Cyanobacteria are the most abundant oxygenic photosynthetic organisms inhabiting various ecosystems on earth. As with all other photosynthetic organisms, cyanobacteria release oxygen as a byproduct during photosynthesis. In fact, some cyanobacterial species are involved in the global nitrogen cycles by fixing atmospheric nitrogen. Environmental factors influence the dynamic, physiological characteristics, and metabolic profiles of cyanobacteria, which results in their great adaptation ability to survive in diverse ecosystems. The evolution of these primitive bacteria resulted from the unique settings of photosynthetic machineries and the production of bioactive compounds. Specifically, bioactive compounds play roles as regulators to provide protection against extrinsic factors and act as intracellular signaling molecules to promote colonization. In addition to the roles of bioactive metabolites as indole alkaloids, terpenoids, mycosporine-like amino acids, non-ribosomal peptides, polyketides, ribosomal peptides, phenolic acid, flavonoids, vitamins, and antimetabolites for cyanobacterial survival in numerous habitats, which is the focus of this review, the bioactivities of these compounds for the treatment of various diseases are also discussed.

This research aims to determine the antibacterial activity of Curcuma xanthorrhiza leaves and rhizomes essential oil with different distillation time of 2 hours, 4 hours and 6 hours against Escherichia coli and Staphylococcus aureus. The essential oils produced then separated by thin layer chromatography (TLC) with n-hexane: toluene: dichloromethane 1:8:1 as the mobile phase. The result shows that on the first two hours distillation gave the highest yield compared to the next two hours or four hours. Based on TLC chromatograms, the highest content of compounds found at 4-6 hours distillation time. TLC bioautography contact was used for antibacterial activity tested on chromatogram and the clear zone appears on it indicates the spots were active as antibacterial activity against both bacteria with Rf values of 0.35 and 0.49 for rhizomes, rhizome essential oils 4-6 hours distillation time as the most significance active.