Rapid Apta-Chromogenic Detection Method for Nitrofuran Metabolite Determination.

Nitrofuran (NF) contamination in food products is a global problem resulting in the banned utilization and importation of nitrofuran contaminated products. A novel chromogenic detection method using a specific DNA aptamer with high affinity and specificity to nitrofurans was developed. Single-stranded DNA aptamers specific to nitrofuran metabolites, including 3-amino-2-oxazolidinone (AOZ), 3-amino-5-methylmorpholino-2-oxazolidinone (AMOZ), and 1-aminohydantoin (AHD), were isolated using magnetic bead-SELEX. The colorimetric detection of nitrofurans using gold nanoparticles (AuNPs) exhibited an AOZ detection range of 0.01-0.06 ppb with a limit of detection (LOD) of 0.03 ppb. At the same time, this system could detect AMOZ and AHD at a range of 0.06 ppb and 10 ppb, respectively. The fast nitrofuran extraction method was optimized for food, such as fish tissues and honey, adjusted to be completed within 3-6 h. This novel apta-chromogenic detection method could detect NF metabolites with a sensitivity below the minimum required performance limit (MPRL). This analysis will be valuable for screening, with a shortened time of detection for aquaculture products such as shrimp and fish muscle tissues.

Dual-color aggregation-induced emission nanoparticles for simultaneous lateral flow immunoassay of nitrofuran metabolites in aquatic products.

Nitrofurans such as furaltadone and nitrofurantoin are a type of synthetic broad-spectrum antibiotics. Various fluorescent nanomaterials have been used as labeling materials in immunochromatographic assays (ICAs) for nitrofurans detection. However, previous fluorescent nanomaterials can undergo aggregation-caused quenching, leading to a decrease in the detection sensitivity. In this study, we developed a multiplex immunochromatographic assay (mICA) based on dual-color aggregation-induced emission nanoparticles (AIENPs) as signal labels for the simultaneous detection of 3-amino-5-morpholino-methyl-1,3-oxazolidinone (AMOZ) and 1-aminohydantoin (AHD), which were the metabolites of furaltadone and nitrofurantoin, respectively. Under optimal conditions, the cut-off values of the mICA for derivatized AMOZ (2-NP-AMOZ) and AHD (2-NP-AHD) reached up to 3 and 5 ng/mL, respectively. These values are at least 166-and 200-fold higher than those of the commercial gold nanoparticles (GNPs)-based test strip, respectively. Furthermore, the test strip was successfully applied to the samples, with acceptable recoveries in the range of 83.0-98.2%.

Bioactive constituents from the leaves of Lonicera japonica.

Six new isolates including three new alkaloids (1-3), one new secoiridoid glycoside (4) and one new 11-delactonization-secoiridoid glycoside (5), and one new organic acid (6) were identified from the leaves of Lonicera japonica, among which 1 and 2 assigned as a pair of configurational isomers possessed two oxazolidin-2-one fragments connected through NN bond. The structures were elucidated by the NMR data and ICD analysis. All the compounds (1-6) were tested for their antioxidant and hepatoprotective activities using cell models of ABAP-induced HepG2 cell and APAP-induced HepG2 cell by the MTT method. Outstandingly, compound 2 exhibited remarkable antioxidative activity with inhibitory rate of 117.2%, and compounds 2, 4, 6 exhibited significant effects with inhibitory rates of 68.1%, 69.3%, 69.2%, respectively.

Residues and dietary intake risk assessments of clomazone, fomesafen, haloxyfop-methyl and its metabolite haloxyfop in spring soybean field ecosystem.

Soybean is an important oilseed crop, but weed can have a significant effect on soybean yield. Clomazone, fomesafen, and haloxyfop-methyl are high-efficacy herbicides, and the combination of these herbicides shows an ideal effect on weed control. However, the residues of these herbicides and their impacts on human health are still largely unknown. In the current study, a rapid, sensitive, and selective method using modified QuECHERS procedure combined with HPLC-MS/MS was established to detect these herbicides in soybean matrices. The limits of quantification were 0.01, 0.01 and 0.025 mg/kg for haloxyfop-methyl, haloxyfop and fomesafen, and 0.005, 0.005 and 0.0125 mg/kg for clomazone in green soybean, soybean grain, and straw, with the average recoveries ranging from 80% to 107%. The terminal residues of the target compounds were all below the corresponding limits of quantification. The dietary risk assessment showed that the risk quotient values were far below the acceptable human consumption levels.

UPLC-MS/MS assay of Tedizolid in rabbit aqueous humor: Application to ocular pharmacokinetic study.

Tedizolid phosphate (TZP) a prodrug of Tedizolid (TDZ) is a novel oxazolidinone antibiotic, used for the treatment of acute bacterial skin, skin structure infections and other serious gram positive and MRSA infections. In the present study, a sensitive UPLC-MS/MS analytical method was developed and validated for the quantification of TDZ in rabbit's aqueous humor (AqH) by using linezolid as internal standard (IS). Both TDZ and IS were separated on an Acquity™ HILIC column using an isocratic mobile phase comprising of acetonitrile: 20 mM ammonium acetate (85:15, v/v), eluted at 0.3mLmin-1 flow rate with total run time of 3 min. The AqH samples were processed by protein precipitation method by using acetonitrile as precipitating agent. TDZ and IS were detected in positive mode using electrospray ionization source. The precursor to product ion transitions at m/z 371.15 to 343.17 for TDZ and m/z 338.18 to 296.22 for IS were used for the quantification in multiple reaction monitoring mode. The calibration curve was linear in the concentration range of 4.98-1000ngmL-1 and the lower limit of detection was 1.97ngmL-1 only. The method was validated following US-FDA-guidelines and the results of validation parameter were found within the set limits. The developed UPLC-MS/MS method was fast, sensitive and reliable for the quantification of TDZ in the rabbit AqH and was successfully employed for ocular pharmacokinetic study of TDZ in AqH after topical ocular application of TZP-containing formulations in rabbit eyes.

Determination of four nitrofuran metabolites in gelatin Chinese medicine using dispersive solid phase extraction and pass-through solid phase extraction coupled to ultra high performance liquid chromatography-tandem mass spectrometry.

This study established a validated analytical method for the first time on the determination of nitrofuran metabolites, including semicarbazide (SEM), 1-aminohydantoin (AHD), 3-amino-2-oxazolidinone (AOZ) and 3-amino-5-morpholinomethyl-2-oxazolinone (AMOZ) in gelatin Chinese medicine. A C18 column with the mobile phase consisting of acetonitrile and 5 mmol/L ammonium acetate in water was used to separate these nitrofuran metabolites. The limit of detection of SEM, AHD, AOZ and AMOZ were found to be 0.2 µg/kg, 0.3 µg/kg, 0.2 µg/kg and 0.2 µg/kg, whereas their limit of quantification were 0.6 µg/kg, 0.8 µg/kg, 0.6 µg/kg and 0.5 µg/kg. These nitrofuran metabolites exhibited a good linear standard curve (regression coefficients above 0.99) with a concentration range of 2 µg/L to 100 µg/L. Regarding extraction procedure, gelatin Chinese medicine was pre-treated with pepsin and then extracted using 5% formic acid (v/v) in acetonitrile. The resultant extract was purified through dispersive solid phase extraction using 1000 mg anhydrous sodium sulfate, 300 mg octadecyl carbon silica gel sorbent absorbent and 500 mg ethylenediamine-N-propyl carbon silica gel absorbent, and then further purified on Oasis PRiME HLB cartridges. The matrix effect was effectively eliminated after the clean-up procedure as confirmed by comparing the ratio of standard curves prepared by standards dissolved in both matrix solvent and 5 mmol/L ammonium acetate in water: acetonitrile (95:5, v/v). The recoveries of these nitrofuran metabolites under the 1 µg/kg, 2 µg/kg and 10 µg/kg spiking levels were between 77.4% and 95.6%. These metabolites after the extraction were stable at 4 °C for 24 h. The validated method was used to analyze the residue level of these nitrofuran metabolites in 25 gelatin Chinese medicines. Results showed that only one Colla Corii Asini sample contained SEM (2.52 µg/kg) and AOZ (6.27 µg/kg), whereas one Testudinis Carapacis et Plastri sample had SEM (1.27 µg/kg) and AMOZ (9.53 µg/kg).

Chiral separation and thermodynamic investigation of WCK 3023: A novel oxazolidinone antibacterial agent, application to pre-clinical pharmacokinetic study.

A chiral liquid chromatographic method was developed and validated for the quantification of R-enantiomer impurity (RE) in WCK 3023 (S-enantiomer), a new drug substance. The separation was achieved on Chiralpak IA (amylose-based immobilized chiral stationary phase), using a mobile phase consisting of n-hexane-ethanol-trifluoroacetic acid (70:30:0.2, v/v/v) at a flow rate of 1.0 mL/min. The method was extensively validated for the quantification of RE in WCK 3023 and proved to be robust. For RE the detector response was linear over the concentration range of 0.11-5 µg/mL. The limit of quantitation and limit of detection for RE were 0.11 and 0.04 µg/mL respectively. Average recovery of the RE was in the range of 98.11-99.55%. The developed method was specific, sensitive, precise and accurate for quantitative determination of RE in WCK 3023. The impact of thermodynamic parameters on the chiral separation was evaluated. The method was employed for controlling the enantiomeric impurity in the lots of WCK 3023 used for pre-clinical studies. The method was successfully applied to evaluate the possible conversion of WCK 3023 to RE in rat serum samples during pre-clinical pharmacokinetic studies.

Development and Validation of the Chiral Liquid Chromatography Method for Separation of Enantiomeric Impurity in Novel Oxazolidinone Antibacterial Agent WCK 4086.

A highly stereo-specific liquid chromatographic method was developed and validated for the quantification of enantiomeric impurity (R-enantiomer) in novel oxazolidinone antibacterial agent (WCK 4086), a drug substance. The separation was achieved on Chiralpak AD-H (amylose-based chiral stationary phase) using a mobile phase consisting of n-hexane:2-propanol:methanol:trifluoroacetic acid (80:10:10:0.4, v/v/v/v) at a flow rate of 1.0 mL min-1. Chromatographic resolution between two enantiomers was found to be more than 2.0. Method was extensively validated for the quantification of R-enantiomer in WCK 4086 and proved to be robust. Method was found to be highly specific as all other related impurities were separated from the enantiomers. The calibration curve for R-enantiomer showed an excellent linearity over the concentration range of 1-5 µg mL-1. Limit of quantitation (LOQ) and limit of detection (LOD) for R-enantiomer were 0.009 µg and 0.003 µg, respectively. Average recovery of the R-enantiomer was in the range of 94.55-109.67%. Analytical solutions were found to be stable up to 70 h at room temperature. Developed method was found to be specific, sensitive, precise and accurate for quantitative determination of R-enantiomer in WCK 4086 and useful for controlling the enantiomeric impurity in drug substance used for preclinical studies.

Highly sensitive furazolidone monitoring in milk by a signal amplified lateral flow assay based on magnetite nanoparticles labeled dual-probe.

We presented a signal amplified lateral flow assay (LFA) based on magnetite nanoparticles (MNPs) labeled dual-probe and applied it in the high sensitive and rapid on-site detection of furazolidone metabolite of 3-amino-2-oxazolidinone (AOZ). The amplified signal benefited from high affinity between two probes of MNPs labeled murine monoclonal antibody (MNPs-MAb) and goat anti-mouse antibody (MNPs-GAMA) and was achieved by the generation of dual-probe network complex. This developed method could realize high sensitive detection of AOZ with a threshold value of 0.88 ng mL-1 and a detection limit of 0.044 ng mL-1, the sensitivity was at least 10-fold improved than that of the traditional gold nanoparticle based LFA. This facile developed assay was successfully applied for rapid detection of AOZ in milk samples. The proposed method paves a new way for on-site screening of other hazardous substances in food and can be referred in all lateral flow assays.

Responses of macroinvertebrate communities to pesticide application in irrigated rice fields.

The ability to recover to original states after disturbances makes macroinvertebrates useful tools for assessing the impacts of pesticides. Many studies showed that direct exposure to pesticides decreases macroinvertebrate richness and alters their composition. The main objective of this study was to assess recovery patterns in macroinvertebrate communities after pesticide application in irrigated rice fields. We analyzed short-term temporal dynamics of macroinvertebrate communities after application of the herbicides bispyribac-sodium and clomazone and the insecticide chlorantraniliprole, over the rice-growing season in southern Brazil. We selected three conventional rice fields and the recovery of macroinvertebrate communities was also compared with three adjacent natural ponds. The study was developed from November 2011 to February 2012 (rice-growing season). Five macroinvertebrate collections were carried out 3, 7, 14, 38, and 60 days after pesticide application (November 25). Rice fields showed lower richness and abundance than ponds in the period immediately after pesticide application, and recovery rates in the richness of macroinvertebrate communities were more conspicuous as pesticide residuals dissipated from the fields. Macroinvertebrate community structure in rice fields also became more similar to natural ponds as pesticide traces were scarcer. However, macroinvertebrate abundance patterns were not related to pesticide concentrations in the fields. Our results supported the general hypothesis on the negative effects of pesticide application on macroinvertebrate community in irrigated rice fields, although other environmental features (e.g., length of the flooded period) also contributed to explain temporal dynamics in the macroinvertebrate communities from irrigated rice fields.

Enantioselective recognition of radezolid by cyclodextrin modified capillary electrokinetic chromatography and electronic circular dichroism.

A method for the enantioseparation of radezolid (RAD), an analogue of a truly new class of antibacterial agents, oxazolidinones, was developed based on capillary electrokinetic chromatography using a cyclodextrin as a chiral pseudophase (CD-cEKC). The mechanism of RAD separation, together with its precursor, were investigated to directly define the relationship between the oxazolidinone structure and the complexation process. During the development of the method, anionic single isomer cyclodextrins were tested. They were ranked in order from hydrophilic to hydrophobic as follows: heptakis-(2,3-dihydroxy-6-sulfo)-ß-cyclodextrin (HS-ß-CD), heptakis-(2,3-diacetyl-6-sulfo)-ß-cyclodextrin (HDAS-ß-CD) and heptakis-(2,3-dimethyl-6-sulfo)-ß-cyclodextrin (HDMS-ß-CD). Experiments were performed at pH values of 2.5, 6.6, 8.2 and 9.6. The cyclodextrins that had an acetyl or methyl group at the C2 and C3 positions, referred to as HDAS-ß-CD and HDMS-ß-CD, respectively, exhibited partial and baseline separation of enantiomers in a low pH buffer. However, higher temperatures were required for HDAS-ß-CD and acetonitrile addition was required for HDMS-ß-CD. During the experiments, different organic solvents, varying in their amphiprotic or aprotic nature, were tested. The best results for the separation of enantiomers using the CD-cEKC method were obtained with 40mM HDMS-ß-CD dissolved in a 50mM phosphate buffer (pH 2.5) with the addition of acetonitrile (65:35, v/v) at 27°C, reversed polarity and a voltage equal to 28kV. The apparent binding constants for each enantiomer to HDAS-ß-CD or HDMS-ß-CD were calculated. Finally, the stereochemistry of (S) and (R)-RAD and the behaviour of selected complex formations were established using electronic circular dichroism.

Feasibility of a novel multispot nanoarray for antibiotic screening in honey.

Practical solutions for multiple antibiotic determination in food are required by the food industry and regulators for cost-effective screening purposes. This study describes the feasibility in development and preliminary performance of a novel multispot nanoarray for antibiotic screening in honey. Using a multiplex approach, the metabolites of the four main nitrofuran antibiotics, including morpholinomethyl-2-oxazolidone (AMOZ), 3-amino-2-oxazolidinone (AOZ), semicarbazide (SEM), 1-aminohydantoin (AHD) and chloramphenicol (CAP), were simultaneously detected. Antibodies specific to the five antibiotics were nano-spotted onto microtitre plate wells and a direct competitive assay format was employed. The assay characteristics and performance were evaluated for feasibility as a screening tool for antibiotic determination in honey to replace traditional ELISAs. Optimisation of the spotting and assay parameters was undertaken with both individual and multiplex calibration curves generated in PBS and a honey matrix. The limits of detection as determined by the 20% inhibitory concentrations (IC20) were determined as 0.19, 0.83, 0.09, 15.2 and 35.9 ng ml-1 in PBS, 0.34, 0.87, 0.17, 42.1 and 90.7 ng ml-1 in honey (fortified at the start of the extraction), and 0.23, 0.98, 0.24, 24.8 and 58.9 ng ml-1 in honey (fortified at the end of the extraction) for AMOZ, AOZ, CAP, SEM and AHD respectively. This work has demonstrated the potential of multiplex analysis for antibiotics with results available for 40 samples within a 90-min period for antibiotics sharing a common sample preparation. Although both the SEM and AHD assay do not show the required sensitivity with the antibodies available for use to meet regulatory limits, with further improvements in these particular antibodies this multiplex format has the potential to show a reduction in cost with reduced labour time in combination with the high-throughput screening of samples. This is the first 96-well spotted microtitre plate nanoarray for the semi-quantitative and simultaneous analysis of antibiotics.

Simultaneous detection of four nitrofuran metabolites in honey by using a visualized microarray screen assay.

A visualized microarray sensing technique has been developed and applied to the screening of honey samples for residues of banned nitrofuran antibiotics. Using a multiplexed approach, metabolites of four main nitrofuran antibiotics can be detected simultaneously. Individual antigens were spotted onto 96-well plates. An indirective competitive assay format, with visualized signal response, was employed. An extraction method, based on derivatization with 2-nitrobenzaldehyde and partition into ethyl acetate, was used for screening. The limits of detection were 0.10, 0.04, 0.04, and 0.10ngg-1 for 3-amino-5-morpholino-2-oxazolidone (AMOZ), 3-amino-2-oxazolidinone (AOZ), semicarbazide (SEM), and 1-aminohydantoin (AHD), respectively. The recovery rate ranged from 78% to 93% for the four targets. In addition, this method was easy to operate with low detection cost and fast speed. This microarray method possesses the potential to be a fit-for-purpose screening technique in the arena of food safety monitoring.

Rapid and Sensitive Detection of 3-Amino-2-oxazolidinone Using a Quantum Dot-Based Immunochromatographic Fluorescent Biosensor.

To monitor the levels of furazolidone in edible animal tissues, a fluorescent sensor was developed for the determination of 3-amino-2-oxazolidinone (AOZ), the metabolite of furazolidone, featuring an immunochromatographic test strip assay (ITSA) integrated with a quantum dot (QD) label. The optimal QD-based ITSA sensor exhibits good dynamic linear detection for AOZ over the range of 0.1-100 µg/L, with a 50% inhibitory concentration (IC50) of 1.06 µg/L. The decision limit and the detection capability were 0.14-0.15 and 0.27-0.33 µg/kg, respectively, for this analyte using the QD-based ITSA sensor. These values represent an improvement over a previously reported gold nanoparticle-based immunochromatographic assay. The recoveries of AOZ in kinds of animal tissues were between 76.3 and 98.4% at the levels of 1.0, 5.0, and 10.0 µg/kg. The performance and practicality of our QD-based fluorescent immunosensor were confirmed by commercial ELISA kit and LC-MS/MS. In conclusion, the proposed sensor was a feasible detection method for AOZ analysis on site.

Influence of Formulation on Mobility of Clomazone in Soil.

The mobility of clomazone [2-(2-chlorobenzylo)-4,4-dimetylo-1,2-oxazolidin-3-one] in a loamy sand soil and a sand soil was studied in a soil column under laboratory conditions. Commercial clomazone formulation (Command 480 EC) and clomazone immobilized in an alginate matrix were used for a leaching experiment. For both formulations, the same dose of 2.0 mg of the active substance was applied. After an application of a herbicide, the columns were irrigated with: 100, 40 and 3.7 mm of water. After 1 h, when an addition of water was completed, the soils were sampled in the 5 cm segments and were used for the analysis of the residues. The use of an alginate formulation reduced the vertical mobility of clomazone into a soil layer in comparison with the formulation EC.

Postmortem Metaxalone (Skelaxin®) Data from North Carolina.

The North Carolina Office of the Chief Medical Examiner Toxicology Laboratory identified 61 cases from 2002 to 2014 where metaxalone was detected during routine postmortem drug screening in support of a determination of cause and manner of death. Decedents were divided into groups based on the manner of death with the goal of studying metaxalone concentrations in overdose and non-overdose situations (natural, accident, suicide and undetermined). Subgroups were established for cases in which metaxalone contributed to the cause of death (attributed) and cases in which it did not (unattributed). Attributed cases were divided into those where metaxalone additively combined with other drugs and cases in which the drug was present in sufficient amounts to be the primary cause of death, regardless of other drugs present and the concentrations of those drugs. The mean metaxalone concentration for the additive deaths was 14.2 mg/L with a median value of 11 mg/L (n = 18) and a mean metaxalone concentration of 36.7 mg/L with a median value of 32 mg/L (n = 9) for primary deaths. For unattributed metaxalone concentrations, the mean was 3.4 mg/L with a median value of 2.9 mg/L (n = 31). Of the 61 cases, 34% fall at or below a therapeutic concentration of ≤4 mg/L. The selected case studies offer valuable information regarding postmortem interpretation.

Bioaccumulation and Elimination of the Herbicide Clomazone in the Earthworms Eisenia fetida.

Acute toxicity, bioaccumulation, and elimination of herbicide clomazone in the earthworm Eisenia fetida were investigated in the different exposure systems. The LC50 values of clomazone on earthworms were 5.6 µg cm(-2) in the contact filter paper test (48 h), 174.9 mg kg(-1) (7 days) and 123.4 mg kg(-1) (14 days) in artificial soil test, respectively. Clomazone could rapidly bioaccumulate in earthworms and reached the highest concentration after 3 days exposure, with the maximum concentrations of 9.0, 35.3 and 142.3 mg kg(-1) at 10.0, 40.0 and 160.0 mg kg(-1) of clomazone, respectively. Clomazone uptake showed a good correlation with exposure concentration. After the 14th day, clomazone declined to minimum value. About 74%-80% of accumulated clomazone was eliminated within 1 day after exposed to clomazone-free soil. However, a trace amount of clomazone persisted for a relatively long time in earthworms.

Thinking outside the "bug": a unique assay to measure intracellular drug penetration in gram-negative bacteria.

Significant challenges are present in antibiotic drug discovery and development. One of these is the number of efficient approaches Gram-negative bacteria have developed to avoid intracellular accumulation of drugs and other cell-toxic species. In order to better understand these processes and correlate in vitro enzyme inhibition to whole cell activity, a better assay to evaluate a key factor, intracellular accumulation of the drug, is urgently needed. Here, we describe a unique liquid chromatography (LC)-mass spectrometry (MS) approach to measure the amount of cellular uptake of antibiotics by Gram-negative bacteria. This method, which measures the change of extracellular drug concentration, was evaluated by comparing the relative uptake of linezolid by Escherichia coli wild-type versus an efflux pump deficient strain. A higher dosage of the drug showed a higher accumulation in these bacteria in a dosing range of 5-50 ng/mL. The Escherichia coli efflux pump deficient strain had a higher accumulation of the drug than the wild-type strain as predicted. The approach was further validated by determining the relative meropenem uptake by Pseudomonas aeruginosa wild-type versus a mutant strain lacking multiple porins. These studies show great promise of being applied within antibiotic drug discovery, as a universal tool to aid in the search for compounds that can easily penetrate bacterial cells.

[Influence of drying method on content of epigoitrin and uridine in isatidis radix].

OBJECTIVE: To study the influence of different drying methods on the content of epigoitrin and uridine in Isatidis Radix. METHODS: Fresh Isatidis Radix was processed by four drying methods including airing drying and drying in far infrared oven at different temperature,drying in the sun and drying in the shade. The contents of epigoitrin and uridine were determined by HPLC. RESULTS: The contents of epigoitrin as well as uridine in samples valued from 3.847 - 5.204 mg/g and 0.701 - 1.028 mg/g, respectively. CONCLUSION: The optimal drying method is airing drying at 55 degrees C, which will be serviced in the large-scale processing of Isatidis Radix.

[Screening bioactive compounds inhibiting influenza virus from isatidis radix by ultrafiltration mass spectrometry].

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.