A SARS-CoV-2 Mpro fluorescent sensor for exploring pharmacodynamic substances from traditional Chinese medicine.

The main protease of SARS-CoV-2 (SARS-CoV-2 Mpro) plays a critical role in the replication and life cycle of the virus. Currently, how to screen SARS-CoV-2 Mpro inhibitors from complex traditional Chinese medicine (TCM) is the bottleneck for exploring the pharmacodynamic substances of TCM against SARS-CoV-2. In this study, a simple, cost-effective, rapid, and selective fluorescent sensor (TPE-S-TLG sensor) was designed with an AIE (aggregation-induced emission) probe (TPE-Ph-In) and the SARS-CoV-2 Mpro substrate (S-TLG). The TPE-S-TLG sensor was characterized using UV-Vis absorption spectroscopy, fluorescence spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), zeta potential, and Fourier transform infrared (FTIR) spectroscopy techniques. The limit of detection of this method to detect SARS-CoV-2 Mpro was measured to be 5 ng mL-1. Furthermore, the TPE-S-TLG sensor was also successfully applied to screen Mpro inhibitors from Xuebijing injection using the separation and collection of the HPLC-fully automatic partial fraction collector (HPLC-FC). Six active compounds, including protocatechualdehyde, chlorogenic acid, hydroxysafflower yellow A, caffeic acid, isoquercetin, and pentagalloylglucose, were identified using UHPLC-Q-TOF/MS that could achieve 90% of the Mpro inhibition rate for the Xuebijing injection. Accordingly, the strategy can be broadly applied in the detection of disease-related proteases as well as screening active substances from TCM.

Self-Assembled Matrine-PROTAC Encapsulating Zinc(II) Phthalocyanine with GSH-Depletion-Enhanced ROS Generation for Cancer Therapy.

The integration of a multidimensional treatment dominated by active ingredients of traditional Chinese medicine (TCM), including enhanced chemotherapy and synergistically amplification of oxidative damage, into a nanoplatform would be of great significance for furthering accurate and effective cancer treatment with the active ingredients of TCM. Herein, in this study, we designed and synthesized four matrine-proteolysis-targeting chimeras (PROTACs) (depending on different lengths of the chains named LST-1, LST-2, LST-3, and LST-4) based on PROTAC technology to overcome the limitations of matrine. LST-4, with better anti-tumor activity than matrine, still degrades p-Erk and p-Akt proteins. Moreover, LST-4 NPs formed via LST-4 self-assembly with stronger anti-tumor activity and glutathione (GSH) depletion ability could be enriched in lysosomes through their outstanding enhanced permeability and retention (EPR) effect. Then, we synthesized LST-4@ZnPc NPs with a low-pH-triggered drug release property that could release zinc(II) phthalocyanine (ZnPc) in tumor sites. LST-4@ZnPc NPs combine the application of chemotherapy and phototherapy, including both enhanced chemotherapy from LST-4 NPs and the synergistic amplification of oxidative damage, through increasing the reactive oxygen species (ROS) by photodynamic therapy (PDT), causing an GSH decrease via LST-4 mediation to effectively kill tumor cells. Therefore, multifunctional LST-4@ZnPc NPs are a promising method for killing cancer cells, which also provides a new paradigm for using natural products to kill tumors.

An aggregation-induced emission sensor combined with UHPLC-Q-TOF/MS for fast identification of anticoagulant active ingredients from traditional Chinese medicine.

Xuebijing injection (XBJ) has a good therapeutic effect on the patients with severe coronavirus disease, but the material basis of XBJ with the anticoagulant effect to improve the coagulopathy and thromboembolism is still unclear. Herein, we developed a new strategy based on aggregation-induced emission (AIE) for monitoring thrombin activity and screening thrombin inhibitors from XBJ. The molecule AIE603 and the thrombin substrate peptide S-2238 were formed into AIE nanoparticle (AIENP) which emitted notable fluorescence due to the restriction of intramolecular motions. In the presence of thrombin, AIENP was specifically hydrolyzed and AIE603 was released from AIENP, leading to the decrease of fluorescence intensity. Furthermore, AIENP was combined with ultra-high performance liquid chromatography-fraction collector (UHPLC-FC) and ultra-high performance liquid chromatography quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) for separation, preparation, screening and identification of the thrombin inhibitors from XBJ, a total of 58 chemical constituents were identified, among which 6 compounds possessed higher anticoagulant activity. Notably, the overall inhibition rate of the 6 mixed standards was equivalent to about 60% of the inhibition rate of XBJ. Therefore, this work provides a novel, cheap and simple method for monitoring thrombin activity and is promising to screen active substances from traditional Chinese medicines.

Electrochemical deoxygenative homo-couplings of aromatic aldehydes.

An electrochemical deoxygenative homo-coupling of aromatic aldehydes is achieved to selectively access bibenzyl and stilbene derivatives. The protocol allows the homo-coupling of aldehydes to occur after single-electron-reduction at the cathode. Taking advantage of the oxophilicity of triphenylphosphine, the electrochemical deoxygenation proceeds smoothly to give reductive homo-coupling products.

A Multichannel Fluorescent Array Sensor for Discrimination of Different Types of Drug-Induced Kidney Injury.

The differences in urinary proteins could provide a novel opportunity to distinguish the different types of drug-induced kidney injury (DIKI). In this research, Au nanoparticles-polyethyleneimine (AuNPs-PEI) and the three fluorophore-labeled proteins (FLPs) have been constructed as a multichannel fluorescent array sensor via electrostatic interaction, which was used to detect the subtle changes in urine collected from the pathological state of DIKI. Once the urine from different types of DIKI was introduced, the binding equilibrium between AuNPs-PEI and FLPs would be broken due to the competitive binding of urinary protein, and the corresponding fluorescence response pattern would be generated. Depending on the different fluorescence response patterns, the different types of DIKI were successfully identified by principal component analysis (PCA) and linear discriminant analysis (LDA). Accordingly, the strategy was expected to be a powerful technique for evaluating the potential unclear mechanisms of nephrotoxic drugs, which would provide a promising method for screening potential renal-protective drugs.

Electrochemical deoxygenative arylation of aldehydes and ketones.

The construction of diaryl alkanes from aromatic aldehydes or ketones with electron-deficient arenes is achieved in the presence of trivalent phosphine under electrochemical conditions. Reductive coupling between electron-deficient arenes and the carbonyl groups of aldehydes or ketones occurs at the cathode to yield diaryl alcohols. At the anode, the trivalent phosphine reagent may undergo single-electron oxidation to generate its radical cation, which reacts with the diaryl alcohols to form dehydroxylated products.

Electrochemical deoxygenative reduction of ketones.

Electrochemical reduction via paired electrolysis has been used to achieve deoxygenative reduction of ketones. As a result of the complexing of ketones with the triphenylphosphine radical cation generated by anodic oxidation, the reduction of carbonyl groups occurs readily. Through spontaneous ß-scission of phosphoranyl radicals, C-O bonds are cleaved to form benzylic radical intermediates. These radical species are either able to abstract hydrogen from MeCN or undergo reduction at the cathode to give carbanions, upon workup forming reductive hydrogenation of ketones.

N2-Selective ß-Thioalkylation of Benzotriazoles with Alkenes.

Herein, N2-selective ß-thioalkylation of benzotriazoles with unactivated alkenes and styrenes is reported. The N2-selective ß-thioalkylation of benzotriazoles is highly stereospecific and works under simple and mild conditions, exhibiting excellent functional group tolerance. The high N2-selectivity is a consequence of the combination of hydrogen bonding and Lewis acid/base activation, which reverses the N2-position to be favored for alkylation.