Alpha-tocopherol roba (Tocopherol, Alpha-tocopherol roba, bitamin E, E307) wani antioxidant ne wanda ke kare kwayoyin halitta daga lalacewa ta hanyar rage yawan iskar shaka na lipids (fats) da kuma samuwar free radicals.
Alpha-tocopherol an san shi da al'ada a matsayin mafi girman antioxidant na halitta a jikin mutum. Ma'auni na aikin bitamin E a cikin sassan duniya (IU) ya dogara ne akan karuwar haihuwa saboda rigakafin rashin zubar da ciki ba tare da bata lokaci ba a cikin berayen ciki lokacin shan alpha-tocopherol. Yana ƙaruwa da kusan 150% na al'ada a jikin uwa yayin daukar ciki a cikin mata.
1 IU na bitamin E an bayyana shi azaman ilimin halitta daidai da 0.667 milligrams na RRR-alpha-tocopherol (wanda ake kira d-alpha-tocopherol ko 1 milligram na all-rac-alpha-tocopheryl acetate (wanda ake kira dl-alpha-tocopheryl acetate). ainihin d, mahaɗin kwayoyin halitta l-synthetic, mai suna 2-ambo-alpha-tocopherol daidai, ba a kera shi ba).