1.Palm Tocotrienols Reduce Lipopolysaccharide-Stimulated Inflammatory Responses of Microglia
Shi Wei Tan ; Maha Abdullah ; Daud Ahmad Israf Ali ; Sharmili Vidyadaran
Malaysian Journal of Medicine and Health Sciences 2016;12(2):1-8
Introduction: The potential immunoregulatory effects of
tocotrienols, the less studied form of vitamin E, had not been
determined for microglia until our last publication showcased
primary evidence of palm tocotrienols limiting microglia
activation, explicitly by inhibiting nitric oxide (NO) production.
Here we further explored the nitrite scavenging activity of the
two most potent NO-reducing tocotrienol isoforms - δ-
tocotrienol and Tocomin50% (contains a spectrum of
tocotrienols and α-tocopherol) based on their inhibitory effects
on NO production and also their effects on CD40 (a microglial
co-stimulator molecule) expression of BV2 microglia. Methods:
BV2 cells were treated with two different doses of tocotrienols
(δ-tocotrienol: 3.96 μg/mL and 19.80 μg/mL; Tocomin50%:
47.50 μg/mL and 237.50 μg/mL) followed by stimulation with 1
μg/mL of lipopolysaccharide (LPS). A chemical scavenging
assay was conducted to study the nitrite scavenging activity of δ-
tocotrienol. Together with Tocomin50%, we also determined
their effects on CD40 expression of BV2 microglia via flow
cytometry. Results: We demonstrate that the inhibitory effect of
tocotrienols on NO production by microglia is not attributed to
their nitrite scavenging activity. Additionally, tocotrienols also
reduced the expression of the microglial co-stimulator molecule,
CD40. Conclusions: Our data aids the further characterisation
of the actions of tocotrienols on microglia, offering insight into
the potential modulatory properties of palm tocotrienols on
microglial inflammatory responses within the central nervous
system (CNS).