Beta carotene, the coloration pigment of dark green and orange plants, is a highly effective antioxidant, particularly against singlet oxygen radicals.
Most beta carotene is converted in the intestines and liver to Vitamin A, but some is absorbed intact by the lymphatic system and circulates in the blood. While preformed vitamin A can be toxic at extremely high doses given over a prolonged period, beta carotene has extremely low toxicity.
