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.

Assessment of the protective effects of oral tocotrienols in arginine chronic-like pancreatitis

“…Both tocopherols and tocotrienols are potent antioxidants, are well absorbed from dietary nutrients, and concentrate in cellular membranes in a dose-and time-dependent manner (40). However, tocotrienols show a higher potency than tocopherols in inducing apoptosis in transformed cells in vitro, particularly in cancer cells (33), and inhibit colon, prostate, mammary, and lung carcinogenesis (19). Intriguingly, ␣-tocopherol may counteract tocotrienol-induced cytotoxicity in cancer cells (41).…”

Isolation and physico-chemical characterization of <em>Butea parviflora</em> seed oil

“…However, the tocopherol contents in these two seeds were slightly higher and were reported to contain about 630.8 and 603.5 µg/g (Górnas et al, 2015). Thus the Butea parviflora seed oil is a good source of gamma tocopherol which is known as the most potent free radical scavenger among the other tocopherol isomers and is also reported to be exhibiting an inhibitory effect on carcinogénesis (Ju et al, 2010).…”

Natural Sources of Tocotrienols: A Note on Absorption

“…Tocotrienols showed significant in vivo anticancer activity in breast cancer, pancreatic cancer and melanoma. Their anticancer activity is mediated by apoptosis, autophagy, and NFkB mediated pathways [48][49][50][51][52].…”