Cancer-preventive activities of tocopherols and tocotrienols.

Abstract

The cancer-preventive activity of vitamin E has been studied. Whereas some epidemiological studies have suggested a protective effect of vitamin E against cancer formation, many large-scale intervention studies with alpha-tocopherol (usually large doses) have not demonstrated a cancer-preventive effect. Studies on alpha-tocopherol in animal models also have not demonstrated robust cancer prevention effects. One possible explanation for the lack of demonstrable cancer-preventive effects is that high doses of alpha-tocopherol decrease the blood and tissue levels of delta-tocopherols. It has been suggested that gamma-tocopherol, due to its strong anti-inflammatory and other activities, may be the more effective form of vitamin E in cancer prevention. Our recent results have demonstrated that a gamma-tocopherol-rich mixture of tocopherols inhibits colon, prostate, mammary and lung tumorigenesis in animal models, suggesting that this mixture may have a high potential for applications in the prevention of human cancer. In this review, we discuss biochemical properties of tocopherols, results of possible cancer-preventive effects in humans and animal models and possible mechanisms involved in the inhibition of carcinogenesis. Based on this information, we propose that a gamma-tocopherol-rich mixture of tocopherols is a very promising cancer-preventive agent and warrants extensive future research.

• Authors: Jihyeung Ju, Sonia C Picinich, Zhihong Yang, Yang Zhao, Nanjoo Suh, Ah-Ng Kong, Chung S Yang
• Journal: Carcinogenesis (Carcinogenesis) Vol. 31 Issue 4 Pg. 533-42 (Apr 2010) ISSN: 1460-2180 [Electronic] England
• PMID: 19748925 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Review)

Chemical References

• Anticarcinogenic Agents
• Antioxidants
• Cyclooxygenase 2 Inhibitors
• Reactive Nitrogen Species
• Reactive Oxygen Species
• Receptors, Cytoplasmic and Nuclear
• Tocotrienols
• Tocopherols

Topics

• Animals
• Anticarcinogenic Agents (pharmacology)
• Antioxidants (pharmacology)
• Apoptosis (drug effects)
• Case-Control Studies
• Cyclooxygenase 2 Inhibitors (pharmacology)
• Female
• Humans
• Male
• Neoplasms (prevention & control)
• Reactive Nitrogen Species (metabolism)
• Reactive Oxygen Species (metabolism)
• Receptors, Cytoplasmic and Nuclear (drug effects)
• Tocopherols (metabolism, pharmacology)
• Tocotrienols (pharmacology)