Pilot study of the pharmacokinetics of betel nut and betel quid biomarkers in saliva, urine, and hair of betel consumers

Overlap in oncogenic and pro-inflammatory pathways associated with areca nut and nicotine exposure

Background

Betel nut/areca nut/Areca catechu is one of the most commonly used psychoactive substance, and is also a major preventable cause of cancer. Unlike other psychoactive substances, such as nicotine, the mechanisms underlying addiction to areca nuts and related oncogenesis remain elusive. Recent reports suggest a possible overlap in the mechanisms of action of nicotine and areca nuts in the human body. Thus, this study aimed to investigate the interactome of human proteins associated with areca nut exposure and the intricate similarities and differences in the effects of the two psychoactive substances on humans.

Methods

A list of proteins associated with areca nut use was obtained from the available literature using terms from Medical Subject Headings (MeSH). Protein-protein interaction (PPI) networks and functional enrichment were analyzed. The results obtained for both psychoactive substances were compared.

Results

Given the limited number of common proteins (36/226, 16%) in the two sets, a substantial overlap (612/1176 nodes, 52%) was observed in the PPI networks, as well as in Gene Ontology. Areca nuts mainly affect signaling pathways through three hub proteins (alpha serine/threonine-protein kinase, tumor protein 53, and interleukin-6), which are common to both psychoactive substances, as well as two unique hub proteins (epidermal growth factor receptor and master regulator of cell cycle entry and proliferative metabolism). Areca nut-related proteins are associated with unique pathways, such as extracellular matrix organization, lipid storage, and metabolism, which are not found in nicotine-associated proteins.

Conclusions

Areca nuts affect regulatory mechanisms, leading to systemic toxicity and oncogenesis. Areca nuts also affect unique pathways that can be studied as potential markers of exposure, as well as targets for anticancer therapeutic agents.

Arecoline in buccal cells reflects Areca nut dose

Areca nut (AN) is a carcinogen; its chewing cessation is, therefore, of worldwide interest. However, cessation biomarkers are lacking. We sought to establish arecoline in chewers' buccal cells (BCs) as a biomarker for AN dose. Self-reported AN doses, expressed as the average AN load ("AANL"), the product of AN amount, chewing time, and chewing frequency, were correlated by regression analysis with chewers' BC arecoline, measured by liquid chromatography mass spectrometry. We then determined whether associations differed between Class 1 chewers (who consume AN alone or with slaked lime, leaf, and/or spices) and Class 2 chewers (who consume any combination of the aforementioned ingredients plus tobacco). Among the 103 chewers, 28 Class 1 and 39 Class 2 chewers had detectable arecoline levels, which were used for analyses. A linear regression of cube-root transformed AANL on equally transformed BC arecoline levels provided the best model fit; resulting slopes and corresponding correlation coefficients were 0.86 and 0.40 (p < 0.01) for all; 1.09 and 0.51 (p < 0.01) for Class 1 chewers; 0.35 and 0.17 (p = 0.29) for Class 2 chewers; and 0.94 and 0.45 (p < 0.01), and 0.79 and 0.37 (p = 0.08), respectively, for those who included or excluded lime. Relationships between AANL and BC arecoline levels were similar between chewers who included or excluded lime (p = 0.76), but less between chewing classes (p = 0.14). This provides confidence that BC arecoline can generally act as a reliable biomarker for AN dose, useful for estimating efficacy in AN cessation studies and population-based chewing assessments.

Honey dressing for penile skin avulsion caused by traditional circumcision: a case report

OBJECTIVE

Penile skin avulsion is a rare complication of circumcision but commonly encountered as the result of traditional practice. We aimed to present the use of honey dressing and the benefit of its wound healing properties for management of such a complex wound.

CASE

A 24-year-old male patient with penile bleeding presented to the emergency department after undergoing traditional circumcision. Complete degloving of the penis with active bleeding and foul odour, along with heavy contamination of chewed betel leaves and powdered amoxicillin was found. Honey (Madu Nusantara, PT. Madu Nusantara, Indonesia) was used as dressing after copious irrigation using saline and povidone-iodine with bleeding control.

RESULTS

Honey dressing was shown to be effective for secondary wound healing of such a complicated and contaminated wound-in this case due to its antimicrobial, anti-inflammatory, immunostimulatory and autolytic debridement properties. A complete re-epithelialisation of the wound was achieved without progression to the hard-to-heal state by day 43. Suboptimal sexual function and aesthetic result due to wound contracture were observed as surgical reconstruction via split-thickness skin graft was refused due to cost.

CONCLUSION

In this case report, honey dressing was shown to be effective for wound healing, even in a penile avulsion with complete skin loss and heavy contamination. In rural settings, where penile avulsion due to traditional circumcision is common, honey should be considered as one of the dressing choices.

Systematic review of determinants and interventions of areca nut cessation: curbing a public health menace

BACKGROUND

Areca nut (AN) is a proven human carcinogen and a global public health menace. There is yet no review providing comprehensive information on the determinants and interventions available for cessation of AN. This systematic review was aimed at summarizing the available literature on drivers and interventions for cessation of AN chewing habit and to highlight the research lacunae.

METHODS

A systematic literature search (from 1990 till March 2021) was conducted for studies on AN cessation. Relevant data were extracted independently by two authors.

RESULTS

A total of 16 studies were included, which highlighted the influence of socio-cultural factors, addictive nature of AN and withdrawal symptoms as barriers to quitting. However, the knowledge of ill-effects of AN use on health, absence of concurrent alcohol use or smoking and family pressure were associated with likelihood of AN cessation. The interventions utilized for AN cessation have been behavioural in majority of the studies except for one where antidepressants were used for this purpose.

CONCLUSIONS

The current review emphasizes the imperative need of appropriate cessation strategies for AN chewing habit including enhancing awareness of the harmful effects and research into additional behavioural and pharmacologic cessation therapies to control this significant public health problem.

Salivary Areca and tobacco alkaloids for bioverification in the Betel Nut Intervention Trial

BACKGROUND

The Betel Nut Intervention Trial (BENIT) is the first known randomized controlled intervention trial designed to help minority Pacific Islanders in Guam and Saipan quit chewing the carcinogenic Areca catechu nut (AN). We report the BENIT's saliva bioverification results against the self-reported chewing status ("quitter" or "chewer") at day 22 follow-up.

MATERIAL AND METHODS

AN-specific (arecoline, arecaidine, guvacoline, and guvacine) and tobacco-specific (nicotine, cotinine, and hydroxycotinine) alkaloids were analyzed in saliva from 176 BENIT participants by an established and sensitive liquid chromatography mass spectrometry-based assay.

RESULTS

The combined four AN alkaloid levels decreased from baseline in quitters (n = 50) and chewers (n = 108) by 32% and 9%, respectively. In quitters, decreases were significant for arecoline (p = 0.044)-the most prominent AN alkaloid, along with arecaidine (p = 0.042) and nicotine (p = 0.011). In chewers, decreases were significant only for hydroxycotinine (p = 0.004). Similar results were obtained when quitters and chewers were stratified by treatment arm.

DISCUSSION

Salivary AN alkaloid levels generally agreed with self-reported chewing status, which suggests the former can be used to verify the latter.

CONCLUSION

Our results can help to objectively evaluate compliance and program effectiveness in AN cessation programs.

Metabolism of the areca alkaloids - toxic and psychoactive constituents of the areca (betel) nut

Areca nut (AN) is consumed by millions of people for its therapeutic and psychoactive effects, making it one of the most widely self-administered psychoactive substances in the world. Even so, AN use/abuse is associated with myriad oral and systemic side effects, affecting most organ systems in the body. Alkaloids abundant in the nut (e.g. arecoline, arecaidine, guvacoline, and guvacine), collectively called the areca alkaloids, are presumably responsible for the major pharmacological effects experienced by users, with arecoline being the most abundant alkaloid with notable toxicological properties. However, the mechanisms of arecoline and other areca alkaloid elimination in humans remain poorly documented. Therefore, the purpose of this review is to provide an in-depth review of areca alkaloid pharmacokinetics (PK) in biological systems, and discuss mechanisms of metabolism by presenting information found in the literature. Also, the toxicological relevance of the known and purported metabolic steps will be reviewed. In brief, several areca alkaloids contain a labile methyl ester group and are susceptible to hydrolysis, although the human esterase responsible remains presumptive. Other notable mechanisms include N-oxidation, glutathionylation, nitrosamine conversion, and carbon-carbon double-bond reduction. These metabolic conversions result in toxic and sometimes less-toxic derivatives. Arecoline and arecaidine undergo extensive metabolism while far less is known about guvacine and guvacoline. Metabolism information may help predict drug interactions with human pharmaceuticals with overlapping elimination pathways. Altogether, this review provides a first-of-its-kind comprehensive analysis of AN alkaloid metabolism, adds perspective on new mechanisms of metabolism, and highlights the need for future metabolism work in the field.

Validation of a high-throughput method for simultaneous determination of areca nut and tobacco biomarkers in hair using microwave-assisted extraction and isotope dilution liquid chromatography tandem mass spectrometry

For people with habits of chewing betel nuts and smoking, the probability of suffering from oral cancer is ten to a hundred times higher than others. Due to the serious health consequences of areca nut and tobacco, a reliable cessation program is needed. Hair is the best option to document long-term exposure. Unfortunately, the research on betel nut in hair did not attract much attention. In this study, a high-throughput method based on microwave-assisted extraction (MAE) and isotope dilution liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed to measure the four biomarkers of betel nuts and cigarettes, including areca alkaloids (arecoline), tobacco alkaloids (nicotine), and their metabolites (arecaidine and cotinine). The hair sample was washed, cut, weighed, and incubated for 3 min MAE with methanol/trifluoroacetic acid, then evaporated and reconstituted for LC-MS/MS analysis. The total experiment time was 50 min. The lower limits of quantification (LOQ) were 5-10 pg/mg. The intra-day and inter-day precision were 2.2-7.6%. Intra-day and inter-day accuracy were - 6.1-8.2%. The method showed good linearity (r2 > 0.995) over LOQ - 1000 pg/mg concentration ranges. It was successfully applied to analyze 11 subjects of regular areca nut chewers, also smokers. Eight samples were black hair; three samples were naturally black hair with partially gray hair. Measured concentrations in black hair were in the range 56.9 pg/mg to 3.2 ng/mg for arecoline, 12.8 pg/mg to 222.2 pg/mg for arecaidine, 3.8 ng/mg to 33.4 ng/mg for nicotine and 1.1 ng/mg to 6.1 ng/mg for cotinine. The results showed lower levels in gray hair. This method was utilized successfully to analyze pg/mg levels of arecoline, arecaidine, nicotine, and cotinine, and good recoveries were obtained. The mean concentration of arecaidine and cotinine in hair was 15% and 20% of arecoline and nicotine, respectively. A good positive correlation was found between the concentrations of these compounds and self-report. This method improved extraction speed, concentration, and analysis of samples and is useful for monitoring betel nut and smoking cessation programs.

Occurrence of areca alkaloids in wastewater of major Chinese cities

Areca nut is a widely used psychoactive product that can cause multiple health problems, such as oral and pharyngeal cancers. Therefore, it is important to estimate areca nut use and the exposure levels of areca alkaloids that are responsible for its health effects. China is a major producer of areca nut and has a large number of areca nut chewers. In this study, occurrence of areca alkaloids and metabolites in wastewater of major cities across China was examined via wastewater-based epidemiology (WBE). Arecoline, arecaidine, and their metabolite, N-methylnipecotic acid (NMNA) were detected in the overwhelming majority of wastewater samples, with concentrations up to several μg/L. In contrast, guvacoline was only occasionally detected and guvacine was below detection limit in all samples, possibly due to their low contents in areca nut products, low excretion rates, and/or low stability in sewer systems. Strong positive correlations existed between arecoline, arecaidine, and NMNA concentrations. In addition, their loads were much higher in Central and Southern China. This geographic pattern is consistent with previous survey results on prevalence of areca nut chewing. These results indicate that WBE is a potentially useful method to monitor areca nut consumption and to estimate the exposure levels of areca alkaloids.

The Effectiveness of Betel Quid Cessation among Workers through the Adoption of the Five Action Areas of the Ottawa Charter

This study aimed to increase workers' awareness of betel quid cessation. Methods: Using community and workplace resources, a workplace health promotion program was developed in accordance with the five action areas of the Ottawa Charter. Questionnaires were administered to examine the changes in the knowledge and attitudes of 714 workers in different occupations before and three months after the intervention. Results: Regardless of subjects' pre-intervention chewing status, their knowledge and attitude scores relating to betel quid cessation increased significantly after the intervention. The effect of occupation was significant on the post-intervention knowledge and attitude scores among chewers. Furthermore, 16 (11.6%) of the 138 study subjects who chewed betel quid before the intervention and had no willingness to quit, did quit betel quid chewing following the intervention. The factors contributing to an unwillingness to quit among chewers with no intention to quit before the intervention were examined. Workers in the electronic material manufacturing industry had a greater willingness to quit compared to those in the metal, machinery, and related trades (odds ratio [OR] = 0.15; 95% confidence interval [CI] = 0.02-0.94). Travel attendants, tour guides, cleaners, and helpers were the least willing to quit (OR = 21.29; 95% CI = 2.51-180.81). Conclusions: This study promoted workers' awareness of betel quid cessation by adopting the five action areas of the Ottawa Charter framework, the effectiveness of the intervention varied in different occupations. Workers with a high-income and better education level had a higher awareness of betel quid cessation.

Betel Quid Health Risks of Insulin Resistance Diseases in Poor Young South Asian Native and Immigrant Populations

Betel quid, traditionally prepared with areca nut, betel leaf, and slaked lime, has been consumed for thousands of years, mainly in the form of chewing. Originally used for cultural, medicinal, and ceremonial purposes mainly in South Asian countries, its use has recently spread across the globe due to its psychoactive, euphoric, and aphrodisiac properties. Now it is widely used as a social lubricant and source of financial profit. Unfortunately, the profit motive has led to high rates of habitual consumption with eventual conversion to addiction among young girls and boys. Moreover, the worrisome practice of including tobacco in quid preparations has grown, particularly among pregnant women. Major health concerns include increased rates of malignancy, oral pathology, and cardiovascular, hepatic, fertility, metabolic, and neuropsychiatric disorders. Metabolic disorders and insulin resistance disease states such as type 2 diabetes, obesity, and metabolic syndrome contribute to cognitive decline and neurodegeneration. Mechanistically, the constituents of areca nut/betel quid are metabolized to N-nitroso compounds, i.e., nitrosamines, which are carcinogenic at high doses and cause insulin resistance following chronic low-level exposures. From an epidemiological perspective, the rising tide of insulin resistance diseases including obesity, diabetes, and dementias that now disproportionately burden poor countries has been propagated by rapid commercialization and enhanced access to betel quid. Public health measures are needed to impose socially and ethically responsible barriers to yet another cause of global health disparity.

Testing for Betel Nut Alkaloids in Hair of Papuans Abusers using UPLC-MS/MS and UPLC-Q-Tof-MS

Betel nut is the fruit of Areca palm, growing in Papua New Guinea. Mixed with limestone and stick mustard, arecoline and guvacoline, which are present in betel nut, are hydrolyzed into arecaidine and guvacine, respectively. As part of the study on dietary habits of Papuans residents, our laboratory was asked to analyze the four alkaloids in hair to document long-term exposure. Hair samples were collected from 19 adult subjects (males = 11; females = 8), by some of the authors, and were sent to the laboratory for analysis. The four alkaloids have very similar chemical structures. In order to accurately identify the drugs, two methods were developed. First, the compounds were identified using an ultra-high-performance liquid chromatography system coupled to time-of-flight mass spectrometry. Then, they were quantified by an ultra-high-performance liquid chromatography system coupled to tandem mass spectrometry. After decontamination with dichloromethane, hair samples were cut into very small segments and 20 mg were incubated in methanol for 2 h 30 min in an ultrasound bath. After cooling, the methanol was evaporated to dryness in presence of 20-μL octanol to prevent volatilization. Nicotine-d4 was used as an internal standard. Linearity was observed for concentrations ranging from the limit of quantification to 20 ng/mg for arecoline, arecaidine, guvacine and guvacoline. Measured concentrations were in the range 60 pg/mg to 18 ng/mg for arecoline (n = 19), 14 pg/mg to 2.5 ng/mg for guvacoline (n = 11), 63 pg/mg to 3.8 ng/mg for arecaidine (n = 11) and 100 pg/mg to 3.2 ng/mg for guvacine (n = 6). There was no correlation between concentrations of arecoline and arecaidine (ratio from 0.01 to 0.18) and guvacoline and guvacine (ratio from 0.06 to 3.50). However, the identification of these substances in hair is a good marker of consumption of betel nut and allows us to document a local practice that remains difficult to evaluate just by questioning.

Betel quid-associated cancer: Prevention strategies and targeted treatment

Betel quid (BQ) and areca nut use are at risk of cancer. This review includes the latest evidence of carcinogenesis caused by BQ exposure, suggests possible prevention strategies. We conducted a systematic literature search in the PubMed and Web of Science databases to identify relevant articles published in the past 10 years according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. Arecoline N-oxide, a metabolite of areca nut, is likely an initiator in carcinogenesis and is detoxified by N-acetylcysteine. Oral potentially malignant disorder and reactive oxygen species involved in carcinogenesis pathways may be treatable using antioxidants. Screening programs conducted by trained physicians are useful for identifying patients with early stages of oral cancer in high-risk groups. Anti-inflammatory medications may be used as chemopreventive agents in the disease-free stage after surgery. The association between survival and tumor somatic mutations in patients who chew BQ should be addressed in cancer studies. Current evidence on the natural course from BQ exposure to cancer occurrence and development provides information for developing primary, secondary, and tertiary prevention strategies against BQ-associated cancer at clinical or translational levels.

Rationale and design of a randomized, controlled, superiority trial on areca nut/betel quid cessation: The Betel Nut Intervention Trial (BENIT)

Background

Areca nut (AN) is the seed endosperm of the Areca catechu L. palm and a Group 1 carcinogen chewed by 10–20% of the world population. AN is often chewed with Piper betle L. leaf, slaked lime, and tobacco to form a betel quid (BQ). The negative health effects associated with AN/BQ consumption warrant the need for an evidence-based cessation program. However, systematic research on AN/BQ cessation is rare.

Methods/design

The Betel Nut Intervention Trial (BENIT; trial #NCT02942745) is a randomized controlled trial designed to test the efficacy of an intensive AN/BQ cessation program. The trial is ongoing in Guam and Saipan with adult chewers who include tobacco in their BQ. Enrolled participants are assessed for their primary (chewing status) and secondary (saliva bio-verification) outcome at baseline, 22 days, and 6 months. Participants randomized into the control arm receive an educational booklet while those randomized into the intervention arm receive the educational booklet and a 22-day cessation program modeled after a smoking cessation program and led by trained facilitators. Information on chewing behavior (history, reasons for chewing, and AN/BQ composition and dependency) are collected. The intervention effectiveness is assessed using the logistic mixed model to compare cessation status between randomization groups.

Discussion

AN/BQ chewing affects a large population of people, many of whom live in low and moderate income countries in the Asia-Pacific region. Although the BENIT focuses on chewers in Guam and Saipan, it has the potential for greater regional and global importance.

Altered Fluorescence of Buccal Cells as a Candidate Biomarker for Areca Nut Chewing

Background: Betel nut is used by an estimated 600 million people globally and is the 4th most widely used psychoactive substance in the world. Its use has been shown to cause oral and esophageal cancers. Therefore, cessation programs are needed in which an effective biomarker can be employed. Objectives: Buccal cells are highly exposed to the betel nut during its use and are also easy to collect. However, it is unknown if there are significant changes to these cells upon exposure or how long any changes may last as the turnover of buccal cells is relatively fast. We sought to determine if optical changes could be detected on buccal cells after exposure to betel nut and if detected, how long these changes were sustained. Methods: Flow cytometry was employed to determine whether fluorescence intensities differ between buccal cells exposed to betel nut and naïve cells. We further characterized the optical signature of buccal cells exposed to betel nut and other polyphenol-rich substances using lambda scans performed on a laser scanning confocal microscope. Results: We demonstrate that the fluorescence of betel nut exposed cells is greater than that of cells exposed to other optically active compounds such as polyphenol-rich foods. We also demonstrate that the fluorescence spectra of betel nut quid exposed cells are distinct from that of cells exposed to other polyphenol-rich substances. Conclusions: We conclude that detecting the altered fluorescence of buccal cells following exposure to betel nut quid may serve as a candidate biomarker for betel nut quid use.

Chemical Markers for Short- and Long-Term Areca Nut Exposure

Background: Areca nut (AN) chewing causes oral cancer. AN cessation programs are the most effective approach to reduce AN chewing induced cancers but require biomarkers to determine program compliance and success. Objectives: To explore chemical markers for short- and long-term AN exposure using non-invasively collected saliva, buccal cells (BCs), and scalp hair of chewers. Methods: Saliva was collected from a male chewer before and up to 2 days after AN chewing. Saliva was separated into supernatant and pellet (BCs) then analyzed by spectrophotometry and liquid chromatography (LC) with UV/VIS detection. Scalp hair was collected from four chewers and analyzed for areca alkaloids using direct analysis in real time-tandem mass spectrometry (DART-MSMS). Results: The red pigmented saliva after chewing showed no valuable signals when either the saliva supernatant or pellet (BCs) were analyzed by spectrophotometry. Saliva analysis by LC-UV/VIS showed diagnostically valuable signals at 488 nm up to 5 and 24 h post chewing in the supernatant and pellet, respectively. DART-MSMS analysis detected two of the four AN specific alkaloids (arecoline and arecaidine) in male but none in female hair. Conclusions/Importance: LC-UV/VIS analysis of the red pigments extracted from saliva and BCs after AN chewing showed distinct signals up to 24 h post chewing while DART-MSMS analysis in BCs and scalp hair showed selective signals of AN alkaloids for several weeks or months after AN exposure. Chemical hair treatment might prevent detection of areca alkaloids in hair. AN cessation trials and other programs now have essential tools for bioverification.

Areca Nut and Betel Quid Control Interventions: Halting the Epidemic

Background: Areca nut (AN) and betel quid (BQ) are classified as Group 1 carcinogens. There are approximately 600 million AN/BQ users globally; the majority of users live in the Asia-Pacific region which, correspondingly, has the highest rates of oral cancer. Despite significant disease burden associated with AN/BQ use, there have been no systematic reviews of interventions to reduce product use. Objectives: To analyze interventions that prevent use of AN/BQ, present a basis for a future systematic review on the topic, and provide decision makers with examples of strategies that have demonstrated reduced AN/BQ use. Methods: To identify publications, we searched the literature using terms for AN/BQ and related synonyms in three databases: PubMed, Embase, and Scopus. Interventions that prevent AN/BQ use, that are published in English and that provide original data analysis, were included in this review. Interventions focused primarily on disease outcomes e.g. oral cancers (secondary prevention) were excluded. Results: Our search revealed 21 interventions targeting AN/BQ use between 1990 and 2018. Strategies include product bans, media campaigns, education, cessation, and taxation at individual and population levels, with varying evidence of impact. While these studies yielded some novel and promising findings, particularly regarding the impact of product bans, mass media campaigns, and cessation interventions, research on interventions specific to AN/BQ use remains limited. Conclusions: We have assessed published interventions that reduce AN/BQ use and identified future research priorities. These findings can be used to develop evidence-based interventions and help guide policymakers in implementing evidence-based policy to regulate these products.

Areca alkaloids measured from buccal cells using DART-MS serve as accurate biomarkers for areca nut chewing

BACKGROUND

Areca nut (AN) chewing is carcinogenic and biomarkers reflecting it are urgently needed to determine the effectiveness of emergent cessation programs. Buccal cells (BCs) may serve as an ideal matrix to measure such biomarkers; however, their utility for this purpose is unknown. Direct analysis in real time-mass spectrometry (DART-MS) is a sensitive technique that analyzes materials in the open air and requires minimal/no sample preparation. We utilized DART-MS to analyze BCs to test the usefulness of this method in measuring areca alkaloids as biomarkers for AN chewing.

METHODS

We applied DART-MS in positive-ion mode to quantitate over time human BCs: (a) exposed ex vivo to betel quid extracts (BQE) consisting of young AN, Piper betle L. leaf, slaked lime, and tobacco; and (b) obtained from seven chewers before and after BQ chewing. Quantification was performed by normalizing DART-MS alkaloid signal intensities to cholesterol intensities.

RESULTS

Signals for areca alkaloids arecoline and arecaidine-guvacoline were detected in BCs exposed ex vivo to BQE up to 7 days (the last day tested) after exposure and in BCs from chewers up to 3 days (the last day tested) post chewing.

DISCUSSION

The presence of alkaloid signals in BQ-exposed BCs verified BCs as a valid matrix and DART-MS as a suitable technique to measure biomarkers for AN chewing and provided reliable information on AN chewing timing.

CONCLUSION

DART-MS analyses of BCs can be used to accurately determine areca alkaloids as AN chewing biomarkers up to 3 days post chewing and possibly longer.

Toxicological hair analysis: Pre-analytical, analytical and interpretive aspects

Background and aims Hair analysis for drug detection is one of the widely accepted imperative techniques in the field of forensic toxicology. The current study was designed to investigate the efficacy of chromatography for detection of drugs of abuse in hair. Method A comprehensive review of articles from last two decades on hair analyses via PubMed and similar resources was performed. Issues concerning collection, decontamination and analytical techniques are summarised. Physiochemical nature of hair, mechanism of drug incorporation and its stability in hair are briefly discussed. Furthermore, various factors affecting results and interpretation are elucidated. Result A hair sample is chosen over traditional biological samples such blood, urine, saliva or tissues due to its inimitable ability to provide a longer time frame for drug detection. Its collection is almost non-invasive, less cumbersome and does not involve any specialised training/expertise. Recent advances in analytical technology have resulted in better sensitivity, reproducibility and accuracy, thus providing a new arena of scientific understanding and test interpretation. Conclusion Though recent studies have yielded many insights into drug binding and drug incorporation in hair, the major challenge in hair analysis lies in the interpretation of results, which may be affected by external contamination and thus lead to false-positives. Therefore, there is a need for more sensitive and selective analysis methods to be developed in order to minimise factors that induce the effect of melanin, age and so on, and this would certainly provide a new dimension to hair analysis and its applications.

Development and validation of a rapid LC-MS/MS method for simultaneous quantification of arecoline and its two active metabolites in rat plasma and its application to a pharmacokinetic study

Arecoline is the primary active and toxic constituent of areca nut. Arecaidine and arecoline N-oxide are two major active metabolites of arecoline. In this work, an accurate and simple high performance liquid chromatography tandem mass spectrometry method for simultaneous quantification of arecoline, arecaidine and arecoline N-oxide in rat plasma was developed and fully validated to study their pharmacokinetic behaviors in rats. After extracted from rat plasma by protein precipitation with methanol and then concentrated, the analytes were chromatographic separated on a Sepax Sapphire C₁₈ analytical column. The mobile phase consisted of methanol and 2 mM ammonium acetate buffer solution containing 0.2% (v/v) formic acid (8:92, v/v) under isocratic elution. The analytes were detected by multiple reaction monitoring (MRM) with an electrospray ionization source in the positive ion mode. The transitions of m/z 156.2 → 53.2, m/z 142.2 → 44.2 and m/z 172.2 → 60.2 were selected for arecoline, arecaidine and arecoline N-oxide, respectively. The method was linear over the concentration range of 0.5-100 ng/mL for arecoline, 5-5000 ng/mL for arecaidine and arecoline N-oxide with no carry-over effect. The accuracies and intra- and inter-batch precisions were all within the acceptance limits. No matrix effect and potential interconversion between the analytes and other metabolites were observed in this method. The validated method was further employed to a preclinical pharmacokinetic study of arecoline, arecaidine and arecoline N-oxide after oral treatment with 20 mg/kg arecoline to rats.