Methylxanthine content in hot drinks consumed in the State of Kuwait

Author: Hetham Al-Obaidi ¹ and Mohammad Afzal ^2*

Received 15 September 2009, accepted 2 January 2010.

Abstract

Apart from four major catechins present in Camellia sinensis (tea), four major methylxanthines are also present in tea aqueous extract. Caffeine with its structural similarity to uric acid is the predominant methylxanthine in tea and it is known to contribute to hypertension and obesity leading to diabetes. Caffeine intake from tea, soft drinks and candies may be contributing to high level of obesity and diabetes prevalent in Kuwait. There are a variety of hot drinks that are traditional to the culture of Kuwait and their caffeine content has not been established. In this study we have undertaken to establish caffeine content in traditional hot drinks used in Kuwait and have found that Arabic Gahwa, a very popular hot drink in Kuwait, has one of the lowest caffeine content among coffee drinks but its high frequency of consumption may have an additive effect on caffeine intake. Caffeine content of commercial brands and herbal teas used in Kuwait has also been established and found that Rabea black tea had the highest caffeine and theobromine content, while Red label black tea has the lowest caffeine. Reverse phase high performance liquid chromatography (HPLC) was used to establish methylxanthine content in different tea aqueous extracts. A comparison of caffeine content in various hot drinks is presented.

Key words: Tea, coffee, methylxanthine, caffeine, theophylline, theobromine, HPLC.