Rapid detection of aflatoxin B_1 in Chinese herbal medicines by indirect and direct competitive enzyme-linked immunosorbent assays: a comparative analysis / 中国中药杂志

The indirect competitive enzyme-linked immunosorbent assay(ic-ELISA) and direct competitive enzyme-linked immunosorbent assay(dc-ELISA) were performed for the rapid detection of aflatoxin B_1(AFB_1) in Astragali Radix, Zingiberis Rhizoma Recens, Jujubae Fructus, and Nelumbinis Semen with self-made antigens and antibodies. Different extraction methods were investigated to reduce the matrix effects of different medicinal parts in Chinese herbal medicines. The sensitivity of dc-ELISA method was improved by optimizing the molar ratio of AFB_1 to horseradish peroxidase(HRP). In this study, the sensitivity(IC_(50)) of ic-ELISA and dc-ELISA was 0.046 and 0.023 ng·mL~(-1), with the limit of detection(LOD) of 0.007 and 0.004 ng·mL~(-1), respectively. The detection time was 3 h and 50 min for ic-ELISA and dc-ELISA, respectively. The recovery rates were within the range of 62.96%-104.4%, with RSDs of less than 10%. Confirmed by LC-MS/MS, three positive samples of Nelumbinis Semen were detected from 53 samples. Two ELISA methods established in this study were accurate, rapid and sensitive, and can be used for rapid screening of AFB_1 in Chinese herbal medicines such as Astragali Radix, Zingiberis Rhizoma Recens, Jujubae Fructus, and Nelumbinis Semen. In addition, the advantages and limitations of the two methods were compared and discussed, which can provide a reference for the testing institutions to choose the proper method.

Preparation of an anti-cotinine monoclonal antibody and its application in immunological detection / 浙江大学学报·医学版

OBJECTIVE@#To prepare monoclonal antibody against cotinine (COT) and to establish immunoassay for detecting COT in human urinary samples.@*METHODS@#BALB/c mice were immunized with synthesized cotinine-bovine serum albumin (COT-BSA) to screen monoclonal antibody with technique of cell fusion. The monoclonal antibody was used for the indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and colloidal gold immunochromatographic strip assay for the detection of COT in human urine.@*RESULTS@#The monoclonal antibody against COT was identified by ic-ELISA with a 50%inhibitive concentration (IC@*CONCLUSIONS@#The ic-ELISA and colloidal gold immunochromatographic strip assay using the prepared monoclonal antibody against COT have been proved to be reliable for the rapid detection of COT in human urines, which may be used for monitoring of environmental tobacco smoke.

Effect of Puerarin on the Pharmacokinetics of Baicalin in Gegen Qinlian Decoction () in Mice / 中国结合医学杂志

<p><b>OBJECTIVE</b>To study the pharmacokinetics of puerarin (PUE) in Gegen Qinlian Decoction (, GQD), and the effects of PUE dosage variations on the pharmacokinetics of baicalin (BAL) in mice.</p><p><b>METHODS</b>GQD is composed of the concentrated granules of four Chinese herbs. Three dosages with different levels of PUE, including GQD, GQD co-administered with PUE, and GQD co-administration with two times the amount of PUE, were used to research the pharmacokinetics of PUE and BAL in mice. The indirect competitive enzyme-linked immunosorbent assay (icELISA) methods based on an anti PUE-monoclonal antibody (MAb)and BAL-MAb were employed to determine the concentration of PUE and BAL in mice blood.</p><p><b>RESULTS</b>After the co-administration of GQD with PUE, the area under the curves (AUC) of PUE increased 2.8 times compared with GQD. At the dose of GQD co-administration at two times that of PUE, the (AUC) of PUE was almost equal to that of GQD co-administration of PUE, showing non-linear pharmacokinetics. The (AUC) of BAL showed a good dose-related increase of PUE (r=0.993) in the range from 100 to 300 mg/kg, indicating that PUE dramatically affects the absorption of BAL in mice. There was no significant difference in the other pharmacokinetic parameters, such as the first time of maximum concentration (T), the second T, or the mean residence time.</p><p><b>CONCLUSIONS</b>The icELISA methods were successfully applied to pharmacokinetic studies of PUE and BAL in GQD in mice. The dosage variability of PUE of the main ingredient in GQD affects its own pharmacokinetic characteristics and the absorption characteristics of BAL.</p>