Flax sed also known as flax oil and linseed oil, is derived from the seeds of the plant Linium usitatissimum. Flax seed oil is a very rich source of alpha-linolenic acid. Alpha-linolenic acid concentration in flaxseed oil ranges from approximately 40 to 60%.lower amounts of linoleic acid and oleic acid (each about 15%) are also present in flaxseed oil.ın addition, flaxseed contains varying amounts of the lignan, secoisolariciresinol diglycoside (SDG).