A new method for synthesizing terminal olefins from esters using the Corey-Chaykovsky reagent.

A new method for the synthesis of terminal olefins was developed through the reaction of the Corey-Chaykovsky reagent (dimethyl-sulfonium methylide) with readily available esters. After the domino process of nucleophilic addition, elimination and rearrangement in one pot, the terminal olefins were synthesized in high yields (up to 84%) under mild conditions. The synthetic method was well tolerated by many functional groups and a new route for the synthesis of various terminal olefin derivatives is provided. In the end, a possible reaction mechanism is proposed, which is supported by DFT calculations.

Rapidly screening of pancreatic lipase inhibitors from Clematis tangutica using affinity ultrafiltration-HPLC-QTOFMS technique combined with targeted separation, in vitro validation, and molecular docking.

INTRODUCTION: Screening of novel pancreatic lipase inhibitors from complex natural products is a meaningful task. OBJECTIVES: Through accurately screening and separating pancreatic lipase inhibitors from Clematis tangutica (C. tangutica), to discover new leading compounds for slimming and accelerate the development and utilization of Tibetan medicine resources. METHODS: An integrated strategy that combines affinity ultrafiltration and high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (AU-HPLC-QTOFMS), targeted separation, in vitro validation, and molecular docking was developed to screen pancreatic lipase inhibitors from C. tangutica. The AU-HPLC-QTOFMS technique was performed to fish for the potential active substances. Macroporous resin, preparative liquid chromatography, and high-speed countercurrent chromatography were implemented for the accurate and targeted separation of active compounds. The inhibitory activities of target compounds to pancreatic lipase were detected by the inhibition experiments in vitro. The binding affinities and binding sites were analyzed using molecular docking. RESULTS: A total of eleven kinds of pancreatic lipase inhibitory substances were screened from C. tangutica. Seven triterpenoid saponins were screened for the first time as lipase inhibitors and successfully prepared with purities higher than 97%. Tanguticoside B, clematangoticoside J, hederoside H1, and rutin showed stronger inhibitory effects with IC50 values of 1.539 ± 0.048, 1.661 ± 0.092, 1.793 ± 0.069, and 1.792 ± 0.094 mmol/l. Moreover, they have the lowest ΔG values of -10.84, -9.97, -10.87, and -9.39 kcal/mol to pancreatic lipase. CONCLUSION: The integrated strategy using AU-HPLC-QTOFMS, targeted separation, in vitro validation, and molecular docking was feasible for rapidly screening and directionally isolating pancreatic lipase inhibitors from C. tangutica.

Integrated strategy for the screening of cyclooxygenase-2 inhibitors from triterpenoid saponins in Clematis tangutica.

INTRODUCTION: Screening of novel cyclooxygenase-2 (COX-2) inhibitors from complex natural products is not an easy task. OBJECTIVES: To establish an efficient and feasible strategy for screening COX-2 inhibitors from triterpenoid saponins (TPSs) in Clematis tangutica. METHODS: Taking TPSs in C. tangutica as example, an optimized macroporous resin (MR) method was established for the enrichment of TPSs. High-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC-QTOFMS) was performed to establish the phytochemical profiling of TPSs. Molecular docking was performed to predict the ligand-target interactions and discover the active substances. Chemometric techniques were performed to visualize the structure-effect relationships. High-speed countercurrent chromatography and preparative HPLC were performed to prepare the targets. In vitro activity experiment of COX-2 was performed to verify the virtual screening results. RESULTS: TPSs in C. tangutica were well enriched with the recovery rate of (80.22 ± 2.37)%. Thirty-four kinds of TPSs of oleanane type were deduced by HPLC-QTOFMS. Five TPSs of clematangoside C, clematangoside D, clematangoticoside J, hederoside H1 , and hederasaponin B showed stronger binding abilities with COX-2. The structure with more sugar groups at C-28 may be more conducive to the combination with COX-2. Targets were prepared with purities all above 98%. The IC50 values of target TPSs were 6.03 ± 0.24, 12.44 ± 0.15, 9.36 ± 0.19, 4.78 ± 0.13, and 2.59 ± 0.11 µmol/L, respectively. CONCLUSION: The integrated strategy using MR, HPLC-QTOFMS, molecular docking, chemometrics, target preparation, and in vitro verification was feasible for rapidly screening COX-2 inhibitors from TPSs in C. tangutica.

[Comparison of mouse models of depression induced by different modeling methods].

The present article was aimed to compare the effectiveness of different induction methods for depression models. Kunming mice were randomly divided into chronic unpredictable mild stress (CUMS) group, corticosterone (CORT) group, and CUMS+CORT (CC) group. The CUMS group received CUMS stimulation for 4 weeks, and the CORT group received subcutaneous injection of 20 mg/kg CORT into the groin every day for 3 weeks. The CC group received both CUMS stimulation and CORT administration. Each group was assigned a control group. After modeling, forced swimming test (FST), tail suspension test (TST) and sucrose preference test (SPT) were used to detect the behavioral changes of mice, and the serum levels of brain-derived neurotrophic factor (BDNF), 5-hydroxytryptamine (5-HT) and CORT were detected with ELISA kits. Attenuated total refraction (ATR) spectra of mouse serum were collected and analyzed. HE staining was used to detect morphological changes in mouse brain tissue. The results showed that the weight of model mice from the CUMS and CC groups decreased significantly. There was no significant change in immobility time of model mice from the three groups in FST and TST, while the glucose preference of model mice from the CUMS and CC groups was significantly reduced (P < 0.05). The serum 5-HT levels of model mice from the CORT and CC groups were significantly reduced, while the serum BDNF and CORT levels of model mice from the CUMS, CORT, and CC groups showed no significant changes. Compared with their respective control groups, the three groups showed no significant difference in the one-dimensional spectrum of serum ATR. The difference spectrum analysis results of the first derivative of the spectrogram showed that the CORT group had the greatest difference from its respective control group, followed by the CUMS group. The structures of hippocampus in the model mice from the three groups were all destroyed. These results suggest that both CORT and CC treatments can successfully construct a depression model, and the CORT model is more effective than the CC model. Therefore, CORT induction can be used to establish a depression model in Kunming mice.

Separation of five flavone glycosides including two groups with similar polarities from Dracocephalum tanguticum by a combination of three high-speed counter-current chromatography modes.

The separation of compounds with similar polarities is challenging. In the present study, five flavone glycosides, including two groups with similar polarities, were obtained from Dracocephalum tanguticum by three high-speed counter-current chromatography modes, including flow rate conversion mode, recycling mode, and heart-cut mode. With flow rate conversion mode, compounds 3 and 4 with similar polarities and compound 5 were separated by high-speed counter-current chromatography with ethyl acetate/methanol/water (5.0% acetic acid) (8:2:10, v/v) system. The flow rate was controlled as: 1.8 mL/min for 0-160 min, 2.2 mL/min for 160-200 min, and 2.5 mL/min for 200-400 min. However, compounds 1 and 2 with similar polarities were not separated due to the similar distributive properties. Then, a recycling and heart-cut mode were introduced to improve the separation efficiency. The heart-cut mode was introduced in the second and third cycles, and compounds 1 and 2 were well separated in the fourth cycle. Consequently, five flavone glycosides, including two groups with similar polarities were obtained and identified as cosmosiin (1), pedaliin (2), quercetin-3-O-rutinoside (3), pedaliin-6''-acetate (4), and sorbifolin-6-O-ß-glucopyranoside (5). The current strategy provides a reference for separating compounds with similar polarities from a crude sample.

Separation of five flavonoids with similar polarity from Caragana korshinskii Kom. by preparative high speed counter-current chromatography with recycling and heart cut mode.

Five flavonoids with similar polarity were obtained from Caragana korshinskii Kom. by preparative high speed counter-current chromatography. Due to their similar polarity, it is difficult to select a suitable solvent system for one-step separation. Three fractions including one pure compound were only obtained with a relatively suitable solvent system of ethyl acetate: n-butanol:water (0.5% glacial acetic acid) (4:6:10, v:v:v). In order to improve the separation efficiency, recycling and heart cut modes were introduced. As a result, two flavonoids with separation factor value at 1.13 and the other two with separation factor value at 1.20 were successfully separated. Finally, five flavonoids with purity higher than 98% were obtained. Fortunately, a new compound named myricetin 3'-methyl ether 3-O-glucoside-7-O-rhamnoside was obtained. The results indicated that the recycling combined with heart-cut mode could be effective for the preparation of natural compounds with similar polarity.

Separation of a new triterpenoid saponin together with six known ones from Clematis tangutica (Maxim.) Korsh and evaluation of their cytotoxic activities.

A new triterpenoid saponin, 3-O-ß-D-allopyranosyl (1→3)-α-L-rhamnopyranosyl (1→2)-α-L-arabinopyranosyl hederagenin 28-O-α-L-rhamnopyranosyl (1→4)-ß-D-glucopyranosyl (1→6)-ß-D-glucopyranosyl ester (IV), together with six known ones Hederacholichiside F (I), Tanguticoside B (II), Tauroside St-H1 (III), Hederoside H1 (V), Kalopanaxsaponin G (VI), Hederasaponin B (VII) were separated from Clematis tangutica (Maxim.) Korsh. Their cytotoxic activities were evaluated. Saponins IV (new compound) and I showed selective inhibitory activities against HGC-27 with IC50 values of 20.17 and 66.18 µM. Saponin VII exhibited extensive inhibitory action against HGC-27, Hela and SK-OV-3 with IC50 values of 16.47-71.36 µM. Saponin III showed selective inhibitory activity against SK-OV-3 with the IC50 value of 48.70 µM. All isolated saponins were inactive (IC50 >150 µM) to GES-1.

Efficient One-Step Separation of Five Flavonoids from the Crude Extract of the Waste Pomace of Sea Buckthorn Berries through Counter-Current Chromatography.

The pomace of sea buckthorn berries is usually discarded when transforming into nonalcoholic or alcoholic beverages, jellies, jams, juices, candies and dairy products. Here, we established a promising approach for one step separation of five flavonoids from the waste pomace of sea buckthorn berries through counter-current chromatography. The crude extract of waste pomace of sea buckthorn berries after juicing was injected into counter-current chromatography with hexane/ethyl acetate/ethanol/water (v/v/v/v, 5:7:5:7) as the solvent system. As a result, five flavonoids, including quercetin, laricitrin, isorhamnetin-7-O-rhamnoside, kaempferol and isorhamnetin, were obtained in a single step separation. Our finding showed that ethanol is a good substitute for methanol to regulate the partition coefficient in hexane/ethyl acetate/ methanol/water system. This study provided a significant measure to utilize the waste pomace of Sea buckthorn berries.

Complete mitochondrial genome of the hybrid of Simmental and Qinghai local cattle breed (Bos taurus).

In this study, the complete mitochondrial DNA of the hybrid of Simmental and Qinghai local cattle breed was sequenced and analyzed. The total mitochondrial genome sequence is 16,339 bp in length including 1 control region (D-loop), 22 tRNA genes, 2 rRNA genes and 13 protein-coding genes. The description of all genes is similar to the typical mitochondrial genomes of cattle. All the protein-coding genes were located on the heavy strand (H strand) except for ND6. The COX3, ND3, and ND4 genes own incomplete stop codon.