Tocotrienols in Female Reproductive Cancers: A Long Way to Go

Siti Syairah Mohd Mutalip

Faculty of Pharmacy, Universiti Teknologi MARA (UiTM) Puncak Alam Campus, Selangor 42300, Malaysia

*Correspondence to: Dr. Siti Syairah Mohd Mutalip, Faculty of Pharmacy, Universiti Teknologi MARA (UiTM) Puncak Alam Campus, Selangor 42300, Malaysia.

Copyright © 2018 Dr. Siti Syairah Mohd Mutalip. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Vitamin E
Vitamin E, which was first discovered by Evans and Bishop in 1922, has been reported as a potential reproductive protectant. This was following the finding of a particular ‘anti-sterility factor X’ that was necessary for reproduction [1]. Since then, vitamin E becomes well-recognized as an important lipid-soluble antioxidant [2-4]. Vitamin E contains two major substances, tocopherols (TOCs) and tocotrienols (TCTs). These substances are present in eight different homologs, namely α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol, α-tocotrienol, β-tocotrienol, γ-tocotrienol and δ-tocotrienol [5]. Earlier reports on the benefits of vitamin E were emphasized mainly on the effects of TOCs, particularly alpha-TOC (α-TOC), where it has been claimed and continuously reported as the most powerful lipid-soluble antioxidant [2,6-15].

During the earlier period of vitamin E researches, TCTs was not been studied as extensively as TOCs. However, there were few reports stated that α-TCT possesses better antioxidant properties than α-TOC [16,17] due to the unsaturated side chain of TCTs that allows for efficient penetration through better distribution on tissue membranes with saturated fatty layer [18]. The benefits of TCTs have become into the attention only during the late 1980s, when their cholesterol-lowering potential [19] and anticancer effects were published [20,21]. Since then, the benefits of TCTs especially as an anticancer have been extensively reported including its effects on breast [22-25], cervix, colon [26,27], liver [28,29], lung [30,31], ovary, pancreas [32,33], prostate [34,35], skin [36,37] and stomach cancers [38].

Analyses on the available reports on anticancer effects of vitamin E particularly on the cervical and ovarian cancers (female reproductive cancers other than breast cancer) are very limited with only a few reports are available, as shown in Table 1.

Conclusion
Vitamin E has been widely known to have the ability to prevent cell proliferations in cancer cells. The limited reports on the effects of vitamin E on cervical and ovarian cancers are impeding the possible potential of using vitamin E to treat these diseases. This demands more researches in future to understand the mechanisms of actions of vitamin E against these two types of cancer cells. With the available little evidences, this marks a long way to go to make use of the research findings in initiating the development of new vitamin E-based drugs that could be used therapeutically to fight against cervical and ovarian cancers in females.

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