Phytochemical Analysis of Nothapodytes tomentosa and Distribution and Content of Camptothecin and its Analogues in Four Plants

Abstract

Camptothecin (CPT) and its derivatives have attracted worldwide attention due to their notable anticancer activity. However, the growing demand for CPT in the global pharmaceutical industry has caused a severe shortage of CPT-producing plant resources. In this study, phytochemical analysis of Nothapodytes tomentosa resulted in the isolation and identification of CPT (13) and 16 analogues (1-12, 14-17), including a new (1) and five known (9, 10, 12, 15 and 17) CPT analogues with an open E-ring. In view of the potential anticancer activity of CPT analogues with an open E-ring, the fragmentation pathways and mass spectra profiles of these six CPT analogues (1, 9, 10, 12, 15 and 17) were investigated, providing a reference for the rapid detection of these compounds in other plants. Furthermore, based on the fragmentation patterns of CPT (13) and known analogues (2-8, 11, 14, 16, 18-26), the distribution and content of these compounds in different tissues of N. tomentosa, N. nimmoniana, Camptotheca acuminata, and Ophiorrhiza japonica were further studied. Our findings not only provide an alternative plant resource for further expanding the development and utilization of CPT and its analogues, but also lay a foundation for improving the utilization of known CPT-producing plant resources.

Identification and characterization of camptothecin tailoring enzymes in Nothapodytes tomentosa

“…In this process, a set of well-characterized natural biosynthetic enzymes are fundamental components, although some artificial enzymes with high catalytic efficiency have been synthesized (Huang et al, 2021). Our earlier research revealed a relatively high content of C-9 hydroxylated CPT derivatives in N. tomentosa (Li et al, 2023), resulting in the inaugural report of the isolation of 9-HCPT from a plant source. These findings underscore the potential for developing synthetic biology approaches to introduce C-9 decorations on CPT using natural biosynthetic enzymes.…”

“…C amptothecin (CPT) is a structurally unique monoterpenoid indole alkaloid found in a number of angiosperm plants, including Camptotheca acuminata (Nyssaceae), Nothapodytes tomentosa (Icacinaceae), and Ophiorrhiza pumila (Rubiaceae), among others (Pu et al, 2019;Li et al, 2023). Camptothecin has become increasingly relevant due to its extraordinary antitumor activity, which occurs through the selective inhibition of DNA topoisomerase I and induction of protein-linked DNA complex breaks (Hsiang et al, 1985).…”

“…C-9 functionalized CPT derivatives including 9-MCPT and 9-β-D-glucosyloxycamptothecin (9-GCPT) have previously been discovered in Nothapodytes nimmoniana (Wu et al, 2008) and O. pumila (Kitajima et al, 1998). Conspicuously, our recent phytochemical analysis of N. tomentosa has led to the first report of the isolation of 9-HCPT from a plant source (Li et al, 2023). Although the raw mass fraction of C-9 modified CPT derivatives in these plants is low, the existence (and likely accessibility) of the corresponding biosynthetic genes highlights the potential for producing C-9 modified CPT drugs through synthetic biology approaches.…”