**5.3 Potential application in pharmaceuticals and cosmetics sector**

Cyanobacteria are a rich source of organic chemicals and can be utilized to make food. Cyanobacteria-derived compounds are often used in cosmetics as thickening,

water-binding, and antioxidant ingredients. Cosmetic companies typically base their skin or health claims on ingredients such as carrageenan, vitamin A, polysaccharides, iron, phosphorus, salt, copper, vitamin B1, and minerals such as calcium, magnesium, or others [71].

Since they frequently target tubulin or actin filaments in eukaryotic cells, cyanobacteria cytotoxic metabolites are appealing anticancer medicines. Dolastatins, produced by NRPS-PKS enzymes and present in *Leptolyngbya* and *Simploca* sp., can interfere with the development of microtubules. Other cyanobacterial byproducts, such as the cyclic depsipeptide derivatives known as lyngbyastatins, which are also suspected elastase inhibitors, function as protease inhibitors [70]. A mixture NRPS-PKS pathway is utilized in the biosynthesis of apratoxins such apratoxin-a from *Lyngbya majuscule*. Due to its capacity to cause G1-phase cell cycle arrest and death, it is cytotoxic.

In the cosmetics sector, secondary metabolites can be employed as natural components. Sunscreens contain photoprotective MAAs that protect the skin from UVR damage. In addition to serving as natural colorants, pigments like carotenoids and phycobiliproteins can act as antioxidants to shield the skin from UV-induced mutilation [71].

### **6. Future prospects**

Due to their intricate structures and a range of bioactivities, these secondary metabolites can also be used as lead molecules in developing new drugs. A biosynthetic pathway study employing genomic data with over 208 publicly available cyanobacterial genome sequences can find new natural compounds. Even though cyanobacterial secondary metabolites have been the subject of intensive research, a variety of species still need to be sequenced and examined, and there are still a lot of secondary metabolites that may be significant but have not yet been identified. The growth study of cyanobacteria under peroxidation is still in its initial phases. Most of the information we know about the production of reactive oxygen species in the photosystem mechanism comes from plant findings. Still, cyanobacteria, as a distinct type for photochemical research, will help us understand peroxidation in photosynthesis in general. Analyzing the particular reaction for each reactive form is challenging because many ROS are created concurrently in cells. Future studies should concentrate on the biological consequences and particular targets of specific ROS species in cyanobacteria and the functional reactions they cause. In recent years, significant advancements have been achieved in identifying ROS-scavenging enzymes. The recognition or finding of ROS-scavenging enzymes has advanced significantly in recent years. Still, much more investigation is required to comprehend their function in vivo fully, as well as to determine which areas of the cell they act in and the range of oxidants they can detoxify.

### **7. Conclusion**

Natural algae antioxidants are significant bioactive substances that help fight various ailments and shield cells from oxidative stress. It is an important source of chemicals that are neuroprotective. Algae have exceptional nutritional value, and therapeutic properties have higher demands for natural algal products. This gives

*Cyanobacteria as the Source of Antioxidants DOI: http://dx.doi.org/10.5772/intechopen.110598*

microalgae clear benefits over conventional components, making them worth investigating for future use in the feed, food, cosmetic, and pharmaceutical industries. The extensive evolutionary history of cyanobacteria has resulted in adaptations that allow them to cope with natural and man-made stress. The enormous quantity of secondary metabolites produced by cyanobacteria, each with its unique roles supporting the organism's survival, results from the diversity of their morphological, biochemical, and physiological makeup.
