Carotene
Carotenoids are a type of pigment that ranges in colour from red to yellow and are widely dispersed in bacteria, algae, fungi, and plants. Carotenoids are a class of lipid-soluble compounds linked to the lipidic fractions that are sensitive to oxygen, heat and light (Kirti et al., 2014). Carotenoid serves as a significant part in the photosynthetic process. It absorbs light energy ranging from 300 to 600 nm to drive the photosynthetic process (Kusmita et al., 2017). The production of carotenoids by using some marine yeast (Rhodotorula spp.) and some filamentous fungi (M. purpureus ) is capable of synthesizing specific types of carotenoids (torularhodin, -carotene and torulene) that have shown pro-vitamin and antioxidant properties. They have been used as food colourants, cosmetics, and feed additives, and their other biological importance is given in Table. 2 (Velmurugan et al., 2020). Furthermore, carotenoids can act as shelters for photosynthetic organisms to protect them from hazardous exposure (Kusmita et al., 2017). From a chemical point of view, carotenoid is a polyisoprenoid compound with two main groups: Carotenes are hydrocarbon carotenoid compounds made up of carbon and hydrogen atoms, whereas xanthophylls are oxygenated hydrocarbon derivatives with one oxygen functional moieties such as hydroxyl, keto and epoxy, methoxy, or carboxylic acid groups. Carotenoids are not only beneficial for pigmentation, but they also offer unique photochemical properties that provide the basis for their application as nutritional components, vitamin A precursor, prevention of human diseases like cancer, and an industrial perspective (Kirti et al., 2014).
Marine carotenoids can be used as skin photo protection against the damaging effects of UV radiation or as a nutraceutical/cosmeceutical ingredient to treat oxidative stress-related illnesses because they have potent antioxidant, healing, antiproliferative, and anti-inflammatory properties. Some carotenoid compounds are produced by marine species known as astaxanthin (red pigment), and they possess significant anti-free radical and pro-oxidant activity. Fucoxanthin is one of the most prevalent carotenoids in nature, especially in the marine environment, and it accounts for around 10% of total carotenoid production. Carotenoids like fucoxanthin, zeaxanthin, and lutein have antioxidant capabilities like ROS scavenging, DNA damage protection, protein and lipid oxidation protection. Canthaxanthin is a carotenoid that is derived from crustaceans and algae and can be used as anticancer agent in human colon adenocarcinoma cells, human and murine melanoma cells (SK-MEL-2, JB/MS, and B16F10), and fibro sarcoma cells (SK-MEL-2, JB/MS, and B16F10) (PYB6) (Galasso et al., 2017).