Table 8

Inhibitory effects of oral administration of green and black tea on the formation of UVB-induced keratoacanthomas and squamous cell carcinomas in DMBA-initiated SKH-1 mice

Female SKH-1 mice (30/group) were treated topically with 200 nmol of DMBA. One week later the mice were treated with gradually increasing concentrations of tea leaf extracts as drinking fluid for 6 days and full-strength teas (1.25 g tea leaves/100 ml hot water; ∼4 mg tea solids/ml) for an additional 8 days before and during treatment with UVB (30 mJ/cm2) twice weekly for 31 weeks. (Taken from Ref. 317 .)

TreatmentTea solids (mg/ml)% mice with keratoacanthomasNo. of keratoacanthomas per mouse% mice with carcinomasNo. of carcinomas per mouse
Water control976.33330.60
Green tea4.0431.3770.07
Black tea4.4351.3540.04
Decaf. green tea3.6771.90170.17
Decaf. black tea3.9671.73170.20