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Antitumor-promoting activities of hydrolyzable tannins in mouse skin
H U Gali1, E M Perchellet, D S Klish
1Division of Biology, Kansas State University, Manhattan 66506-4901.
Abstract:
Ellagic acid and gallic acid and its derivatives, applied topically to female CF-1 mice 20 min before each 12-O-tetradecanoylphorbol-13-acetate (TPA) treatment inhibit the inductions of epidermal ornithine decarboxylase activity, hydroperoxide production and DNA synthesis caused by this potent tumor promoter in relation with their abilities to inhibit the promotion of skin papillomas and carcinomas in the two-step initiation-promotion protocol. Because of its potency against TPA promotion, tannic acid, which is already known to inhibit tumor initiation, may inhibit the multistage process of carcinogenesis.
Insights
Ellagic acid, gallic acid, and tannic acid derivatives show potential in preventing skin cancer by inhibiting key tumor promotion factors. These compounds effectively reduce tumor development in mice treated with a potent carcinogen.
Area of Science:
- Oncology
- Dermatology
- Natural Products Chemistry
Background:
- 12-O-tetradecanoylphorbol-13-acetate (TPA) is a potent tumor promoter used in research.
- Carcinogenesis involves multiple stages, including initiation and promotion.
- Epidermal ornithine decarboxylase activity, hydroperoxide production, and DNA synthesis are key indicators of tumor promotion.
Purpose of the Study:
- To investigate the inhibitory effects of ellagic acid, gallic acid, and their derivatives on TPA-induced skin carcinogenesis.
- To evaluate the potential of tannic acid in inhibiting both tumor initiation and promotion.
Main Methods:
- Topical application of ellagic acid, gallic acid derivatives, and tannic acid to female CF-1 mice.
- Administration of 12-O-tetradecanoylphorbol-13-acetate (TPA) to induce skin tumors.
- Measurement of epidermal ornithine decarboxylase activity, hydroperoxide production, and DNA synthesis.
- Assessment of tumor inhibition in a two-step initiation-promotion protocol.
Main Results:
- Ellagic acid and gallic acid derivatives inhibited TPA-induced epidermal ornithine decarboxylase activity, hydroperoxide production, and DNA synthesis.
- These compounds demonstrated significant inhibition of skin papilloma and carcinoma promotion.
- Tannic acid showed potency against TPA promotion and is known to inhibit tumor initiation.
Conclusions:
- Ellagic acid, gallic acid derivatives, and tannic acid are effective inhibitors of skin tumor promotion.
- These natural compounds hold promise for chemoprevention strategies against skin cancer.
- Tannic acid may inhibit the multistage process of carcinogenesis by acting on both initiation and promotion phases.