Insights into chlorogenic acids' efficient biosynthesis through Carthamus tinctorius cell suspension cultures and their potential mechanism as -glucosidase inhibitors

Carthamus tinctorius is commonly used as food and medicine because it contains various bioactive components, particularly chlorogenic acids (CGAs). However, few research works focused on the development and application of C. tinctorius-derived CGAs. In this study, the technology system for efficient CGAs biosynthesis through C. tinctorius cells was successfully developed, and the feasibility of C. tinctorius cells-derived CGAs as a-glucosidase inhibitors was evaluated. At first, the inflorescence explant was used to induce C. tinctorius embryogenic callus (induction rate: 95%), in which a total of 10 CGAs, including rare caffeoyl and feruloyl-substituted derivatives, were identified and quantified by liquid chromatography-mass spectrometry. Secondly, an excellent C. tinctorius cell suspension culture was established. To further promote CGAs biosynthesis, parameters of elicitation combined with precursor feeding were optimized through Plackett-Burman's Design and Central Composite Design. Under the optimal condition [cinnamic acid: 283.05 mu M, methyl jasmonate: 80.98 mu M and yeast extract: 666.66 mg center dot L-1], CGAs content could reach up to 103.234 mg center dot g(-1) (DW), which was 2.55 times that of the cells in the initial condition. The CGAs production first time reached the highest level among plant-cultured cells in the available literature. At last, the inhibition activity test results indicated good inhibitory activities of C. tinctorius cells-derived CGAs against a-glucosidase (IC50: 0.15-1.38 g center dot L-1), especially di- and tri-acyl CGAs. Moreover, molecular docking simulation showed that these CGAs could interact with the active site pocket of a-glucosidase to thereby achieve the inhibitory activity. Therefore, these results provided a solid foundation for the large-scale production of CGAs and revealed the application prospects of CGAs in functional food and pharmaceutical industries as a-glucosidase inhibitor.