Natural biosynthesis, pharmacological applications, and sustainable biotechnological production of ornamental plant-derived anthocyanin: beyond colorants and aesthetics.

Flowers have long been admired for their aesthetic qualities and have even found their way to be included in the human diet. Among the many chemical compounds found in flowers, anthocyanins stand out for their versatile applications in the food, cosmetic, and nutraceutical industries. The biosynthetic pathway of anthocyanins has been thoroughly studied in certain flower species, leading to the detection of key regulatory genes that can be controlled to enhance the production of anthocyanins via biotechnological methods. Nevertheless, the quantity and form of anthocyanins found in natural sources differ, both qualitatively and quantitatively, depending on the ornamental plant species. For this reason, research on in vitro plant cultures has been conducted for years in an attempt to comprehend how these essential substances are produced. Different biotechnological systems, like in vitro plant cell, organ, and tissue cultures, and transgenic approaches, have been employed to produce anthocyanins under controlled conditions. However, multiple factors influence the production of anthocyanins and create challenges during large-scale production. Metabolic engineering techniques have also been utilized for anthocyanin production in microorganisms and recombinant plants. Although these techniques are primarily tested at lab- and pilot-scale, limited studies have focused on scaling up the production. This review analyses the chemistry and biosynthesis of anthocyanin along with the factors that influence the biosynthetic pathway. Further emphasis has been given on strategies for conventional and non-conventional anthocyanin production along with their quantification, addressing the prevailing challenges, and exploring ways to ameliorate the production using the in vitro plant cell and tissue culture systems and metabolic engineering to open up new possibilities for the cosmetic, pharmaceutical, and food industries.