Background: The marine red alga Plocamium naturally produces halogenated monoterpenes with various biological activities.
Objective: To discover new lead compounds for the treatment of HIV/AIDS as well as novel antibacterial compounds.
Methods: A Namibian Plocamium species was investigated and the major metabolite was screened using various anti-HIV assays and antimicrobial tests.
Results: A rare but known compound namely 1E,3R,4S,5E,7Z-1-bromo-3,4,8-trichloro-7-(dichloromethyl)-3-methylocta-1,5,7-triene (1) was isolated from a Namibian Plocamium red alga. Compound 1 demonstrated selective in vitro inhibition against HIV-1 integrase with a 50% inhibition concentration of <0.06 mM. Weak inhibitory activity was observed against HIV-1 reverse transcriptase and protease. Using the disc diffusion method, compound 1 also showed antibacterial activity against Staphylococcus aureus (ATCC 25923), Alcaligenes faecalis (ATCC 8750) and Serratia marcescens (ATCC 8100) with MIC values of 0.65mM, and 1.29 mM for Klebsiella pneumonia (ATCC 13883).
Conclusion: The results of this study highlight the potential of halogenated monoterpenes from red seaweed as possible leads in the development of new anti-HIV and antimicrobial pharmaceuticals.