A Review on Phytochemicals of the Genus Maytenus and Their Bioactive Studies.

The genus Maytenus is a member of the Celastraceae family, of which several species have long been used in traditional medicine. Between 1976 and 2021, nearly 270 new compounds have been isolated and elucidated from the genus Maytenus. Among these, maytansine and its homologues are extremely rare in nature. Owing to its unique skeleton and remarkable bioactivities, maytansine has attracted many synthetic endeavors in order to construct its core structure. In this paper, the current status of the past 45 years of research on Maytenus, with respect to its chemical and biological activities are discussed. The chemical research includes its structural classification into triterpenoids, sesquiterpenes and alkaloids, along with several chemical synthesis methods of maytansine or maytansine fragments. The biological activity research includes activities, such as anti-tumor, anti-bacterial and anti-inflammatory activities, as well as HIV inhibition, which can provide a theoretical basis for the better development and utilization of the Maytenus.

Occurrence and spatial distribution of maytansinoids in Putterlickia pyracantha, an unexplored resource of anticancer compounds.

Maytansinoids possess remarkable antibiotic activities along with high cytotoxicity, many of which are currently used (or in clinical trials) in the treatment of breast cancer. Celastraceous plants and their associated microorganisms serve as an important resource of maytansinoids. Here, we report the occurrence and structural elucidation of several maytansinoids in Putterlickia pyracantha plants bioprospected in South Africa. In addition to maytansine, which is already known to be present in this species, we show the presence of maytanprine, maytanbutine, maytanvaline, normaytancyprine and an abundant maytansine precursor in different tissues using high-resolution mass spectrometry. Furthermore, we identified two new hydroxylated maytansinoids by HRMS(2) analyses. We also employed MALDI-imaging-HRMS to study the spatial distribution and localization of the maytansinoids within the different plant tissues. On the one hand, the fragmentation pathways of the maytansinoids we report herein using HRMS(n) will allow quick identification of these compounds in the future without isolating from the natural resources. On the other hand, MALDI-imaging-HRMS revealed insights into the plausible ecological roles and biosynthetic pathways of these compounds in P. pyracantha plants.