Preincubation format for a sensitive immunochromatographic assay for monocrotaline, a toxic pyrrolizidine alkaloid

Abstract

Introduction Monocrotaline (MCT), which is classified as a 1,2‐dehydropyrrolizidine alkaloid (DHPA), is a toxic compound that is mainly produced by Crotalaria spp. MCT contamination in cereals and herbs leads to hepatitis, gastroenteritis, pulmonary vasculitis and hypertension, and different types of cancer. The current analytical methods for MCT are complicated and expensive using liquid chromatography equipped with mass spectrometry detection. Objective The aim of this study was to develop a simple and sensitive preincubation format for an immunochromatographic assay (PI‐ICA) for MCT detection. Methodology We conducted the PI‐ICA via incubation of an MCT‐containing sample with an anti‐MCT monoclonal antibody conjugated with colloidal gold before strip dipping. We compared the PI‐ICA detection sensitivity with that of the conventional ICA (Conv‐ICA) format. Results The PI‐ICA was sensitive with a limit of detection (LOD) of 0.61 ng/mL, which is a 16‐fold improvement over the Conv‐ICA format. These results indicated that the PI‐ICA method exhibits high binding specificity for MCT and low cross‐reactivity towards retronecine, retrorsine, senecionine and heliotrine. Sample solutions from plants containing MCT and related DHPAs produced positive results via PI‐ICA analysis. Conclusions The proposed PI‐ICA system provides a highly sensitive method compared to Conv‐ICA. In addition, the developed PI‐ICA method is simple and highly effective for detecting MCT contamination.

Immunochromatographic assay for the detection of kwakhurin and its application for the identification of Pueraria candollei var. mirifica (Airy Shaw & Suvat.) Niyomdham

“…Preparation of the mAb 11F-AuNP conjugate was performed according to a previous method 16 with some modifications. Briefly, an aqueous K 2 CO 3 solution [2% (w/v), 20 μL] was added to the AuNP suspension (1 mL).…”

Lateral flow immunoassay for small-molecules detection in phytoproducts: a review

“…This contains target-specific antibody-reporter molecule conjugates. In cases where the conjugate pad was omitted, the antibody-reporter molecule conjugates were mixed into the sample with an appropriate amount [33,34,[45][46][47].When the liquid passes through the conjugates reservoir, the antibody-reporter molecule conjugates are slowly released. Few antibodies start to bind with the antigen and move together to the test zone.…”

“…The compounds with carboxylic acid and hydroxyl functional groups are usually conjugated by a carbodiimidemediated reaction [33,34,47,[95][96][97][98][99][100][101][102], whereas compounds with active hydrogen, e.g., α-picolines, ketones, esters, and acetylenes, can be conjugated to an amine or amide group of the carrier by a Mannich reaction [103,104]. Furthermore, structure modifications of the parent compounds to add the reactive functional group to the molecule can be conducted when necessary.…”

“…The ideal conjugate pad should act as a bank of antibody–reporter molecule conjugates, which readily release once the liquid passes through and not permanently retain the antibody–reporter molecule conjugates. In certain LFA formats, this component is omitted, and the antibody–reporter molecule conjugates are directly added into the sample [ 33 , 34 ].…”

Progress in Immunoassays of Toxic Alkaloids in Plant-Derived Medicines: A Review

“…BSA is most commonly used in the toxic alkaloids field due to its stable physicochemical properties, non- dewaterability, low cost, and easy availability, as well as its high lysine content (i.e., high coupling density of hapten and carrier) [ 52 , 53 , 57 , 58 , 64 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 ]. Similarly, HSA also has a large amount of lysine and more free amino acids, which are widely used [ 59 , 75 ]. KLH is also commonly used as an immunogen protein [ 53 , 70 , 76 , 77 ].…”