Mass Spectrometry-Imaging Analysis of Active Ingredients in the Leaves of Taxus cuspidata

BACKGROUND

Taxus cuspidata is an endangered evergreen conifer mainly found in Northeast Asia. In addition to the well-known taxanes, several active ingredients were detected in the leaves of T. cuspidata. However, the precise spatial distribution of active ingredients in the leaves of T. cuspidata is largely unknown.

RESULTS

in the present study, timsTOF flex MALDI-2 analysis was used to uncover the accumulation pattern of active ingredients in T. cuspidata leaves. In total, 3084 ion features were obtained, of which 944 were annotated according to the mass spectrometry database. The principal component analysis separated all of the detected metabolites into four typical leaf tissues: mesophyll cells, upper epidermis, lower epidermis, and vascular bundle cells. Imaging analysis identified several leaf tissues that specifically accumulated active ingredients, providing theoretical support for studying the regulation mechanism of compound biosynthesis. Furthermore, the relative accumulation levels of each identified compound were analyzed. Two flavonoid compounds, ligustroflavone and Morin, were identified with high content through quantitative analysis of the ion intensity.

CONCLUSIONS

our data provides fundamental information for the protective utilization of T. cuspidata.

Chemoselective Electrochemical Cleavage of Sulfonimides as a Direct Way to Sulfonamides

A new method for selective cleavage of sulfonimides into sulfonamides in high yields using a simple electrochemical approach is shown. As revealed by the electrochemical study, the aromatic sulfonimides can be selectively cleaved by electrolysis of the starting compound at a given potential (only -0.9 V vs SCE for the nosyl group). The high chemoselectivity was confirmed by preparative electrolysis, and the results were supported with DFT calculations of a set of substances bearing different sulfonimide functions. Moreover, various experimental setups together with other attempts to simplify the procedure were tested. Finally, the removal of the p-nosyl group from the corresponding sulfonimides proceeds smoothly regardless of the number of nosyl groups and the overall shape of the complex molecule. Thus, the method is interesting for use in the field of multifunctional molecules such as calix[n]arenes.

Synthesis of novel flavone derivatives possessing substituted benzamides and their biological evaluation against human cancer cells

Baicalein is a well-known flavone derivative that possesses diverse biological properties, such as anticancer, antioxidant and anti-inflammatory activities. Numerous baicalein derivatives, including 5,6,7-trimethoxyflavone, have been synthesized with the aim of enhancing its inherent biological activities. In the present work, new flavones, possessing an N-aroylamine-substituent on the B-ring, were synthesized to improve the cytotoxicity of baicalein and 5,6,7-trimethoxyflavone against human cancer cell lines. The majority of the flavones synthesized exhibited greater cytotoxicity than baicalein and 5,6,7-trimethoxyflavone against HepG2 and MCF-7 cells. Among them, compounds 5n, possessing a 3-methoxybenzoylamino group, exhibited great cytotoxic effects on HepG2 (GI50=7.06μM) and MCF-7 (GI50=7.67μM) cells. In contrast, N-aroylamine-substituted 5-hydroxy-6,7-dimethoxyflavone derivatives showed greater cytotoxicity against MCF-7 than HepG2 cells, indicating that the replacement of a 5-methoxy group on the A-ring with a 5-hydroxy group has a marked influence on the cytotoxicity profile.

Mining the Chemical Space: Application of 2/4-Nitrobenzenesulfonamides in Solid-Phase Synthesis

Polymer-supported benzenesulfonamides prepared from various immobilized primary amines and 2/4-nitrobenzenesulfonyl chloride have been used as key intermediates in different chemical transformations, including unusual rearrangements to yield a number of diverse privileged scaffolds. This review summarizes individual strategies in their application to date.