Densely Functionalized Macrocyclic Sesquiterpene Pyridine Alkaloids from Maytenus austroyunnanensis.

Eleven densely functionalized new dihydro-ß-agarofuran sesquiterpenoid derivatives, named maytenoids A-K (1-11), as well as one known analog, were isolated and characterized from Maytenus austroyunnanensis. Their structures were assigned based on analysis of spectroscopic data and X-ray crystallography. Compounds 1-9 are macrocyclic sesquiterpene pyridine alkaloids generated by the respective acylation of the hydroxy groups at C-3 and C-13 of dihydro-ß-agarofuran sesquiterpenoids via diverse pyridine dicarboxylic acids. Compounds 1, 2, 5-10, and 12 exhibited significant inhibitory effects on NO production at 10 µM in lipopolysaccharide (LPS)-stimulated BV2 cells.

Two New Cytotoxic Maytansinoids Targeting Tubulin from Trewia nudiflora.

Two new maytansinoids, N-methyltreflorine (1: ) and methyltrewiasine (2: ), were isolated from the dried fruits of Trewia nudiflora, together with three known congeners (3:  - 5: ). Their structures were elucidated by spectroscopic methods, and the absolute configuration of 1: and 2: was determined by X-ray crystallographic analysis. Compounds 1:  - 5: exhibited strong cytotoxicity against human tumor cell lines, including HeLa, MV-4 - 11, and MCF-7, with IC50 values ranging from 0.12 to 11 nM. Compounds 1: and 4: also showed inhibitory activity against the MCF-7/ADR cell line with IC50 values of 13 and 28 nM, respectively. Compounds 1: and 2: significantly inhibited tubulin polymerization in vitro with IC50 values of 3.6 and 3.2 µM, respectively.

Determination of maytansinoids in Trewia nudiflora using QuEChERS extraction combined with HPLC.

Three maytansinoids with strong cytotoxicities, dehydrotrewiasine, maytanbutine, and trewiasine, were isolated and identified from Trewia nudiflora, and maytanbutine was obtained from this plant for the first time. A quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction combined with high-performance liquid chromatography (HPLC) was established to determine the three maytansinoids in T. nudiflora. The effects of major factors on the extraction efficiency of the QuEChERS method were evaluated and the optimal conditions using acetonitrile-ethyl acetate (1:1, v/v) as the extraction solvent and PestiCarb as the clean-up sorbents were established. Compared with Soxhlet extraction (SE) and ultrasonic-assisted extraction (UAE), the QuEChERS method was easy-to-operate and afforded a cleaner extract. A phenomenex HyperClone BDS C18 column was used for HPLC analysis. Methanol-acetonitrile-water was chosen as mobile phase for gradient elution. Method validation showed that all analytes showed good linearity (r > 0.999) over the investigated ranges and satisfactory recoveries ranging from 95.0% to 105.0%. The developed QuEChERS-HPLC method was simple, efficient, and applicable to the determination of maytansinoids in T. nudiflora.

Four new species of Gesneriaceae from Yunnan, Southwest China.

Four new species of Gesneriaceae from Yunnan, southwest China, are described and illustrated. They are Petrocosmea rhombifolia, Petrocosmea tsaii, Didymocarpus brevipedunculatus, and Henckelia xinpingensis. Diagnostic characters between the new species and their morphologically close relatives are provided. Their distribution, ecology, phenology, and conservation status are also described.

Anticancer effect of the traditional Chinese medicine herb Maytenus compound via the EGFR/PI3K/AKT/GSK3ß pathway.

BACKGROUND: Cancer is a leading cause of death worldwide; folk anticancer medicinal plants have applied for cancer treatment. The Maytenus compound tablet as traditional Chinese compound medicine has been approved for alleviating hyperplasia of mammary glands, whether it can inhibit cancer still unknown. The study was to evaluate the anticancer activity of the Maytenus compound tablet. METHODS: MTS assay evaluated the anti-proliferation effect of the Maytenus compound on H226, A2058, 786O and HeLa cancer cells and two normal epithelial cell lines, namely, 16HBE and Hecate. Nude mouse xenograft tumor model using H226 and HeLa cells examined the drug's anticancer effect in vivo. Western blot assay studied the possible mechanism. RESULTS: The Maytenus compound indicated obvious ability to against proliferation in four strains of cancer cells, particularly against H226 cells by an IC50 of 85.47±10.06 µg/mL and against HeLa cells by an IC50 of 128.74±17.46 µg/mL. However, it had a low cytotoxicity in human normal epithelial cell lines 16HBE with an IC50 of 4,555.86±25.21 µg/mL and Hecate with an IC50 of 833.56±181.88 µg/mL. The Maytenus compound at the 2.45 g/kg oral dosages inhibited the proliferation of H226 cells and HeLa cells in nude mouse with inhibitory rates of 36.06% and 26.45%, respectively, and no organ toxicity. The Maytenus compound could significantly downregulate the expression of pEGFR, pPI3K, pAKT, pGSK3ß, ß-catenin, and c-MYC and upregulate the protein expression of GSK3ß. CONCLUSIONS: The Maytenus compound has significant anticancer activities against human cancer H226 and HeLa cells both in vitro and in vivo, highlighting it may be an anticancer medicine.

[Diversity and distribution of the threatened medicinal vascular plants in Lancang].

The rich diversity in medicinal plants provides an important material basic for the development of Traditional Chinese medicine in China. It is important to explore the present situation of medicinal plants within special regions in order to provide scientific instructions for their sustainable protection and exploitation and utilization. In this study, we carried out the field survey according to the guideline of national survey of Chinese material medica resources and the guideline of plant species diversity survey and estimation at county level with the line transect method. With the field surveyed data, we explored the diversity and distribution of the threatened medicinal vascular plants in Lancang. We found that there were 33 species of the threatened medicinal vascular plants in this county. These species were from 23 genera and 17 families, and were composed of one critical endangered, 10 endangered and 22 vulnerable species. They were widely distributed across the whole county and were most concentrated in the town of Nuozhadu, Fazhanhe, Nuofu and Zhutang, which were located in the southeastern, southwestern and western of Lancang, respectively. We also found that the plant species richness followed a unimodal pattern along elevation. In addition, we found that the areas of Nuozhadu Nature Reserve in Lancang only covered six threatened medicinal vascular plants, while most of the regions with high species richness were not well protected. Therefore, we proposed to make more efforts to improve the protection measurements in order to better protect and utilize the medicinal plants in Lancang.