An activity-integrated strategy of the identification, screening and determination of potential neuraminidase inhibitors from Radix Scutellariae

Surface-Controlled Sialoside-Based Biosensing of Viral and Bacterial Neuraminidases

Neuraminidases (NA) are sialic acid-cleaving enzymes that are used by both bacteria and viruses. These enzymes have sialoside structure-related binding and cleaving preferences. Differentiating between these enzymes requires using a large array of hard-to-access sialosides. In this work, we used electrochemical impedimetric biosensing to differentiate among several pathogene-related NAs. We used a limited set of sialosides and tailored the surface properties. Various sialosides were grafted on two different surfaces with unique properties. Electrografting on glassy carbon electrodes provided low-density sialoside-functionalized surfaces with a hydrophobic submonolayer. A two-step assembly on gold electrodes provided a denser sialoside layer on a negatively charged submonolayer. The synthesis of each sialoside required dozens of laborious steps. Utilizing the unique protein-electrode interaction modes resulted in richer biodata without increasing the synthetic load. These principles allowed for profiling NAs and determining the efficacy of various antiviral inhibitors.

Investigation of the Material Basis of Xiexin Tang to Alleviate Type 2 Diabetes Mellitus Based on Spectrum-Effect Analysis by UPLC-Q-TOF/MS

Xiexin Tang (XXT) is a classic prescription for treating diabetes in clinical practices for thousands of years in China, which has been also proved by a large number of modern pharmacological studies. However, due to its complex composition, the bioactive ingredients of XXT is still unclear. In present researches, spectrum-effect relationship analysis is widely used to explore the material basis of traditional medical herbs, so this method was adopted in this study. Firstly, the extract of XXT was separated and enriched into 5 fractions by macroporous adsorption resin. Then, UPLC-Q-TOF/MS method was used for qualitative identification of components in each eluting part, and efficacy of each fraction was assessed by the T2DM rat model. Based on grey relational analysis and pearson bivariate correlation analysis, it was found that the components such as berberine, gallic acid, catechin, epicatechin, acteoside, berberastine and 1-O-galloyl-β-D-glucose might be the main effective basis of XXT to improve T2DM.

Periplocymarin alleviates pathological cardiac hypertrophy via inhibiting the JAK2/STAT3 signalling pathway

Pathological cardiac hypertrophy is the most important risk factor for developing chronic heart failure. Therefore, the discovery of novel agents for treating pathological cardiac hypertrophy remains urgent. In the present study, we examined the therapeutic effect and mechanism of periplocymarin (PM)‐mediated protection against pathological cardiac hypertrophy using angiotensinII (AngII)‐stimulated cardiac hypertrophy in H9c2 cells and transverse aortic constriction (TAC)‐induced cardiac hypertrophy in mice. In vitro, PM treatment significantly reduced the surface area of H9c2 cells and expressions of hypertrophy‐related proteins. Meanwhile, PM markedly down‐regulated AngII‐induced translocation of p‐STAT3 into the nuclei and enhanced the phosphorylation levels of JAK2 and STAT3 proteins. The STAT3 specific inhibitor S3I‐201 or siRNA‐mediated depleted expression could alleviate AngII‐induced cardiac hypertrophy in H9c2 cells following PM treatment; however, PM failed to reduce the expressions of hypertrophy‐related proteins and phosphorylated STAT3 in STAT3‐overexpressing cells, indicating that PM protected against AngII‐induced cardiac hypertrophy by modulating STAT3 signalling. In vivo, PM reversed TAC‐induced cardiac hypertrophy, as determined by down‐regulating ratios of heart weight to body weight (HW/BW), heart weight to tibial length (HW/TL) and expressions of hypertrophy‐related proteins accompanied by the inhibition of the JAK2/STAT3 pathway. These results revealed that PM could effectively protect the cardiac structure and function in experimental models of pathological cardiac hypertrophy by inhibiting the JAK2/STAT3 signalling pathway. PM is expected to be a potential lead compound of the novel agents for treating pathological cardiac hypertrophy.

Evaluation of Neuraminidase Inhibitory Activity of Compounds and Extracts from Traditional Medicines by HPLC-FLD

A simple and effective method was established and validated to determine 4-methylumbelliferone (4-MU) for screening the natural neuraminidase inhibitors (NAIs) from traditional medicines (TMs) by high performance liquid chromatography combined with fluorescence detection (HPLC-FLD). 4-MU and TMs compounds were separated on a Hedera TM ODS column (5 μm, 4.6 × 250 mm) using an isocratic elution of 55% methanol at 35°C. The flow rate was 1 mL min^-1. The excitation and emission wavelength were performed at 320 nm and 480 nm. Some extracts of TMs and compounds were selected as examples to demonstrate the feasibility of the new HPLC-FLD method. It was found that the results of most compounds except for the auto fluorescence substances determined by HPLC-FLD were in good agreement with NA enzyme-based inhibitory assays. Comparing to traditional NA enzyme-based inhibitory assays, the HPLC-FLD method could prevent interference from fluorescence pigments of compounds. It was considered a simple, effective, and economical technique for the screening the natural neuraminidase inhibitors from traditional medicines.

Neuraminidase 1 and its Inhibitors from Chinese Herbal Medicines: An Emerging Role for Cardiovascular Diseases

Neuraminidase, also known as sialidase, is ubiquitous in animals and microorganisms. It is predominantly distributed in the cell membrane, cytoplasmic vesicles, and lysosomes. Neuraminidase generally recognizes the sialic acid glycosidic bonds at the ends of glycoproteins or glycolipids and enzymatically removes sialic acid. There are four types of neuraminidases, named as Neu1, Neu2, Neu3, and Neu4. Among them, Neu1 is the most abundant in mammals. Recent studies have revealed the involvement of Neu1 in several diseases, including cardiovascular diseases, diabetes, cancers, and neurological disorders. In this review, we center the attention to the role of Neu1 in cardiovascular diseases, including atherosclerosis, ischemic myocardial injury, cerebrovascular disease, congenital heart disease, and pulmonary embolism. We also summarize inhibitors from Chinese herbal medicines (CHMs) in inhibiting virus neuraminidase or human Neu1. Many Chinese herbs and Chinese herb preparations, such as Lonicerae Japonicae Flos, Scutellariae Radix, Yupingfeng San, and Huanglian Jiedu Decoction, have neuraminidase inhibitory activity. We hope to highlight the emerging role of Neu1 in humans and potentially titillate interest for further studies in this area.

Systematically Characterizing Chemical Profile and Potential Mechanisms of Qingre Lidan Decoction Acting on Cholelithiasis by Integrating UHPLC-QTOF-MS and Network Target Analysis

Qingre Lidan Decoction (QRLDD), a classic precompounded prescription, is widely used as an effective treatment for cholelithiasis clinically. However, its chemical profile and mechanism have not been characterized and elucidated. In the present study, a rapid, sensitive, and reliable ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry method was established for comprehensively identifying the major constituents in QRLDD. Furthermore, a network pharmacology strategy based on the chemical profile was applied to clarify the synergetic mechanism. A total of 72 compounds containing flavonoids, terpenes, phenolic acid, anthraquinones, phenethylalchohol glycosides, and other miscellaneous compounds were identified, respectively. 410 disease genes, 432 compound targets, and 71 related pathways based on cholelithiasis-related and compound-related targets databases as well as related pathways predicted by the Kyoto Encyclopedia of Genes and Genomes database were achieved. Among these pathways and genes, pathway in cancer and MAPK signaling pathway may play an important role in the development of cholelithiasis. EGFR may be a crucial target in the conversion of gallstones to gallbladder carcinoma. Regulation of PRKCB/RAF1/MAP2K1/MAPK1 is associated with cell proliferation and differentiation. Thus, the fingerprint coupled with network pharmacology analysis could contribute to simplifying the complex system and providing directions for further research of QRLDD.