Development of Fluorescence-Linked Immunosorbent Assay for Paeoniflorin

Development of a Quantum Dot-Based Fluorescence-Linked Immunosorbent Assay for Puerarin

In this study, a rapid and highly sensitive fluorescence-linked immunosorbent assay for puerarin determination was developed by the conjugation of quantum dots with an antibody against puerarin. The linear range and detection limit of the fluorescence-linked immunosorbent assay were validated. The detection curve (y = -1041ln(x)+5366, R² = 0.999) was linear in the range of 7.8-125 ng/mL. The 50% inhibitory concentration determined by fluorescence-linked immunosorbent assay was 33.8 ng/mL puerarin in water. The limit of detection for PUE was 6.1 ng/mL. To our knowledge, this is the first report on the quantitative detection of a natural product using quantum dots as fluorescent markers. Furthermore, the newly developed fluorescence-linked immunosorbent assay was successfully applied to determine puerarin in several commercial Gegen Qinlian tablets, with a higher sensitivity than that of conventional enzyme-linked immunosorbent assays.

Development of a Competitive Time-Resolved Fluoroimmunoassay for Paclitaxel

INTRODUCTION

Paclitaxel (Tax) is a diterpene alkaloid isolated from Taxus species and has proved clinically effective in treating a number of malignancies. Current quantitative analytical methods for Tax such as high-performance liquid chromatography (HPLC) often involve complicated sample preparation procedures with low recovery rates.

OBJECTIVE

To establish a rapid and sensitive time-resolved fluoroimmunoassay (TRFIA) for measuring Tax in Taxus materials with convenient sample preparation and a high recovery rate.

METHODS

Rabbit anti-mouse IgG was coated onto a 96-well microplate, which was then incubated with standard solutions of Tax and anti-Tax monoclonal antibody 3A3. A Eu³⁺ -labelled conjugate of Tax and human serum albumin was used as the tracer. The luminescent system was enhanced with a solution containing 2-naphthoyltrifluoroacetone.

RESULTS

The established TRFIA showed a linear response within the Tax concentration range of 3.2 to 80 ng/mL, with a limit of detection of 1.4 ng/mL. The intra- and inter-assay coefficient of variation of the assay was 9.6% and 9.7%, respectively, with an average recovery rate from spiked samples of 108.5%. Tax contents in Taxus samples were determined using both the established TRFIA system and a previously established enzyme-linked immunosorbent (ELISA), and the results of two assays were well correlated.

CONCLUSION

This TRFIA system shows a high sensitivity, precision and accuracy for detection of Tax. This assay, which is convenient and less time-consuming, allows rapid analysis of Tax and provides another option for Tax measurement for quality control of Taxus materials and products. Copyright © 2017 John Wiley & Sons, Ltd.

Development of Fluorescence-Linked Immunosorbent Assay for Icariin

We have been looking for a faster and simpler method for traditional Chinese medicine and natural product assay. In this study, we developed a fluorescent immunoassay approach to detect icariin (ICA) using a fluorescently labelled monoclonal antibody. The ICA-specific antibody was purified by the caprylic acid-ammonium sulphate method and then labelled with rhodamine B isothiocyanate (RBITC). Subsequently, an indirect competitive fluorescence-linked immunosorbent assay (icFLISA) was developed to detect ICA using RBITC-labelled anti-ICA MAbs. The RBITC-labelled monoclonal antibody was highly specific for ICA. The fluorescence assay demonstrated an effective ICA measurement range of 1.28 ng/mL to 20 μg/mL (R² = 0.9946) with relative standard deviations below 10% for both intra-assay and inter-assay repeatability and precision. This icFLISA for ICA is simple, rapid, and sensitive, with a 20-fold greater linear range and a 10-fold lower limit of detection than with the previously developed indirect competitive enzyme-linked immunosorbent assay (ELISA). Thus, this study establishes a useful method for detecting ICA, enabling in vivo visualization research. In the future, FLISA can be also used to assay the concentrations of ICA in biological samples, as well as to investigate the pharmacokinetics of ICA in different tissues to explore the targets of ICA in vivo.

Monoclonal Antibodies and Immunoassay for Medical Plant-Derived Natural Products: A Review

Owing to the widespread application value, monoclonal antibodies (MAbs) have become a tool of increasing importance in modern bioscience research since their emergence. Recently, some researchers have focused on the production of MAbs against medical plant-derived natural products (MPNP), the secondary metabolites of medical plants. At the same time, various immunoassay methods were established on the basis of these MPNP MAbs, and then rapidly developed into a novel technique for medical plant and phytomedicine research in the area of quality control, pharmacological analysis, drug discovery, and so on. Dependent on the research works carried out in recent years, this paper aims to provide a comprehensive review of MAbs against MPNP and the application of various immunoassay methods established on the basis of these MAbs, and conclude with a short section on future prospects and research trends in this area.

Pharmacokinetic analysis of orally administered puerarin in human saliva using an indirect competition ELISA

The pharmacokinetics of puerarin in human saliva following oral administration of pueraria capsules were successfully studied by an icELISA method.