Development of monoclonal antibody-based enzyme-linked immunosorbent assay for quantitative quality control of Derris scandens (Roxb.) Benth

Derris scandens (Roxb.) Benth. is a medicinal plant used for treatment of musculoskeletal pain in Thai traditional medicines. Its stem contains active compound genistein-7-O-[α-rhamnopyranosyl-(1 to 6)-β-glucopyranoside] (GTG) which is used as a biomarker for standardization of D. scandens extracts. As an alternative for rapid quantitation of GTG, a monoclonal antibody against GTG was prepared and applied for an indirect competitive enzyme-linked immunosorbent assay (ELISA) to determine GTG in plants and herbal products. The established method provided a quantification range of 0.31-10 µg/mL with a limit of detection of 0.29 µg/mL. The assay was validated for precision and accuracy by intra- and interassay variation analyses, recovery test, and comparison analysis between the amounts of GTG determined by ELISA and HPLC. The results exhibited that the developed ELISA is sensitive and effective for determination of GTG in D. scandens plant materials and herbal products.

Production of carbazole alkaloids through callus and suspension cultures in Clausena harmandiana

Carbazole alkaloids are major constituents in Clausena spp. and exhibit a wide range of biological activities. The roots of Clausena harmandiana are a rich source of active carbazole alkaloids. However, its roots take several years to grow to be able to harvest. To obtain an alternative source of carbazole alkaloids, in vitro callus cultures of C. harmandiana were induced, and the formation of two active carbazole alkaloids was investigated. The effects of precursor, concentrations of sucrose, elicitors and light were studied to improve carbazole alkaloids formation. In this study, light had a strong effect on the formation of both carbazole alkaloids. The highest yields of clausine K and 7-methoxymukonal were 4.74 ± 0.26 and 0.92 ± 0.04 mg/g DW, respectively, which have more than 10-fold found in intact roots. According to the results of this study, C. harmandiana callus cultures can be used as an alternative source of carbazole alkaloids for additional biological studies.

Improvement of stilbenoid production by 2-hydroxypropyl-β-cyclodextrin in white mulberry (Morus alba L.) callus cultures

Mulberroside A, oxyresveratrol and resveratrol, commonly found in Morus alba L., are potent anti-aging phytostilbenes. In this study, the effect of the addition of 2-hydroxypropyl-β-cyclodextrin on the levels of phytostilbenes in M. alba callus cultures was investigated. Commercial cyclodextrin was used in the hydrolytic and culture processes of the M. alba callus cultures. The hydrolytic study indicated that 2-hydroxypropyl-β-cyclodextrin acted as a retardant for stilbenoid hydrolysis. It reduced mulberroside A deglycosylation and stabilised oxyresveratrol. The elicitation result showed that extracellular oxyresveratrol was increased by adding 2-hydroxypropyl-β-cyclodextrin to the culture media of both free and immobilised M. alba callus (>730-fold and >169-fold, respectively) compared with those of the control. However, the intracellular mulberroside A levels in the treatment groups did not increase compared with those of the control. The results show that the addition of 2-hydroxypropyl-β-cyclodextrin significantly changed the patterns and levels of the stilbenoids in M. alba callus cultures.

Sodium periodate-mediated conjugation of harringtonine enabling the production of a highly specific monoclonal antibody, and the development of a sensitive quantitative analysis method

Harringtonine (HT) is a promising natural product that is mainly isolated from plants of the genus Cephalotaxus. Due to its remarkable antileukemic activities, HT has been utilized clinically in China for the treatment of acute promyelocytic leukemia (APL). No antibody that recognizes free HT has been reported to date due to the difficulty of preparing antigen conjugates in which haptens bind to a carrier protein. To overcome this difficulty, we focused on sodium periodate (NaIO₄), which catalyzes unique oxidative reactions; the resulting conjugates enabled the production of a highly specific monoclonal antibody (MAb) against HT (MAb 1D2) and the establishment of an indirect competitive enzyme-linked immunosorbent assay (icELISA) for the determination of HT. Further analysis revealed that MAb 1D2 was produced by the HT3 (8-carbonyl HT)-based conjugate antigen; HT3 was synthesized by a NaIO₄-mediated oxidative reaction. The minimum detectable concentration for HT in the icELISA system was found to be 0.76 ng mL^-1, which is approximately 13 to 160 times more sensitive than a conventional HPLC system. Several validation analyses revealed that the icELISA using MAb 1D2 is sufficiently accurate, reliable, and sensitive to assess small amounts of HT in plant samples.

Alginate immobilization of Morus alba L. cell suspension cultures improved the accumulation and secretion of stilbenoids

Morus alba L. (Moraceae) has been used in traditional medicine for the treatment of several illnesses. Recent research also revealed several pharmacological activities from many groups of secondary metabolites, including the stilbenoids mulberroside A, oxyresveratrol, and resveratrol, which are promising compounds for cosmetic and herbal supplement products. In our previous study, cell cultures of M. alba showed high productivity of these compounds. In this study, we attempted to develop immobilized cell cultures of M. alba and to test the effect of elicitors and precursors on the production of stilbenoids. The immobilization of the M. alba cells significantly promoted the secretion of mulberroside A into the extracellular matrix and culture media to 60%, while enhancing the level of oxyresveratrol and resveratrol by 12- and 27-fold, respectively. The elicitation of immobilized cells with a combination of 50 µM methyl jasmonate and 0.5 mg/mL yeast extract for 24 h promoted a twofold increase in the production of all three stilbenoids. Furthermore, the addition of 0.05 mM L-phenylalanine, 0.03 mM L-tyrosine, or a combination resulted in the enhancement of mulberroside A production for up to twofold. The addition of L-tyrosine significantly enhanced the production of oxyresveratrol and resveratrol. This is the first report of stilbenoid production using immobilized cell cultures of M. alba. The cultures have benefits over normal cell suspension cultures by promoting the secretion of mulberroside A and enhancing the levels of oxyresveratrol and resveratrol. Thus, it could be a candidate method for the production of these stilbenoids.

A Monoclonal Antibody-Based Enzyme-Linked Immunosorbent Assay for Determination of Homoharringtonine

Homoharringtonine (HHT), also known as omacetaxine, is a natural compound found in the genus Cephalotaxus and is a promising pharmaceutical drug used for the treatment of chronic or accelerated phase chronic myeloid leukemia. As a tool for the quantitative determination of HHT, a specific monoclonal antibody against HHT (MAb 6A1) was generated by conjugates prepared via sodium periodate-mediated oxidation. The developed indirect competitive enzyme-linked immunosorbent assay (icELISA) using MAb 6A1 was found to be highly specific and sensitive with a limit of detection for HHT of 48.8 ng/mL. Validation assays to evaluate precision and accuracy of the method were conducted by the use of intra- and inter-assay analysis, recovery test, and comparison analysis between the amounts of HHT determined by ELISA and high-performance liquid chromatography. These results revealed that the established icELISA using MAb 6A1 is specific, sensitive, and reliable enough to be applied to the qualitative analysis for HHT. Furthermore, the results of this study support the usefulness of sodium periodate as a reagent for the conjugation between Cephalotaxus alkaloids and proteins for producing specific antibodies.

A New Highly Selective and Specific Anti-puerarin polyclonal Antibody for Determination of Puerarin Using a Mannich Reaction Hapten Conjugate

Background

Puerarin (PUE) is a phytoestrogen found in Pueraria candollei and Pueraria lobata. These plants are substantial for traditional medicine in various Asian countries. PUE is a key marker that can be found only in the Pueraria species.

Objective

To establish the method for determination of PUE content which is required for quality control of pharmaceutical products.

Materials and Methods

PUE-cationized bovine serum albumin conjugate was created via Mannich reaction. After the rabbit immunization, the obtain anti-PUE polyclonal antibody (PAb) was used to develop an enzyme-linked immunosorbent assay (ELISA).

Results

An anti-PUE PAb possess a great sensitivity and specificity. The cross-reactivity analysis shows no cross-reaction of an established antibody against other substances. In addition, we successfully developed an indirect competitive ELISA (icELISA) for the quantitative analysis of PUE. The result of method validation conforms to acceptance criteria and correlates with high-performance liquid chromatography, the reference method. The icELISA was applied to determine PUE content in Pueraria spp. plant samples and its derived pharmaceutical products.

Conclusion

This highly specific immunogen was created from the Mannich reaction. An icELISA can also be applied to other research propose in the further studies.

SUMMARY

The new immunogen conjugated (puerarin-cBSA) via Mannich reaction was successfully in rising of antibody against puerarin (PUE)The obtained anti-PUE polyclonal antibody (PAb) was high sensitivity and specificity to PUEAn indirect competitive enzyme-linked immunosorbent assay (icELISA) was developed and validated using anti-PUE PAbThe established icELISA was applied to determine PUE content in various tuberous root of Pueraria sppMoreover, icELISA method can be applicable in Pueraria spp. derived products. Abbreviations used: PUE: Puerarin; PAb: Polyclonal antibody; ELISA: Enzyme-linked immunosorbent assay; icELISA: Indirect competitive ELISA; cBSA: Cationized bovine serum albumin.

Enzyme-linked immunosorbent assay for the quantitative/qualitative analysis of plant secondary metabolites

Immunoassays are antibody-based analytical methods for quantitative/qualitative analysis. Since the principle of immunoassays is based on specific antigen-antibody reaction, the assays have been utilized worldwide for diagnosis, pharmacokinetic studies by drug monitoring, and the quality control of commercially available products. Berson and Yalow were the first to develop an immunoassay, known as radioimmunoassay (RIA), for detecting endogenous plasma insulin [1], a development for which Yalow was awarded the Nobel Prize in Physiology or Medicine in 1977. Even today, after half a century, immunoassays are widely utilized with some modifications from the originally proposed system, e.g., radioisotopes have been replaced with enzymes because of safety concerns regarding the use of radioactivity, which is referred to as enzyme immunoassay/enzyme-linked immunosorbent assay (ELISA). In addition, progress has been made in ELISA with the recent advances in recombinant DNA technology, leading to increase in the range of antibodies, probes, and even systems. This review article describes ELISA and its applications for the detection of plant secondary metabolites.

Development of an immunochromatographic strip incorporating anti-mitragynine monoclonal antibody conjugated to colloidal gold for kratom alkaloids detection

A lateral flow-based immunochromatographic strip was developed for the rapid detection of mitragynine (MG), a dominant alkaloid found in the leaves of kratom. Monoclonal antibody (mAb) against MG (anti-MG mAb) was conjugated to colloidal gold and used as a recognition probe. MG-ovalbumin conjugate (MG-OVA) and goat anti-mouse IgG were immobilized on the strip to produce a test zone and control zone, respectively. Based on the principle of a competitive assay, MG in a test sample competed with MG-OVA resident in the test zone to bind with colloidal gold-anti-MG mAb, resulting in an inverse relation of color intensity at the test zone and MG amount. The limit of detection (LOD) of the immunochromatographic strip is determined at 1 mg/mL of MG by visual assessment and 0.60 mg/mL by Image J analysis. The developed immunochromatographic strip can determine MG in kratom cocktails and kratom leaf samples. It could serve as a rapid and simple diagnostic kit for the detection of MG in kratom samples.

A pilot pharmacokinetic study of miroestrol and deoxymiroestrol on rabbit sera using polyclonal antibody-based icELISA analysis

Miroestrol (ME) and deoxymiroestrol (DME) are the most potent phytoestrogens and bioactive markers in Pueraria candollei var. mirifica tuberous roots. To understand their pharmacokinetic profiles, a pharmacokinetic study of ME and DME, at 0.43 and 0.21 mg per kg body weight, respectively, in three rabbits was performed after orally administering a single dose of P. candollei var. mirifica enriched fraction extract. Two established polyclonal antibody-based indirect competitive enzyme-linked immunosorbent assays were validated to determine ME and DME in rabbit sera. In rabbits, the area under the 0- to 48-hr concentration-time curve of ME and DME were 854.92 and 1,692.84 ng·h/ml, respectively. The maximum concentration of ME was measured 1 hr after administration as 69.62 ± 8.28 ng/ml, and the maximum concentration of DME was measured at 3 hr as 81.8 ± 5.43 ng/ml. These results provide an initial approach for designing and studying the relationship between the ME and DME levels and their therapeutic effects based on their pharmacokinetic profiles.

Antioxidant Activity and Upregulation of Antioxidant Enzymes of Phenolic Glycosides from Aquilaria crassna Leaves

The leaves of Aquilaria crassna Pierre ex Lecomte (Thymelaeaceae) have been used in the traditional medicine and consumed as a health-promoting tea in several Asian countries. This study investigated the antioxidant activity of three major bioactive constituents of A. crassna leaves, genkwanin 5- O-β-primeveroside (1), iriflophenone 3,5- C-β-D-diglucoside (2) and iriflophenone 3- C-β-D-glucoside (3) using DPPH and superoxide scavenging assays, as well as their effects on induction of mRNA and protein expressions of antioxidant enzymes in HEK-293 cells. The benzophenone glycoside 3 exhibited significant scavenging activity against both types of free radicals and increased the mRNA expression of antioxidant enzymes such as glutathione peroxidase-1, glutathione reductase and heme oxygenase-1 in HEK-293 cells. In addition, all three compounds also increased the protein expression of glutathione peroxidase-1. These findings revealed the effects of these compounds at cellular level, and might be useful for the development of A. crassna leaves as supplements for prevention of oxidative stress.

Development of an Enzyme-Linked Immunosorbent Assay for Determination Of Miroestrol Using an Anti-miroestrol Monoclonal Antibody

Miroestrol is a chromene with potent estrogenic activity present in Pueraria candollei, commonly known as White Kwao Krua. Although this compound is only present in low amounts in the plant, it plays an important role in the estrogenic action of P. candollei products. As a tool for further studies about the efficacy and safety of P. candollei as a phytoestrogenic supplement, we generated a novel monoclonal antibody against miroestrol. This anti-miroestrol monoclonal antibody was used to develop an immunoassay for the determination of miroestrol content, which can be used for quality control purposes of P. candollei. The developed ELISA against miroestrol has a calibration range of 10-780 ng/mL miroestrol, a limit of detection of 3.5 ng/mL, and a limit of quantitation of 12.2 ng/mL. According to the validation analysis, the established ELISA is precise, accurate, specific, and sensitive for miroestrol detection in plants. Furthermore, the anti-miroestrol monoclonal antibody was used to prepare an immunoaffinity column for the isolation of miroestrol from the tuberous root of P. candollei. The column provides a simple procedure for miroestrol isolation, with a capacity of 3.91 µg of miroestrol per 1 mL of immunogel.

Immunoaffinity Knockout of Saponin Glycosides from Asparagus racemosus to Assess Anti-lipid Peroxidation

INTRODUCTION

Asparagus racemosus Willd (Asparagaceae family), known as Shatavari, is important in Ayurveda and traditional Thai medicines. The saponin glycosides, shatavarin I and IV are major constituents in its roots and may be responsible for their actions including protection against lipid peroxidation and carcinogenesis.

OBJECTIVE

To develop an immunoaffinity column for isolating compounds with structures related to shatavarin IV from crude extracts of A. racemosus root.

METHODOLOGY

The monoclonal antibody recognising shatavarin IV (mAbShavIV) was coupled to an Affi-Gel Hz gel to isolate compounds with structures related to shatavarin IV from the other components of crude extracts of A. racemosus root. The saponin glycosides in each fraction were analysed by mAbShavIV ELISA and LC-MS/MS.

RESULTS

The pooled wash-through fractions contained 3% of loaded mAbShavIV reactive saponin glycosides, while eluted fractions released ~ 90% of shatavarin saponin glycosides in a single step. Using thiobarbiturate (TBARs) to measure lipid-peroxidation, the extract, and the pooled wash-through fractions showed moderate protection against Cu⁺ -induced oxidation of human low density lipoprotein (LDL) (IC₅₀ 11.3 ± 1.4 and 12.6 ± 0.9 μg/mL, respectively). In contrast, the saponin glycosides eluted from the mAbShavIV-column had weaker protectant (IC₅₀ 29.7 ± 1.8 μg/mL) suggesting that A. racemosus shatavarins do not inhibit carcinogenesis through preventing lipid peroxidation.

CONCLUSION

The strategy described here demonstrates its utility for isolating a group of related compounds from the rest of the extract with selectivity and recovery rate. Pharmacological efficacy and synergistic effects of the components obtained can be further investigated. Copyright © 2017 John Wiley & Sons, Ltd.

A monoclonal antibody-based immunoassay for the determination of oxyresveratrol from Artocarpus lacucha Buch.-Ham

Oxyresveratrol is a major active compound in the heartwood of Artocarpus lacucha. It plays an important role in anti-tyrosinase, antioxidant, anti-inflammatory, antiviral and neuroprotective properties. There are many A. lacucha commercial products available on the market for skin whitening and anti-aging effects. To evaluate the quality of raw material from the plant, a monoclonal antibody (MAb) against oxyresveratrol was generated in this study. The immunogen was prepared by the Mannich reaction for the conjugation of oxyresveratrol and cationized bovine serum albumin (cBSA). The conjugation of oxyresveratrol-cBSA at a ratio of 1:50 was used for the immunization. The novel MAb (E4) was specific to oxyresveratrol and resveratrol. An indirect competitive enzyme-linked immunosorbent assay (ELISA) using the MAb (E4) was developed for the determination of oxyresveratrol. The linear range for the measurement of oxyresveratrol was 63-500 ng/mL and the precision (% relative standard deviation) was found to be <10% with the percentages of recovery from 95.93-103.55%. According to the validation analysis, the established ELISA can be applied for the determination of oxyresvertrol in the heartwood of A. lacucha and samples of the traditional drug Puag-Haad. With reliability and high sensitivity, this assay can provide an alternative approach for the quantitative analysis of oxyresveratrol in A. lacucha samples.