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.

CYP712K4 Catalyzes the C-29 Oxidation of Friedelin in the Maytenus ilicifolia Quinone Methide Triterpenoid Biosynthesis Pathway.

The native Brazilian plant Maytenus ilicifolia accumulates a set of quinone methide triterpenoids with important pharmacological properties, of which maytenin, pristimerin and celastrol accumulate exclusively in the root bark of this medicinal plant. The first committed step in the quinone methide triterpenoid biosynthesis is the cyclization of 2,3-oxidosqualene to friedelin, catalyzed by the oxidosqualene cyclase friedelin synthase (FRS). In this study, we produced heterologous friedelin by the expression of M. ilicifolia FRS in Nicotiana benthamiana leaves and in a Saccharomyces cerevisiae strain engineered using CRISPR/Cas9. Furthermore, friedelin-producing N. benthamiana leaves and S. cerevisiae cells were used for the characterization of CYP712K4, a cytochrome P450 from M. ilicifolia that catalyzes the oxidation of friedelin at the C-29 position, leading to maytenoic acid, an intermediate of the quinone methide triterpenoid biosynthesis pathway. Maytenoic acid produced in N. benthamiana leaves was purified and its structure was confirmed using high-resolution mass spectrometry and nuclear magnetic resonance analysis. The three-step oxidation of friedelin to maytenoic acid by CYP712K4 can be considered as the second step of the quinone methide triterpenoid biosynthesis pathway, and may form the basis for further discovery of the pathway and heterologous production of friedelanes and ultimately quinone methide triterpenoids.

Seasonal variation of gastroprotective terpenoids in Maytenus robusta (Celastraceae) quantified by gas chromatography-flame ionization detection (GC-FID).

The triterpenes friedelin (1), ß-friedelinol (2) and 3,15-dioxo-21α-hydroxyfriedelane (3) in the aerial parts of Maytenus robusta, a Brazilian medicinal plant with antiulcer potential, were seasonally quantified by gas chromatography flame-ionization detection (GC-FID) using an external standard. The method was found to be linear, precise and sensitive. Compounds 1 and 2 were found in M. robusta leaves and branches, with highest concentrations in the leaves collected in autumn, i.e. 3.21 ± 0.16 and 12.60 ± 1.49 mg g-1 dry weight of 1 and 2, respectively. On the other hand, compound 3 was found only in the branches, with the highest concentrations in winter and autumn (0.21 ± 0.01 and 0.20 ± 0.02 mg g-1). The results allow to define the optimal season and plant parts for the collection of M. robusta as a phytotherapeutic drug.

Espinheira-santa (Maytenus ilicifolia Mart. ex Reiss.): saber de erveiros e feirantes em Pelotas (RS) / Espinheira-santa (Maytenus ilicifolia Mart. ex Reiss.): knowledge by herbalists and marketers in Pelotas (RS)

RESUMO O objetivo deste trabalho é descrever o conhecimento popular relacionado à espinheira-santa (Maytenus ilicifolia) entre erveiros e feirantes que comercializam a planta no centro de Pelotas, Rio Grande do Sul, Brasil. Foi realizada uma pesquisa de abordagem qualitativa, exploratória e descritiva, de agosto a outubro de 2013. Entrevistas semi-estruturadas, com questões sobre os saberes e práticas relacionados à espinheira-santa, foram aplicadas a cinco erveiros e três feirantes do mercado informal de plantas medicinais. Para a análise dos dados foi utilizada a proposta operativa de Minayo, sendo Capra o referencial teórico para este estudo. Foi verificado que o saber relacionado ao uso da espinheira-santa é transmitido de geração a geração, embora existam outras fontes de conhecimento. As indicações do uso popular da espinheira-santa com finalidade terapêutica estão relacionadas a distúrbios gástricos, cicatrização e depuração do sangue. As diferentes formas dos sujeitos deste estudo interagirem com o ambiente, com sua família e em outras relações interpessoais resultam em diferentes saberes relacionados à espinheira-santa.

ABSTRACT The aim of this study was to describe the popular knowledge related to the espinheira-santa (Maytenus ilicifolia) among herbalists and marketers that sell this plant in the center of Pelotas/Rio Grande do Sul State, Brazil. A qualitative, exploratory and descriptive research was performed between August and July of 2013. Semi-structured interviews, with questions regarding the knowledge and practices related to this plant, were applied to five herbalists and three marketers inserted in the informal market of medicinal plants. The operative proposal by Minayo was used in order to analyze the data, and the theoretical framework by Capra was used in the discussion. The popular knowledge related to the use of espinheira-santa is passed on from generation to generation, although nowadays there are other sources ofinformation. The popular clueswith therapeutic purposes are related to gastric disorders, healing and blood clearance. The study participants have different forms of interaction with the environment, the family and other interpersonal relationships, resulting in different popular knowledges related to this medicinal plant.

Evaluation of antioxidant capacity and synergistic associations of quinonemethide triterpenes and phenolic substances from Maytenus ilicifolia (Celastraceae).

This work describes the isolation of the secondary metabolites identified as the quinonemethides maytenin (1) and pristimerin (2) from Maytenus ilicifolia extracts obtained from root barks of adult plants and roots of seedlings and their quantification by high performance liquid chromatography coupled to a diode array detector. The electrochemical profiles obtained from cyclic voltammetry and a coulometric detector coupled to high-performance liquid chromatography contributed to the evaluation of their antioxidant capacity. The antioxidant properties of individual components and the crude extracts of the root barks of Maytenus ilicifolia were compared and the possible synergistic associations of quinonemethide triterpenes and phenolic substances were investigated by using rutin as a model phenolic compound.

Folate receptor-specific antitumor activity of EC131, a folate-maytansinoid conjugate.

EC131, a new folate receptor (FR)-targeted drug conjugate, was prepared by covalently attaching the vitamin folic acid (FA) to a potent microtubule-inhibiting agent, maytansinoid DM1, via an intramolecular disulfide bond. When tested on cells in culture, EC131 was found to retain high affinity for FR-positive cells and to provide FR-specific cytotoxicity with an IC(50) in the low nanomolar range. The activity of EC131 was completely blocked in the presence of an excess of free FA, and no activity was detected against FR-negative cells. When evaluated against s.c. FR-positive M109 tumors in BALB/c mice, EC131 showed marked antitumor efficacy. Furthermore, this therapeutic effect occurred in the apparent absence of weight loss or noticeable organ tissue degeneration. In contrast, no significant antitumor activity was observed in EC131-treated animals that were codosed with an excess of FA, thus demonstrating the targeted specificity of the in vivo activity. EC131 also showed marked antitumor activity against FR-positive human KB tumors, but not against FR-negative A549 tumors, in nude mice with no evidence of systemic toxicity during or after the therapy. In contrast, therapy with the free maytansinoid drug (in the form of DM1-S-Me) proved not to be effective against the KB model when administered at its maximum tolerated dose (MTD). Taken together, these results indicate that EC131 is a highly potent agent capable of producing therapeutic benefit in murine tumor models at sub-MTD levels.