Quantitative determination of major alkaloids in areca nut products by high-performance liquid chromatography coupled with ion mobility spectrometry.

Areca nut is a popular and addictive food as well as a traditional herbal medicine in many countries. Areca nut contains alkaloids including arecoline, guvacine, and arecaidine, which are the major bioactive compounds in areca products. Areca alkaloids can be carcinogenic, and thus sensitive and specific analytical methods are urgently desired for the identification and quantification of these compounds. High-performance liquid chromatography-based methods are often preferred, but areca alkaloids do not have chromophores, and detection using a traditional UV detector can be difficult. The complexity of areca sample extracts can also lead to the co-elution of peaks leading to poor quantitative performance. We report here high-performance liquid chromatography coupled with an ion mobility spectrometer for sensitive determination of areca alkaloids in various products including areca nut, areca nut products, and herbal oral liquid. An X-Bridge reversed-phase C18 column was used in the experiment and was combined with high-performance liquid chromatography coupled to an ion mobility spectrometer system. A custom-made adjustable post-column splitter acted as an interface between the high-performance liquid chromatography and the ion mobility spectrometer; it also acted as the electrospray ionization source. The mobile phase was methanol and 0.5% ammonium hydroxide. The results demonstrate that the splitter can afford a wide range of split ratios that match the ion mobility spectrometer ionization source while keeping the separation efficiency of high-performance liquid chromatography. Three major alkaloid compounds were then accurately determined using the resulting method without dativization steps. Many coeluted high-performance liquid chromatography peaks are effectively separated in the ion mobility spectrometer dimension, which in turn improved the quantification accuracy.

Comparison of the psychoactive activity of four primary Areca nut alkaloids in zebrafish by behavioral approach and molecular docking.

Areca palm nut (Areca catechu) has been listed as one of the most addictive substances, along with tobacco, alcohol, and caffeine. It belongs to the family Arecaceae and is widely used in Asia. Areca nut contains seven psychoactive alkaloids; however, the effects of these alkaloids on behaviors are rarely to be addressed in zebrafish. Therefore, this study aims to compare the psychoactive and potential adverse effects of four primary alkaloids (arecoline, arecaidine, guvacine, and guvacoline) isolated from areca nut on zebrafish. We found that four alkaloids induced hyperactivity-like behaviors in zebrafish larvae. Cooperating the results with the previous study, molecular docking scores suggested these alkaloids might bind to multiple muscarinic acetylcholine receptors (mAChRs), and various best binding modes were shown. According to the adult zebrafish behavioral test, arecoline was found to slightly increase the locomotor activity and caused tightening shoaling formations of adult zebrafish. Meanwhile, zebrafish exposed to arecaidine have reduced aggressiveness and conspecific social interaction. Similar to arecaidine, guvacoline treatment also caused abnormalities in zebrafish social behaviors. Furthermore, the fish displayed abnormal exploratory behaviors after being exposed to guvacoline. Interestingly, altered fear response behaviors were only displayed by guvacine-treated fish besides their lower locomotor activity. Based on the results of molecular docking, we hypothesize that the behavior alterations might be a consequence of the interaction between alkaloids and multiple mAChRs in the nervous system. In summary, our study found that each alkaloid specifically affects adult zebrafish behaviors.

Synthesis and Biological Evaluation of Nipecotic Acid and Guvacine Derived 1,3-Disubstituted Allenes as Inhibitors of Murine GABA Transporter mGAT1.

A new class of nipecotic acid and guvacine derivatives has been synthesized and characterized for their inhibitory potency at mGAT1-4 and binding affinity for mGAT1. Compounds of the described class are defined by a four-carbon-atom allenyl spacer connecting the nitrogen atom of the nipecotic acid or guvacine head with an aromatic residue. Among the compounds investigated, the mixture of nipecotic acid derivatives rac-{(Ra )-1-[4-([1,1':2',1''-terphenyl]-2-yl)buta-2,3-dien-1-yl](3R)-piperidine-3-carboxylic acid} and rac-{(Sa )-1-[4-([1,1':2',1''-terphenyl]-2-yl)buta-2,3-dien-1-yl](3R)-piperidine-3-carboxylic acid} (21 p), possessing an o-terphenyl residue, was identified as highly selective and the most potent mGAT1 inhibitor in this study. For the (R)-nipecotic acid derived form of 21 p, the inhibitory potency in [3 H]GABA uptake assays was determined as pIC50 =6.78±0.08, and the binding affinity in MS Binding Assays as pKi =7.10±0.12. The synthesis of the designed compounds was carried out by a two-step procedure, generating the allene moiety via allenylation of terminal alkynes which allows broad variation of the terminal phenyl and biphenyl subunit.

[Comparative study on contents of four alkaloids in homologous herbal medicines--Arecae Pericarpium and Arecae Semen].

To establish a high performance liquid chromatography (HPLC) method for simultaneous determination of four alkaloids(arecoline， guvacoline， arecaidine， and guvacine) in Arecae Pericarpium (AP) and Arecae Semen (AS), and compare the contents of these four alkaloids between different medicinal parts. The chromatographic conditions were as follows:Welch SCX（4.6 mm×250 mm， 5 µm）column, with acetonitrile-0.2% phosphoric acid solution (adjusted to pH 3.85-3.90 with ammonium hydroxide) at 50:50 as the mobile phase, at a flow rate of 0.5 mL·min⁻¹. The column temperature was set at 35 °C, and the detection wavelength was 215 nm. The results of content determination in 7 batches of AS and 10 batches of AP showed that, the contents of 4 alkaloids in AS (arecaidine 0.020%-0.045%, guvacine 0.031%-0.086%, arecoline 0.194%-0.346%, and guvacoline 0.065%-0.094%) were generally higher than those in AP (arecaidine 0.10%-0.032%, guvacine 0.006%-0.029% arecoline 0.00%-0.070%, and guvacoline 0.00%-0.020%), and most of the APs had no arecoline and arecaidine at all in fruit peel. The above results indicated that different alkaloids can be used to distinguish the different medicinal parts of Arera catechu. Arecoline， guvacoline， arecaidine， and guvacine can be used as the quality control markers of AS, while for AP, only arecaidine and guvacine were needed.

Comparative study on contents of four alkaloids in homologous herbal medicines--Arecae Pericarpium and Arecae Semen / 中国中药杂志

To establish a high performance liquid chromatography (HPLC) method for simultaneous determination of four alkaloids(arecoline， guvacoline， arecaidine， and guvacine) in Arecae Pericarpium (AP) and Arecae Semen (AS), and compare the contents of these four alkaloids between different medicinal parts. The chromatographic conditions were as follows:Welch SCX（4.6 mm×250 mm， 5 μm）column, with acetonitrile-0.2% phosphoric acid solution (adjusted to pH 3.85-3.90 with ammonium hydroxide) at 50:50 as the mobile phase, at a flow rate of 0.5 mL·min⁻¹. The column temperature was set at 35 °C, and the detection wavelength was 215 nm. The results of content determination in 7 batches of AS and 10 batches of AP showed that, the contents of 4 alkaloids in AS (arecaidine 0.020%-0.045%, guvacine 0.031%-0.086%, arecoline 0.194%-0.346%, and guvacoline 0.065%-0.094%) were generally higher than those in AP (arecaidine 0.10%-0.032%, guvacine 0.006%-0.029% arecoline 0.00%-0.070%, and guvacoline 0.00%-0.020%), and most of the APs had no arecoline and arecaidine at all in fruit peel. The above results indicated that different alkaloids can be used to distinguish the different medicinal parts of Arera catechu. Arecoline， guvacoline， arecaidine， and guvacine can be used as the quality control markers of AS, while for AP, only arecaidine and guvacine were needed.

Analysis of Alkaloids in Areca Nut-Containing Products by Liquid Chromatography-Tandem Mass Spectrometry.

Chewing of areca nut in different forms such as betel quid or commercially produced pan masala and gutkha is common practice in the Indian subcontinent and many parts of Asia and is associated with a variety of negative health outcomes, particularly oral and esophageal cancers. Areca nut-specific alkaloids arecoline, arecaidine, guvacoline, and guvacine have been implicated in both the abuse liability and the carcinogenicity of the areca nut. Therefore, variations in the levels of areca alkaloids could potentially contribute to variations in addictive and carcinogenic potential across areca nut-containing products. Here, we developed an accurate and robust liquid chromatography-tandem mass-spectrometry (LC-MS/MS) method for simultaneous quantitation of all four areca alkaloids and applied this method to the analysis of a range of products obtained from India, China, and the United States. The results of the analyses revealed substantial variations in the levels of alkaloids across the tested products, with guvacine being the most abundant (1.39-8.16 mg/g), followed by arecoline (0.64-2.22 mg/g), arecaidine (0.14-1.70 mg/g), and guvacoline (0.17-0.99 mg/g). Substantial differences in the relative contribution of individual alkaloids to the total alkaloid content were also observed among the different products. Our results highlight the need for systematic surveillance of constituent levels in areca nut-containing products and a better understanding of the relationship between the chemical profile and the harmful potential of these products.