Combination Effect of δ-Tocotrienol and γ-Tocopherol on Prostate Cancer Cell Growth

J Nutr Sci Vitaminol (Tokyo). 2017;63(5):349-354. doi: 10.3177/jnsv.63.349.


Tocotrienols (T3s) and tocopherols (Tocs) are both members of the vitamin E family. It is known that δ-tocotrienol (δ-T3) has displayed the most potent anti-cancer activity amongst the tocotrienols. On the other hand, γ-tocopherol (γ-Toc) is reported to have a protective effect against prostate cancer. Therefore, we investigated whether the combination of γ-Toc and δ-T3 could strengthen the inhibitory effect of δ-T3 on prostate cancer cell growth. In this study the effect of combined δ-T3 (annatto T3 oil) and γ-Toc (Tmix, γ-Toc-rich oil) therapy was assessed against human androgen-dependent prostate cancer cells (LNCaP). We found that combined treatment of δ-T3 (10 μM) and γ-Toc (5 μM) resulted in reinforced anti-prostate cancer activity. Specifically, cell cycle phase distribution analysis revealed that in addition to G1 arrest caused by the treatment with δ-T3, the combination of δ-T3 with γ-Toc induced G2/M arrest. Enhanced induction of apoptosis by the combined treatment was also observed. These findings indicate that combination of δ-T3 and γ-Toc significantly inhibits prostate cancer cell growth due to the simultaneous cell cycle arrest in the G1 phase and G2/M phase.

Keywords: combination; prevention; prostate cancer; γ-tocpherol; δ-tocotrienol.

Publication types

  • Comparative Study

MeSH terms

  • Anticarcinogenic Agents / chemistry
  • Anticarcinogenic Agents / metabolism*
  • Antineoplastic Agents, Phytogenic / agonists*
  • Antineoplastic Agents, Phytogenic / metabolism
  • Apoptosis*
  • Bixaceae / metabolism
  • Carotenoids / agonists
  • Carotenoids / metabolism
  • Cell Line, Tumor
  • Cell Proliferation
  • Cell Survival
  • Chromans / agonists*
  • Chromans / metabolism
  • G1 Phase
  • G2 Phase
  • Humans
  • Male
  • Osmolar Concentration
  • Plant Extracts / agonists
  • Plant Extracts / metabolism
  • Prostatic Neoplasms / metabolism*
  • Prostatic Neoplasms / pathology
  • Prostatic Neoplasms, Castration-Resistant / metabolism
  • Prostatic Neoplasms, Castration-Resistant / pathology
  • Vitamin E / agonists
  • Vitamin E / analogs & derivatives*
  • Vitamin E / metabolism


  • Anticarcinogenic Agents
  • Antineoplastic Agents, Phytogenic
  • Chromans
  • Plant Extracts
  • Vitamin E
  • tocotrienol, delta
  • Carotenoids
  • plastochromanol 8
  • annatto