INTRODUCTION:

Caffeine can be classified as an alkaloid, a term used for substances produced as products of nitrogen metabolism in some plants. Caffeine is available in various natural and synthetic products such as tea, coffee plants and cola, cacao, analgesics, respectively. It can also be synthesized from dimethyl urea.¹

Caffeine has been used widely around the world over centuries, and United States Food and Drug Administration (US-FDA) estimates that 80% of the world’s adult population consumes caffeine in any one of the forms.² It produces increased wakefulness, and thought-processing, increased focus, and better general body coordination. The amount of caffeine needed to produce these effects varies with individuals’ physiology. The recommended optimum level of caffeine for a normal adult is 500 mg/d, however, over 1000 mg/d is overdose, and termed as caffeinism.³

The impact of caffeine in human body is its ability to stimulate the central nervous system.⁴ It has pharmacological uses as cardiac and respiratory stimulant and as an agent that promotes kidney diuresis. Caffeine enters the bloodstream about ten minutes after its ingestion and stays in the body for up to twelve hours. Once caffeine is absorbed into the blood stream, it can reach all parts of the body, and causes a variety of effects. It makes the heart pump more blood, but it decreases the blood flow to the brain by constricting blood vessels there. Perhaps it compensates for this by stimulating the cerebral cortex, to give us a more alert feeling.

Like other alkaloids, caffeine has powerful physiological effects on humans and animals. It stimulates heart muscle and relaxes certain structures that contain smooth muscle, including the coronary arteries and the bronchi. Some of the appreciable qualities^5-⁷of caffeine are i) can stimulate hair growth on balding men and women, ii) increases stamina during exercise and reduces post-workout muscle pain by half, iii) may protect against Parkinson’s and Alzheimer’s diseases, iv) prevents skin cancer in hairless mice, v) reduces the risk of developing melanoma and may reduce fatty liver.

The most popular effect due to caffeine consumption is the ability to postpone exhaustion. The reason why most people become alert when they consume caffeine is that the molecule fits into the binding sites meant for adenosine, a neurotransmitter that serves to create a calming effect in the body.⁸ Caffeine structurally resembles to that of adenosine and fit into the brain’s adenosine receptors by effectively blocking them off (adenosine produced over time locks into these receptors and produces a feeling of tiredness).⁹However overdose of caffeine may cause irritability, nervousness, jumpiness, irregular heartbeat, headaches, insomnia and other unpleasant symptoms.

Based on the above information, it is very clear that, the quantity of caffeine is an important factor and hence, we undertaken this study to estimate the percentage of caffeine in various tea samples from different landscapes of the Darjeeling district of West Bengal state, India.

MATERIALS AND METHODS:

Isolation Procedure:

The following protocol⁷ has been used to identify the quantity of caffeine in the tested samples. In a RB flask, 40gm of sample was taken and refluxed for about an hour with 250 ml of distilled water. The brown color extract was separated.

On the other hand, to the boiling lead acetate solution, the lead oxide was added slowly with constant stirring, filtered and again boiled. The filtrate thus obtained was added drop wise to this extract till the completion of precipitation. Then the filtrate is treated with activated charcoal, and chloroform after separating by filtration. Then the solution allowed for slow evaporation to achieve good crystalline caffeine

Fig. 1: Scheme of Caffeine estimation

RESULTS AND DISCUSSION:

All the ten samples were collected from the Darjeeling district of West Bengal. Of them, six samples from Darjeeling and two samples from Dooars and one sample each from Siliguri and New Jalpaiguri. Based on the reported caffeine isolation protocol, the following tea samples were used for caffeine estimation. They are Darjeeling-BPS, New Jalpaiguri brown leaves, Darjeeling SFT, Darjeeling green tea, Darjeeling black tea, Siliguri tea, Dooars tea, Dooars dust tea, Darjeeling silver tip and Darjeeling CTC BP.

The caffeine quantity of all samples was estimated by adopting the same protocol and the results are reproduced in Table 1 along with image of appropriate sample. This table provides a clear understanding of the caffeine percentage of all the tested tea samples.

Table 1: Estimation of caffeine from Darjeeling District tea samples 1-10.

The bar graph (Fig. 2) better understanding of the percentage of caffeine in the tested tea samples

Fig. 2: Bar graph between percentage of Caffeine and Tea samples of Darjeeling district.

A close analysis of the table and graph clearly indicate the the Green Tea (Sample 4, 2.67%),Siliguri tea (Sample 6, 2.12%), Darjeeling BPS (Sample 1, 2.02%) and Darjeeling CTC BP (Sample 10, 2.02%) possess more than two percentage of caffeine. Of them However, the New Jalpaiguri variety (Sample 2, 0.77%) registered the lowest quantity of caffeine among the tested samples.

CONCLUSION:

Ten samples were chosen from the Darjeeling district of West Bengal, India for the assessment of caffeine quantity by a simple method. Among the ten samples, six samples chosen from Darjeeling and two samples from Dooars and one sample each from Siliguri and New jalpaiguri. All the samples were subjected to a non-laborious chemical method using lead acetate and lead oxide to estimate the quantity of caffeine present. As a result, it has been observed that “Darjeeling Green Tea (Sample 4)” is the best one among the ten samples, which has 2.67% of caffeine.

REFERENCES:

1. Available at http://www.chemistrydaily.com/chemistryCaffeine#Chemical_properties

2. Available at https://en.wikipedia.org/wiki/Caffeine

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5. Available from http://www.skincancer.org/media-and-press/press-release-2015/coffee

6. Available from http://www.webmd.com/melanoma-skin-cancer/news/20120702/caffeine-linked-to-lower-skin-cancer-risk Markovic SN, Erickson LA, Rao RD, et al. Malignant melanoma in the 21^st century, part 2: staging, prognosis, and treatment. Mayo Clin Proc. 2007;82(4):490–513.

7. Niel B, Elizabeth M, Gizem K, Allen C, Joseph MW, Maria L, John PT, Michael AY. Post-study caffeine administration enhances memory consolidation in humans. Nature Neuroscience. 2014; 17: 201–203.

8. Wardle MC, Treadway MT, Wit, HD. Caffeine increases psychomotor performance on the effort expenditure for rewards task. Pharmacol. Biochem. Behav. 2012; 102(4): 526-531.

9. Dhaka NP, Kumar K. To isolate caffeine from the given tealeaves laboratory skills-chemistry. 1^st ed. India: Pradeep Publications; 2006. p.124-5.

Received on 19.01.2018 Modified on 12.02.2018

Research J. Pharm. and Tech 2018; 11(5):1981-1983.

DOI: 10.5958/0974-360X.2018.00368.2