More Theaflavins Please!

During the oxidation of tea leaves, which is the main process involved in the production of black tea, over 75% of a tea leaf’s catechins (a type of polyphenol I discussed in my previous blog post) are transformed into ‘polyphenol derivatives’. These include: theaflavins, thearubigins, and also theasinensins. Theaflavins and thearubigins are predominantly found in black tea, while theasinensins are predominantly found in oolong tea. 

In this blog post I will talk about the health benefits of one of these tea compounds - theaflavins. But first, I will need to get a little bit sciencey with you, and go over some of the basics. 

WHAT ARE THEAFLAVINS?

So far, more than 25 theaflavins have been found in black teas. They account for 2-6% of black tea dry matter. 

The most important theaflavins found in black teas are: 

• theaflavin
• theaflavin-3-gallate
• theaflavin-3’-gallate
• theaflavin-3,3’-digallate

Theaflavins are orange or orange-red pigments which determine the specific colour, taste and aroma of black teas. They create the mouthfeel of astringency and the long-lasting coating sensation in the mouth and at the back of the throat. Theaflavin content also correlates positively with tea liquor brightness – a valued marker in the marketability of tea. 

To put it simply, theaflavins are ultimately formed through the process of oxidation, specifically when the tea leaf’s catechins come into contact with oxidation enzymes.

SO WHAT ARE THE HEALTH BENEFITS OF THEAFLAVINS?

Here are just a few…  

Antioxidant Activity

Theaflavins are characterised as antioxidants that engage in free radical scavenging activity. In fact, theaflavin-3-gallate, theaflavin-3’-gallate, and theaflavin-3,3’-digallate are stronger antioxidants than the catechin epigallocatechin gallate (EGCG) that I discussed in my previous blog post, which is considered one of the most powerful antioxidants in foods. 

Anti-Mutagenic Activity

Mutagenic activity is the genetic mutation of DNA of cells caused by chemicals or radiation. A study on male rats found antimutagenic effects of theaflavins on heavy metal-induced testicular toxicity, as well as reduction in cell damage to testis, increased testosterone levels, and improved sperm characteristics (Wang et al. 2012). 

Anti-Obesity Activity

Theaflavins have been found to prevent obesity through the suppression of ‘lipogenesis’ (the metabolic formation of fat), inhibition of fat storage in liver, and the production of fatty acids which aid in weight loss (He 2017).

Anti-Inflammatory and Anti-Cancer Activity

Theaflavin-3’-gallates have been found to have anti-inflammatory and pro-apoptotic (causing cell death) effects on cancer cells associated with inflammation (Gosslau et al. 2011). Theaflavins have also been suggested to prevent oral cancers and tooth decay (Lee et al. 2004), prostate cancer (He 2017), and liver cancer (Weerawatanakorn et al. 2015).

Anti-Microbial Activity

Theaflavin-3,3’-digallates had been found in epidemiological studies (the study of the distribution of health-related conditions in populations) to be a strong inhibitor of ‘3C-like protease’ that is found in coronaviruses. (The protease is an enzyme essential for viral replication.) Theaflavins were also found to have strong inhibitory effects on influenza and HIV viruses by blocking the initial steps of infection (He 2017). 

Various concentrations of theaflavins have also been found to have strong antibacterial effects on Stenotrophomonas maltophilia and Acinetobacter baumannii that are pathogens resistant to multiple antibiotics (Betts et al. 2011). 

 LAST WEEK

Now you know some of the special health benefits you get to enjoy from drinking black tea. It turns out it’s not all about green tea!

Last week I shared with you some of the benefits of drinking oolong tea as we delve into the science behind the compound of theasinensins. I have something exciting planned next week so stay tuned!

Jaq James has a botany diploma and has studied tea culture and tea science in the birthplace of black tea and oolong tea - Mount Wuyi in China.