Engineering Crocin Production in Heterologous Host Plants

Crocins are a valuable group of water-soluble carotenoid pigments primarily biosynthesized in the stigmas of Crocus sativus L. (saffron) and the fruits of Gardenia jasminoides. Buddleja davidii also produces low quantities of crocin. Crocins are known for their pharmacological properties, including analgesic and sedative, antihypertensive, anti-atherosclerotic, anti-HSV-1, and anti-HIV-1, and useful in neurodegenerative diseases such as Alzheimer's and other neurological diseases, depression, dementia, and various liver ailments, including chemical liver injury, liver fibrosis, liver cancer, and so forth. However, their natural distribution is limited, leading to scarcity and high costs. Hence, there is a crucial prerequisite to design a green and effective strategy for the production of crocin. Recently, advancements in the synthesis of these metabolites using heterologous hosts have created opportunities for extensive and sustainable production of crocins, specifically the active phytocompounds, that is, crocin I and crocin II. Tomato, potato, citrus, and Nicotiana serve as the heterologous hosts for the production of apocarotenoids.