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Concept: Areca nut

208

Habitual chewing of “betel nut” preparations constitutes the fourth most common human self-administration of a psychoactive substance after alcohol, caffeine, and nicotine. The primary active ingredient in these preparations is arecoline, which comes from the areca nut, the key component of all such preparations. Arecoline is known to be a relatively non-selective muscarinic partial agonist, accounting for many of the overt peripheral and central nervous system effects, but not likely to account for the addictive properties of the drug. We report that arecoline has activity on select nicotinic acetylcholine receptor (nAChR) subtypes, including the two classes of nAChR most related to the addictive properties of nicotine: receptors containing α4 and β2 subunits and those which also contain α6 and β3 subunits. Arecoline is a partial agonist with about 6-10% efficacy for the α4* and α6* receptors expressed in Xenopus oocytes. Additionally, arecoline is a silent agonist of α7 nAChR; while it does not activate α7 receptors when applied alone, it produces substantial activation when co-applied with the positive allosteric modulator PNU-120696. Some α7 silent agonists are effective inhibitors of inflammation, which might account for anti-inflammatory effects of arecoline. Arecoline’s activity on nAChR associated with addiction may account for the habitual use of areca nut preparations in spite of the well-documented risk to personal health associated with oral diseases and cancer. The common link between betel and tobacco suggests that partial agonist therapies with cytisine or the related compound varenicline may also be used to aid betel cessation attempts.

Concepts: Nicotine, Acetylcholine, Muscarinic acetylcholine receptor, Nicotinic acetylcholine receptor, Acetylcholine receptor, Ibogaine, Cytisine, Areca nut

169

BACKGROUND: Areca nut (commonly known as betel nut) chewing has been shown to be associated with metabolic syndrome and cardiovascular disease (CVD). The mechanism by which betel nut ingestion could lead to development of CVD is not precisely known; however, dyslipidemia hyperhomocysteinemia, hypertriglyceridemia and inflammation could be some of the potential risk factors. This study was undertaken to investigate the effects of two dosages of betel nut on homocysteinemia, inflammation and some of the components of metabolic syndrome, such as hypertriglyceridemia, low HDL-cholesterol, obesity and fasting hyperglycemia in a rat model. METHODS: Thirty-six adult female Sprague Dawley rats, aged 10–12 weeks were divided into three equal groups. Group-1 served as the control group (n = 12) and received water, whereas groups 2 and 3 were given water suspension of betel nut orally in two dosages, 30 mg and 60 mg, respectively for a period of 5 weeks. At the end of the fifth week, the animals were weighed and sacrificed, blood was collected and liver, kidney, spleen and stomach were removed for histological examination.Plasma/serum was analyzed for glucose, total cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides, homocysteine, folate, vitamin B12 and N-acetyl-beta-D-glucosaminidase (NAG) – a marker of inflammation. RESULTS: When the mean concentration values of 3 groups were compared using one way ANOVA followed by Tukey’s HSD-test, there was a significant increase in the concentration of total cholesterol (p = 0.04) in the group receiving 30 mg/day betel nut compared to the control group. However, administration of a higher dose of betel nut (60 mg/day) had no significant effect on the serum concentrations of glucose, total cholesterol, HDL-cholesterol, LDL-cholesterol, and NAG. Histological examination of spleen revealed a dose-dependent extramedullary hematopoiesis. No other remarkable change in the tissues (liver, kidney and stomach) was observed.Mean serum/plasma levels of folate, vitamin B12 and homocysteine were not found to be significantly different in all the groups. Betel nut ingestion had no effect on the mean body weights of rats. CONCLUSIONS: Low dosage of betel nut is found to be associated with hypercholesterolemia. However, betel nut ingestion is not associated with hyperhomocysteinemia, hypertriglyceridemia, hyperglycemia, inflammation and increase in body weight in a rat model.

Concepts: Cholesterol, Nutrition, Atherosclerosis, Cardiovascular disease, Low-density lipoprotein, Folic acid, Laboratory rat, Areca nut

145

Oral cancers are attributed to a number of causal agents including tobacco, alcohol, human papillomavirus (HPV), and areca (betel) nut. Although betel nut chewing has been established as an independent cause of oral cancer, the mechanisms of carcinogenesis are poorly understood. An investigation was undertaken to evaluate the influence of betel nut chewing on the oral microbiome and oral premalignant lesions. Study participants were recruited from a dental clinic in Guam. Structured interviews and oral examinations were performed. Oral swabbing and saliva samples were evaluated by 454 pyrosequencing of the V3- V5 region of the 16S rRNA bacterial gene and genotyped for HPV. One hundred twenty-two adults were enrolled including 64 current betel nut chewers, 37 former chewers, and 21 with no history of betel nut use. Oral premalignant lesions, including leukoplakia and submucous fibrosis, were observed in 10 chewers. Within-sample bacterial diversity was significantly lower in long-term (≥10 years) chewers vs. never chewers and in current chewers with oral lesions vs. individuals without lesions. Between-sample bacterial diversity based on Unifrac distances significantly differed by chewing status and oral lesion status. Current chewers had significantly elevated levels of Streptococcus infantis and higher and lower levels of distinct taxa of the Actinomyces and Streptococcus genera. Long-term chewers had reduced levels of Parascardovia and Streptococcus. Chewers with oral lesions had significantly elevated levels of Oribacterium, Actinomyces, and Streptococcus, including Streptococcus anginosus. In multivariate analyses, controlling for smoking, oral HPV, S.anginosus, and S. infantis levels, current betel nut chewing remained the only predictor of oral premalignant lesions. Our study provides evidence that betel nut chewing alters the oral bacterial microbiome including that of chewers who develop oral premalignant lesions. Nonetheless, whether microbial changes are involved in betel nut-induced oral carcinogenesis is only speculative. Further research is needed to discern the clinical significance of an altered oral microbiome and the mechanisms of oral cancer development in betel nut chewers.

Concepts: Cancer, Bacteria, Human papillomavirus, Ribosomal RNA, Head and neck cancer, Dentistry, Areca nut, Betel

137

Betel nut consumption has significant implications for the public health globally, as the wide-spread habit of Areca chewing throughout Asia and the Pacific is associated with a high prevalence of oral carcinoma and other diseases. Despite a clear causal association of betel nut chewing and oral mucosal diseases, the biological mechanisms that link Areca nut-contained molecules, inflammation and cancer remain underexplored. In this study we show that the whole Areca nut extract (ANE) is capable of mobilizing Ca2+ in various immune cell lines. Interestingly, none of the four major alkaloids or a range of other known constituents of Areca nut were able to induce such Ca2+ signals, suggesting that the active components might represent novel or so far unappreciated chemical structures. The separation of ANE into aqueous and organic fractions has further revealed that the calcium-mobilizing molecules are exclusively present in the aqueous extract. In addition, we found that these calcium signals are associated with the activation of several immune cell lines as shown by the release of pro-inflammatory cytokines and increased cell proliferation. These results indicate that calcium-mobilizing molecules present in the aqueous fraction of the Areca nut may critically contribute to the inflammatory disorders affecting betel nut chewers.

Concepts: Immune system, Inflammation, Antibody, Epidemiology, Chemistry, Areca nut, Areca catechu, Betel

26

Oral submucous fibrosis is a pre-malignant fibrotic condition caused by areca nut use and involves reduced mucosal vascularity. Arecoline is the principal areca nut alkaloid and is cytotoxic for epithelium and fibroblasts. Endothelial cell cycle arrest is reported on exposure to arecoline, as is cytotoxicity for endothelial-lung carcinoma hybrid cells. We here describe cytotoxicity for primary human endothelial cultures from seven separate donors.

Concepts: Cell, Chromosome, Epithelium, Endothelium, Cytotoxicity, Cornea, Areca nut

5

The number of people being diagnosed with mouth cancer (oral cancer) is increasing, with notable rises in incidence in younger people and in females. There are certain lifestyle habits that can increase the risk of mouth cancer, such as smoking or chewing tobacco, drinking alcohol above recommended levels (especially in those who also smoke), and chewing betel nut (areca nut). Infection with human papillomavirus (HPV) increases the risk of some types of mouth cancer, and too much sun exposure may also raise the risk of lip cancers. The signs and symptoms of mouth cancer can often be seen or felt, and any red or white patch, ulcer or lump can be an early sign if it lasts for three or more weeks. If people notice any of these changes, they should seek help from their dentist, doctor, or another healthcare professional without delay, because if mouth cancer is diagnosed at an early stage, when the lesions are small, treatment is generally less complicated and more effective.

Concepts: Immune system, Cancer, Metastasis, Human papillomavirus, Tobacco, Tobacco smoking, Head and neck cancer, Areca nut

0

This paper provides a review of various image analysis approaches that have been previously used for recognition of dysplasia in images of the epithelium of the oral cavity. This domain has become especially admissible with the uncovering of the importance of image analysis which can probably be an aid to subjective diagnosis by histopathologists. Oral malignancy is a rampant form of cancer found among people of the Indian subcontinent due to various deleterious habits like consumption of tobacco, areca nut, betel leaf etc. Oral Submucous Fibrosis, a precancer, whose pathological category falls between normal epithelium and epithelial dysplasia, is caused because of these habits and can ultimately lead to oral cancer. Hence early detection of this condition is necessary. Image analysis methods for this purpose have an enormous potential which can also reduce the heavy workload of pathologists and to refine the criterion of interpretation. This paper starts with a critique of statistics of oral carcinoma in India and distribution of cancer in intra-oral sites and moves on to its causes and diagnostic approaches including causative agents, problems in curative approach and importance of image analysis in cancer detection. The various image analysis methods to appraise the cytological and architectural changes accompanied by Oral Epithelial Dysplasia in the images of the oral epithelial region have been described in relation to 2005 WHO Classification System and it was found that in future, analysis of images based on the mentioned methods has the potential in better interpretation and diagnosis of oral carcinoma.

Concepts: Cancer, Pathology, Epithelium, Carcinoma, Sarcoma, Oral cancer, Areca nut, Betel

0

Betel nut of Areca catechu is chewed by millions of people for increased capacity to work and stress reduction, but it contains arecoline that causes hypothyroidism. The aim is to investigate the role of arecoline on thyroid activity in cold stress in mice. Arecoline treatment (10 mg/kg body wt/day, for 7 d) caused a reduction in thyroid weight and ultrastructural degeneration of thyro-follicular cells with depletion of T3 and T4 levels compared with the control mice. Cold stress (4 °C for 2 h, twice daily, for 7 d) stimulated thyroid activity ultrastructurally with an elevation of T3 and T4 levels. Arecoline treatment in cold stress suppressed thyroid activity by showing reversed changes to those of cold stress. In contrast, TSH concentrations were consistently increased under all experimental conditions. The findings suggest that cold stress causes hyperthyroidism which arecoline can ameliorate in mice.

Concepts: Thyroid-stimulating hormone, Thyroid disease, Hypothyroidism, Hashimoto's thyroiditis, Hyperthyroidism, Triiodothyronine, Areca nut, Areca catechu

0

Betel nut (BN) is a psychoactive oral carcinogen that is commonly used among Asian communities. This study aims to investigate BN usage patterns and the effectiveness of a visually guided educational initiative in a high-risk refugee population. All adult patients presenting to a private practice clinic, free community clinic, or health fair in the refugee community of Clarkston, Georgia during days when survey staff were present were approached for the study. Participants were first categorized into a familiar and unfamiliar cohort depending on participant-reported familiarity with BN. Depending on familiarity, subjects were then administered a pre-intervention test surveying health awareness for BN and usage patterns where relevant; subsequently, a visually guided educational brochure was reviewed, and a post-intervention test was administered. Results were statistically analyzed (STATA 12). Forty-eight participants were surveyed for the familiar cohort and 25 for the unfamiliar cohort. Among the familiar cohort, South and Southeast Asians comprised 91% of participants. On frequency of use, 42.8% reported social, 28.6% reported usage during celebrations only, and 28.6% reported daily. The most common reasons for use were for taste (40.9%), enjoyment (38.6%), and addiction (25%). Among the familiar cohort, 75% believed BN was harmful for health compared to 8% among the unfamiliar (p < 0.0001). In the familiar cohort, 52.3% believed BN alone could cause cancer compared to 4% among the unfamiliar (p < 0.0001). Following the educational intervention, 100% of participants believed BN mastication is harmful in both cohorts (p < 0.01), while 87.5% of participants in both cohorts recognized that BN alone could cause cancer (p < 0.0007). This study illustrates gaps in understanding regarding oral cancer and the health consequences of chronic BN mastication, as well as the efficacy of a visually guided educational brochure to improve participant knowledge among a high-risk refugee population.

Concepts: Epidemiology, Clinical trial, Participation, Demography, Efficacy, Surveying, Areca nut, Betel

0

Tannin acyl hydrolase (tannase, EC3.1.1.20) catalyzes the hydrolysis of hydrolyzable tannins. It is used in the manufacture of instant tea and in the production of gallic acid. In this study, we reported that the overexpression, purification and characterization of an Aspergillus niger tannase. The tannase gene was cloned from A.niger SH-2 and expressed in the A.niger strain Bdel4 which is low-background of secreted proteins. The recombinant tannase was purified by desalting, followed by gel filtration for characterization. The tannase activity achieved 111.5 U/mL at 168 h, and the purity of the enzyme in the broth supernatant was estimated to be over 70%. The optimum temperature and pH of the recombinant tannase was ∼40 °C and 7.0, respectively. The tannase activity was inhibited by Mg(2+), Ca(2+), Cu(2+), Ba(2+) and EDTA, and was enhanced by Mn(2+) and Co(2+). Since A. niger is a GRAS microorganism, the recombinant tannase could be purification-free due to its high purity. The results of this study suggested that this recombinant strain could be subjected to large-scale production of A.niger tannase.

Concepts: Protein, Gene expression, Molecular biology, Enzyme, Microbiology, Tannin, Gallic acid, Areca nut