Integrative toxicity assessment of tocotrienol-rich fraction from palm oil using in silico methods and zebrafish embryotoxicity model

Abstract

Tocotrienol-rich fraction (TRF), a natural form of vitamin E derived from palm oil, possesses antioxidant properties. However, its potential embryonic developmental toxicity remains unclear. This study investigated TRF's toxicity using in silico methods and zebrafish embryos. Zebrafish embryos were exposed to TRF (31.25 to 2000 μg/mL) for 96 h post-fertilization (hpf). Mortality, hatching rate, heart rate, and morphological malformations were assessed at 24, 48, 72, and 96 hpf. In silico analysis predicted good pharmacokinetic properties and minimal side effects for five TRF constituents, except for hERG II inhibition, which is associated with cardiac toxicity. TRF exposure up to 96 hpf showed no embryotoxicity in zebrafish at ≤1000 μg/mL. However, TRF at concentrations of ≥1000 μg/mL significantly inhibited hatching rate at 72 hpf, indicating a delay in the hatching process. Additionally, 1000 μg/mL of TRF resulted in reduced heart rate and hypopigmentation in the embryos. Moreover, higher TRF concentrations (≥500 μg/mL) caused morphological malformations including spinal curvature, pericardial edema, and yolk sac edema, in the embryos. These findings suggest that TRF from palm oil is likely safe at concentrations below 500 μg/mL during embryonic development. However, the potential effects of long-term exposure and chronic toxicity warrant further investigation to ensure safety during early pregnancy.