Chiral metal-organic frameworks grown in situ for monolithic capillary electrochromatographic enantioseparation.

Chiral metal-organic frameworks (CMOFs) with chiral selectivity are one of the high-quality stationary phases for capillary electrochromatography (CEC). However, there is a problem of unsatisfactory enantioseparation performance of capillary columns due to insufficient loading. In this work, a lamellar CMOF (Cu-TC) was grown in situ on the surface of the monolith in a capillary monolithic column to obtain a Cu-TC@monolithic column. The CEC system constructed based on the Cu-TC@monolithic column shows a satisfactory chiral separation performance. Compared with the Cu-TC-based coated column (Cu-TC@coated column), the enantioseparation performance of the CEC system based on the Cu-TC@monolithic column was greatly improved, and the resolutions (Rs) of the model analytes were increased by 80-500%. In addition, the effects of experimental conditions such as the number of cycles of Cu-TC in situ growth, buffer concentration, buffer pH, organic solvent addition and applied voltage on the performance of CEC were also investigated. Finally, the chiral selection mechanism of the stationary phase was explored by selective adsorption experiments. The present work provides a new idea for the development of capillary stationary phases, which has great potential considering the diversity of CMOFs.

Design, synthesis and antitumor activity of novel 4-methyl-(3'S,4'S)-cis-khellactone derivatives.

An asymmetric synthesis of a series of novel 4-methyl-(3'S,4'S)-cis-khellactone derivatives 3a-o is reported for the first time. Their structures were confirmed by 1H-NMR, 13C-NMR and MS. Their cytotoxic activity was evaluated by the MTT assay against three selected human cancer cell lines: HEPG-2 (human liver carcinoma), SGC-7901 (human gastric carcinoma), LS174T (human colon carcinoma). Some compounds showed high inhibitory activity against these human cancer cell lines. Among them, compound 3a exhibited strong cytotoxicity, with IC50 values ranging from 8.51 to 29.65 µM. The results showed that 4-methyl-cis-khellactone derivatives with S,S configuration could be a potential antitumor agents.

Pharmacokinetics and tissue distribution study of Praeruptorin D from Radix peucedani in rats by high-performance liquid chromatography (HPLC).

Praeruptorin D (PD), a major pyranocoumarin isolated from Radix Peucedani, exhibited antitumor and anti-inflammatory activities. The aim of this study was to investigate the pharmacokinetics and tissue distribution of PD in rats following intravenous (i.v.) administration. The levels of PD in plasma and tissues were measured by a simple and sensitive reversed-phase high-performance liquid chromatography (HPLC) method. The biosamples were treated by liquid-liquid extraction (LLE) with methyl tert-butyl ether (MTBE) and osthole was used as the internal standard (IS). The chromatographic separation was accomplished on a reversed-phase C(18) column using methanol-water (75:25, v/v) as mobile phase at a flow rate of 0.8 mL/min and ultraviolet detection wave length was set at 323 nm. The results demonstrate that this method has excellent specificity, linearity, precision, accuracy and recovery. The pharmacokinetic study found that PD fitted well into a two-compartment model with a fast distribution phase and a relative slow elimination phase. Tissue distribution showed that the highest concentration was observed in the lung, followed by heart, liver and kidney. Furthermore, PD can also be detected in the brain, which indicated that PD could cross the blood-brain barrier after i.v. administration.