New bromoditerpenes from the red alga Sphaerococcus coronopifolius

The organic extract of the red alga Sphaerococcus coronopifolius, collected along the Atlantic coast of Morocco, was tested for biological activities and exhibited antibiotic and antimalarial. activities. Two new bromoditerpenes have been isolated from S. coronopifolius, sphaerolabdadiene-3,14-diol (1) and bromosphaerone (2), along with the known compounds 12S-hydroxybromosphaerodiol (3) and sphaerococcenol A (4). Bromosphaerone and 12S-hydroxybromosphaerodiol showed antibacterial activity against the Gram-positive bacterium species Staphylococcus aureus with a minimum inhibitory concentration of 0.104 and 0.146 muM, respectively. Sphaerococcenol A (4) was responsible for the antimalarial activity of the extract, against the chloroquine resistant Plasmodium falsciparum FCB1 strains with an IC50 of 1 muM. Their structures have been assigned using 1 and 2 D NMR and HRMS.