Anti-Tumor and Anti-Tumor Promoting Activity of α- and β-Carotene

Summary

Carotenoids are known to inactivate certain reactive oxygen species, such as singlet oxygen. Since antioxidants have been suggested to be one of the promising agents for cancer control, it is worthwhile to evaluate the anti-cancer potency of these carotenoids.

In the course of the study, we found that palm oil derived natural carotene which contains 60% β-carotene, 30% α-carotene and 10% others, showed potent anti-tumor activity. Therefore, we compared the activity of a- and β-carotene, and found that α-carotene showed more potent anti-proliferative effect than β-carotene. a-Carotene was also proved to have higher potency than β-carotene to suppress tumor promotion in two-stage skin and lung carcinogenesis experiments. Thus, α-carotene seems to be a promising agent for cancer control.

Further study to find other types of useful carotenoids in natural materials, especially in our daily foods, was also carried out.