Borstkanker: Extract van groene thee (EGCG) stopt significant groei borstkankercellen blijkt uit gerandomiseerde dierstudies.

Extract van groene thee (EFGG) stopt groei borstkankercellen.

11 april 2008: Bron: http://www.nutraingredients.com

EFGG een stofje uit groene thee stopt de groei van borstkankercellen blijkt uit gerandomiseerde studie met muizen. De onderzoekers aan de universiteit van Michigan verklaren dit succes als volgt: Groene thee bevat tussen 30 % en 40 % water-opneembare polyphenols, terwijl zwarte thee tussen de 3% en 10% water-opneembare polyphenols bevat. De vier primaire polyphenols in verse theeblaadjes zijn epigallocatechin gallate (EGCG), epigallocatechin, epicatechin gallate, en epicatechin.

De onderzoekers verdeelden 7-weken oude vrouwtjes muizen in twee groepen – een groep kreeg gedurende vijf weken EGCG in hun drinkwater met een dosis van 25 mg per 50 ml, terwijl de andere groep gewoon neutraal drinkwater kreeg zonder toevoegingen. De dosis EGCG was ongeveer gelijk aan 50-100 mg per kg per dag.

Gedurende de tweede week van de studie werden de linker vier borstklieren van de muizen geinjecteerd met muisborstkankercellen, en gemonitoord op tumor progressie in de vorm van tumorgrootte (TCSA), tumorgewicht, en de waarden van VEGF, een eiwit gevonden bij verschillende borstkankersoorten.

Aan het eind van de studie, de muzien in de EGCG groep toonden 66 % kleinere tumoren, met 68 % vermindering in gewicht. Verder waren de VEGF waarden significant lager bij de groep EGCG muizen, vergeleken met de controlegroepmuizen - 26.5 versus 40.8 pg per ml, respectievelijk.

"In deze studie we hebben aangetoond dat frequente inname van EGCG significant borstumor groiei, VEGF expressie en tumor angiogenesis in muizen afremt," concludeert Dr. Gu. "We geloven dat onze bevindingen zullen helpen om nieuwe behandelingen voor preventie en behandeling van borstkanker bij vrouwen te ontwikkelen."

Source: Experimental Biology 2008
121st Annual Meeting of the American Physiological Society
"Oral Administration of EGCG, an Antioxidant Found in Green Tea, Inhibits Tumor Angiogenesis and Growth of Breast Cancer in Female Mice"
Authors: J.-W. Gu, E. Young, J. Covington, J.W. Johnson, W. Tan

08-Apr-2008 - Epigallocatechin gallate (EGCG) from green tea may stop the growth and spread of breast cancer cells by impacting on the tumour's blood vessels, results from an animal study suggest.

Daily ingestion of ECGC led to a reduction in the weight of breast tumours in mice by 68 per cent, researchers from the University of Mississippi told attendees at the 121st Annual Meeting of the American Physiological Society, part of the Experimental Biology 2008 scientific conference.

In an email to NutraIngredients.com, lead researcher Jian-Wei Gu stated: "Epidemiology study has indicated that green tea and its extracts such as EGCG protect against progression of cancers including breast cancer. However, the anti-cancer mechanisms of EGCG and green tea are poorly understood.

"We believe that this animal study provide a new insight mechanisms how green tea can suppress cancer progression," added Dr. Gu.

Green tea contains between 30 and 40 per cent of water-extractable polyphenols, while black tea (green tea that has been oxidized by fermentation) contains between 3 and 10 per cent. Oolong tea is semi-fermented tea and is somewhere between green and black tea.

The four primary polyphenols found in fresh tealeaves are epigallocatechin gallate (EGCG), epigallocatechin, epicatechin gallate, and epicatechin.

Tea time for mice

Dr. Gu and co-workers used seven week-old female mice and divided them into two groups - one received EGCG in their drinking water at a dose of 25 mg per 50 ml, while the other received no EGCG in their drinking water, for five weeks. The dose of EGCG was approximately equal to 50-100 mg per kg per day.

"The dosage in this animal study is not very high and this should be attainable in a dietary supplement," Gu told this website. "However, we need further studies in humans."

During the second week of the study the left fourth mammary glands of the mice was injected with mouse breast cancer cells, a tumour progression monitored as a function of tumour size (as a measure of the tumour cross section area: TCSA), tumour weight, and levels of vascular endothelial growth factor (VEGF), a protein found in a variety of breast cancer types.

At the end of the study, mice in the EGCG group exhibited 66 per cent smaller tumours, with a 68 per cent decrease in weight. Furthermore, levels of VEGF were significantly lower in the EGCG mice, compared to the control mice - 26.5 versus 40.8 pg per ml, respectively.

"In this study we have demonstrated that the frequent ingestion of EGCG significantly inhibits breast tumour growth, VEGF expression and tumour angiogenesis in mice," concluded Dr. Gu. "We believe our findings will help lead to new therapies for the prevention and treatment of breast cancer in women."

Source: Experimental Biology 2008
121st Annual Meeting of the American Physiological Society
"Oral Administration of EGCG, an Antioxidant Found in Green Tea, Inhibits Tumor Angiogenesis and Growth of Breast Cancer in Female Mice"
Authors: J.-W. Gu, E. Young, J. Covington, J.W. Johnson, W. Tan