One recent study of the properties of Hong Cha (or in many cultures incorrectly named “black tea”) stood out to me.
Mohammad and Flayyih (2021) investigated alcoholic extracts of black tea to act as an antimicrobial against Staphylococcus aureus.
Staphylococcus aureus widely and prolifically colonises human upper respiratory airways , membranes and skin. It is considered a commensal pathogen, meaning its interactions with the human organism is mostly tolerated and benign. However frequent mutation or adaptive strains that are capable of binding with antibodies or produce toxic proteins have led to worldwide concerns.
MRSA or methicillin resistant staphylococcus aureus has been a major concern for at least 20 years now, impacting upon health care delivery and human health in normally healthy populations. It has also brought us upto date with the threat human populations face from the overuse of antimicrobials in healthcare and emergence of antibiotic resistant strains of otherwise mild pathogenic agents.
Mohammad and Flayyih (2021) found that alcoholic extraction of black tea was superior than vancomycin in skin infections, it’s effect on the expression of virulence gene expression of Staphylococcus aureus neign note worthy. Vancomycin is an antibiotic medication of choice for infections caused by methicillin-resistant bacteria.
The impact of this study is in regard to the benefits of tea preparations for developing post-surgical or burns related wound treatment and healing. However equally it supports hundreds of years of folk medicine use of water extracts of tea in topical wound treatment as well as for likely upper respiratory and oral diseases caused by Staphylococcus aureus infections.
Whilst Hong Cha has been identified as a potential for developing new health care applications, similarly less processed green tea extracts have been identified as offering new applications for wound healing. Much of recent studies have focused on green tea extract role as anti-inflammatory. Whilst this is less directly tackling antibiotic resistant pathogens there is a key role to play where anti-inflammatory medicine used in a timely manner can halt the prevalence of bacteria due to depriving them of the conditions that accelerate their numbers. As part of wound healing, the inflammatory cycle can lead to the leaking and breakdown of tissues that provide a rich source of nutrients for bacterial growth.
Xu et al (2021) postulated that the anti-inflammatory effect of Epigallocatechin gallate (EGCG) could be optimized if the topical product was applied for a short period at an appropriate time of wound healing.
EGCG is a catechin most abundant in green tea and green tea extracts. It’s absorption through the human gut is actually minimal but it’s antioxidant properties are profound, perhaps it’s greater benefit being gained through topical applications. It’s anti-oxidative properties allow it to interact with the inflammatory cycle of wound healing in effective ways.
EGCG was reported to have the inhibitory effects on the infiltration of neutrophils. Whilst neutrophils are important in the front-line defense against invading pathogens and immune response, actively undertaking phagocytosis of bacteria at wound sites, they also produce cytokines. Cytokines are small secreted proteins released by neutrophils that interact with cells and key processes of inflammation and wound healing. Too many cytokines can lead to adverse health effects as recently discovered in COVID-19 infections, at tissue level too much pro-inflammatory cytokines released from neutrophils lead to delayed healing and therefore increased risk of bacterial infections and bacterial resistance. It is the role of EGCG and it’s timely interactions and neutrophil inhibition that can potentially prevent antibiotic resistant strains of bacteria developing at wound sites.
Mohammad AJ, Flayyih MT. The therapeutic role of Alcoholic Extract of Black Tea (Camellia sinensis) against Infection with Staphylococcus aureus.
Xu FW, Lv YL, Zhong YF, Xue YN, Wang Y, Zhang LY, Hu X, Tan WQ. Beneficial effects of green tea EGCG on skin wound healing: A comprehensive review. Molecules. 2021 Oct 11;26(20):6123.