Abstract
Tocotrienol-rich fraction (TRF), a subtype of vitamin E, has recently been reported to demonstrate promising neuroprotective properties. However, it remains to be fully determined how it confers protection in the brain. This scoping review aimed to explore and understand the intricate role of TRF in promoting and preserving neuronal well-being. A systematic literature search, based on the framework by Arksey and O'Malley and adhering to the PRISMA-ScR guidelines, was conducted across several databases, including PubMed, Scopus, and Web of Science (WOS), using the following phrases and Boolean operators: ("tocotrienol-rich fraction") AND (("neuroprotect") OR ("cognit") OR ("brain")). The search yielded a total of 24 eligible articles, shortlisted based on predetermined inclusion and exclusion criteria established at the outset of the study. The findings highlight a diverse array of TRF-related studies, both in vivo and in vitro, that revealed functional mechanisms through which TRF confers neuroprotection. These include, but are not limited to, antioxidant and anti-inflammatory effects via attenuation of superoxide dismutase (SOD) activity and pro-inflammatory mediators; regulation of metabolic pathways; regulation of neuronal genes, proteins, and maintenance of cellular functions; and subsequent improvements in memory and cognitive performance in animal models following TRF treatment. The convergence of these neuroprotective effects suggests that TRF holds potential as a supplement to support healthy ageing or, at the very least, slow neurodegeneration by mitigating pathological changes that often begin insidiously before the onset of symptoms associated with cognitive decline.