Green tea (Hoa Tran , University of Mississippi School of Pharmacy

Hoa Tran, Student pharmacist Spring 2022

Scientific Name: Camellia Sinenesis Scientific Family: Theaceae Common names: Green tea; Green tea extract; Tea

Common Use

Use: Green tea has beneficial effects on some heart disease risk factors, including blood pressure and cholesterol. It also plays a role in metabolic syndrome because it could impact body weight, glucose homeostasis, and other cardiovascular risk factors. Some studies show green tea can prevent cancer, stroke, and chronic obstructive pulmonary disease (COPD). Topical as well as oral formulations could protect skin from ultraviolet (UV) damage.1,2

Effectiveness

FDA Approved Indications: approved sinecatechins (Veregen) topical ointment that includes extracted components of green tea leaves and is used for the treatment of genital warts.1

Dosing

Daily intake of three to five cups/day (720 to 1,200 mL) of green tea will produce at least 180 mg of catechins and at least 60 mg of theanine. Should not take green tea extract on an empty stomach due to hepatotoxicity from excessive levels of epigallocatechin gallate (EGCG).

Background history

The origin of green tea began in China. Chinese Emperor Shennong accidently drank water with dead tea leaf and found that the flavor refreshing.

Mechanism of Action

The anti-tumor mechanism of green tea appears to include the induction of apoptosis by EGCG through production of H2O2, inhibition of cell-cycle progression, inhibition of nuclear factor kappa B (NF-kB), activation of the mitogen0activated protein kinase cascade, and binding to a 67 kDa laminin receptor.

Contraindications: Use caution for hepatic failure patients.1

Hypersensitivity and Allergic Reactions:

Hepatic Impairment: People with liver disease should talk to their provider before taking green tea extract products. Discontinue use and consult a health care provider if you develop symptoms of liver trouble such as dark urine, abdominal pain, or jaundice.2

Pregnancy: take up to 6 cups per day (no more than about 300 mg of caffeine). Drinking more than 6 cups a day may be unsafe and increase the risk of negative effects. It could also be associated with folic acid deficiency, which will increase the risk of birth defects. Caffeine can also affect a breastfeeding infant when caffeine passes into breast milk. The FDA advises those who are or may become pregnant to avoid caffeine.2

Geriatric Use: green tea has shown the significance of a lower prevalence of depressive symptoms, independent of other risk factors.4 There are no reports of clinical toxicity from daily tea consumption. The most common adverse event associated with green tea extract includes headaches, dizziness, and GI symptoms.

Toxicity

High amount can link with liver injury.

Interaction

At high doses, it has been shown to reduce blood levels and effectiveness of the drug nadolol, a beta-blocker used for high blood pressure and heart problems.

Professional Opinion:

Green tea has been used in Asian countries for medicinal purposes for thousands of years. Much research has been shown that green tea shows many benefits, including impact on body weight, glucose homeostasis, other cardiovascular risk factors, preventing cancer, stroke, and chronic obstructive pulmonary disease. Green tea also interacts with many medications, which reduces the medication’s effects. Therefore, the FDA recommends talking to a healthcare provider before taking green tea. Especially, pregnant women should avoid green tea due to birth defects. Do not use it in high amount and too often.

~ H. Tran

Reference

1.Lexicomp, 03 Mar. 2022, https://online.lexi.com/lco/action/doc/retrieve/docid/fc_rnp2/3750176?cesid=8ygHUs1WRs0&searchUrl=%2Flco%2Faction% 2Fsearch%3Fq%3Dgreen%252520tea%26t%3Dname%26va%3Dgreen%252520tea. Green tea. Accessed 3 Mar. 2022.

2.National Center for Complementary and Integrative Health, 3 Mar. 2022, https://www.nccih.nih.gov/health/green-tea. Accessed 3 Mar. 2022.

3.Kajita, Naoki et al. “Green tea-induced anaphylaxis: The first pediatric case report.” Allergology international: official journal of the Japanese Society of Allergology vol. 70,4 (2021): 507-508. doi:10.1016/j.alit.2021.05.007