Lobophora variegata

Red Sea coral reefs are on of the natural habitat of Lobophora variegata ©KAUST

Biplab Das reports in NatureAsia.com that a research team has found aqueous extracts of the marine brown algae Lobophoro variegate that can inhibit the replication of human immunodeficiency virus type 1 (HIV-1) by preventing its entry into host cells.

The algae extracts inhibit various HIV-1 strains – including a multi-drug resistant strain – that cause infection by binding to different cell-surface proteins of host cells. This could mean the brown algae is a potential natural source for developing a broad-spectrum anti-HIV-1 drug, suggests the research published in PLOS ONE.

L. variegata is a common brown alga that thrives in the coral reefs of the Caribbean, the Indian Ocean and the Red Sea. It contains high concentrations of phenolic compounds, mainly bromophenols, and no previous studies had identified its antiviral effects.

“Our study is the first to demonstrate the anti-viral effects of L. variegata and thus contributes to the extraordinary bioactive spectrum of this abundant marine brown alga,” says Stephan Kremb, one of the authors of the study, a marine biologist from the King Abdullah University of Science and Technology (KAUST), Saudi Arabia, and Institute of Virology, Helmholtz Zentrum Muenchen, Germany.

The scientists exposed aqueous extracts of the brown algae to various patient-derived HIV-1 strains grown in peripheral blood mononuclear cells prepared from the whole blood of healthy donors. The algae extracts were non-toxic and inhibited the replication of the HIV-1 strains in the cells.

To understand how the algae extracts inhibit the virus, the researchers added fluorescent-protein-labeled HIV-1 particles and specific indicator cells to the algae extracts. They found that the algae extracts prevented the attachment of the HIV-1 particles to the cells, suggesting it inhibits HIV-1 entry into the cells.