The study investigated the extraction of alkaloids and glycosides from the Camptotheca acuminata Decne using deep eutectic solvent (DES). 18 types of deep eutectic solvents (DESs) were prepared, and it was found that the extraction performance of choline chloride (ChCl)-formic acid (FA) was optimal, surpassing traditional solvents such as methanol/70 % methanol. In comparison to methanol, the extracted amount of compounds by DES was 2–3 times higher. The extraction processes involving the molar ratio of ChCl-FA, pH, DES/H 2 O mass ratio, solid/liquid ratio, as well as ultrasonic power were optimized. A mathematical model for solid/liquid extraction kinetics from Camptotheca acuminata Decne was developed. The extraction mechanism was investigated using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and 1 H nuclear magnetic resonance( 1 H NMR). The results revealed that the DES caused dissociation in Camptotheca acuminata Decne and formed hydrogen bonds with Camptothecin (CPT). Meanwhile, density functional theory (DFT) calculations verified that FA-based exhibited the highest extracted amount for CPT. In addition, this study investigated the recovery rate of DES, and the results showed that after 10 cycles, the DES system remained effective for the extraction of alkaloids and glycosides.
The biosynthetic route for flavonol in Camptotheca acuminata has been recently elucidated from a chemical point of view. However, the genes involved in flavonol methylation remain unclear. It is a critical step for fully uncovering the flavonol metabolism in this ancient plant. In this study, the multi-omics resource of this plant was utilized to perform flavonol O -methyltransferase-oriented mining and screening. Two genes, CaFOMT1 and CaFOMT2 are identified, and their recombinant CaFOMT proteins are purified to homogeneity. CaFOMT1 exhibits strict substrate and catalytic position specificity for quercetin, and selectively methylates only the 4′-OH group. CaFOMT2 possesses sequential O -methyltransferase activity for the 4′-OH and 7-OH of quercetin. These CaFOMT genes are enriched in the leaf and root tissues. The catalytic dyad and critical substrate-binding sites of the CaFOMTs are determined by molecular docking and further verified through site-mutation experiments. PHE181 and MET185 are designated as the critical sites for flavonol substrate selectivity. Genomic environment analysis indicates that CaFOMT s evolved independently and that their ancestral genes are different from that of the known Ca10OMT . This study provides molecular insights into the substrate-binding pockets of two new CaFOMTs responsible for flavonol metabolism in C. acuminata .
危险品化学品经营许可证（带存储）