Regression of experimental cancer by oral administration of combined α‐tocopherol and β‐carotene

Abstract

alpha-Tocopherol (vitamin E) and beta-carotene have been shown to be capable of regressing established epidermoid carcinomas of hamster buccal pouch when injected locally into the tumor site. Neither has yet been shown to be effective in regressing cancer when administered by oral route. However, a combination of both alpha-tocopherol and beta-carotene was shown to be effective in regressing epidermoid carcinomas of hamster buccal pouch when the mixture was administered orally in vegetable oil. The epidermoid carcinomas were induced in the right buccal pouch of 100 Syrian hamsters by painting three times weekly for 14 weeks with a 0.5% solution of 7,12-dimethylbenz[a]anthracene in mineral oil. The animals were then divided into five equal groups of 20 animals. Group 1 animals received no further treatment and represented tumor controls. Group 2 animals received 200 micrograms beta-carotene and 200 micrograms dl-alpha-tocopherol acid succinate combined in 0.2 ml vegetable oil. Animals received the mixture daily by mouth using a 1-ml syringe. Groups 3 and 4 received beta-carotene and alpha-tocopherol individually in double amounts (400 micrograms in 0.2 ml vegetable oil). Group 5 animals received only the vegetable oil (0.2 ml daily) and were controls for vehicle. The animals in Groups 1, 3, 4, and 5 were killed after 22 weeks because the tumors were extensive, large, and necrotic and the animals were weak and cachectic. After 22 weeks, the tumors in Group 2 animals were small in 15 out of 20 animals. The tumors were reduced in size compared with tumor burden at 14 weeks, the point at which the beta-carotene/alpha-tocopherol was started.

The effectiveness of a mixture of β‐carotene, α‐tocopherol, glutathione, and ascorbic acid for cancer prevention

“…Recent studies further indicated that antioxidants such as P-carotene and vitamin E function in a synergistic manner to inhibit tumor cell growth (11). This synergistic relationship could be explained by the variable function of these antioxidants at different partial pressures of oxygen (12).…”

“…Recently, it has been shown that a mixture of p-carotene and vitamin E is more effective than p-carotene and vitamin E separately in preventing the growth of experimental cancer and in the regression of early malignant tumors (11). The experimental results indicated a synergistic effect of the two agents acting together.…”

Effects of α‐tocopherol and β‐carotene on hepatic lipid peroxidation and blood lipids in rats with dietary iron overload

“…The roles of the lipid-soluble antioxidants α-tocopherol and β-carotene have been intensely investigated, and several reports (15,16) suggest that antioxidants such as β-carotene and α-tocopherol protect against carcinogenesis. It has also been suggested that β-carotene and α-tocopherol play complementary roles in protecting lipids from peroxidation in vivo (17).…”

Vitamin E in the Genesis and Prevention of Cancer a Review

“…Many recent findings also indicate an influence of vitamin E during carcinogenesis. Alpha-tocopherol used with beta-carotene was shown to cause regression of epidermoid carcinomas of hamster buccal pouch induced by DMBA (29). Preventive effect of vitamin E, as a constituent of betel leaf extract, (along with beta-carotene) was reported by Azuine & Bhide (30) in nitrosamine-induced oral carcinogenesis in Syrian hamsters.…”