By Dr Siddhartha Sharma
The pandemic that COVID-19 has created around the globe needs no description. As there is no vaccine yet or a specific drug against this virus, various suggestions, speculations and probabilities have been doing the round. Amongst these was the use of Green Tea for curing the disease in China, which subsequently many authorities have refuted.
However, it would be interesting to study what normal therapeutic affects does the compounds viz. methylxanthine, theophylline and theobromine which are present in tea, coffee and cocoa have. This review article takes a look at the available data pertaining to the contribution of xanthine and other tea extracts in the treatment of respiratory diseases caused by viral infection in general.
At the outset, it will be pertinent to clarify that this study does not recommend anything with regard to cure or protection of COVID-19, but wish to bring forward to researchers, some existing reports for further focused research in this field relating to COVID-19 due to the beneficial properties of these compounds.
Properties of tea
Tea, the finished product of the plant Camellia sinensis, mainly contains polyphenols (catechins) and caffeine amongst other phytochemicals. These are present in Green Tea, Oolong Tea and Black Tea. Black tea contains two other characteristic compounds called Theaflavin and Thearubigin formed due to the oxidation of part of the polyphenols.
Caffeine (trimethylxanthine) occurs with small quantities of the ophylline and the obromine, the compounds generally called methylxanthine. Apart from tea, these compounds are present in coffee, cocoa / chocolate in varying proportions. All of these compounds have several physiological effects on the human body and drinking 5-10 cups of tea can help in assimilating them. Huge experimental efforts in recent years have confirmed that methylxanthines have a great potential in prevention, therapy and/or management of a variety of diseases.
Methylxanthines, abronchodilators, display benefits in diseases involving cell death in the nervous system and in neurodegenerative and respiratory diseases, diabetes and cancer. Other reports mention that methylxanthines in coffee, tea and cacao have protective effects on the respiratory system and beneficial in diseases of the airways with increasing prevalence in children, in particular in asthma and cough.
Theobromine and caffeine improve lung function and produce bronchodilatation in asthma patients and found to suppress cough without the side effects displayed by other antitussive drugs, such as codeine. Theobromine stimulates the heart, being a vasodilator, meaning it can open up the blood vessels and cause the blood pressure to drop.
Clinically evaluated in different countries by Texas-based PernixTM and London-based SeekTM, theobromine is a first-in-class non-codeine non-opioid drug for cough that has successfully completed trials and regulatory review in South Korea (sold as AnyCoughTM).
Theophylline has been used for various decades in the treatment of asthma and is still among the most prescribed drugs. Theophylline also has a bronchodilator action and decreases inflammation underlying asthma and is used to prevent and treat wheezing, shortness of breath, and chest tightness caused by asthma, chronic bronchitis, emphysema, and other lung diseases. It relaxes and opens air passages in the lungs, making it easier to breathe.
Experiments showed that both black and green teas and their isolated constituents contribute to the preventive and therapeutic armamentarium against HIV infection in humans as EGCG (epigallocatechin gallate) was found to exhibit inhibitory effects on the life cycle of HIV-1. It was also proved experimentally that the antioxidant properties of tea can inactivate influenza virus. Adenovirus infects the mucous membranes of the respiratory and urinary tracts as well as the linings of the eyes and intestine causing conjunctivitis, gastroenteritis, and other symptoms. Tea catechins and tea infusions were found to inhibit both adenovirus infection and the viral protein adenain.
From the above data, which is not exhaustive, it can be seen that the biochemicals present in tea, have been found to be clinically beneficial against a number of pathogens which infest the human body.
Caffeine, composed of methylxanthine, theophylline, theobromine along with the polyphenols seem to have curative properties for a number of bacteria and virus inflicted diseases including those affecting the respiratory and cardiovascular system. There are also reports of methylxanthine and theobromine being used as a medicine against respiratory diseases caused by influenza virus, asthma and also in managing infections by HIV-1.
Methylxanthine is considered to have a bronchodilating effect that could be effective in managing asthma and other respiratory diseases. Methylxanthine has been reported to be effective against gram-positive bacteria. Pneumonia is one disease caused by a gram-positive bacterium.
Both Theobromine and Theophylline have similar properties as methylxanthine, according to the reports and are also used to treat cases relating to asthma and other related respiratory / lung diseases. Over and above this, the obromine being a vasodilator can regulate the blood pressure. Crude tea extract has been reported to be effective against Bovine-corona virus. The four the aflavins in tea have the ability to govern viral infectivity. Therefore, under the present circumstances, more focused research is required to be carried out to see if the bio-chemicals of tea can be used in any way against COVID 19.
Studies have to be carried out to see if tea when used as a beverage can help or certain chemicals have to be extracted from the beverage and can be used. The bio-synthesis of caffeine by tea leaf extracts is also possible. Availability is not an issue with tea being the most commonly available and accessible product. The concentrations of bio-chemicals are high in good quality tea but reduce with drop in quality. However, as the virus causing Covid19, SAR-CoV-2 is a new mutant, it has to be seen whether the phytochemicals of tea works against this virus also, as in others. Moreover, it has to be investigated whether tea extracts can be used as a supporting drug or used to improve the general immune system during Covid19 infection which by itself should be beneficial in combating the disease.
(The author is former senior general manager at J Thomas & Co. Pvt. Ltd)