(L)-Ascorbyl oleate and (L)-ascorbyl linoleate were synthesized by an immobilized lipase from Candida antarctica with yields of 38% and 44%, respectively. (L)-Ascorbyl oleate was stable in sterile culture medium over 12 h at 37 degreesC but (L)-ascorbyl linoleate degraded by 17%. Ascorbyl oleate had a better protective effect on human umbilical cord vein endothelial cells treated with H2O2 than Of (L)-ascorbic acid-2-phosphate-6-palmitate (Asc2P6P).