Anticancer activities of tocotrienols: A Systematic Scoping Review

Abstract

Background: The increasing number of cancer cases requires developing newer approaches to treat this disease. One approach uses natural compounds with known anticancer effects, such as tocotrienols. Many cell-based and animal-model studies found that tocotrienols possess potent anticancer activities. However, the exact molecular regulatory mechanism through which tocotrienols exert anticancer actions remains unclear. Methods: This scoping review analysed data from original research articles reporting on the anticancer effects of tocotrienols on human cancer cell lines published in the last seven years (January 2015 and September 2021) using a systematic scoping review approach. From the initial 619 research papers [ProQuest (n= 61), PubMed (n= 84), Embase (n = 148), Ovid Medline (n =53), Scopus (n = 137), Web of Science (n =136)] identified using pre-defined keywords, only 37 articles met the inclusion and exclusion criteria for this review. Human cancers commonly studied in the 37 research articles include breast, lung, prostate and colorectal cancer cell lines. Results: The analysis showed that exposing human cancer cell lines to tocotrienols triggered common anticancer mechanisms such as activation of apoptosis and inhibition of proliferation, angiogenesis and cell migration through regulation of key regulatory genes and proteins involved in these pathways. Conclusions: The findings show that tocotrienols regulate a number of biomarkers that induce cell death and regulate cell cycle in various types of human cancer cells. Further targeted studies are required to map the definite pathways by which T3 exerts their action and to better understand the cellular actions and the regulatory pathways.