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.

Protective Effect of Nanoparticles from Platycladi Cacumen Carbonisata on 2,4,6-Trinitrobenzene Sulfonic Acid (TNBS)-Induced Colitis in Rats.

Aim: To evaluate the protective effects of Platycladi Cacumen Carbonisata-derived nanoparticles (PCC-NPs) against 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced ulcerative colitis (UC) in rats. Methods: This study developed and characterized novel PCC-NPs synthesized by a green and simple pyrolysis process using Platycladi Cacumen (PC) as the sole precursor. The UC model prepared with rectal instillation of TNBS was used to evaluate the potential efficacy of PCC-NPs, and the underlying mechanisms were preliminarily explored from the perspective of anti-inflammatory and antioxidative stress for the first time. Results: PCC-NPs exhibited low cytotoxicity, good dispersibility and copious surface functional groups. Nanoparticles with diameters ranging from 40-60 nm mainly manifested a therapeutic effect by downregulating tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6) and upregulating interleukin-10 (IL-10). In addition, PCC-NPs relieved colon injury by inhibiting myeloperoxidase (MPO) activity, limiting the release of malondialdehyde (MDA) and increasing the activity of superoxide dismutase (SOD). Conclusion: Green synthetic PCC-NPs is a potential candidate as a complementary drug for intestinal inflammation of inflammatory bowel disease, and its regulatory mechanisms may be to balance the levels of pro-/anti-inflammatory cytokines and improve resistance to oxidative stress.

Effect of Puerarin on the Pharmacokinetics of Baicalin in Gegen Qinlian Decoction () in Mice.

OBJECTIVE: 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. METHODS: 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. RESULTS: After the co-administration of GQD with PUE, the area under the curves (AUC0-14h) of PUE increased 2.8 times compared with GQD. At the dose of GQD co-administration at two times that of PUE, the (AUC0-14h) of PUE was almost equal to that of GQD co-administration of PUE, showing non-linear pharmacokinetics. The (AUC0-48h) 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 (Tmax), the second Tmax, or the mean residence time. CONCLUSIONS: 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.

Mechanism of baicalin compatibility in chinese medicine formula Banxia Xiexin Decoction () by pharmacokinetics and indirect competitive enzyme-linked immunosorbent assays in mice.

OBJECTIVE: To determine the effects of different formulations of Banxia Xiexin Decoction ( , BXD) on the pharmacokinetics of baicalin (BAL) in mice. METHODS: Pungent, bitter, and sweet components of BXD (totaling 7 Chinese herbs) were formulated into the following groups: K (bitter herbs), XK (pungent and bitter herbs), KG (bitter and sweet herbs), and BXD (all 7 herbs) groups. These different formulations were administered intragastrically in mice, and blood was collected via the tail vein for continuous monitoring. BAL, which is a main active constituent in Scutellaria baicalensis Georgi., was detected in this study. Indirect competitive enzyme-linked immunosorbent assays (icELISAs) based on anti-BAL-monoclonal antibodies were employed to determine BAL concentrations in each group. RESULTS: The concentrations of BAL in blood samples from mice in the K and XK groups were lower than those in other groups. In all groups, BAL concentrations peaked at around 1-1.5 h and again at 5-7 h. There were no significant differences in the timing of peak BAL concentrations between groups. However, the peak concentrations and area under curve (AUC)0-36 h in the KG and BXD groups were almost 3 times of those in the K and XK groups. CONCLUSIONS: Differing compatibilities of BXD caused dissimilar pharmacokinetics of BAL. Moreover, we demonstrated a method for the continuous detection of blood concentrations of Chinese medicines in mice, and icELISA may be a feasible technique for the study of pharmcokinetic mechanisms of Chinese medicine.

[Preparation and identification of Jujuboside A artificial antigen].

Immunogenic antigen (jujuboside A-BSA) and coating antigen (jujuboside A-OVA) of jujuboside A were synthesized by sodium periodate oxidation method for the first time. Jujuboside A artificial antigen was confirmed by matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI-TOF-MS). The titer and specificity of the antibody in serum of immunized mice were detected by enzyme-linked immunosorbent assay (ELISA). The corrected relation curve of inhibition rate showed that the antibody against Jujuboside A obtained from immunized mice could bind to jujuboside A and the titer was up to 1∶4 000. The jujuboside A artificial antigen was synthesized, which can be used further to preparation of monoclonal antibody and the pharmacokinetics study of jujuboside A in laboratory animals.

[Synthesis, identification of artificial antigen of catalpol and preliminary study of immunogenicity].

The method of monoclonal antibody-based immunoassay has a great importance in the study of quality control of traditional Chinese medicine (TCM) and detection of trace components in vivo animals. Synthesis of small molecule artificial antigen is the prerequisite for the establishment of this method. In present study, catalpol-BSA was synthesized by sodium periodate oxidation method. Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry ( MALDI-TOF-MS) and molecular exclusion chromatography showed that catalpol was successfully conjugated with BSA. The mice could specifically produce anti-catalpol antibodies with titer up to 1:8000. The artificial antigen of catalpol was successfully synthesized.

[Synthesis and Identification of Artificial Antigen of Mangiferin].

OBJECTIVE: To establish an enzyme linked immunosorbent assay(ELISA) for mangiferin (MRn), artificial antigen of MRn was synthesized. METHODS: Oxidation method using sodium iodide was used to synthesize immunogenic antigen (MRn-BSA) and coating antigen(MRn-OVA) of MRn. The characterization of the synthesis was examined by UV spectrometry. BALB/c mice were immunized with the prepared MRn-BSA immunogenic antigen. The titer of the anti-serum was detected by ELISA, in the meanwhile the immunogenicity of MRn-BSA was confirmed by indirect competitive ELISA (icELISA). RESULTS: UV spectroscopy showed that MRn was successfully conjugated with OVA and BSA,so the new compound of MRn-BSA was synthesized, the coupling ratio was 6: 1. After immuned MRn-BSA, the mice could produce anti-MRn antibodies specifically, of which titer was up to 1: 4 000, and the general range was 1 - 100 µg/mL. CONCLUSION: Anti-MRn antibodies are discovered in the serum of mice, which indicates that artificial antigen of MRn is successfully synthesized,for the purpose of preparing monoclonal antibodies, as well as the establishment of appropriate immune methods.

[Synthesis and identification of artificial antigens of paneoniflorin].

Oxidation method with sodium iodide was used to synthesize immunogenic antigen (PF-BSA) and coating antigen (PF-OVA) of paeoniflorin. UV spectroscopy showed that paeoniflorin was successfully conjugated with BSA and OVA. After immunized by PF-BSA, the mice can produce anti-paeoniflorin antibodies specifically. The ELISA test results showed the high titer (1:12 800) and specificity (IC50 = 0.791 mg x L(-1)) of the antiserum from mice injected with PF-BSA. Also, the antiserum showed low cross activities against nine traditional Chinese medicine (TCM) of small molecules. These artificial antigens were successfully synthesized and the anti-paeoniflorin antibody well prepared, which provides the experimental basis for the further study of ELISA and its kit.

[Synthesis and identification of artificial antigen of forsythin].

The establishment of high specificity and sensitivity method of small molecule monoclonal antibody-based immunoassay has a great importance in the study of small molecule compounds in Chinese medicine, wherein synthesis of small molecule artificial antigen is a critical step in the preparation of small molecule antibodies. Oxidation method using sodium iodide was used to synthesize immunogenic antigen (FRn-BSA) and coating antigen (FRn-OVA) of forsythin. UV spectroscopy and thin layer chromatography showed that forsythin was successfully conjugated with BSA and OVA. After immuned FRn-BSA, the mice could specifically produce anti-forsythin antibodies with titer up to 1:8 000, and the linear range was from 1 mg x L(-1) to 100 mg x L(-1). In this paper, the artificial antigen of forsythin was successfully synthesized, which can be applied for preparation of monoclonal antibodies and establishment of appropriate immune method.

Pharmacokinetics of geniposide by monoclonal antibody-based icELISA in mice after oral administration of Huanglian-Jiedu-Tang.

Geniposide, Geniposide, the main active component in extracts of Gardenia jasminoides ELLIS., is one of the main components of Huanglian-Jiedu-Tang (HJT). This study aimed to validate an indirect competitive enzyme-linked immunosorbent assay (icELISA) based on monoclonal antibodies (mAb) against geniposide (anti-geniposide mAb), which was developed by our lab, and apply the assay to study the pharmacokinetics of geniposide in HJT in mice. Blood samples were drawn from mice at predetermined time points after oral administration of HJT in three dosages. A linear correlation was obtained for geniposide concentrations in the range from 1.17 to 37.50 µg/mL. The intra-day and inter-day precision values of the icELISA method were well within the recommended range (≤10%). The recovery rates ranged from 99.74 to 102.40%. Stability studies showed that geniposide sample solutions were intact for 12 h. The Tmax and mean residence time (MRT) of geniposide of the three groups were consistent with previous data. The results suggest that a reliable and effective method was established and could be applied to the study of the pharmacokinetics of geniposide in HJT.

New Perspectives on Specific Immune-Depletion Technique Using Monoclonal Antibodies against Small Active Molecules in Herbs.

One of the main focuses in Chinese Medicine research is the identification of efficacious components in Chinese herbal medicine (CHM). Studies in such area are difficult due to the complexity and the synergistic characteristics of CHM. Current methods to track and separate active components are not adequate to meet the needs of revealing effects and identify substances and pharmacological mechanisms, which directly restrict the modernization and globalization of CHM. In this paper, a new methodology to deplete a single active component via immunoassay was introduced. The specific active component in a CHM mixture can then be identified and studied through comparative analyses of the pharmacological effects before and after immune depletion. With this new methodology, degree of contribution of a particular component to the whole complex herbal mixture can be elucidated, and its synergistic property with other components can be determined. The new method can reflect not only the overall combined pharmacological effects of CHM but also the effect of individual component. It is an effective way to explain the degree of contribution of one specific component to the overall activity of a CHM prescription.

[New method for analyzing pharmacodynamic material basis of traditional Chinese medicines by using specific knockout technology with monoclonal antibodies].

Study on pharmacodynamic material basis of traditional Chinese medicines is one of the key issues for the modernization of traditional Chinese medicine. Having introduced the monoclonal antibody technology into the study on pharmacodynamic material basis of traditional Chinese medicines, the author prepared the immunoaffinity chromatography column by using monoclonal antibodies in active components of traditional Chinese medicines, so as to selectively knock out the component from herbs or traditional Chinese medicine compounds, while preserving all of the other components and keeping their amount and ratio unchanged. A comparative study on pharmacokinetics and pharmacodynamics was made to explicitly reveal the correlation between the component and the main purpose of traditional Chinese medicines and compounds. The analysis on pharmacodynamic material basis of traditional Chinese medicines by using specific knockout technology with monoclonal antibodies is a new method for study pharmacodynamic material basis in line with the characteristics of traditional Chinese medicines. Its results can not only help study material basis from a new perspective, but also help find the modern scientific significance in single herb or among compounds of traditional Chinese medicines.

[A new thought of compound compatibility mechanism based on active small molecules monoclonal antibodies in herbs].

Compatibility mechanism study of Chinese herbal compound (CHC) has been one of key contents in Chinese medical research, but the present research methods are not suitable for its own features due to its complexity, which has restricted the process of modernization and intemationalization of Chinese medicine. In this paper, we addressed that the compatibility is closely correlated to their in vivo metabolic processes. The preparation of active small molecules monoclonal antibodies in herbs and testing a variety of effective compositions simultaneously using immunoassay can clarify the in vivo metabolism and mutual interactions of Chinese herbs, which is a new thought of studying the compound compatibility mechanisms.