Effect of the tocotrienol-rich fraction (TRF) on the healthspan of Caenorhabditis elegans

Abstract

Vitamin E is an established antioxidant. However, the effect of vitamin E on healthspan, which deteriorates during ageing, has not been determined because most related studies have emphasized its effects on lifespan. Therefore, the purpose of this study was to determine the effect of palm tocotrienol-rich fraction (TRF) on the lifespan, locomotion and thermotolerance of Caenorhabditis elegans, which share many common gene sequences with humans. The nematodes were treated with different concentrations of TRF (0 - 200 μg/mL), and the number of surviving nematodes at each concentration (N=30, duplicate) was counted daily under a light microscope to determine the optimal dose of treatment. The nematodes were divided into 3 groups, namely; control, Tween-80 (vehicle) and TRF-treated. Locomotion and thermotolerance were determined on day 4 and 12 of treatment in adult nematodes. ImageJ was used for locomotion analysis, and thermotolerance was determined based on nematode survivals after exposure to 37 °C. TRF-treated C. elegans had significantly longer lifespans compared to controls (P = 0.003). The TRF group (50 μg/mL) had the longest mean lifespan (23.5 days), which was significantly longer compared to controls, (18.5 days; (P = 0.002). However, locomotion was similar between all groups. In the thermotolerance assay, the survival determined on day 4 and day 12 of TRF-treatment was higher compared to controls (P= 0.046). Interestingly, the Tween- 80-treated group showed similar results as the TRF-treated group compared to controls. The findings indicate that TRF prolongs the lifespan and increases the thermotolerance of C. elegans but does not improve the locomotion of the worms as they age.