A selective and sensitive assay of berberine using total internal reflected resonance light scattering technique with fluorescein at the water/1,2-dichloroethane interface

An aptamer-based fluorometric method for the rapid berberine detection in Kampo medicines

BACKGROUND

Berberine (BBR), a key component in Kampo medicine, is a cationic benzylisoquinoline alkaloid whose detection plays a critical role in the quality control of these traditional remedies. Traditional methods for detecting BBR often involve complex procedures, which can be time-consuming and costly. To address this challenge, our study focuses on developing a simpler, faster, and more efficient detection method for BBR in Kampo medicine formulations.

RESULTS

We successfully developed a rapid fluorometric detection method for BBR using colloidal gold nanoparticle-based systematic evolution of ligands by exponential enrichment (GOLD-SELEX). Initially, specific single-stranded DNA (ssDNA) sequences were selected for their ability to enhance BBR's fluorescence intensity. The optimal ssDNA sequence, identified as BBR38, was further truncated to produce BBR38S, a stem-loop ssDNA that improved fluorescence upon interaction with BBR. To further enhance the fluorescence, the BBR38S aptamer underwent additional modifications, including stem truncation and nucleotide mutations, resulting in the higher fluorescence variant BBR38S-3 A10C. The final product, TetBBR38S, a tetramer version of BBR38S-3 A10C, exhibited a linear detection range of 0.780-50.0 μg mL-1 and a limit of detection of 0.369 μg mL-1. The assay demonstrated sufficient selectivity and was successfully applied to analyze 128 different Kampo medicine formulations, accurately detecting BBR content with high precision.

SIGNIFICANCE

This study represents an advancement in Kampo medicine research, marking the first successful application of an aptamer-based approach for BBR detection in complex matrices. The developed method is not only simple and rapid (with a detection time of 5 min) but also cost-effective, which is crucial for widespread application.

A fluorometric and colorimetric approach for the rapid detection of berberine hydrochloride based on an anionic polythiophene derivative

In this report, we develop a dual-output sensor with fluorometric and colorimetric responses, for the rapid and simple detection of berberine hydrochloride (BRH) in 100% aqueous solution based on an anionic polythiophene derivative, poly(2-(2-(4-methylthiophen-3-yloxy)-ethyl) malonic acid) (PTMA). The sensing performance and mechanism were carefully examined by absorption and emission spectra. It can be applied to quantitatively detect BRH in aqueous solution with a detection limit 0.27 μM. The appealing performance of the sensor was demonstrated to originate from the electrostatic and π-π interactions between PTMA and BRH, which promoted the conformational change and aggregation of the PTMA backbone. Moreover, this method allowed rapid detection of BRH in urine samples and BRH tablets with high accuracy.

A highly fluorescent lanthanide metal-organic framework as dual-mode visual sensor for berberine hydrochloride and tetracycline

A microscale highly fluorescent Eu metal-organic framework (Eu-MOF) was synthesized with terephthalic acid and 1H-1,2,4-triazole-3,5-diamine by one-pot hydrothermal method. And it was characterized by scanning electron microscope, Fourier transform infrared spectroscopy, powder X-ray diffraction, fluorescence spectroscopy, thermogravimetric analysis, and energy dispersive X-ray mapping. The prepared Eu-MOF has high quantum yield of 30.99%, excellent water dispersibility, good fluorescence stability, and favorable thermal stability. Based on the distinctly different fluorescence responses of different emission, the prepared Eu-MOF was used as dual-mode visual sensor for the sensitive detection of berberine hydrochloride and tetracycline. The limits of detection are 78 nM and 17 nM, respectively. The sensing mechanism was also discussed. Moreover, a filter paper sensor has been designed for sensing tetracycline with a notable fluorescence color change from blue to red. The prepared Eu-MOF is promising to be developed as a multi-mode luminescent sensor for visual detection in biochemical analysis. Graphical abstract Illustration of the synthesis of Eu-MOF and its sensing applications for berberine hydrochloride and tetracycline.

Determination of berberine hydrochloride using a fluorimetric method with silica nanoparticles as a probe

The interaction of silica nanoparticles (SiO₂NPs) with berberine hydrochloride (BRH) was studied in aqueous solution at pH 9.0 and room temperature by using fluorophotometry. Based on a significant enhancement of the fluorescence intensity of the SiO₂NPs–BRH aggregates, a spectrofluorimetric method which was simple, sensitive and green was developed for the determination of BRH in aqueous solution. The linear range of the method was from 2.0–50.0 μg L⁻¹ with a detection limit of 0.73 μg L⁻¹. There was no interference from the compounds normally used to formulate pharmaceutical tablets. The proposed method was applied to the determination of BRH in tablets with satisfactory results and good consistency with the results obtained by standard methods.

A simple, green and sensitive spectrofluorimetric method was proposed for the determination of berberine hydrochloride (BRH) in aqueous solution.

Spontaneous formation of fluorescent nanofibers and reticulated solid from berberine palmitate: a new example of aggregation-induced emission enhancement in organic ion pairs

The salt formed between the large aromatic berberine cation and the long-chain palmitate anion was synthesized and used to prepare aqueous suspensions of particles owing to a solvent-exchange method. Under these conditions, elongated particles were readily obtained. They were studied by transmission microscopy with polarized light, as well as by fluorescence and electron microscopy. They were shown to be probably crystallized nanofibers, which were stable in suspension. Unexpectedly, upon filtration and drying, these fibers evolved to give a reticulated solid. The fluorescence properties of the compound were analyzed in solution, in aqueous suspension and in the powder crystalline state. Interestingly, berberine palmitate is virtually not fluorescent in aqueous solution because of the quenching effect of water, but transition to the solid state was accompanied by a strong increase in fluorescence intensity. This phenomenon was explained by the original molecular arrangement in the solid state. Actually, in the crystal, the anions form a distinct layer, which limits parallel-stacking of the fluorescent cations. Moreover, the berberine cations are protected from the access of water molecules, and so no quenching effect can take place. This example confirms that the newly introduced concept of ion-pair aggregation-induced fluorescence enhancement can be extended to a variety of structures. It also shows the interest of ion pairs for preparing fluorescent nanofibers and reticulated solids using a solvent-exchange method that is particularly easy to implement.

A simple fluorescence quenching method for berberine determination using water-soluble CdTe quantum dots as probes

A novel method for the determination of berberine has been developed based on quenching of the fluorescence of thioglycolic acid-capped CdTe quantum dots (TGA-CdTe QDs) by berberine in aqueous solutions. Under optimum conditions, the relative fluorescence intensity was linearly proportional to the concentration of berberine between 2.5x10(-8) and 8.0x10(-6)mol L(-1) with a detection limit of 6.0x10(-9)mol L(-1). The method has been applied to the determination of berberine in real samples, and satisfactory results were obtained. The mechanism of the proposed reaction was also discussed.