Genital Warts

Genital warts are thought to be caused by the epidermotropic human papillomavirus (HPV). More than 100 types of double-stranded HPV viruses have been identified but the list is ever increasing. They are common, developing in about 67% of those who have sexual contact with an infected partner. The incubation period is generally regarded to be 3 months.

Sometimes during pregnancy genital warts grow and/or bleed, much to the puzzlement of doctors. Although it is rare, complications may develop if the warts grow and obstruct the birth canal or perineum, making delivery or episiotomy more challenging.

There are few effective treatment options so research is underway to improve treatment of this viral condition. Catechins in green tea have been identified at powerful antioxidants, anti-inflammatory agents and antimicrobial treatments. Researchers are looking at the use of a sinecatechin ointment, which contains catechins from green tea.1 Researchers tested the effects of placebo, 10% sinecatechin or 15% sinecatechin containing ointments. One of 3 ointments was applied 3 times daily either until the warts cleared up or 16 weeks lapsed.

A follow up assessment of wart recurrence was conducted after a 12-week period when no wart treatment was used. They observed that around 50% of the cases of genital warts were cured whether using the 10% or 15% sinecatechin ointment, compared to 30% cure rate for the placebo ointment. A recurrence rate of 7% was observed in patients using sinecatechin ointment. They also concluded that the treatments are well-tolerated by patients.

A topical ointment called Polyphenon E (made by MediGene AG, Munich, Germany) has been tested as a treatment for genital warts.2 Two strengths (10% or 15% Polyphenon E) were randomly assigned to study subjects along with a placebo treatment. Results were similar to the study using sinecatechins, with the higher strength ointment providing clearance from warts in 53% of the cases and the lower strength ointment clearing up 51% of the cases. They also noted that effectiveness varied by gender. Women experienced 60% effectiveness and men gained 45% effectiveness. Follow up assessments were made and the recurrence rate was less than 7%.

Candida albicans

Candida albicans is another bothersome condition that can be treated with green tea catechins during pregnancy. It is a fungal species that normally exists in mucous membranes like the mouth, stomach and vagina. Under certain conditions the environment of the mucous membranes can change, or the immune system can become depressed leading to rapid growth of Candida albicans. The end result can be the development of disease or infection, neither of which is desirable.

Until green tea was credited with antimicrobial properties the typical course of treatment was topical application of antifungals from the azole family. These ointments gave limited results because they are not toxic to fungi. Their mode of action is to inhibit enzymes that produce cholesterol but they are not effective enough to prevent recurrences.

EGCG has been found to inhibit folate activity which was found to be effective against Candida albicans by scientists in Spain.3,4 Folate metabolism in Candida albicans was disrupted by EGCG and prevented the fungi from propagating. An additive effect on growth and survival inhibition of Candida albicans was observed when EGCG was administered along with topical azole antifungals. This means that the combined treatment was more effective against the fungi than either treatment alone.

1Sinecatechins, a Defined Green Tea Extract, in the Treatment of External Anogenital Warts (2008). Silvio, T; Swinehart, JW; Thielert, C; Tawfik, H; Mescheder, A and Beutner, KR. Obstetrics & Gynecology 2008. 111:1371-1379.

2Topical Polyphenon E in the treatment of external genital and perianal warts: a randomized controlled trial. Stockfleth E, Beti H, Orasan R, Grigorian F, Mescheder A, Tawfik H, Thielert C. Br J Dermatol. 2008.158(6):1329-38.

3Influence of green and black tea on folic acid pharmacokinetics in healthy volunteers: potential risk of diminished folic acid bioavailability. Alemdaroglu, NC; Dietz, U; Wolffram, S; Spahn-Langguth, H and Langguth, P. Biopharm Drug Dispos. 2008. 29(6):335-48.

4Effects of folate cycle disruption by the green tea polyphenol epigallocatechin-3-gallate. Navarro-Perán, E; Cabezas-Herrera, J; Campo, LS and Rodríguez-López, JN. Int J Biochem Cell Biol. 2007. 39(12):2215-25.

Pregnant? Skip the Tea, Take the Supplement? Or Maybe Not…

Green tea (Camellia sinensis) has been credited with improving health benefits for conditions as diverse as aging, cancer, inflammatory diseases, cardiovascular disease, autoimmune disorder, microbial infections and diabetes. The active ingredients in green tea are polyphenols in the catechin sub-group. The most noteworthy catechin in green tea is epigallocatechin gallate (EGCG) because it is present in the highest quantities in green tea and has been reported to be the most beneficial. There are many different green tea formulations being created and tested as replacements for drinking green tea, since the EGCG in tea is metabolized relatively quickly in the body. Most of the preparations do not contain caffeine. The following research results make it clear that extreme caution should be taken before using any herbal preparations, including things as seemingly safe as green tea.

Teavigo™

Teavigo™ is an EGCG preparation currently on the market that contains no caffeine. Researchers tested its effects on rat fetal development to evaluate potential effects of EGCG on the fetus.1 Teavigo, containing more than 91% pure EGCG was administered to gestating rats during organ creation and development. To study the potential of EGCG causing birth defects, pregnant rat diets were supplemented with 1400, 4200 or 14,000 mg EGCG per kilogram of rat weight. Mothers and fetuses showed no signs of toxicity at any concentration of EGCG. In a two-generation study, rats were fed 1200, 3600 or 12,000 mg EGCG per kilogram of food and there were no detrimental effects on reproduction or fertility. The 12,000 mg EGCG treatment resulted in reduced growth rate of offspring and a slight increase in rat pup mortality. Reduced growth rate was also observed at the 3600 mg EGCG per kilogram of food rate in the second generation of rats.

Green Tea Extract

Another herbal preparation is green tea extract (GTE) that comes from steeping a strong tea and washing the leaves with alcohol to ensure complete removal of catechins from the leaves. Scientists reported in 2009 results of a study testing the effect of GTE on incidence of birth defects in a rat model treated with a teratogenic amide.2 Pregnant rats were given 100 mg GTE per kg of rat weight from days 6-12 gestation. A cyclophosphamide was given to the pregnant rats 1 hour after the last GTE treatment, at a dose of 11 mg per kg rat weight.

Pregnancy was stopped on the 20th day gestation and maternal and fetal defects were determined following Cesarean birth of the pups. Fetal and placental weights were depressed. More significantly, 95% of live fetuses exhibited skull and limb defects, 41% had cleft palate and ureteric dilation and 100% had skeletal abnormalities. Repeated dosage of GTE during pregnancy can lead to birth defects and reduced fetal and placental weights.

As always, its crucial to consult with your healthcare provider before ingesting any non-food preparations, including items like green tea that are generally regarded as safe by the US Food and Drug Administration.

1Safety studies on epigallocatechin gallate (EGCG) preparations. Part 3: Teratogenicity and reproductive toxicity studies in rats, Isbruckera, RA; Edwards, JA; Wolzb, E; Davidovichc, A and Bauschb, J. Food and Chemical Toxicology. 2006. 44(5): 651-661.

2Green tea extract increases cyclophosphamide-induced teratogenesis by modulating the expression of cytochrome P-450 mRNA. Park D, Jeon JH, Shin S, Joo SS, Kang DH, Moon SH, Jang MJ, Cho YM, Kim JW, Ji HJ, Ahn B, Oh KW, Kim YB. Reprod Toxicol. 2009. 27(1):79-84.

Anti-Aging

The sun causes skin to age by altering connective tissue. Specifically, exposure to UV light leads to lipid, enzyme and oxygen free radical (OFR) formation. All of these factors can damage the cell structure of connective tissue in the skin. Natural skin aging is attributed to decreased skin elasticity as we get older.

Catechins are polyphenols in green tea (Camellia sinensis) that are effective against damage to collagen and elastin in skin cells. Collagen comprises some 80% of the content of skin and is responsible for maintaining the structural stability of the skin. Elastin content in skin ranges between 2 and 4% and is responsible for the elasticity of skin.1

The catechin epigallocatechin gallate (EGCG) and other catechins in green tea inhibit collagenase and elastase.2 These enzymes are the active factors that break down the proteins of collagen and elastin in skin. The characteristic signs of aging; wrinkles, changes in pigmentation and changes in skin thickness are the results of these enzymes.

In a study of anti-aging properties of extracts from 21 plants, Tamsyn and colleagues found promising results for the use of green tea to slow the telltale signs of aging.1 Athough they did not find green tea extracts (GTE) to exhibit significant anti-elastase effects (10% reduction), GTE reduced collagenase activity by about 47%. In comparison, white tea extracts showed 89% collagenase inhibition and 87% elastase inhibition. When antioxidative power of plant extracts was tested with a superoxide dismutase (SOD) assay, white tea produced an 88% reduction of oxygen radicals and green tea resulted in an 86% reduction. When the SOD enzymes work on free radicals the end products are oxygen molecules (O2) and hydrogen peroxide (H2 O2).

Protection Against Damage from UV Light

EGCG is the catechin in green tea present in the highest concentration and that is the most promising as a chemopreventative agent for the treatment of cancer. Various studies have led to the common knowledge that exposure to UV light can cause melanoma and non-melanoma skin cancers.

A 2009 study has shown that both green and white tea extracts have protective qualities from UV sun damage to human skin.4 Skin samples from study participants were treated with tea extracts and then exposed to UV light. As compared to non-treated control skin, both tea extract treatments prevented the characteristic inflammation and redness associated with sun damage. Scientists verified that the protection was not related to sunscreen effects because a test of the sun protection factor (SPF) determined an SPF of 1. More human trials are needed, but it seems that white or green tea extracts may be topically applied along with sunscreen to prevent the symptoms of UV damage on skin.

Scientists have yet to pinpoint definitive dosages and formulations of green tea components for oral or topical preparations to stop of reverse skin aging and damage from the sun. However, new findings are published nearly monthly in the scientific journals as scientists learn more about the mechanisms of skin aging, damage and repair and actions of green tea on cellular processes. Pharmaceutical preparations are also being developed and tested and perhaps soon they will be on the market.

1Anti-collagenase, anti-elastase and anti-oxidant activities of extracts from 21 plants.

Tamsyn, SA; Thring, PH and Declan P Naughton. BMC Complement Altern Med. 2009. 9:27.

2Inhibition effects of (+)-catechin-aldehyde polycondensates on proteinases causing proteolytic degradation of extracellular matrix. Kim, Y; Uyama, H and Kobayashi, S. Biochem Biophys Res Commun. 2004. 320:256–261.

3Skin photoprotection by green tea: antioxidant and immunomodulatory effects. Katiyar SK. Curr Drug Targets Immune Endocr Metabol Disord. 2003 Sep;3(3):234-42.

4Topical application of green and white tea extracts provides protection from solar-simulated ultraviolet light in human skin. Camouse MM, Domingo DS, Swain FR, Conrad EP, Matsui MS, Maes D, Declercq L, Cooper KD, Stevens SR, Baron ED. Exp Dermatol. 2009. 18(6):522-6.

Rheumatoid arthritis (RA) is an autoimmune disease in which cartilage in the joints is inflamed and leads to bone mass reduction. RA can also cause inflammation of organs. The reason RA exists is the body’s production of antibodies toward its own tissue, or attacking itself. White blood cells infiltrate the joints and organs causing inflammation, and bone loss. Chemokines are a group of proteins that among other actions, cause inflammation and can play a role in infectious diseases and cancer.

To control RA researchers have concentrated on stopping chemokine activity and the inflammation the protein is responsible for. The site of the protein activity is in cells called fibroblasts that make and distribute collagen in the body. When the body turns against itself and overproduces collagen in the fibroblasts causing inflammation, the result can be RA.

A catechin in green tea (from the Camellia sinensis plant), epigallocatechin-3-gallate (EGCG) has been studied as an anti-inflammatory agent because it can regulate proteins and enzymes responsible for various cell growth factors. Pakozdi and Koch reported that

EGCG reduced the activity of a specific protein labeled MCP-1.1 They also found another specific protein that EGCG blocked labeled MCP-2. Finally, EGCG inhibited activation and distribution of joint fibroblasts, leading to reduced production of collagen. These results indicate a possible use of EGCG for inhibiting the causes of joint inflammation and destruction in RA.

Scientists reported in 2010 that green tea extract (GTE) suppressed cartilage production and inhibited the production of proteins that activate white blood cells.2 Research in human models is needed to verify GTE as a viable anti-inflammatory therapy for RA.

Green Tea and Osteoarthritis

Osteoarthritis (OA) is an inflammatory disease that is primarily age-related. Cartilage cells are activated by certain metabolic products to produce cartilage. Under normal conditions, these cells are responsible for balancing growth and destruction of cartilage structure and tissue functioning. OA develops when abnormal cartilage production and degradation activities occur. It is not well-known what causes these conditions, but researchers are finding pieces of the OA puzzle regularly. A recent clue is that anti-aging therapy may play a supporting role in OA treatment. 3 Aigner and others concluded in 2007 targets for future study include therapies that regulate cartilage synthesis and destruction, give anti-inflammatory qualities to cells and regulate cell death.4

Epigallocatechin-3-gallate (EGCG), due to its previously reported anti-inflammatory qualities, has been tested for use in treating OA. A 2009 journal article reported success in using natural or synthetic EGCG to treat OA. The authors concluded that treatment with EGCG has potential to prevent cartilage destruction by repressing the production of proteins and metabolic products ultimately result in joint inflammation.3 Additional targets for future study include anti-aging strategies might complement existing therapies related to anabolism, catabolism, inflammation, and apoptosis-processes that are integral to the pathogenesis of osteoarthritis.

A study reported in early 2010 the potential anti-inflammatory benefits of a combination of avocado and soybean oils (known as ASU) with EGCG.5 The researchers used an equine model and found an enhanced anti-inflammatory effect on cartilage-producing cells when EGCG and ASU were given together. They concluded that the combination may be a useful therapy for OA.

1Regulation of interleukin-1beta-induced chemokine production and matrix metalloproteinase 2 activation by epigallocatechin-3-gallate in rheumatoid arthritis synovial fibroblasts. Ahmed S, Pakozdi A, Koch AE. Arthritis Rheum. 2006. 54(8):2393-2401.

2Green tea extract inhibits chemokine production, but up-regulates chemokine receptor expression, in rheumatoid arthritis synovial fibroblasts and rat adjuvant-induced arthritis

H. Marotte, J. H. Ruth, P. L. Campbell, A. E. Koch, S. Ahmed. Rheumatology. 2010. 49(3): 467-79.

3Green tea polyphenol epigallocatechin-3-gallate inhibits advanced glycation end product-induced expression of tumor necrosis factor-alpha and matrix metalloproteinase-13 in human chondrocytes. Rasheed, Z; Anbazhagan, AN; Akhtar, N; Ramamurthy, S; Voss, FR and Haqqi, TM. Arthritis Res Ther. 2009. 11(3):R71.

4Mechanisms of disease: role of chondrocytes in the pathogenesis of osteoarthritis–structure, chaos and senescence. Aigner, T; Söder, S; Gebhard, PM; McAlinden, A and Haag, J. Nat Clin Pract Rheumatol. 2007. 3(7):391-9.

5Inhibition of cyclooxygenase-2 expression and prostaglandin E2 production in chondrocytes by avocado soybean unsaponifiables and epigallocatechin gallate. Heinecke LF, Grzanna MW, Au AY, Mochal CA, Rashmir-Raven A, Frondoza CG. Osteoarthritis Cartilage. 2010. 18(2):220-7.

Polyphenon E is a preparation that is decaffeinated and contains defined green tea catechins. Catechins are known to be powerful antioxidants, antimicrobial agents, anticancerous agents and have anti-inflammatory properties. The predominant catechin in green tea is epigallocatechin gallate (EGCG) and it is reported to be the most beneficial catechin in green tea.

Researchers conducted a trial focused on the effects of dosages of Polyphenon E on human subjects and its effect on UV-induced skin redness.1 The dosages, administered randomly were 800 mg EGCG once a day, 400 mg EGCG twice a day, 800 mg EGCG as Polyphenon E once a day, 400 mg EGCG twice a day as Polyphenon E or placebo once a day. The 800 mg EGCG per day dosage is equivalent to the amount of EGCG in 8-16 cups of green tea per day. There were 8 subjects assigned to each dosage and the treatment period was 4 weeks.

Results included more than 60% increase in EGCG in the blood at the highest dosage of EGCG or Polyphenon E. There were no significant changes in blood chemistry after 4 weeks and none of the treatments protected skin from UV light damage, as indicated by skin redness.

A study was conducted by Chow and others to assess catechin availability in human test subjects following single doses of EGCG or Polyphenon E at 4 dosage levels.2 There were 5 subjects assigned to each of four dose levels, 200, 400, 600 and 800 mg EGCG. Blood and urine samples were collected until 24 hours following ingestion of the EGCG product. Concentration of EGCG in blood was significantly higher with the 800 mg dosage than with the other 3 dosages. No differences were observed based on the source of EGCG (pure EGCG or Polyphenon E).

Scientists have found that bioavailability of catechins is low when they are taken orally. A 2005 study was conducted to test the hypothesis that catechin levels in humans are higher when the catechins are ingested after fasting. The treatments were 400, 800 or 1200 mg Polyphenon E, based on EGCG content. There were 10 subjects for each treatment and they participated in an overnight fast before receiving the supplement. One half of the subjects were given one or two muffins and water before treatment and the other half did not. After one week the subjects were crossed over and received the same Polyphenon E dosage with the opposite fast/fed condition.

EGCG in the blood was present as metabolites, meaning the compound had been broken down in the subject’s body. Other catechins were present in the blood in their original form (epicatechin and epigallocatechin). The catechins in their original form in the blood were more than 3.5 times higher when Polyphenon E was taken in the fasting condition as compared to taken with food. The researchers concluded that better bioavailability of catechins in the blood are achieved when Polyphenon E is given orally under fasting conditions. They also concluded that the optimum dosage to realize the best health benefits from catechins was 800 mg EGCG and that this dosage is tolerated well by subjects undergoing an overnight fast.

1Pharmacokinetics and safety of green tea polyphenols after multiple-dose administration of epigallocatechin gallate and polyphenon E in healthy individuals. Chow HH, Cai Y, Hakim IA, Crowell JA, Shahi F, Brooks CA, Dorr RT, Hara Y, Alberts DS. Clin Cancer Res. 2003 Aug 15;9(9):3312-9.

2Phase I pharmacokinetic study of tea polyphenols following single-dose administration of epigallocatechin gallate and polyphenon E. Chow HH, Cai Y, Alberts DS, Hakim I, Dorr R, Shahi F, Crowell JA, Yang CS, Hara Y. Cancer Epidemiol Biomarkers Prev. 2001 Jan;10(1):53-8.

3Effects of dosing condition on the oral bioavailability of green tea catechins after single-dose administration of Polyphenon E in healthy individuals. Chow, HH; Hakim, IA; Vining, DR; Crowell, JA; Ranger-Moore, J; Chew, WM; Celaya, CA; Rodney, SR; Hara, Y and Alberts, DS. Clin Cancer Res. 2005. 11(12):4627-33.

Dental Caries

Drinking green tea is recommended to help prevent or even reverse the effects of a host of maladies, including cancer, autoimmune disorders and metabolic syndrome. The sub-class of polyphenols called catechins, found in green tea. They are effective antioxidants and have antibacterial properties. It only goes to reason that green tea benefits your mouth as well.

You probably know these as “cavities”. They are the little holes in our teeth that cause us grief and cost us money. Caries are caused by acids produced by several different species of bacteria. In a study published in 2009 researchers reported that polyphenols in green tea interfere with the ability of bacteria to produce plaque necessary to attach to tooth surfaces.1 The primary bacteria involved is Streptococcus mutans. Other microorganisms, Lactobacilli and actinomycetes, also contribute to plaque formation but there is little published information about their susceptibility to green tea.

Plaque

By slowing plaque production, less acid is produced by bacteria and tooth surface erosion is reduced leading to fewer dental caries. In the study mentioned above, Streptococcus mutans was treated with green tea in vitro (in the laboratory).1 Researchers simulated a tooth surface with saliva-coated synthetic beads. In the presence of green tea polyphenols S. mutans cell membranes were altering, making the bacteria less able to adhere to the synthetic tooth surfaces. It is important to note that the antibacterial activity only occurred when streptococcus was in direct contact with green tea.

Antibacterial properties of green tea in the mouth

The growth and survival of S. mutans is also reduced by green tea polyphenols in the sub-class of catechins. There are 8 different catechins in green tea that are concentrated enough to be effective. Epigallocatechin gallate (EGCG) is the catechin in the highest concentration and has the most effective action on the bacteria.

One method of action is to inhibit the production of an enzyme necessary for streptococcus to thrive. Published results show that the catechins can act on the bacteria either alone or in various combinations. Otake and others found a concentration of 167 mg EGCG per liter inhibited streptococcal growth by 91%.2 A study published in 1990 reported a 50% reduction in streptococcal growth at a concentration of 450 mg EGCG per liter.3

Another mechanism is that green tea prevents enzymes that turn starch into sugar from acting on food while it is in the mouth. Zhang and Kashket conducted an experiment where test subjects ate soda crackers then rinsed with black tea, green tea or water for 30 seconds.4 They observed up to a 70% reduction in the conversion of starch to sugar in the mouth following rinsing with the teas.

These findings are significant since tooth decay is not treated with antibiotics. Results on the amount of green tea required to adversely affect streptococcus vary. According to Hamilton-Miller, consensus is that “cup of tea” concentration inhibits and often kills streptococcal bacteria.5 A typical cup of tea contains between 0.5-1.0 g catechins per liter of brewed tea.6

Perhaps in the near future we’ll be using toothpaste, mouthwash and dental floss enriched with green tea extracts.

1Anti-cariogenic effects of polyphenols from plant stimulant beverages (cocoa, coffee, tea). Ferrazzano, GF; Amato, I; Ingenito, A; De Natale, A; and Pollio, A. Fitoterapia. 2009. 80(5):255-62. Epub 2009 May 3.

2Anticaries effects of polyphenolic compounds from Japanese green tea. Otake, S; Makimura, M; Kuroki, T; Nishihara, Y and Hirassawa, M. Caries Res. 1991. 25: 438-443.

3Effect of tea polyphenols on glucan synthesis by glucosyltransferase from Streptococcus mutans. Hattori, M; Kusumoto, IT; Namba, T; Ishigami, T and Hara, Y. Chem Pharm Bull. 1990. 38: 717-720.

4Inhibition of salivary amylase by black and green teas and their effects on the intraoral hydrolysis of starch. Zhang, J and Kashket, S. Caries Res. 1998. 3: 233-238.

5Anti-cariogenic properties of tea (Camellia sinensis). JMT Hamilton-Miller. J Med Microbiol. 2001. 50:299-302.

6Antibacterial substance in Japanese green tea extract against Streptococcus mutans, a cariogenic bacterium. Sakanaka, S; Kim, M; Taniguchi, M and Yamamoto, T. Agr Biol Chem. 1989. 53: 2307-2311.

Helicobacter pylori

Helicobacter pylori is the bacteria that causes most stomach ulcers, stomach inflammation (chronic gastritis) and gastric cancer. Catechins of green tea have been found to inhibit the growth of several microorganisms so a study published in 2003 tested the effectiveness of catechins on H. pylori.1

There were 56 strains of H. pylori tested for catechin susceptibility, 19 of the strains were resistant to the antibiotics metronidazole (MTZ) and/or clarithromycin (CLR). Additive effects of epigallocatechin gallate (EGCG) and the antibiotics were observed, meaning that the combination treatment showed more antimicrobial activity that either treatment alone. The only catechins in green tea that showed anti- H. pylori effects were EGCG and epicatechin gallate (ECG). The sensitivity to the two gallates was observed in the antibiotic-resistant strains as well as the non-resistant strains.

As H. pylori strains continue to develop resistance to antibiotics, scientists are searching for other methods of controlling the bacteria. A study published in 2008 used an experimental treatment of green tea catechins and sialic acid on human stomach cells in the laboratory and on a murine model.2

In the human stomach cells, the catechins and sialic acid treatment resulted in an additive effect for inhibiting H. pylori growth. In the murine model, the anti- H. pylori treatment combination was 100% effective against H. pylori infection. When the treatment combination was applied after infection by H. pylori the result in the murine model was suppression of 60% of the H. pylori infections. Next treatment effects must be tested in human subjects.

Candida albicans

Candida albicans is the most prevalent fungal pathogen infecting humans.3 Candida species are an ordinary resident in mucous membranes (mouth, gastrointestinal tract and vagina). The microflora composition in the membranes can become altered or the immune system can become compromised, leading to an unchecked growth of the Candida species and resulting in disease or infections.

Treatment usually involves the use of antifungals in the azole family but they do not reliably control fungal infections because they are not toxic in nature. They inhibit enzymes that have a role in producing cholesterol but are not potent enough to prevent recurrence of infections, and sometimes they confer no anti-microbial activity at all.

EGCG has been found to inhibit folate activity.3,4 The potential of EGCG to alter Candida albicans metabolic pathways was the focus of a study by Navarro-Martinez and colleagues.5 Their results showed that EGCG is effective at arresting folate metabolism in Candida albicans. An additive effect on growth and survival inhibition of Candida albicans was observed when EGCG was administered along with topical azole antifungals.

Salmonella spp.

Researchers in Japan, noting the antimicrobial properties of green tea catechins, conducted a study to test their effectiveness on Salmonella-tainted grains.6 It is possible for foodstuffs to come into contact with animals or soil and become infected with Salmonella bacteria. The bacteria do not grow in grains because they do not have adequate moisture content. In this case they form spores, in which they stay dormant until conditions are favorable for their growth.

This study tested the adequacy of catechins to inhibit Salmonella growth in grain flakes and flours. Grain flakes were dipped in solutions of varying concentrations of catechins and were inoculated with Salmonella enteritidis and Salmonella aureus. The catechins adhered to the flakes. After conducting various tests to ensure desired conditions were met, milk was added to the grain flakes and Salmonella populations were counted. Upon statistical analysis of the population counts, they were able to suggest that catechins might be effective as a food additive to prevent microbial activity.

1A combination effect of epigallocatechin gallate, a major compound of green tea catechins, with antibiotics on Helicobacter pylori growth in vitro. Yanagawa Y, Yamamoto Y, Hara Y, Shimamura T. Curr Microbiol. 2003 Sep;47(3):244-9.

2Effective prevention and treatment of Helicobacter pylori infection using a combination of catechins and sialic acid in AGS cells and BALB/c mice. Yang JC, Shun CT, Chien CT, Wang TH. J Nutr. 2008. 138(11):2084-90.

3Influence of green and black tea on folic acid pharmacokinetics in healthy volunteers: potential risk of diminished folic acid bioavailability. Alemdaroglu, NC; Dietz, U; Wolffram, S; Spahn-Langguth, H and Langguth, P. Biopharm Drug Dispos. 2008. 29(6):335-48.

4Effects of folate cycle disruption by the green tea polyphenol epigallocatechin-3-gallate. Navarro-Perán, E; Cabezas-Herrera, J; Campo, LS and Rodríguez-López, JN. Int J Biochem Cell Biol. 2007. 39(12):2215-25.

5Tea polyphenol epigallocatechin-3-gallate inhibits ergosterol synthesis by disturbing folic acid metabolism in Candida albicans. Navarro-Martínez MD, García-Cánovas F, Rodríguez-López JN. J Antimicrob Chemother. 2006. 57(6):1083-92. Epub 2006 Apr 3.

6Survival of foodborne pathogens in grain products and the effect of catechins. Ui, J; Kondo, K; Sawada, T and Hara-Kudo, Y. Shokuhin Eiseigaku Zasshi. 2009. 50(3):126-30.

This antibiotic is routinely used to control S. aureus infections in the body. S. aureus is a species of bacteria commonly found growing on healthy people. It grows on the skin and less commonly, on the upper respiratory tract membranes. S. aureus enters the body through an open wound, or institutionally, through the use of invasive medical techniques and devices. It can also be transmitted from person to person in everyday contact with each other. It can become a serious infection that has the potential to become life-threatening. S. aureus has also been identified as a cause food poisoning because it produces a chemical that is toxic to humans. Strains of Staphylococcus aureus (S. aureus) that are resistant the antibiotic methicillin are identified as methicillin-resistant staphylococcus aureus (MRSA). MRSA does not represent a single strain of S. aureus but refers to a group of strains that exhibit resistance to methicillin.

How MRSA Came About

Historically, S. aureus was treated with penicillin. As the bacteria defended itself against this treatment it adapted by producing an enzyme called penicillinase that breaks the penicillin molecule rendering it ineffective as a bacteriocide. Next physicians turned to methicillin, another antibiotic in the same family as penicillin, to treat S. aureus infections.

Since bacteria reproduce so quickly in such great numbers, mutations that bring about resistance may occur relatively rapidly. When treated with methicillin over time, S. aureus successful mutations resulted in adaptation again leading to a new strain known as methicillin resistant S. aureus, or MRSA. It resists methicillin by the action of a gene called mecA. This gene tells the bacteria’s genetic code to make and use a certain protein to destroy methicillin in a similar fashion as it does penicillin.1

Back to the Drawing Board

Given the ability of S. aureus strains to adapt to various antibiotics, scientists continue to identify alternate ways to control MRSA. This search has been ongoing since at least the 1990’s. Strategies explored include alternate antibiotics which are broader spectrum, meaning they act upon more kinds of microorganisms than only the target. However, this can result in negative effects because our bodies are dependent on certain microorganisms to function properly.

Scientists are also trying to locate new points of vulnerability of MRSA. They are testing combinations of various antibiotics as well as combinations of antibiotics and other substances not traditionally considered antibiotics.

Green Tea

Somewhere along the way, epicatechin gallate (ECG) and epigallocatechin gallate (EGCG), two polyphenols that are abundant in green tea (Camellia sinensis) were identified as candidates for treating S. aureus. Chromosomal factors, known as “fem factors” are necessary for S. aureus, to show resistance to methicillin.2 Scientists have identified ECG as a potential inhibitor of these fem factors.3 ECG has also been recognized as a selective growth inhibitor of MRSA because it damages the cell wall of the bacteria. It is only effective when ECG is present in high concentrations.

Carbapenems are a newer class of antibiotics that bind to enzymes required for MRSA cell wall synthesis. Without an intact cell wall, the bacteria cannot survive. When Carbapenems are combined with EGCG the potency of carbapenems is increased. This is true for two carbapenems: panipenem and meropenem.4 Ampicillin and sulbactam are two more antibiotics that are effective against MRSA when given with EGCG in concentrations of 6.25 and 25 mg per liter of EGCG.5

1Methicillin resistance in Staphylococcus aureus mechanisms and modulation. Stapleton, PD and Taylor, PW. Sci Prog. 2002. 85(Pt 1): 57–72.

2 The effect of a component of tea (Camellia sinensis) on methicillin resistance, PBP2′ synthesis, and β-lactamase production in Staphylococcus aureus. Yam, TS; Hamilton-Miller, JMT and Shah S. J. Antimicrob. Chemother. 1998. 42(2):211–216.

3Mapping and Characterization of Multiple Chromosomal Factors Involved in Methicillin Resistance in Staphylococcus aureus. Berger-Bachi, B; Strassle, A; Gustafson, JE and Kayser, FH. Antimicrobial Agents and Chemotherapy. 1992. 36(7): 1367-1373.

4 Epigallocatechin Gallate Synergistically Enhances the Activity of Carbapenems against Methicillin-Resistant Staphylococcus aureus. Zhi-Qing Hu, Wei-Hua Zhao, Nozomi Asano, Yoshiyuki Yoda, Yukihiko Hara, and Tadakatsu Shimamura. Antimicrob Agents Chemother. 2002. 46(2): 558–560.

5Epigallocatechin gallate synergy with ampicillin/sulbactam against 28 clinical isolates of methicillin-resistant Staphylococcus aureus. Hu, ZQ; Zhao, WH; Hara, Y and Shimamura, T. J Antimicrob Chemother. 2001. 48(3):361-4.

Green tea comes from the leaves of the tea plant (Camellia sinensis). It is rich in antioxidants. There are hundreds of published scientific articles that discuss health benefits of green tea constituents that come from experimental studies. Scientists have studied green tea effects on the cell level, in animal models and in human trials. Researchers have also collected green tea drinking information and health information from people by using surveys.

Ingredients

What have scientists learned from all this research? First of all, the active ingredients in green tea are antioxidants called polyphenols. Researchers performing a study on the chemistry of tea polyphenols found that flavonols and flavonols account for about 30% of the dry weight of fresh tea leaves.1 A sub-class of polyphenols, catechins, include epigallocatechin-gallate (EGCG). This is the most abundant catechin in green tea. Researchers reported in 2009 that a 6-8 ounce cup of green tea has about 90 mg EGCG in it.2

When it comes to caffeine, brewed black, green and white tea contain between 14 and 61 mg caffeine per 6-8ounce serving.3 In comparison, decaffeinated tea contains less than 12 mg caffeine per serving.

Antioxidant Capacity

A study comparing antioxidant ability of vitamins C and E to EGCG at the cellular level was reported in 2007.4 EGCG was found to have more effective antioxidizing power than both vitamins. However, when all 3 compounds were tested together, EGCG boosted the antioxidative level of protection of both vitamins. The scientists concluded that human trials should be conducted to see if the cell-level results can be obtained in vivo.

Another study reported in 2009 compared antioxidative power of various plant extracts, including extracts of white and green teas.5 Green tea extract (GTE) produced an 86% reduction of oxygen free radicals, as assayed with superoxide dismutase.

Dosage

For the prevention of cancer, Boehm and colleagues recommend a daily consumption of 3-5 cups of green tea per day.2 This dosage provides at least 250 mg of catechin per day. Another study led scientists to recommend drinking 10-15 ounces green tea per day to significantly increase the antioxidative power of blood plasma.3 In this study scientists measured antioxidant capacity of blood plasma at the time of drinking 5 ounces green tea and 60 and 120 minutes after drinking the tea.

To reduce the risk of heart attack researchers suggest drinking 3 cups of green tea each day to realize an 11% decrease in the risk of having a heart attack. To reduce the risk of dying following a heart attack, another study reported that drinking 4 cups of tea per day was warranted.6

When the analyses of the 15 tea drinks were completed they conducted human trials with the objective of measuring EGCG content in the blood.7 Their working hypothesis was that by adding EGCG to the processed drinks the catechin and caffeine ratios would be different and their fate in humans would vary from that observed from ingesting unaltered green tea.

Their results indicated that caffeine affects the absorption and metabolism of EGCG in the human body. When EGCG is ingested it is metabolized to glucuronide and sulfate compounds. In the presence of caffeine the metabolism of EGCG is depressed so blood levels of EGCG are elevated.

1The chemistry of tea flavonoids. Balentine, DA; Wiseman, SA and Bouwens, LC. Crit Rev Food Sci Nutr. 1997. 37 :693 –704.

2Green tea (Camellia sinensis) for the prevention of cancer. Boehm, K; Borrelli, F; Ernst, E; Habacher, G; Hung, SK; Milazzo, S and Horneber, M. Cochrane Database System Rev. 2009.

3Caffeine content of brewed teas. Chin, JM; Merves, ML; Goldberger, BA; Sampson-Cone, A and Cone EJ. J Anal Toxicol. 2008. 32(8):702-4.

4Physiological levels of tea catechins increase cellular lipid antioxidant activity of vitamin C and vitamin E in human intestinal Caco-2 cells. Janjira, I and S-M, Kuo. Chem Biol Interact. 2007. 169(2): 91–99.

5Anti-collagenase, anti-elastase and anti-oxidant activities of extracts from 21 plants.

Tamsyn, SA; Thring, PH and Declan P Naughton. BMC Complement Altern Med. 2009. 9:27.

6Heart Disease and Stroke Statistics—2009 Update. A Report from the American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Lloyd-Jones D, Adams R, Carnethon M, et al. Circulation. 2009.119:e21-e181.

7Effects of co-administration of tea epigallocatechin-3-gallate (EGCG) and caffeine on absorption and metabolism of EGCG in humans. Nakagawa, K; Nakayama, K; Nakamura, M; Sookwong, P; Tsuduki, T; Niino, H; Kimura, F and Miyazawa, T. Biosci Biotechnol Biochem. 2009. 73(9):2014-7.

Green Tea and Pregnancy

Congratulations, you’re expecting! You’re following doctor’s orders to a tee; drinking lots of water, limiting how much fish and shellfish you are eating and taking your prenatal vitamins. You are well on your way to the day you will meet your healthy baby. What about tea? Is it okay to have some green tea with breakfast or a snack? Although green tea is generally regarded as safe by the US Food and Drug Administration, you might want to reevaluate drinking green tea before and during pregnancy no matter the health benefits it provides.

There is little scientific information about the effects of green tea on the baby in utero. This is why there aren’t concrete guidelines for how much caffeine is all right. Evaluate the information for yourself. You and your healthcare provider can make a more informed decision. You will feel more confident that you are providing the best possible environment for your baby to live and thrive.

Folic Acid

Getting enough folate is a simple yet very important thing you can do to help your baby. Neural tube defects cause spine, head and brain malformations and are associated with low levels of folate in the blood. The US recommended daily amount (RDA) of folate in women of childbearing age is 400 micrograms, according to the Office of Dietary Supplements at the National Institutes of Health.

Mothers-to-be, this includes you too! Researchers recommend that you begin taking 400 micrograms folic acid daily at least one month before conception to prevent neural tube disorders.

Here’s where green tea comes into the picture. Scientists have found that taking 5mg folic acid with green tea decreased the amount of folate in the blood by 39.9%.1 The tea they was made with 0.3 g green tea extract/250 ml water, which is a weak tea.

Scientists in Spain discovered that one of the polyphenols in green tea, epigallocatechin-3-gallate (EGCG), inhibits the enzyme that synthesizes DNA and RNA.2 This is significant because DNA contains our genetic information and determines which proteins are made according to the genetic code unique to each of us. EGCG also affects DNA methylation; a process that allows DNA to be used repeatedly without being altered. When methylation is changed, DNA’s tumor growth suppression ability is unavailable. The effect of EGCG on folate is so significant that it is labeled an “antifolate compound” in scientific literature.

Caffeine

What about your caffeine intake? Do you need that “get me going” cup of hot tea in the morning? Of course, green tea contains caffeine. Healthcare practitioners know that caffeine crosses through the placenta and stimulates the baby’s nervous system. They usually recommend that you limit your intake of caffeine-containing foods (chocolate?) and beverages. The amount that is okay for baby is unknown, because doctors don’t know the effects of caffeine on babies in utero or how babies metabolize it.

Chin and others showed that the amount of caffeine in brewed black, green and white tea products ranges from 14-61 mg per 6-8 oz serving.3 Decaffeinated teas contained less than 12 mg caffeine per serving. There was no trend in caffeine content by type of tea (black, green or white).

1Influence of green and black tea on folic acid pharmacokinetics in healthy volunteers: potential risk of diminished folic acid bioavailability. Alemdaroglu, NC; Dietz, U; Wolffram, S; Spahn-Langguth, H and Langguth, P. Biopharm Drug Dispos. 2008. 29(6):335-48.

2Effects of folate cycle disruption by the green tea polyphenol epigallocatechin-3-gallate. Navarro-Perán, E; Cabezas-Herrera, J; Campo, LS and Rodríguez-López, JN. Int J Biochem Cell Biol. 2007. 39(12):2215-25. Epub 2007 Jun 26.

3Caffeine content of brewed teas. Chin, JM; Merves, ML; Goldberger, BA; Sampson-Cone, A and Cone EJ. J Anal Toxicol. 2008. 32(8):702-4.