Arecoline inhibits and destabilizes agrin-induced acetylcholine receptor cluster formation in C2C12 myotubes

Comprehensive insights into areca nut: active components and omics technologies for bioactivity evaluation and quality control

Areca nut (AN), the fruit or seed of Areca catechu Linn, has many uses, including chewing and medicinal purposes. It has sparked worries about health due to the presence of alkaloids. Chewing AN may have a variety of negative consequences; however, the medicinal use of AN has no notable adverse effects. To completely understand and effectively use AN, researchers have investigated its chemical makeup or biological activity, analyzed the variations between different AN species and different periods, and improved extraction and processing procedures. Today, an increasing number of researchers are exploring the underlying reasons for AN variations, as well as the molecular mechanisms of biosynthesis of chemical components, to comprehend and change AN at the genetic level. This review presents an overview of the clinical study, pharmacology, and detection of the main bioactive components in AN, and the main factors influencing their content, delving into the omics applications in AN research. On the basis of the discussions and summaries, this review identifies current research gaps and proposes future directions for investigation.

Biological Effects and Biomedical Applications of Areca Nut and Its Extract

The dried, mature fruit of the palm tree species Areca catechu L. is known as the areca nut (AN) or betel nut. It is widely cultivated in the tropical regions. In many nations, AN is utilized for traditional herbal treatments or social activities. AN has historically been used to address various health issues, such as diarrhea, arthritis, dyspepsia, malaria, and so on. In this review, we have conducted a comprehensive summary of the biological effects and biomedical applications of AN and its extracts. Initially, we provided an overview of the constituents in AN extract. Subsequently, we summarized the biological effects of AN and its extracts on the digestive system, nervous system, and circulatory system. And we elucidated the contributions of AN and its extracts in antidepressant, anti-inflammatory, antioxidant, and antibacterial applications. Finally, we have discussed the challenges and future perspectives regarding the utilization of AN and its extracts as emerging pharmaceuticals or valuable adjuncts within the pharmaceutical field.

N-acetyl cysteine prevents arecoline-inhibited C2C12 myoblast differentiation through ERK1/2 phosphorylation

Arecoline is known to induce reactive oxygen species (ROS). Our previous studies showed that arecoline inhibited myogenic differentiation and acetylcholine receptor cluster formation of C2C12 myoblasts. N-acetyl-cysteine (NAC) is a known ROS scavenger. We hypothesize that NAC scavenges the excess ROS caused by arecoline. In this article we examined the effect of NAC on the inhibited myoblast differentiation by arecoline and related mechanisms. We found that NAC less than 2 mM is non-cytotoxic to C2C12 by viability analysis. We further demonstrated that NAC attenuated the decreased number of myotubes and nuclei in each myotube compared to arecoline treatment by H & E staining. We also showed that NAC prevented the decreased expression level of the myogenic markers, myogenin and MYH caused by arecoline, using immunocytochemistry and western blotting. Finally, we found that NAC restored the decreased expression level of p-ERK1/2 by arecoline. In conclusion, our results indicate that NAC attenuates the damage of the arecoline-inhibited C2C12 myoblast differentiation by the activation/phosphorylation of ERK. This is the first report to demonstrate that NAC has beneficial effects on skeletal muscle myogenesis through ERK1/2 upon arecoline treatment. Since defects of skeletal muscle associates with several diseases, NAC can be a potent drug candidate in diseases related to defects in skeletal muscle myogenesis.

Mutation Analysis of Second Primary Tumors in Oral Cancer in Taiwanese Patients through Next-Generation Sequencing

Head and neck cancer has poor overall survival. Patients with head and neck cancer more frequently develop second primary tumors than do patients with other cancers, leading to a poor prognosis. In this study, we used next-generation sequencing to analyze and compare mutations between first tumors and second tumors in oral cancer. We retrieved tumor tissues collected from 13 patients who were diagnosed twice as having cancer. We used driver gene and trunk mutations to distinguish between recurrent cancer and primary cancer in oral cancer. We observed unique driver gene mutations in three patients with an initial clinical diagnosis of recurrent cancer; hence, we believe that the corresponding patients had primary cancer. Four patients with an initial clinical diagnosis of primary cancer were found to actually have recurrent cancer according to our results. Genetic testing can be used to enhance the accuracy of clinical diagnosis.

Consumption of betel quid contributes to sensorineural hearing impairment through arecoline-induced oxidative stress

Betel quid is one of the most widely used psychoactive substances, and is consumed by approximately 10% of the world’s population. In addition to its carcinogenicity, betel quid has also been reported to affect many organs, including the brain, heart, lungs, gastrointestinal tract, and reproductive organs. As betel quid contains several neurotoxic ingredients, we hypothesize that it also possesses ototoxicity and may lead to sensorineural hearing impairment (SNHI). In this study, we investigated the contribution of betel quid consumption to SNHI in a large clinical cohort, and validated the pathogenetic mechanisms in ex vivo tissue explants. We enrolled a total of 2364 volunteers, and determined their audiologic results based on Z-scores converted from their original frequency-specific hearing thresholds. Using generalized linear regression, we identified a positive correlation between betel quid consumption and the Z-scores across different frequencies. Subsequently, we explored the toxicity of arecoline, the main neuroactive component of betel quid, on tissue explants from murine cochleae. Arecoline reduced cell activity in the explant cultures and induced apoptosis in the hair cells, probably through the effects of oxidative stress. These findings have expanded the potential hazards of betel quid to common neurological disorders, and provide insights into preventive strategies against SNHI caused by neurotoxic substances.

Collagen VI is required for the structural and functional integrity of the neuromuscular junction

The synaptic cleft of the neuromuscular junction (NMJ) consists of a highly specialized extracellular matrix (ECM) involved in synapse maturation, in the juxtaposition of pre- to post-synaptic areas, and in ensuring proper synaptic transmission. Key components of synaptic ECM, such as collagen IV, perlecan and biglycan, are binding partners of one of the most abundant ECM protein of skeletal muscle, collagen VI (ColVI), previously never linked to NMJ. Here, we demonstrate that ColVI is itself a component of this specialized ECM and that it is required for the structural and functional integrity of NMJs. In vivo, ColVI deficiency causes fragmentation of acetylcholine receptor (AChR) clusters, with abnormal expression of NMJ-enriched proteins and re-expression of fetal AChRγ subunit, both in Col6a1 null mice and in patients affected by Ullrich congenital muscular dystrophy (UCMD), the most severe form of ColVI-related myopathies. Ex vivo muscle preparations from ColVI null mice revealed altered neuromuscular transmission, with electrophysiological defects and decreased safety factor (i.e., the excess current generated in response to a nerve impulse over that required to reach the action potential threshold). Moreover, in vitro studies in differentiated C2C12 myotubes showed the ability of ColVI to induce AChR clustering and synaptic gene expression. These findings reveal a novel role for ColVI at the NMJ and point to the involvement of NMJ defects in the etiopathology of ColVI-related myopathies.

Using the "target constituent removal combined with bioactivity assay" strategy to investigate the optimum arecoline content in charred areca nut

Charred areca nut (CAN) is used to treat dyspepsia and abdominal distension in children. However, reports revealed that arecoline, the most important active constituent of CAN, possesses potential toxicities. This study was designed to investigate the optimum arecoline content in CAN, using the "target constituent removal combined with bioactivity assay" strategy. Based on PTLC method, we prepared CAN lacking all arecoline (WAC-100R) and a series of different ratios of arecoline-removed CAN samples (WAC-Rx). MTT and acute toxicity assays indicated that decreasing content by 50% decreased CAN toxicity significantly. Animal results revealed arecoline contents over 50% could guarantee the beneficial effects of CAN on gastrointestinal tract. Additionally, decreasing arecoline content in CAN by 50% decreased its pro-apoptotic effects significantly. Furthermore, decreasing 50% arecoline content in CAN down-regulated the expressions of Cleaved-Caspase-3, c-jun, c-fos, COX-2, PGE2, and IL-1α. Thus, our results revealed that CAN with 50% arecoline content (WAC-50R) has similar beneficial effects on the gastrointestinal tract to CAN, whereas its toxicity was decreased significantly. Collectively, our study suggested that the strategy of "target constituent removal combined with bioactivity assay" is a promising method to identify the optimum arecoline content in CAN, which is approximately 0.12%.

The pharmacology, toxicology and potential applications of arecoline: a review

CONTEXT

Arecoline is an effective constituent of Areca catechu L. (Arecaceae) with various pharmacological effects. However, investigations also revealed that long use of arecoline could arouse some oral diseases.

OBJECTIVE

The present review gathers the fragmented information available in the literature (before 1 October 2015) regarding pharmacology and toxicology of arecoline. We also discussed the potential developments and applications of arecoline in the future.

METHODS

All the available information regarding the arecoline is compiled from scientific databases, including Science Direct, PubMed, Web of Science, Scopus, etc.

RESULTS

Previous research demonstrated that arecoline is one of the major effective constituents in A. catechu. Additionally, arecoline has a wide spectrum of pharmacological activities including effects on nervous, cardiovascular, digestive and endocrine systems and anti-parasitic effects. What's more, arecoline is reported to be the primary toxic constituent of A. catechu, and the main toxic effects include oral submucous fibrosis (OSF), oral squamous cell carcinoma (OSCC) and genotoxicity.

CONCLUSION

Arecoline has great potential to be a therapeutic drug for various ailments. However, further investigations are needed in the future to reduce or eliminate its toxicities before developing into new drug.

Areca catechu L. (Arecaceae): a review of its traditional uses, botany, phytochemistry, pharmacology and toxicology

ETHNOPHARMACOLOGICAL RELEVANCE

Areca catechu L. (Arecaceae), widely distributed in South and Southeast Asia, is a popular traditional herbal medicine that can be chewed for the purpose of dispersing accumulated fluid in the abdominal cavity and killing worms. The present paper aims to provide an up-to-date review on the traditional uses and advances in the botany, phytochemistry, pharmacology and toxicology of this plant. Furthermore, the possible trends and a perspective for future research of this plant are also discussed.

MATERIALS AND METHODS

A literature search was performed on A. catechu based on classic books of herbal medicine, PhD. and MSc. dissertations, government reports, the state and local drug standards, scientific databases including Pubmed, SciFinder, Scopus, the Web of Science, Google Scholar, and others. Various types of information regarding this plant are discussed in corresponding parts of this paper. In addition, perspectives for possible future studies of A. catechu are discussed.

RESULTS

The seeds of A. catechu (areca nut) have been widely used in clinical practice in China, India and other South and Southeast Asian Countries. Currently, over 59 compounds have been isolated and identified from A. catechu, including alkaloids, tannins, flavones, triterpenes, steroids, and fatty acids. The extracts and compounds isolated from A. catechu have many pharmacological activities. These include antiparasitic effects, anti-depressive effects, anti-fatigue effects, antioxidant effects, antibacterial and antifungal effects, antihypertensive effects, anti-inflammatory and analgesic effects, anti-allergic effects, the promotion of digestive functions, suppression of platelet aggregation, regulatory effects on blood glucose and lipids, etc. Although arecoline is the primary active constituent of A. catechu, it is also the primary toxic compound. The main toxicities of arecoline are the promotion of oral submucosal fibrosis (OSF) and cytotoxic effects on normal human cells, which involve inducing apoptosis.

CONCLUSION

As an important herbal medicine, A. catechu has potential for the treatment of many diseases, especially parasitic diseases, digestive function disorders, and depression. Many traditional uses of A. catechu have now been validated by current investigations. However, further research should be undertaken to investigate the clinical effects, toxic constituents, target organs, and pharmacokinetics and to establish criteria for quality control for A. catechu-derived medications. In addition, it will be interesting to investigate the active macromolecular compounds and active constituents other than alkaloids in both raw and processed products of A. catechu.

Arecoline inhibits intermediate-conductance calcium-activated potassium channels in human glioblastoma cell lines

Arecoline (ARE) is an alkaloid-type natural product from areca nut. This compound has numerous pharmacological and toxicological effects. Whether this agent interacts with ion channels to perturb functional activity of cells remains unknown. The effects of ARE on ionic currents were studied in glioma cell lines (U373 and U87MG) using patch-clamp technique. Like TRAM-34(1-[(2-chlorophenyl)-diphenylmethyl]pyrazole), ARE suppressed the amplitude of whole-cell voltage-gated K(+) currents in U373 cells elicited by a ramp voltage clamp. In cell-attached configuration, ARE did not modify the single-channel conductance of intermediate-conductance Ca(2+)-activated K(+) (IKCa) channels; however, it did reduce channel activity. Its inhibition of IKCa channels was accompanied by a significant lengthening in the slow component of mean closed time of IKCa channels. Based on minimal kinetic scheme, the dissociation constant (KD) required for ARE-mediated prolongation of mean closed time was 11.2µM. ARE-induced inhibition of IKCa channels was voltage-dependent. Inability of ARE to perturb the activity of large-conductance Ca(2+)-activated K(+) (BKCa) channels was seen. Under current-clamp recordings, ARE depolarized the membrane of U373 cells and DCEBIO reversed ARE-induced depolarization. Similarly, ARE suppressed IKCa-channel activities in oral keratinocytes. This study provides the evidence that ARE block IKCa channels in a concentration, voltage and state-dependent manner. ARE-induced block of IKCa channels is unrelated to the binding of muscarinic receptors. The effects of ARE on these channels may partially be responsible for the underlying cellular mechanisms by which it influences the functional activities of glioma cells or oral keratinocytes, if similar findings occur in vivo.