Development of eastern blotting technique for sennoside A and sennoside B using anti-sennoside A and anti-sennoside B monoclonal antibodies

Immunological Separation of Bioactive Natural Compounds from Crude Drug Extract and Its Application for Cell-Based Studies

In this study, we present a review on a useful approach, namely, immunoaffinity column coupled with monoclonal antibodies (MAbs), to separate natural compounds and its application for cell-based studies. The immunoaffinity column aids in separating the specific target compound from the crude extract. The column capacity was stable even after more than 10 purification cycles of use under the same conditions. After applying the crude extract to the column, the column was washed with washing buffer and eluted with elution buffer. The elution fraction contained the target compound bound to MAb, whereas the washing fraction was the crude extract, which contained all compounds except a group of target compounds; therefore, the washing fraction was referred to as a knockout (KO) crude extract. Cell-based studies using the KO extract revealed the actual effects of the natural compounds in the crude extract. One-step separation of natural compounds using the immunoaffinity column coupled with MAbs may help in determining the potential functions of natural compounds in crude extracts.

Studies on Natural Products Using Monoclonal Antibodies: A Review

An immunoblotting system ("eastern blotting") was developed for small-molecule herbal medicines like glycosides, with no conjugation function to the membrane. Briefly, the crude extracts of herb medicines were developed by thin-layer chromatography (TLC). The small-molecule herbal medicines on TLC plates were transferred to polyvinylidene fluoride (PVDF) or polyethersulfone (PES) membranes by heating. Antigen components were divided into two categories based on their function, i.e., their membrane recognizing (aglycone part) and fixing (sugar moiety) abilities. This procedure allows for the staining of only target glycosides. Double eastern blotting was developed as a further staining system for two herb medicines using a set of MAbs and substrates.

What we already know about rhubarb: a comprehensive review

Rhubarb (also named Rhei or Dahuang), one of the most ancient and important herbs in traditional Chinese medicine (TCM), belongs to the Rheum L. genus from the Polygonaceae family, and its application can be traced back to 270 BC in "Shen Nong Ben Cao Jing". Rhubarb has long been used as an antibacterial, anti-inflammatory, anti-fibrotic and anticancer medicine in China. However, for a variety of reasons, such as origin, variety and processing methods, there are differences in the effective components of rhubarb, which eventually lead to decreased quality and poor efficacy. Additionally, although some papers have reviewed the relationship between the active ingredients of rhubarb and pharmacologic actions, most studies have concentrated on one or several aspects, although there has been great progress in rhubarb research in recent years. Therefore, this review aims to summarize recent studies on the geographic distribution, taxonomic identification, pharmacology, clinical applications and safety issues related to rhubarb and provide insights into the further development and application of rhubarb in the future.

Isolation of a novel glycyrrhizin metabolite as a causal candidate compound for pseudoaldosteronism

Pseudoaldosteronism is a common adverse effect associated with traditional Japanese Kampo medicines. The pathogenesis is mainly caused by 3-monoglucuronyl glycyrrhetinic acid (3MGA), one of the metabolites of glycyrrhizin (GL) contained in licorice. We developed an anti-3MGA monoclonal antibody (MAb) and an ELISA system to easily detect 3MGA in the plasma and urine of the patients. However, we found that some metabolites of GL cross-reacted with this MAb. Mrp2-deficient Eisai Hyperbilirubinemia rats (EHBRs) were administered glycyrrhetinic acid (GA), and we isolated 22α-hydroxy-18β-glycyrrhetyl-3-O-sulfate-30-glucuronide (1) from the pooled urine with the guidance of positive immunostaining of eastern blot as the new metabolite of GL. The IC₅₀ of 1 for type 2 11β-hydroxysteroid dehydrogenase (11β-HSD2) was 2.0 µM. Similar plasma concentrations of 1 and GA were observed 12 h after oral administration of GA to EHBR. Compound 1 was eliminated via urine, whereas GA was not. In Sprague–Dawley (SD) rats orally treated with GA, compound 1 was absent from both the plasma and the urine. Compound 1 was actively transported into cells via OAT1 and OAT3, whereas GA was not. Compound 1, when produced in Mrp2-deficiency, represents a potential causative agent of pseudoaldosteronism, and might be used as a biomarker to prevent the adverse effect.

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.

Development of Double Eastern Blotting for Major Licorice Components, Glycyrrhizin and Liquiritin for Chemical Quality Control of Licorice Using anti-Glycyrrhizin and anti-Liquiritin Monoclonal Antibodies

Licorice is utilized in various food industries around the world for seasoning agents, confectioneries, drinks, and functional foods. Glycyrrhizin (GL) and liquiritin (Liq) are major quality control chemical markers of licorice that have multifunctional bioactivities. Chemical quality control of licorice is important because its component profiles change depending environmental factors (climate, soil condition, and water deficit) and differences between species. Double eastern blotting using anti-GL and anti-Liq monoclonal antibodies was developed for more convenient, rapid, and specific quality control analysis of GL and Liq, respectively. Moreover, double eastern blotting was applied to investigate the immunohistochemical distributions of GL and Liq in the root of fresh licorice; the localization of both components was then clarified visually. This double eastern blotting technique for GL and Liq may serve as a powerful approach for visually determining the chemical quality of licorice.

Development of an Eastern blotting technique for the visual detection of aristolochic acids in Aristolochia and Asarum species by using a monoclonal antibody against aristolochic acids I and II

INTRODUCTION

Aristolochic acids (AAs) are naturally occurring nephrotoxicants and human carcinogens. Aristolochic acid I (AA-I) and aristolochic acid II (AA-II) are two important AAs with clear toxicity.

OBJECTIVE

To obtain a monoclonal antibody (MAb) recognising AA-I and AA-II and develop an Eastern blotting technique for the specific visualisation and easy determination of AA-I and AA-II in plant extracts or tissues of Aristolochia and Asarum species.

METHODS

A hybridoma secreting MAb against AAs was prepared by cell fusion with splenocytes derived from a mouse immunised with AA-I-keyhole limpet haemocyanin (KLH) conjugate and the myeloma cell line SP2/0-Ag14. AA-I and AA-II were separated by thin-layer chromatography (TLC) and then blotted onto a positively charged polyethersulphone (PES) membrane using a modified carbodiimide method. The resulting membrane-bound AA-protein conjugates were linked to the newly prepared MAb and then to the secondary antibody labelled with peroxidase. 4-Chloro-1-naphthol was then added as the peroxidase substrate for staining.

RESULTS

MAb 2A10-10B showed a high specificity for AA-I (100%) and AA-II (69.3%) and low cross reactivity (≤ 2.2%) toward analogues that may disrupt detection of AA-I and AA-II in plants. An established Eastern blotting method was applied to the immunohistolocalisation of AA-I and AA-II in dry plant tissues, and this analysis showed that the phelloderm, cortex and phloem of Aristolochia manshuriensis stem may contain higher amounts of total AA-I and AA-II as compared with the pith and xylem.

CONCLUSION

This method was extremely useful for the visual screening of AA-I and AA-II among easily mistaken herbal medicines.

Detection of paeoniflorin and albiflorin by immunostaining technique using anti-paeoniflorin monoclonal antibody

INTRODUCTION

Paeoniae radix is one of the most important crude drugs used in Kampo medicines (KMs). A part of its pharmaceutical properties is due to the presence of paeoniflorin (PF) and albiflorin (AF).

OBJECTIVE

For the specific and easy identification of PF and AF, an immunostaining technique was developed using anti-PF monoclonal antibody (MAb).

METHODOLOGY

PF and AF were treated with a NaIO₄ solution and reacted with bovine serum albumin (BSA) preparing PF- and AF-BSA conjugates on the polyethersulphone (PES) membrane. Anti-PF MAb was bound and then antibody labelled with peroxidase directed against anti-PF MAb. Finally, a substrate was added and then PF and AF were detected.

RESULTS

Anti-PF MAb recognised not only PF but also AF when 10 µg was present on the PES membrane. As little as 0.5 µg of PF and AF were still detected under immunostaining. Various Paeoniae radix samples and KMs were qualitatively analysed, and total amounts of PF and AF were visually detected by immunostaining technique. This method was applied to investigate the distribution of PF and AF in fresh peony root using immunoblotting by transferred from peony root to the PES membrane.

CONCLUSION

The technique permitted the visualisation of PF and AF on PES membrane using immunostaining. The immunostaining technique established would be a powerful tool for probing the sources of PF and AF in plant extracts.

Standardization of Licorice and TCM Formulations Using Eastern Blot Fingerprinting Analysis

To prepare the antiglycyrrhizin (GC) monoclonal antibody (MAb), GC was treated with NaIO4resulting in aldehyde which can be combined with carrier protein. An antigen conjugate was performed by a matrix-assisted laser desorption/ionization TOF mass spectrometry to determine the hapten numbers in the conjugate. Anti-GC MAb was prepared from a hybridoma which was fixed from the spleen cells producing anti-GC MAb and the myeloma cells after immunization. The TCM and licorice extract were developed by TLC and blotted to a polyvinylidene difluoride (PVDF) membrane. The membrane was treated by NaIO4and protein, enzyme labeled secondary MAb, and finally substrate was added. Clear spot appeared on PVDF membrane identifying GC against a background containing large amount of impurities. In eastern blotting, the GC molecule was divided into two functions. The aglycone part is recognized as an epitope and the sugar moiety can be combined to membrane. The specific reactivity of sugar moiety in the GC molecule against anti-GC MAb might be modified by the NaIO4treatment on the membrane because glycyrrhetic acid 3-O-glucuronide can be stained although the cross-reactivity is only 4.3%. Eastern blotting for GC can not only apply for the standardization of licorice and TCM, but also it can open for the other bioactive products.