This study aims to establish a quality grading standard that combines the conventional quality evaluation based on morphological characteristics of traditional Chinese medicine with the modern quality evaluation. Based on the existing standards and market circulation of Isatidis Radix, the diameter and color of Isatidis Radix decoction pieces were selected as the appearance traits for preliminary grading. The effects of internal quality indexes such as moisture, total ash, acid-insoluble ash, ethanol-soluble extractives, and 9 water-soluble components on different grades of decoction pieces were comprehensively compared, and the key grading indexes were determined by t-test. The relevance between appearance traits and the internal quality indexes was investigated by multi-dimensional statistical analyses such as correlation analysis, principal component analysis(PCA), orthogonal partial least squares-discriminant analysis(OPLS-DA), and hierarchical cluster analysis(HCA). Furthermore, the fluorescent substrate was employed to investigate the inhibitory effects of different grades of Isatidis Radix decoction pieces on the neuraminidase of influenza virus. The rationality of the selected grading index components was verified by network pharmacology. The results showed that the diameter of decoction pieces had significantly positive correlations with other index components except moisture. Considering the existing commodity specifications, grading standards, and actual market circulation of Isatidis Radix, the quality grading standard of Isatidis Radix decoction pieces was developed with diameter as the appearance trait and(R,S)-goitrin as the limit index component of being qualified. On this basis, the content of ethanol-soluble extractives, total sinigrin, and total nucleoside were selected for quality grading. The in vitro enzyme activity evaluation showed that the first grade of Isatidis Radix decoction pieces had stronger inhibitory effect on the neuraminidase of influenza virus, and the network pharmacology results showed that the selected index components for quality grading had significant correlations with influenza. This study established a quality grading standard combining appearance traits and internal quality indexes, which provides a scientific basis for improving the existing grading standards and the price and quality of Isatidis Radix decoction pieces.
Isatis/chemistry* ; Plant Roots/chemistry* ; Drugs, Chinese Herbal/standards* ; Network Pharmacology ; Neuraminidase/antagonists & inhibitors* ; Quality Improvement/standards* ; Viral Proteins

Anti-influenza Chinese herbal medicines (anti-flu CHMs) have advantages in preventing and treating influenza virus infection. Despite various data on antiviral activities of some anti-flu CHMs have been reported, most of them could not be compared using the standard evaluation methods for antiviral activity. This situation poses an obstacle to a wide application of anti-flu CHMs. Thus, it was necessary to develop an evaluation method to estimate antiviral activities of anti-flu CHMs. In the present study, we searched for anti-flu CHMs, based on clinic usage, to select study objects from commonly-used patented anti-flu Chinese medicines. Then, a neuraminidase-based bioassay, optimized and verified by HPLC method by our research group, was adopted to detect antiviral activities of selected 26 anti-flu CHMs. Finally, eight of these herbs, including Coptidis Rhizoma, Isatidis Folium, Lonicerae Flos, Scutellaria Radix, Cyrtomium Rhizome, Houttuynia Cordata, Gardeniae Fructus, and Chrysanthemi Indici Flos, were shown to have strong antiviral activities with half maximal inhibitory concentration (IC) values being 2.02 to 6.78 mg·mL (expressed as raw materials). In contrast, the IC value of positive control peramivir was 0.38 mg·mL. Considering the extract yields of CHMs, the active component in these herbs may have a stronger antiviral activity than peramivir, suggesting that these herbs could be further researched for active compounds. Moreover, the proposed neuraminidase-based bioassay was high-throughput and simple and could be used for evaluation and screening of anti-flu CHMs as well as for their quality control.
Antiviral Agents ; chemistry ; pharmacology ; Drug Evaluation, Preclinical ; Drugs, Chinese Herbal ; chemistry ; pharmacology ; Enzyme Inhibitors ; chemistry ; pharmacology ; Humans ; Influenza, Human ; drug therapy ; virology ; Neuraminidase ; antagonists & inhibitors ; metabolism ; Orthomyxoviridae ; drug effects ; enzymology ; physiology ; Viral Proteins ; antagonists & inhibitors ; metabolism

Data based on the antiviral-resistant phenotyping characteristics of 884 influenza B viruses circulating in mainland China from October 2013 to March 2014 were analyzed to assess the susceptibility of influenza B viruses to neuraminidase inhibitors. All 884 viruses were sensitive to oseltamivir; two viruses (0.23%) had reduced sensitivity to zanamivir and all other viruses were sensitive to zanamivir. Among the 38 viruses with a B/Victoria lineage, B/Shandong-Kuiwen/1195/2014 exhibited a half-maximal inhibitory concentration (IC50) for zanamivir that was elevated by 5. 12-fold (1.78 nM) compared with neuraminidase inhibitors sensitive to the reference virus (0.34 nM), suggesting that it exhibited reduced inhibition by zanamivir. D35G, N59D and S402T (39, 64 and 399 with N2 number) amino-acid substitutions in the NA gene were detected with no previously reported antiviral-resistant substitutions. Among viruses with the 846 B/Yamagata lineage, B/Hunan-Lingling/350/2013 exhibited a 7.99-fold elevated IC50 for zanamivir (2.72 nM) compared with neuraminidase inhibitors sensitive to the reference virus (0.34 nM), suggesting that it exhibited reduced inhibition by zanamivir. D197N (N2 number), a previously reported antiviral resistant-related amino-acid substitution in the NA gene, was detected in B/Hunan-Lingling/350/2013. These data suggest that recently circulating influenza B viruses in mainland China have retained susceptibility to neuraminidase inhibitors.
Amino Acid Substitution ; Antiviral Agents ; pharmacology ; China ; epidemiology ; Drug Resistance, Viral ; Enzyme Inhibitors ; pharmacology ; Humans ; Influenza B virus ; drug effects ; enzymology ; genetics ; isolation & purification ; Influenza, Human ; epidemiology ; virology ; Microbial Sensitivity Tests ; Neuraminidase ; antagonists & inhibitors ; genetics ; metabolism ; Viral Proteins ; antagonists & inhibitors ; genetics ; metabolism

Catalytic Domain ; Enzyme Inhibitors ; metabolism ; pharmacology ; Influenza A Virus, H1N1 Subtype ; enzymology ; Models, Molecular ; Mutation ; Neuraminidase ; antagonists & inhibitors ; chemistry ; genetics ; metabolism ; Protein Binding

In vitro neuraminidase inhibition assays and ultrafiltration liquid chromatography with diodearray detector coupled to time of flight mass spectrometer (UPLC-DAD-TOF-MS) were combined to screen bioactive compounds inhibiting neuraminidase from Isatidis Radix. By comparing the compounds from Isatidis Radix before and after ultrafiltration, we found that arginine, goitrin and adenosinea can bind with neuraminidase, and the binding degree of the three compounds were (36.23 +/- 1.12)%, (32.54 +/- 1.02)% and (9.38 +/- 0.47)%, respectively. The IC50 of arginine and goitrin were (1.16 +/- 0.02), (1.20 +/- 0.02) g x L(-1), respectively. While the IC50 of adenosinea was higher than 500 g x L(-1). The results showed that arginine and goitrin might be the main compounds with antiviral activity of Isatidis Radix. This study may provide a useful method for the screening of bioactive compounds and quality control of Isatidis Radix.
Antiviral Agents ; analysis ; pharmacology ; Arginine ; analysis ; pharmacology ; Drug Evaluation, Preclinical ; Drugs, Chinese Herbal ; analysis ; pharmacology ; Isatis ; chemistry ; Mass Spectrometry ; Neuraminidase ; antagonists & inhibitors ; metabolism ; Orthomyxoviridae ; drug effects ; enzymology ; Oxazolidinones ; analysis ; pharmacology ; Plant Roots ; chemistry ; Ultrafiltration ; Viral Proteins ; antagonists & inhibitors ; metabolism

This study aimed to investigate the drug susceptibility of wild-type and mutant avian influenza A (H7N9) virus neuraminidase (NA) to oseltamivir and zanamivir. Codon optimized DNA of H7N9 (A/ Hangzhou/1/2013) NA was synthesized and constructed into the pcDNA3.1/His vector (NA(H7N9-WT)). Mutant NA(H7N9-H274Y) and NA(H7N9-R292K) plasmids were constructed by directed mutagenesis PCR using NA(H7N9-WT) plasmid as the template followed by sequencing. NA plasmids were transfected into 293T cells and cell lysates containing NAs were collected 48 h post-transfection. Wild-type and mutant NAs were analyzed by Western blotting and their activities were tested by the 4-MUNANA-based assay. All three NAs were expressed and enzymatic activities were confirmed. The effects of oseltamivir and zanamivir on all three NAs were then tested. It showed that the half maximal inhibitory concentrations (IC50s) of oseltamivir carboxylate on NA(H7N9-WT), NA(H7N9-H274Y) and NA(H7N9-R292K) were 1.6 nM, 15.1 nM, and > 1 000 nM with fold changes of 9 and > 625, respectively. The IC50 values of zanamivir on NA(H7N9-WT), NA(H7N9-H274Y), and NA(H7N9-R292K) were 1.1 nM, 1.4 nM, and 38.0 nM with fold changes of 1.3 and 34, respectively. These results indicated that oseltamivir and zanamivir could significantly inhibit NA(H7N9-WT). NA(H7N9-R292K) showed high-level resistance to both drugs (34-fold and 625-fold) and NA(H7N9-H274Y) was sensitive to both (1.3-fold and 9-fold). These results indicated that both oseltamivir and zanamivir could be used for patients infected with the H7N9 virus. However, when patients carried the H7N9 virus with a NA R292K mutation, other medications would be preferred over oseltamivir or zanamivir.
Antiviral Agents ; pharmacology ; Humans ; Influenza A Virus, H7N9 Subtype ; drug effects ; enzymology ; genetics ; Influenza, Human ; virology ; Microbial Sensitivity Tests ; Mutation ; Neuraminidase ; antagonists & inhibitors ; genetics ; metabolism ; Oseltamivir ; pharmacology ; Viral Proteins ; antagonists & inhibitors ; genetics ; metabolism ; Zanamivir ; pharmacology

The use of antiviral drugs such as influenza neuraminidase (NA) inhibitors is a critical strategy to prevent and control flu pandemic, but this strategy faces the challenge of emerging drug-resistant strains. For a highly pathogenic avian influenza (HPAI) H5N1 virus, biosafety restrictions have significantly limited the efforts to monitor its drug responses and mechanisms involved. In this study, a rapid and biosafe assay based on NA pseudovirus was developed to study the resistance of HPAI H5N1 virus to NA inhibitor drugs. The H5N1 NA pseudovirus was comprehensively tested using oseltamivir-sensitive strains and their resistant mutants. Results were consistent with those in previous studies, in which live H5N1 viruses were used. Several oseltamivir-resistant mutations reported in human H1N1 were also identified to cause decreased oseltamivir sensitivity in H5N1 NA by using the H5N1 NA pseudovirus. Thus, H5N1 NA pseudoviruses could be used to monitor HPAI H5N1 drug resistance rapidly and safely.
Animals ; Birds ; Drug Resistance, Viral ; genetics ; Enzyme Inhibitors ; therapeutic use ; HEK293 Cells ; Humans ; Influenza A Virus, H1N1 Subtype ; drug effects ; genetics ; pathogenicity ; Influenza A Virus, H5N1 Subtype ; drug effects ; genetics ; pathogenicity ; Influenza in Birds ; drug therapy ; genetics ; virology ; Influenza, Human ; drug therapy ; genetics ; virology ; Mutagenesis, Site-Directed ; Neuraminidase ; antagonists & inhibitors ; genetics ; Oseltamivir ; administration & dosage

This study aimed to establish a novel method to screen out the combined components of multi-fractions traditional Chinese medicine (TCM), so that the internal relationship between multi-ingredients could be objectively assessed and the proportioning ratio could be optimized. Taking antiviral effect on neuraminidase activity of influenza virus as the evaluating indicator and using Box-Behnken response surface methodology, the main effective ingredients of Shuanghuanglian injection (SHL) were screened. Meanwhile, the relationship between active ingredients was discussed. Taking SHL as a comparison, the optimum proportioning ratio was predicted. The results indicated that chlorogenic acid, cryptochlorogenic acid, caffeic acid and baicalin have comparatively strong antiviral activity against influenza virus. Moreover, antagonistic action existed between chlorogenic acid and cryptochlorogenic acid, whereas synergistic action between caffeic acid and other components. The optimum proportioning ratio resulted from fitted model is: chlorogenic acid, cryptochlorogenic acid, caffeic acid and baicalin (107 microg x mL(-1) : 279 microg x mL(-1) : 7.99 microg x mL(-1) : 92 microg x mL(-1)). The antiviral activity of the recombined components is stronger than that of SHL, which was consistent with the experiment results (P < 0.05). Box-Behnken response surface methodology has the advantages of general-screening, high-performance and accurate-prediction etc, which is appropriate for screening the combined components of multi-fractions TCM and the optimization of the proportioning ratio. The proposed method can serve as a technological support for the development of modern multi-fractions TCM.
Antiviral Agents ; administration & dosage ; chemistry ; pharmacology ; Caffeic Acids ; isolation & purification ; pharmacology ; Chlorogenic Acid ; isolation & purification ; pharmacology ; Drugs, Chinese Herbal ; administration & dosage ; chemistry ; pharmacology ; Enzyme Inhibitors ; administration & dosage ; chemistry ; pharmacology ; Flavonoids ; isolation & purification ; pharmacology ; Injections ; Medicine, Chinese Traditional ; Neuraminidase ; antagonists & inhibitors ; metabolism ; Orthomyxoviridae ; drug effects ; enzymology

OBJECTIVETo isolate and identify active neuraminidase constituents of Polygonum cuspidatum against influenza A (H1N1) influenza virus.

METHODOn the basis of the bioassay-guided fractionation,such chromatographic methods as silica gel, sephadex LH-20 and HPLC were adopted to isolate active constituents of extracts from Polygonum cuspidatum, and their molecular structures were identifiied on the basis of their spectral data such as NMR and MS and physico-chemical properties.

RESULTSeven compounds were isolated from the ethyl acetate extract of P. cuspidatum and identified as 2-methoxystypandrone (1), emodin (2), resveratrol (3), polydatin (4), emodin-8-O-beta-D-glucopyranoside (5), (E)-3, 5, 12-trihydroxystilbene-3-O-beta-D-glucopyranoside-2'-(3", 4", 5"-trihydroxybenzoate) (6) and catechin-3-O-gallate (7), respectively. Among them, the NA test showed that compounds 3, 6 and 7 had inhibitory effect against NAs activity, with IC50 values of 129.8, 44.8 and 21.3 micromol x L(-1), respectively. Moreover, the further CPE test showed compounds 6 and 7 had significant inhibitory effect against H1N influenza virus (EC50 = 5.9, 0.9 micromol x L(-1), respectively), with very low cytotoxicity to the host cells, their therapeutic selective index(SI) in MDCK cells ranged from 56 to 269.

CONCLUSIONThe neuraminidase inhibitors against H1N1 anti-influenza virus isolated from extracts of P. cuspidatum on the basis of the bioassay-guided fractionation are significant in specifying their therapeutic material basis and drug R&D against influenza.

Cell Line ; Drugs, Chinese Herbal ; chemistry ; isolation & purification ; pharmacology ; Enzyme Inhibitors ; chemistry ; isolation & purification ; pharmacology ; Fallopia japonica ; chemistry ; Humans ; Influenza A Virus, H1N1 Subtype ; drug effects ; enzymology ; Influenza, Human ; virology ; Molecular Structure ; Neuraminidase ; antagonists & inhibitors

Influenza viruses are highly contagious for human population and result in acute respiratory infectious diseases ranging from mild to severe. Neuraminidase (NA) inhibitors (NAIs) (oseltamivir, zanamivir, peramivir and laninamivir), which target the NA glycoproteins of influenza A and B viruses are widely used in the prophylaxis and treatment of influenza virus infection. However, the substitutions of amino acids in NA or HA gene may lead to resistances to NAIs. NAI-resistance-related substitutions are typically specific to certain NA type or subtype. The sensitivity for NAI-resistance detection is affected by different assays used.
Animals ; Antiviral Agents ; pharmacology ; Drug Resistance, Viral ; Enzyme Inhibitors ; pharmacology ; Humans ; Influenza, Human ; drug therapy ; virology ; Neuraminidase ; antagonists & inhibitors ; genetics ; metabolism ; Orthomyxoviridae ; drug effects ; enzymology ; genetics ; physiology ; Viral Proteins ; antagonists & inhibitors ; genetics ; metabolism