Ingredients contribute to variation in production of reactive oxygen species by areca quid

Edible Quality Analysis of Different Areca Nuts: Compositions, Texture Characteristics and Flavor Release Behaviors

The areca nut is one of the most important cash crops in the tropics and has substantial economic value. However, the research information about the edible quality of different areca nuts is still insufficient. This study compared the composition, texture characteristics and flavor release behaviors of four different areca nuts (AN1, AN2, AN3 and AN4) and two commercially dried areca nuts (CAN1 and CAN2). Results showed that AN1 had higher soluble fiber and lower lignin, which was the basis of its lower hardness. Meanwhile, the total soluble solid (TSS) of AN1 was the highest, which indicated that AN1 had a moister and more succulent mouthfeel. After the drying process, the lignification degree of AN1 was the lowest. Through textural analyses, the hardness of AN1 was relatively low compared to the other dried areca nuts. AN1, CAN1 and CAN2 had higher alkaline pectin content and viscosity, and better flavor retention, which indicated better edible quality. The present study revealed the differences of various areca nuts and provided vital information to further advance the study of areca nuts.

Systematic Review of Roles of Arecoline and Arecoline N-Oxide in Oral Cancer and Strategies to Block Carcinogenesis

Betel quid and areca nut are complex mixture carcinogens, but little is known about whether their derived single-agent arecoline or arecoline N-oxide (ANO) is carcinogenic, and the underlying mechanisms remain unclear. In this systematic review, we analyzed recent studies on the roles of arecoline and ANO in cancer and strategies to block carcinogenesis. In the oral cavity, flavin-containing monooxygenase 3 oxidizes arecoline to ANO, and both alkaloids conjugate with N-acetylcysteine to form mercapturic acid compounds, which are excreted in urine, reducing arecoline and ANO toxicity. However, detoxification may not be complete. Arecoline and ANO upregulated protein expression in oral cancer tissue from areca nut users compared to expression levels in adjacent normal tissue, suggesting a causal relationship between these compounds and oral cancer. Sublingual fibrosis, hyperplasia, and oral leukoplakia were diagnosed in mice subjected to oral mucosal smearing of ANO. ANO is more cytotoxic and genotoxic than arecoline. During carcinogenesis and metastasis, these compounds increase the expression of epithelial-mesenchymal transition (EMT) inducers such as reactive oxygen species, transforming growth factor-β1, Notch receptor-1, and inflammatory cytokines, and they activate EMT-related proteins. Arecoline-induced epigenetic markers such as sirtuin-1 hypermethylation, low protein expression of miR-22, and miR-886-3-p accelerate oral cancer progression. Antioxidants and targeted inhibitors of the EMT inducers used reduce the risk of oral cancer development and progression. Our review findings substantiate the association of arecoline and ANO with oral cancer. Both of these single compounds are likely carcinogenic to humans, and their mechanisms and pathways of carcinogenesis are useful indicators for cancer therapy and prognosis.

Evaluation of cytotoxicity of areca nut and its commercial products on normal human gingival fibroblast and oral squamous cell carcinoma cell lines

Consumption of areca nut products is the most common cause of oral cancers, particularly in South Asian countries. This study evaluates the cytotoxic and necrotizing effects of areca nut and its formulations on normal human gingival fibroblasts (HGF-1) and oral squamous cell carcinoma (OSCC, CAL-27) cell lines. Identification of various carcinogens and adulterants using LC-HR-ESI-MS/MS analysis was performed in the extracts of areca nut and its products. Apart from alkaloids and flavonoids, a major adulterant, saccharin was found in all the samples of chalia (one of the most common chewing products of areca nut) in the ranges between 1.697-7.170 mg/g of the sample. Cytotoxic studies showed that most of the areca nut products were found cytotoxic to HGF-1 cells while being relatively non-cytotoxic against CAL-27 cells, rather they promote the growth of cancer cells. Our findings revealed that the components of areca nut and its products were injurious to HGF-1 cells and caused necrosis, which may attenuate HGF-1 protection toward oral epithelial cells. Moreover, the non-cytotoxic effect of these products on cancer cell lines suggests further predisposal of the habitual chewers for developing oral carcinomas. This study will give a better understanding of the hazardous effects of areca nut products.

Arecoline N-oxide initiates oral carcinogenesis and arecoline N-oxide mercapturic acid attenuates the cancer risk

Arecoline N-oxide (ANO), an oxidative metabolite of the areca nut, is a predictable initiator in carcinogenesis. The mechanisms of arecoline metabolites in human cancer specimens is still limited. This present study aims to estimate the oral squamous cell carcinoma (OSCC) inductive activity between arecoline metabolites in human cancer specimens/OSCC cells. We have collected 22 pairs (tumor and non-tumor part) of patient's specimens and checked for clinical characteristics. The identification of arecoline and its metabolites levels by using LC-MS/MS. The NOD/SCID mice model was used to check the OSCC inductive activity. The tumor part of OSCC samples exhibited higher levels of arecoline and ANO. Besides, ANO treated mice accelerates the NOTCH1, IL-17a and IL-1β expressions compared to the control mice. ANO exhibited higher cytotoxicity, intracellular ROS levels and decline in antioxidant enzyme levels in OC-3 cells. The protein expression of NOTCH1 and proliferation marker levels are significantly lower in NOM treated cells. Overall, ANO induced initial stage carcinogenesis in the oral cavity via inflammation, ROS and depletion of antioxidant enzymes. Arecoline N-oxide mercapturic acid (NOM) attenuates the initiation of oral carcinogenesis.

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.

Multifaceted Mechanisms of Areca Nuts in Oral Carcinogenesis: the Molecular Pathology from Precancerous Condition to Malignant Transformation

Oral cancer is one of the most frequent malignant diseases worldwide, and areca nut is a primary carcinogen causing this cancer in Southeast Asia. It has been widely reported that areca nut induced several cytotoxic effects in oral cells, including ROS generation, inflammation, tissue hypoxia, DNA damage, and cell invasion. Recently, through chronic exposure model, more extensive pathological effects due to areca nut have been found. These include the induction of autophagy, promotion of epithelial- mesenchymal transition, and facilitation of cancer stemness conversion. Clinical findings support these adverse effects. Oral submucosal fibrosis, a premalignant condition, is prevalent in the area with habitual chewing of areca nuts. Consistently, oral cancer patients with habitual chewing areca nut exhibit more aggressive phenotypes, including resistance to chemo-radiotherapy. In this review, we comprehensively discuss and concisely summarize the up-to-date molecular and cellular mechanisms by which areca nuts contribute to malignant transformation. This review may provide critical information regarding clinical applications in risk assessment, disease prevention, diagnosis, and personalized therapeutics for areca nut-induced oral malignancy.

Adverse Health Effects of Betel Quid and the Risk of Oral and Pharyngeal Cancers

Global reports estimate 600 million betel quid (BQ) chewers. BQ chewing has been demonstrated not only to be a risk factor for cancers of the oral cavity and pharynx and oral potentially malignant disorders (OPMD) but also to cause other cancers and adverse health effects. Herein, we summarized the international comparison data to aid in the understanding of the close relationship between the prevalence of BQ chewing, the occurrence of oral and pharyngeal cancers, and adverse health effects. Potential biomarkers of BQ carcinogens, such as areca nut, alkaloids, and 3-methylnitrosaminopropionitrile (MNPN), are closely associated with human health toxicology. Molecular mechanisms or pathways involving autophagy, hypoxia, COX-2, NF-κB activity, and stemness are known to be induced by BQ ingredients and are very closely related to the carcinogenesis of cancers of oral and pharynx. BQ abuse-related monoamine oxidase (MAO) gene was associated with the occurrence and progress of oral and pharyngeal cancers. In summary, our review article provides important insights into the potential roles of environmental BQ (specific alkaloid biomarkers and nitrosamine products MNPN) and genetic factors (MAO) and offers a basis for studies aiming to reduce or eliminate BQ-related OPMD and oral/pharyngeal cancer incidences in the future.

Areca nut contributes to oral malignancy through facilitating the conversion of cancer stem cells

Oral cancer is one of the most frequent malignant diseases worldwide, and areca nut is a primary carcinogen causing this cancer in Southeast Asia. Previous studies to examine the effects of this carcinogen often used short-term and high-dose treatment of area nut extract as a research model, which do not recapitulate the conditions of patients with long-term and habitual use of this substance. To approach authentic mechanism of areca nut-induced oral carcinogenesis that occurs in human, we established four isogenic sublines of oral cells which were chronic exposed to areca nut extract. Without eliciting cytotoxicity or senescence, these four sublines cells exhibited significant increase in invasive ability, along with epithelial-mesenchymal transition. These cells also showed resistance to chemotherapeutic drug and irradiation, accompanying with the augmentation of ABCG2 protein efflux and increased ROS clearance. Moreover, these sublines possessed the characteristics of cancer stemness, as demonstrated by enriched CD24-/CD44+ and CD133+ sub-populations, enhanced spheroid cell formation, and induced expressions of pluripotent stemness regulators, including Gp96, Grp78, Slug, Sox9, Snail, and Foxc2. These stemness regulators were further shown up-regulations in oral cancer patients with areca nut-chewing habit, and were statistically correlated with CD44 expression, a stemness marker. In conclusion, our findings suggested that areca nut contributes to oral malignancy through facilitating the conversion of cancer stem cells. This study may further contribute to clinical applications in disease prevention, risk assessment or molecular therapeutics on areca nut- associated diseases.

Association study between novel CYP26 polymorphisms and the risk of betel quid-related malignant oral disorders

BQ chewing may produce significant amounts of reactive oxygen species (ROS), resulting in oral mucosa damage, and ROS may be metabolized by CYP26 families. Because the CYP26 polymorphisms associated with malignant oral disorders are not well known, we conducted an association study on the associations between the single nucleotide polymorphisms (SNP) of CYP26 families and the risks of malignant oral disorders. BQ chewers with the CYP26A1 rs4411227 C/C+C/G genotype and C allele showed an increased risk of oral and pharyngeal cancer (adjusted odds ratio (aOR) = 2.30 and 1.93, respectively). The CYP26B1 rs3768647 G allele may be associated with oral and pharyngeal cancer (aOR = 3.12) and OPMDs (aOR = 2.23). Subjects with the rs9309462 CT genotype and C allele had an increased risk of oral and pharyngeal cancer (aOR = 9.24 and 8.86, respectively) and OPMDs (aOR = 8.17 and 7.87, respectively). The analysis of joint effects between the CYP26A1 rs4411227 and CYP26B1 rs3768647/rs9309462 polymorphisms revealed statistical significance (aOR = 29.91 and 10.03, respectively). Additionally, we observed a significant mRNA expression of CY26A1 and CYP26B1 in cancerous tissues compared with adjacent noncancerous tissues. Our findings suggest that novel CYP26 polymorphisms are associated with an increased risk of malignant oral disorders, particularly among BQ chewers.

The influence of monoamine oxidase variants on the risk of betel quid-associated oral and pharyngeal cancer

Betel quid (BQ) and areca nut (AN) (major BQ ingredient) are group I human carcinogens illustrated by International Agency for Research on Cancer and are closely associated with an elevated risk of oral potentially malignant disorders (OPMDs) and cancers of the oral cavity and pharynx. The primary alkaloid of AN, arecoline, can be metabolized via the monoamine oxidase (MAO) gene by inducing reactive oxygen species (ROS). The aim of this study was to investigate whether the variants of the susceptible candidate MAO genes are associated with OPMDs and oral and pharyngeal cancer. A significant trend of MAO-A mRNA expression was found in in vitro studies. Using paired human tissues, we confirmed the significantly decreased expression of MAO-A and MAO-B in cancerous tissues when compared with adjacent noncancerous tissues. Moreover, we determined that MAO-A single nucleotide polymorphism variants are significantly linked with oral and pharyngeal cancer patients in comparison to OPMDs patients [rs5953210 risk G-allele, odds ratio = 1.76; 95% confidence interval = 1.02-3.01]. In conclusion, we suggested that susceptible MAO family variants associated with oral and pharyngeal cancer may be implicated in the modulation of MAO gene activity associated with ROS.

Relationship between betel quid chewing and risks of cardiovascular disease in older adults: a cross-sectional study in Taiwan

BACKGROUND

The association between betel quid (BQ) chewing and oral cancer is well established. However, evidence regarding the relationship between BQ chewing and cardiovascular disease (CVD) is still insufficient.

METHODS

This cross-sectional study included 2002 men and 1175 women aged 50 and older in a city-level health examination survey of an agricultural and fishing population in 2013. In addition to anthropometric parameters, CVD risks were estimated using high-sensitivity C-reactive protein (hs-CRP), brachial-ankle pulse wave velocity (baPWV) and ankle-brachial index. Age, gender, smoking and alcohol drinking status were all incorporated into the multivariate logistic regression model to delineate the effect of BQ chewing on CVD risks.

RESULTS

Two hundred forty-one (12%) males and eight (0.7%) females were ever chewers. BQ chewing was an independent risk factor for general obesity (odds ratio [OR] 1.43, 95% confidence interval [CI] 1.07-1.91, p=0.017), central obesity (OR 2.27, 95% CI 1.53-3.37, p<0.001) and an elevated hs-CRP level (OR 1.38, 95% CI 1.03-1.85, p=0.029). Subjects who chewed more frequently had a higher systolic blood pressure (p=0.025) and baPWV (p=0.006). The waist circumference (p=0.015) and waist-to-height ratio (p=0.022) were greater in current chewers than in former chewers.

CONCLUSION

These findings suggest that BQ chewing is associated with obesity and a higher CVD risk as estimated by hs-CRP. Furthermore, potential beneficial effects of BQ chewing cessation on central obesity were also found.

Expression of a splice variant of CYP26B1 in betel quid-related oral cancer

Betel quid (BQ) is a psychostimulant, an addictive substance, and a group 1 carcinogen that exhibits the potential to induce adverse health effects. Approximately, 600 million users chew a variety of BQ. Areca nut (AN) is a necessary ingredient in BQ products. Arecoline is the primary alkaloid in the AN and can be metabolized through the cytochrome P450 (CYP) superfamily by inducing reactive oxygen species (ROS) production. Full-length CYP26B1 is related to the development of oral pharyngeal cancers. We investigated whether a splice variant of CYP26B1 is associated with the occurrence of ROS related oral and pharyngeal cancer. Cytotoxicity assays were used to measure the effects of arecoline on cell viability in a dose-dependent manner. In vitro and in vivo studies were conducted to evaluate the expression of the CYP26B1 splice variant. The CYP26B1 splice variant exhibited lower expression than did full-length CYP26B1 in the human gingival fibroblast-1 and Ca9-22 cell models. Increased expression of the CYP26B1 splice variant was observed in human oral cancer tissue compared with adjacent normal tissue, and increased expression was observed in patients at a late tumor stage. Our results suggested that the CYP26B1 splice variant is associated with the occurrence of BQ-related oral cancer.

Monoamine oxidase A variants are associated with heavy betel quid use

Few studies have investigated whether genetic abnormalities predispose individuals to heavy betel quid (BQ) use. One of the major ingredients of BQ, arecoline, is known to affect the expression of monoamine oxidase A (MAO-A). We investigated the extent to which arecoline inhibits MAO-A expression and the role of MAO-A polymorphisms in BQ use in Taiwanese aborigines. Cytotoxicity assays, microarrays and quantitative reverse transcriptase-polymerase chain reaction were used to examine the effects of arecoline and areca nut extract (ANE) on cell viability and MAO-A expression in neuroblastoma SH-SY5Y cells. After identifying the effective concentrations of arecoline and ANE in vitro, we examined the in vivo effects of these compounds using a rat model system. Our results indicate that arecoline and ANE inhibit MAO-A expression both in vitro and in vivo. In addition, we examined the correlation between plasma MAO-A activity and cumulative exposure to BQ in humans. We recruited 1307 aborigines from a large-scale community-based survey to determine whether MAO-A variants were associated with high BQ use and a preference for use with smoking or alcohol and whether gender bias existed. MAO-A expression was significantly downregulated by arecoline and ANE at 100-200 µg/ml and in rat whole brains on days 30 and 45. MAO-A activity levels in human plasma were positively correlated with the extent of BQ exposure, and individuals with at-risk alleles exhibited lower activity, although this result did not reach statistical significance. We found two single nucleotide polymorphism (SNPs) in aboriginal males [rs2283725, odds ratio (OR) = 2.04; rs5953210, OR = 2.03] and females (rs2283725, OR = 1.54; rs5953210, OR = 1.59) that were associated with heavy BQ use. Those individuals carrying at-risk alleles who drank alcohol were twice as likely to be heavy BQ users. However, the effects of these SNPs on BQ use were significant even after controlling for alcohol use. Our results suggest that two specific loci may confer a susceptibility to BQ abuse and affect MAO-A enzymatic activity.

CYP26B1 is a novel candidate gene for betel quid-related oral squamous cell carcinoma

Substantial epidemiological data suggest a role for environmental factors (for example, the use of alcohol, betel quid (BQ), and cigarettes) in the occurrence of oral squamous cell carcinoma (OSCC), but the evidence for the genes involved has been inconsistent. This study was to investigate the role of CYP26B1, together with the use of alcohol, BQ, and cigarettes, on BQ-related OSCC. The association study (247 OSCC cases and 338 controls) was conducted to examine the possible interplay between CYP26B1 polymorphisms and alcohol, BQ, and cigarettes use. Additional gene expression was evaluated between OSCC tissue and adjacent normal tissue. The genetic polymorphism AA of CYP26B1 appeared to correlate with the risk of OSCC (OR=2.26; 95% CI, 1.35-3.80). Chewing BQ multiplicatively interacted with CYP26B1 AA to increase the OSCC risk (aOR=70.04; 95% CI, 13.62-360.11). The independent risk of OSCC was observed among BQ chewers with CYP26B1 AA, and compared with chewers with the CYP26B1 CC genotype (stratified aOR=2.88; 95% CI, 1.07-7.74). Increased expression of CYP26B1 was observed in tumor tissue compared with adjacent normal tissue. The CYP26B1 gene plays a novel role in the BQ dependent pathogenesis of OSCC.

A characterization of the antioxidant enzyme activity and reproductive toxicity in male rats following sub-chronic exposure to areca nut extracts

In the present study, areca nut extracts (ANE) administered to male rats by gavage at a dose of 100mg/kg/day for a period of 15, 30, or 45 days resulted in signs of reproductive toxicity. ANE administration resulted in a significant decline (30-57% in epididymal sperm count and 27-61% in sperm motility) as well as substantial abnormalities in sperm morphology. Significant variances in activities of antioxidant enzymes were also observed. Malondialdehyde (MDA) levels, which represent the level of lipid peroxidation, increased by 16-188% and levels of sialic acid decreased by 2-46% compared with that in controls. These results indicate that ANE induced spermatogenic damage, as indicated by a decrease in sperm counts and sperm motility as well as the activity of antioxidant enzymes, an increase in sperm abnormalities, and alterations in sialic acid and MDA levels. Such effects reflect that ANE administration resulted in reactive oxygen species (ROS)-induced oxidative stress in the testis, cauda epididymis, and sperm of male rats.

Inhibitory effects of safrole on phagocytosis, intracellular reactive oxygen species, and the activity of myeloperoxidase released by human polymorphonuclear leukocytes

BACKGROUND

Safrole, a component of Piper betle inflorescence, inhibits bactericidal activity and the release of superoxide anion (O(2)(-)) by polymorphonuclear leukocytes (PMNs). This in vitro study further investigated the effects of safrole on phagocytic activity, the intracellular production of reactive oxygen species (ROS), and the activity of the lysosomal enzyme myeloperoxidase (MPO), which is released by human PMNs.

METHODS

The possible effects of safrole on the phagocytic activity of PMNs against Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans) were determined using flow cytometry. PMNs were treated with various concentrations of safrole, which was followed by treatment with Hanks balanced salt solution with or without cytochalasin B and fMet-Leu-Phe (CB/fMLP). Intracellular ROS was determined using 2',7'-dichlorofluorescein diacetate and a fluorometer, whereas MPO activity was determined using a substrate assay.

RESULTS

Safrole significantly inhibited the phagocytic activity of PMNs in a dose-dependent manner. Approximately 50% of the phagocytic activity of PMNs was affected when 10 mM safrole was used. Exposure of the PMNs to safrole (up to 5 mM) did not directly affect the intracellular levels of ROS and the extracellular activity of MPO. However, the ability of CB/fMLP to trigger production of intracellular ROS and the activity of MPO released by human PMNs was significantly suppressed by safrole.

CONCLUSIONS

Safrole reduced the uptake of A. actinomycetemcomitans by human PMNs. Safrole also impaired the normal activation activity of PMNs. Alterations in the defensive properties of PMNs by safrole might promote bacterial colonization, and this could result in periodontal infection.

Strategies for comprehensive analysis of amino acid biomarkers of oxidative stress

Despite the wide interest in using modified amino acids as putative biomarkers of oxidative stress, many issues remain as to their overall reliability for early detection and diagnosis of diseases. In contrast to conventional single biomarker studies, comprehensive analysis of biomarkers offers an unbiased strategy for global assessment of modified amino acid metabolism due to reactive oxygen and nitrogen species. This review examines recent analytical techniques amenable for analysis of modified amino acids in biological samples reported during 2003-2007. Particular attention is devoted to the need for validated methods applicable to high-throughput analysis of multiple amino acid biomarkers, as well as consideration of sample pretreatment protocols on artifact formation for improved clinical relevance.

Risk of betel quid chewing on the development of liver cirrhosis: a community-based case-control study

PURPOSE

The role of betel quid on the development of liver cirrhosis is unclear; we thus designed a community-based case-control study to evaluate the association between betel quid chewing and liver cirrhosis.

METHODS

A total of 42 cases of liver cirrhosis and 165 matched controls were included for analysis. Questionnaires were administered to obtain histories of betel quid chewing, alcohol consumption, smoking, and family history of liver disease. Hepatitis B surface antigen and anti-hepatitis C antibody were also determined by immunoassay.

RESULTS

Individuals with more betel quid chewing (more than 55 quid-years vs. less than 55 quid-years and never-chewers, matched odds ratio [OR(m)] = 2.2; 95% confidence interval [CI]: 1.0-5.0) had higher risks for liver cirrhosis. The combined effects on liver cirrhosis by betel quid chewing and the number of other risk factors, including hepatitis B virus (HBV) infection, smoking, and alcohol drinking, were also observed. When individuals with less betel quid chewing (less than 55 quid-years and never-chewers) and with no other risk factors used as a reference, betel quid chewers expressing greater betel quid chewing (more than 55 quid-years) and more risk factors of HBV infection, cigarette smoking, and habitual alcohol drinking expressed a greater risk of liver cirrhosis (OR(m) = 70.8; 95% CI: 4.0-1260.1).

CONCLUSIONS

Our results suggest that betel quid chewing may play an important role in the development of hepatic cirrhosis. Larger study and cohort studies would be necessary to provide further evidence regarding this finding.