Violacein
The violet pigment violacein is an indole derivative isolated primarily from bacteria of the genus Chromobacterium , which live in tropical and subtropical soil and water (Soliev et al., 2011). Bacteria which are found in a variety of natural environments, including marine, freshwater, and soil environments, could be able to produce violacein pigment. This bisindole is a secondary metabolite associated with biofilm production in the majority of violacein-producing bacterial strains isolated from nature. Violacein synthesis by C. violaceumhas been shown to be a useful indicator of quorum-sensing molecules and their inhibitors, and it is easy to monitor. The secondary metabolite violacein acts as a toxic sentinel, protecting against a variety of potential bacterial predators and competitors (Choi et al., 2015).Janthinobacterium lividum and Chromobacterium violaceumhad antipredator activity against bacterivorous nanoflagellates, indicating a protective function (Chatragadda & Dufossé, 2021).Pseudoalteromonas luteoviolacea is the sole marine bacterium producing violet pigment. Shewanella violacea , a deep-sea microorganism isolated from Ryukyu Trench sediments at a depth of 5110 m, also produced a violet pigment that was recently demonstrated to be a new alkylated indigoidine. The bacteria were isolated from seawater at Cape Muroto in Kochi Prefecture, Japan. Among the bacteria isolated, 13 strains of gram negative, rod-shaped bacteria produced a purple pigment similar to violacein (Yada et al., 2008).
Furthermore, violacein is extremely important in cosmetics, textiles, agriculture, and drug discovery. In the pharmaceutical industry, violacein has been used as an immunosuppressive, antinociceptive, analgesic, and antipyretic. According to animal studies, violacein pigment has been applied in ulcer rat models; it decreased gastrointestinal inflammation, perhaps through COX-1-mediated mechanisms. On the other hand, when violacein was injected directly into the intra-peritoneal cavity, it was discovered to have immune modulatory effects through controlling cytokine production; it let down the expression of IL-6 and TNF but increased the expression of IL-1. Non-specific toxicity is normally a drawback of chemotherapeutics, but violacein has been shown to induce apoptosis and have anti-tumor activity against unrepeatable particular tumour lamina lines, such as cancer lamina lines. Violacein seems to have antibiotic potential because of its strong antibacterial properties. Additionally, when combined with other antibiotics, the impact is more successful at killing bacteria than using antibiotics alone (Choi et al., 2015). Anti-protozoan, anti-cancer, anti-viral, antibacterial (both G+ and G-), and antioxidant properties have been discovered. Staphylococcus aureus, Neisseria meningitidis, Streptococcus sp., Bacillussp, Mycobacterium and Pseudomonas , among others is all inhibited by the antibacterial action. Based on these characteristics, violacein appears to be commercially viable for medicinal applications, and it has even been proposed for use in dermatology. Due to its toxicity in VERO and FRhK-4 cells, it has been claimed that violacein should be considered an in vitro genotoxic chemical to mammalian cells, although more research is needed before making any conclusions on violacein’s future therapeutic potential (Hakvåg et al., 2009).