites from Sargassum heterophyllum inhibit the in vitro growth of the malaria parasite Plasmodium falciparum.

In the course of our search for antimalarial leads from marine algae, four metabolites, sargaquinoic acid, sargahydroquinoic acid, sargaquinal and fucoxanthin, were isolated from the South African alga Sargassum heterophyllum. Fucoxanthin and sargaquinal showed good antiplasmodial activity toward a chloroquine-sensitive strain (D10) of Plasmodium falciparum (IC50 1.5 and 2.