Antibacterial Natural Halimanes: Potential Source of Novel Antibiofilm Agents

Abstract

The development of new agents against bacteria is an urgent necessity for human beings. The structured colony of bacterial cells, called the biofilm, is used to defend themselves from biocide attacks. For this reason, it is necessary to know their structures, develop new agents to eliminate them and to develop new procedures that allow an early diagnosis, by using biomarkers. Among natural products, some derivatives of diterpenes with halimane skeleton show antibacterial activity. Some halimanes have been isolated from marine organisms, structurally related with halimanes isolated from Mycobacterium tuberculosis. These halimanes are being evaluated as virulence factors and as tuberculosis biomarkers, this disease being one of the major causes of mortality and morbidity. In this work, the antibacterial halimanes will be reviewed, with their structural characteristics, activities, sources and the synthesis known until now.

Antifouling Activity of Halogenated Compounds Derived from the Red Alga Sphaerococcus coronopifolius: Potential for the Development of Environmentally Friendly Solutions

“…These observations corroborate the fact that marine organisms use a combination of antifouling defenses, some molecules with a broad range of activities and some others displaying very specific modes of action. Moreover, it also corroborates the fact that diterpenes produced by algae are highly bioactive and associated with defense mechanisms [64][65][66]. Depending on the concentrations of each of these compounds and their combination (induced defense vs. constitutive defense), S. coronopifolius is able to efficiently control epibiosis on its surface.…”

Effects of Synthetic Tetronamides and Methylated Denigrins on Bacterial Quorum Sensing and Biofilm Formation

“…To date, a number of natural products and their synthetic analogues have been reported as QS inhibitors and antibiofilm agents. − One class of the best studied natural antibiofilm agents to date are brominated furanones (e.g., compound 1 ; Figure ) derived from the red alga Delisea pulchra . These small molecules and their synthetic derivatives exhibited potent inhibitory activities against biofilm formation of many microbial pathogens such as Escherichia coli, , Pseudomonas aeruginosa, Streptococci spp ., Staphylococcus epidermidis, , Salmonella enterica, and sulfate-reducing bacteria .…”