Less Configuration and More Dimensionality: Preparative Heart-Cut Multidimensional Liquid Chromatography Based on Trapping Arrays.

The resolving power of multiple dimensional liquid chromatography (mD-LC) is multiplicative as it adds dimensions. However, the issue in creating a preparative mD-LC system is that the higher the dimensionality, the more complicated the system configuration. Thus, we presented a new configuration of preparative mD-LC using one set of LC modules and trapping array-based multiple heart-cut interfaces. A preparative two-dimensional liquid chromatography (2D-LC) separation of herbal medicine formulation produced 40 compounds with a purity of >90%. During the separation process, the interface stores the fractions and allocates positions for the fractions from a different dimension; LC draws the fraction from the interface, makes nD separation, and sends isolated fractions to the interface. By repeating this process, we achieved variable dimensionality of LC separations. We also presented a preparative 3D-LC separation of herbal medicines to validate the principle of "less configuration and more dimensionality". Thus, we can explore the higher dimensional preparative separations. The developed preparative mD-LC displayed exceptional power in the isolation of various compounds and has great potential in the application of natural products.

[Trapping array-based preparative two-dimensional liquid chromatography for the purification of four components in tobacco leaves].

Two-dimensional liquid chromatography (2D-LC) has gained increased attention because of its high peak capacity for separating complex samples. However, preparative 2D-LC aimed at isolating compounds is significantly different compared with one-dimensional liquid chromatography (1D-LC) in terms of method development and system configuration; thus, it is less developed than its analytical counterpart. The use of 2D-LC in large-scale product preparation has rarely been reported. Hence, a preparative 2D-LC system was developed in this study. The system was composed of one set of preparative LC modules as a separation system, with a dilution pump, switch valves, and trap column array as the interface, to enable the simultaneous isolation of several compounds. Tobacco was used as a sample, and the developed system was applied to isolate nicotine, chlorogenic acid, rutin, and solanesol. The chromatographic conditions were developed by investigating the trapping efficiency of different types of trap column packings, and chromatographic behaviors under different overload conditions. The four compounds were isolated in one 2D-LC run with high purity. The developed system features low cost because it employs medium-pressure isolation, excellent automation owing to its use of an online column switch, high stability, and capability for large-scale production. The isolation of chemicals from tobacco leaves as pharmaceutical raw materials could aid in the development of the tobacco industry and promote the local agricultural economy.

Photocatalytic Markovnikov-type addition and cyclization of terminal alkynes leading to 4-sulfonyl quinoline-2(1H)-ones.

A new and expedient photocatalytic protocol for the construction of quinolin-2(1H)-ones via Markovnikov-type sulfonylation/6-endo-trig cyclization/selective C(O)-CF3 bond cleavage starting from N-alkyl-N-(2-ethynylphenyl)-2,2,2-trifluoroacetamides and sulfinic acids has been developed. It is as an unprecedented protocol for the preparation of 4-sulfonylquinoline-2(1H)-ones with high efficiency, mild reaction conditions, acceptable yields and a wide range of substrates.

Protective Effect of Lemon Peel Extract on Oxidative Stress in H9c2 Rat Heart Cell Injury.

AIM: Lemon peel, a traditional Chinese medicine, was tested in this study for its novel application in inhibiting cellular oxidative stress, and the effect of lemon peel extract (LPE) on protecting H9c2 rat heart cells from oxidative stress was investigated. METHODS: The scavenging effects of LPE on 1,1-diphenyl-2-picryhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) free radicals were measured in extracellular experiments. The 3-(4,5-dimethyl-2-thiazolinyl)-2,5-diphenyl-2-h-tetrazolylammonium bromide (MTT) assay was used to detect the cell survival rate. The cell supernatant and intracellular oxidation-related indicators were detected by a kit, and the mRNA expression in H9c2 cells was detected by quantitative polymerase chain reaction (qPCR). The chemical substances of LPE were analyzed by high-performance liquid chromatography (HPLC). RESULTS: The results showed that LPE exhibited better DPPH and ABTS free radical scavenging abilities than vitamin C. Compared with the cells in the normal state (control group), the cell survival rate in the model group decreased, and the level of lactate dehydrogenase (LDH) increased, the levels of superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) decreased, and the content of malondialdehyde (MDA) increased. Compared with the control group, the expression of Bcl-2-related X protein (Bax), caspase-3, nuclear factor erythroid 2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) in the model group was increased, and the expression of B-cell lymphoma-2 (Bcl-2) was reduced. Compared with the model group, LPE treatment improved the cell survival rate, reduced the levels of LDH and MDA, increased the levels of SOD, CAT, and GSH, downregulated the expression of Bax, caspase-3, Nrf2 and HO-1, and upregulated the expression of Bcl-2. The composition analysis showed that LPE contained catechin, rutin, naringin, quercetin, and hesperidin. CONCLUSION: The results indicated that LPE could protect H9c2 cells from oxidative stress through five active components. LPE has the potential to be developed into natural medicine or health food for the inhibition of cell oxidative damage.