Anti-infective and Antineoplastic properties of Green Tea Catechins: Examining the Therapeutic Risk-Benefit ratio

Background: Green tea is a commonly used dietary supplement and food product. Green tea contains many polyphenolic compounds known as green tea catechins (GTCs). There are numerous reports exploring the potential benefit of using green tea catechins as chemotherapeutic agents to treat neoplastic disorders and infectious processes. The prevalence of cancer diagnoses, bacterial infections, and viral diseases that include SARS-CoV-2 have led to increased interest in GTCs as a therapeutic option in patients suffering from these conditions. Objective: This concise review explores the evidence related to the therapeutic use of GTCs to treat neoplastic disorders as well as bacterial and viral infections. Methods: PubMed, NIH, OVID online databases were utilized to retrieve relevant scientific literature that address GTCs role in treating cancer and infectious disease. Results: While there are preliminary data indicating potentially adventitious properties of GTCs, there is a paucity of large prospective clinical trial data to support the use of GTCs in a therapeutic capacity to treat these disease processes. There are documented instances of GTCs interacting with medications indicated to treat neoplastic diseases. Conclusions: Currently, it appears the therapeutic benefit of using GTCs is outweighed by the potential risks.

Green Tea: Conventional Facts and its Frontier Prospect on Health- A review

Green tea obtained from the leaves of Camellia sinensis (L.) Kuntze having potential health benefits. It contains significant amounts of antioxidant and is considered as world healthiest drink. Polyphenols in tea are thought to exhibits anti-carcinogenic and anti-inflammatory effects. Green tea catechins acts as immune modulators in immune dysfunction and also play a role in protection from degenerative diseases. Intake of green tea catechins suppress high fat diet induced obesity, prevent lipid and glucose metabolism disorders and reduce risk of coronary heart disease. Green tea constituent epigallocatechin-3-gallate (EGCG) is a potential antioxidant that shows protective effects against photo toxicity and photo carcinogenesis. In vitro animal experiments have suggested that polyphenols in green tea protect from lung cancer by their antioxidant and antimutagenic properties. This study chiefly highlights the convenience of green tea on health and propagates its further prospects.

Anti-Influenza with Green Tea Catechins: A Systematic Review and Meta-Analysis

Influenza is one of the most serious respiratory viral infections worldwide. Although several studies have reported that green tea catechins (GTCs) might prevent influenza virus infection, this remains controversial. We performed a systematic review and meta-analysis of eight studies with 5,048 participants that examined the effect of GTC administration on influenza prevention. In a random-effects meta-analysis of five RCTs, 884 participants treated with GTCs showed statistically significant effects on the prevention of influenza infection compared to the control group (risk ratio (RR) 0.67, 95%CIs 0.51–0.89, P = 0.005) without evidence of heterogeneity (I2= 0%, P = 0.629). Similarly, in three cohort studies with 2,223 participants treated with GTCs, there were also statistically significant effects (RR 0.52, 95%CIs 0.35–0.77, P = 0.001) with very low evidence of heterogeneity (I2 = 3%, P = 0.358). Additionally, the overall effect in the subgroup analysis of gargling and orally ingested items (taking capsules and drinking) showed a pooled RR of 0.62 (95% CIs 0.49–0.77, P = 0.003) without heterogeneity (I2= 0%, P = 0.554). There were no obvious publication biases (Egger’s test (P = 0.138) and Begg’s test (P = 0.103)). Our analysis suggests that green tea consumption is effective in the prophylaxis of influenza infections. To confirm the findings before implementation, longitudinal clinical trials with specific doses of green tea consumption are warranted.

Green Tea Catechin Association with Ultraviolet Radiation-Induced Erythema: A Systematic Review and Meta-Analysis

Catechins are a part of the chemical family of flavonoids, a naturally occurring antioxidant, and a secondary metabolite in certain plants. Green tea catechins are well recognized for their essential anti-inflammatory, photo-protective, antioxidant, and chemo-preventive functions. Ultraviolet radiation is a principal cause of damage to the skin. Studies observed that regular intake of green tea catechins increased the minimal dose of radiation required to induce erythema. The objectives of this systematic review and meta-analysis are to determine the effectiveness of green tea catechins in cutaneous erythema and elucidate whether green tea catechin consumption protects against erythema (sunburn) inflammation. A comprehensive literature search was conducted to identify the relevant studies. Two researchers carried out independent screening, data extraction, and quality assessment according to the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). The pooled effect of green tea catechins on protection against erythema was assessed using approaches fixed-effects or random-effects model to quantify the effectiveness of green tea catechins in the erythema dose–response. Studies not be included in meta-analyses were summarized narratively. Six randomized controlled studies of enrolled studies regularly administrated green tea catechins orally for 6 to 12 weeks involving healthy volunteers comprising a total of 100 participants were included in the analysis. The results revealed green tea catechins have favorable protection against erythema inflammation even at increased minimal erythema dose (MED) of ultraviolet radiation. Meta-analysis results confirm oral supplementation of green tea catechins is highly effective at low-intensity ultraviolet radiation-induced erythema response (MED range; 1.25–1.30) compared to placebo, showing a significant pooling difference (p = 0.002) in erythema index (SMD: −0.35; 95% CI, −0.57 to −0.13; I2 = 4%, p = 0.40) in the random-effects model. The pro-inflammatory signaling pathways through oral supplementation with green tea catechins are an attractive strategy for photo-protection in healthy human subjects and could represent a complementary approach to topical sunscreens. Therefore, studies that involved green tea catechin in topical applications to human subjects were also evaluated separately, and their meta-analysis is presented as a reference. The evidence indicates that regular green tea catechin supplementation is associated with protection against UV-induced damage due to erythema inflammation.

Advances in Nanodelivery of Green Tea Catechins to Enhance the Anticancer Activity

Cancer is one of the leading causes of death globally. A variety of phenolic compounds display preventative and therapeutic effects against cancers. Green teas are rich in phenolics. Catechins are the most dominant phenolic component in green teas. Studies have shown that catechins have anticancer activity in various cancer models. The anticancer activity of catechins, however, may be compromised due to their low oral bioavailability. Nanodelivery emerges as a promising way to improve the oral bioavailability and anticancer activity of catechins. Research in this area has been actively conducted in recent decades. This review provides the molecular mechanisms of the anticancer effects of catechins, the factors that limit the oral bioavailability of catechins, and the latest advances of delivering catechins using nanodelivery systems through different routes to enhance their anticancer activity.