Biomedical Research

Gamma-tocotrienol has been reported to exhibit a protective effect on hepatocarcinogenesis through the enhancement of immune response and anti-proliferation effect on breast cancer cell lines such as MDA-MB-435 and MCF7. The anti-proliferation mechanism was suggested to be via an increase in apoptosis. The effects of palm oil γ-tocotrienol and α-tocopherol on the cell proliferation were determined using 5-Bromo-2’-deoxy-uridine (BrdU) detection method. CaSki and Alexander cells were sensitive to γ-tocotrienol and α-tocopherol-anti proliferation effects with 93.5 to 97.8% (P less than 0.01, n is equal to 4) and 59.7 to 69.1% (P less than 0.001, n is equal to four) inhibition, respectively beginning with a concentration of 100μM and above. Treatment with α-tocopherol showed a lesser inhibition in the proliferation activity of CaSki cell by 19.7 to 39.4% (P less than 0.01, n is equal to four) and Alexander cell by 16.9 to 19.6% (P less than 0.001, n is equal to four) beginning with a concentration of 50μM and 200μM, respectively. However, both the compounds had no effect on Chang cell. Gamma-tocotrienol showed an IC₅₀ inhibition of CaSki and Alexander cells growth at a dose of 75μM (P less than 0.05, n is equal to four) and 66μM (P<0.05, n=4), respectively. Alpha-tocopherol showed a lesser growth inhibition of CaSki cell at IC₄₀ value of a concentration of 75μM (P less than 0.05, n is equal to four) and Alexander cell at IC₂₀ value of a concentration of 300μM (P less than 0.05, n is equal to four), respectively. Gamma-tocotrienol induced maximum apoptotic activity of both CaSki and Alexander cells at a concentration 150μM of treatment as compared to α-tocopherol at a concentration 300μM and 500μM, respectively. Evidence of the cellular DNA laddering fragments induced by both the compounds at similar doses as above was detected using electrophoresis. The results suggested that palm oil γ-tocotrienol and α-tocopherol exhibit antiproliferation effect on CaSki and Alexander cells via selective induction of apoptosis.

Author(s): Narimah AH Hasani, A. Ghapor MT1, Khalid BAK2, Wan Ngah WZ
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