7. Alkaloids present in Areca nut - Part II

 

A study was undertaken by our team in NITK Surathkal in 2021 and 2022 to study the arecoline content in the unripe areca nuts of 6-7 months’ maturity. The areca nut samples were collected from various locations as explained in my Blog 4. Phenolic compounds present in Areca nut (Karnataka, India): Part – II (under the label Chemical constituents of Areca nut). The arecoline content of the fresh areca nut samples was determined immediately after the collection. Very sensitive HPLC method was employed to find the arecoline content in the samples. The results are presented below.

The median arecoline content among the 21 samples was 2.17 mg/g on Fresh weight (FW) basis. Sample from K. Hosur, Tarikere Taluk, Chickmagalur District had the highest arecoline content of 3.66 mg/g (0.366 %) on fresh weight basis. Whereas the sample from Gajanur, Shivamogga district had the lowest arecoline content of  0.71 mg/g (0.071%) on fresh weight basis.

In general, the arecoline content of all the samples analyzed in this study was on the lower side compared to the reports published elsewhere. Only three samples had the arecoline content more than 0.3 % out of 21 samples analyzed. In general, if areca nut is having 0.3% arecoline content (3.0 mg/g) is dried as it is, the dried nut would contain 0.75 % (7.5 mg/g) arecoline on dry weight basis. Interestingly, two samples had arecoline content less than 0.1%, which is a remarkable discovery.                                                                                                                                                                                                      

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6. Alkaloids present in Areca nut - Part I

 

Arecoline, arecaidine, guvacine, and guvacoline are the most important and prominent alkaloids found in areca nut. Nicotine, dichroine, acatechu A, acatechu B, homoarecoline, N-ethyl-1,2,5,6-tetrahydro-1-methyl-3-pyridine carboxamide and arecatemines are some of the minor alkaloids found in some areca nuts. Arecoline is found to be the most important alkaloid among all, due to its role in modulating many physiological functions upon human consumption.

In humans, depending on the dose and individual responsivity, arecoline produces cognition-enhancing, psychostimulant, euphoric, pro-arousal, aphrodisiac, anxiolysis and sedative effects. In other words, arecoline produces enhanced alertness and learnability, enhances the mood, gives a feeling of great pleasure, causes awakening, stimulates the sexual desire, reduces anxiety and promote calmness. Arecoline has a wide spectrum of pharmacological effects beyond Central Nervous System modulating cardiovascular, digestive and endocrine systems as well.  Like nicotine, arecoline also evokes addiction and withdrawal symptoms (upon discontinuation). Withdrawal symptoms could be mood swings, anxiety, irritability and insomnia.

Arecoline content in Green Areca nuts (6-7 month's maturity)

Many research groups have studied the arecoline content in areca nuts cultivated in various geographical locations and at various level of maturity. Mathew et al., (1964) from CFTRI Mysore, had studied the arecoline content of areca nuts of 6-7 months maturity collected from Kyatsandra, Mysore, Thirthahalli and Vittal in Karnataka state and Pudupady in Kerala state of India.  They have concluded that the arecoline content was in the range of 0.14 to 0.19 %.

Huang and Mcleish (1989) had reported an arecoline content of 0.3-0.63 % in fresh areca nuts (perhaps 6-7 months’ maturity) collected from Darwin, Australia using HPLC method. This was the first report of use of HPLC for estimating arecoline. They had estimated the arecaidine (0.31-0.66%), guvacoline (0.03-0.06%) and guvacine (0.19 0.72%) in those samples as well.

Sari et al., (2020) had studied the arecoline content of unripe green areca nuts (6-7 months’ maturity) collected from two different regions of Indonesia. They had reported an arecoline content of 0.44 & 0.69 % (on dry weight basis).

References:

1.  Mathew et al. (1964) Studies on Arecanut: Part I - Changes in Chemical Composition & Physical Characteristics of Nuts with MaturityIndian Journal of Technology, Vol. 2, No.3, pp. 90-96

2.    Huang and McLeish (1989). High-performance liquid chromatographic determination of the alkaloids in betel nut, Journal of Chromatography, 415, pp. 447-450.

3.   Sari et al., (2020). Distinct phenolic, alkaloid and antioxidant profile in betel quids from four regions of Indonesia, Scientific Reports, Vol. 10:16254

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8. Demand & supply of areca nut in Inda: An analysis

 

As per the nationally representative cross-sectional study conducted in 2016-17 by Tata Institute of Social Science (TISS), Mumbai with support from Ministry of Health and Family welfare, Govt. of India, about 23.9% of the adult population consume areca nut. This translates into approximately 22.38 crore people consuming areca nut in one or the other form in 2016-17. Majority users (13.29 crore) consumed areca nut with tobacco. As per the official documents of TISS Mumbai, the survey was conducted in all 29 states and three union territories (UTs) of India. The study involved the survey of 74,037 adults aged 15 and above. A multistage sampling design separately for rural and urban areas was adopted. The overall response rate was 92.9%. The sampling was done independently in each state/Union Territories, and it was done independently for urban and rural areas.

Let us try to apply the similar calculation to the year 2020. The total population of India was 138.88 crores in 2020. In this, the adult (between 15-65 years of age) population was 94.02 crores. As per the TISS survey data, 22.47 crores (23.9% adult population) must have consumed the areca nut in one or the other form. Out of which, 13.34 crores were the habitual areca nut consumers with Chewable tobacco. Rest (9.12 crores) consumed area nut vocationally.

Discussions with Gutkha/tobacco wholesale traders in Hubli, Karnataka and retailers elsewhere, it was evident that those addicted to chewable tobacco (Smokeless tobacco) consume Gutkha, Mawa, or Paan with tobacco, a minimum of 10 times a day. Each time, about 2.5 gram of areca nut is consumed which translates into 25 grams per day. That amounts to 9.125 Kg of areca nut per year. If we apply this calculation to 13.34 crore individuals who consume areca nut with chewable tobacco, the amount of areca nut consumed would be 12,17,275 Tonnes per annum. Apart from this about 9.12 crore adults consume areca nut in the form of Paan (Betel quid). If we assume, one Paan is consumed per day by them, the total areca nut consumption would be 83,220 Tonnes per annum. Thus, the total areca nut consumption by Indian population in 2020 was 13,00,495 Tonnes.

As per Food and Agriculture Organization of the United Nations (FAO) data released in March 2022, the domestic production of India was 13,82,000 Tonnes in 2020. That shows, there was a surplus of 81,505 Tonnes of areca nut in India in 2020. Perhaps, this was exported to the countries having a sizable areca nut consuming population such as Pakistan, Nepal and Gulf nations. Several records shows that India is the sole manufacturer of Gutka in the world and Gutka is highly popular in those nations.

Most recent data indicates that the Chewable tobacco (smokeless tobacco) users are much more than the 2016-17 estimate (TISS study). As per the recent Lancet report, about 19.94 crore adults chew areca nut with tobacco in India. If we consider this data, India would have consumed a whooping 18,19,525 Tonnes in 2022.  India’s domestic production was 13,82,000 Tonnes in 2020. If we assume 15% year-on-year growth in the domestic production, the areca nut production in 2022 would have reached 18,27,000 Tonnes. The actual production figures are yet to be released by Directorate of Areca nut and Spices Development, Calicut and Food and Agriculture Organization of the United Nations (FAO). 

References:

1.    Singh P.K et al. (2021). Areca nut consumption with and without tobacco among the adult population: a nationally representative study from India. BMJ Open; 11: e043987. doi:10.1136/bmjopen-2020-043987

2.     Arakeri et al. (2023). Unsuccessful ban on gutkha and need for tobacco control in India. The Lancet, Vol 401, pp 1154.

3.      Food and Agriculture Organization of the United Nations data released officially in March 2022.

4.       Directorate of Areca nut and Spices Development, Calicut report published in June 2021.

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5. Phenolic compounds present in Areca nut: Part – III

 

Couple of research groups have tried to identify the prominent phenolic compounds present in the areca nut. Considering the fact that most of the phenolic compounds present in areca nut are structurally similar to each other and exhibit similar physico-chemical properties, identifying and quantifying them is not easy. It requires very advanced instruments, expensive reagents and expertise. Hence, the number of reports on this matter is very limited.

First authentic report on the phenolic compounds present in areca nut was published by Govindarajan & Mathew (1963). They were working in Central Food Technology Research Institute (CFTRI) Mysore, and they tried to identify prominent phenolic compounds present in Chali (White supari). They had identified Catechin, Epicatechin and Leucocyanidins, using a very rudimentary “Paper chromatography method”. In 2013, Chavan & Singhal from “Institute of Chemical Technology” Mumbai, confirmed the presence of catechin and epicatechin in Chali (White supari) using advanced Liquid Chromatography- Mass spectroscopy (LC-MS) method.

In China, Zhang et al. (2014) had used most advanced High Performance Liquid Chromatography - Mass Spectroscopy (HPLC-MS) to identify some of the prominent phenolic compounds present in the areca nuts of 5 month's maturity. They had collected the areca nut sample from Hainan Province of China. They have reported the presence of Epicatechin and Syringic acid in the areca nuts of 5 month's maturity.

One more recent report on the prominent phenolic compounds present in areca nut came from Indonesia. Sari et al., (2020) had tried to identify and quantify the prominent phenolic compounds present in unripe (green) areca nuts (6-7 months’ maturity) collected from West Kalimantan & West Papua and ripened areca nuts (perhaps 9-10 months’ maturity), collected from Banda Aceh & North Sumatra, Indonesia. They had used an advanced LC-MS analysis to quantify those phenolic compounds. They have reported the presence of Catechin & Epicatechin in all the four areca nut samples. In areca nut sample collected from West Papua (6-7 months’ maturity), Sinapic acid, quercetin and resveratrol were also reported. However, they were absent in the ripened areca nut samples. Their results are presented below.

Song et al. (2022) have identified and quantified the prominent phenolic compounds present in the areca seed (after dehusking ) of the areca nuts of 5 month's maturity. They had chosen the areca nut samples from Hainan Province of China.  They had used a most advanced UHPLC–MS/MS to identify and quantify the phenolic compounds. They too have reported the presence of large amount of Catechin and Epicatechin, which is in concurrence with the results of Zhang et al. (2014). Furthermore, they have reported the presence of a significant amount of Procyanidins, which was not reported by Zhang et al. (2014). Some major compounds reported by them are listed below.

Our recent study of unripe green areca nut (6-7 months’ maturity) collected from Belur, Sagar Taluk, Shivamogga district using a most advanced UHPLC-MS/MS confirmed the presence of large number of flavonoids. This study was conducted in 2022 in our lab at NITK Surathkal, Karnataka, India. Altogether 61 compounds belong to phenolic acids, flavonoids, proanthocyanidins, alkaloids, lignans, xanthones, Sesquiterpenes classes were identified. Arecatannin B1, Catechin, Propelargonidin, Procyanidin B2, 5,3'-Dihydroxy-6,7,4'-trimethoxyflavanone, Coniferyl alcohol and Nubigenol were the prominent compounds found in areca nut of 6-7 month's maturity. Isorhamnetin, Phloretin, Isoferulic acid, Hydroxybenzoic acids and syringic acid commonly found in Chinese and Indonesian areca nuts were also identified.

References

1.   Govindarajan & Mathew (1963). Polyphenolic substances of arecanut-I. Chromatographic analysis of fresh mature nut. Phytochemistry. Vol. 2. pp. 321t o 326

2.   Chavan & Singhal (2013). Separation of polyphenols and arecoline from areca nut (Areca catechu L.) by solvent extraction, its antioxidant activity, and identification of polyphenols. Journal of Science of Food & Agriculture.  Vol. 93(10), pp. 2580–2589.

3.     Zhang et al. (2014). Optimization of extraction conditions of areca seed polyphenols and evaluation of their antioxidant activities. Molecules. Vol. 19(10), pp. 16416–27

4.   Sari et al., (2020). Distinct phenolic, alkaloid and antioxidant profile in betel quids from four regions of Indonesia, Scientific Reports, Vol. 10:16254

5.  Song et al., (2022). UHPLC-MS/MS identification, quantification of flavonoid compounds from Areca catechu L. extracts and in vitro evaluation of antioxidant and key enzyme inhibition properties involved in hyperglycemia and hypertension. Industrial Crops & Products. Vol. 189, pp. 115787.

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4. Phenolic compounds present in Areca nut (Karnataka, India): Part – II

A comprehensive study on the Total Phenolic Compounds” Present in the unripe (Green) areca nuts of 6-7 month’s maturity was carried out in my lab by my team in NITK Surathkal. Generally, the harvesting season for green nuts starts in September and continues up to December for making Red Supari (Kempadike) in Karnataka State. The fresh nuts of 6-7 months’ maturity harvested by the farmers for making “Red Supari” (kempadike) were collected from various districts of Karnataka in Dec 2021 & Nov 2022. The locations were chosen so that most of the prominent, traditional Red Supari producing Taluks were covered in this study. The goal was to study the effect of geographical locations on the chemical constituents of the areca nut. The sample locations are pictorial represented below.

The total phenolic content of the fresh areca nut samples was determined immediately brought to the lab under frozen state and the chemical constituents were determined the next day.

The data is presented below.

Lot of variations in the phenolic content was noticed among the samples. The areca nuts cultivated in the relatively dry regions of Shivamogga, Davanagere, Chickmagalur and Haveri districts had higher phenolics compared to other regions.

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