https://www.sciencedirect.com/topics/nursing-and-health-professions/alpha-tocotrienol
alpha-Tocotrienol made up 0 to 16.72% of the total Vitamin E content in annatto seeds- https://www.researchgate.net/publication/318601954_Tocotrienol_and_tocopherol_contents_of_annatto_seed_accessions
Tocotrienols are found in ... barley germ... -https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4392014/
(Therefore, it may be worth to seek out unpearled barley.)
https://www.amazon.com/dp/B004KU4S6S