Carotene

Carotenes, a subgroup of the larger carotenoid group of chemicals, are hydrophobic, highly unsaturated compounds with a variety of beneficial health effects due to their antioxidant properties. Both $\alpha$-carotene and $\beta$-carotene are chemical precursors of vitamin A. They are structurally very similar to a number of other carotenoids including lutein, zeaxanthin, cryptoxanthin and lycopene.

Alpha-carotene

© Image: David E. Volk
$\alpha$-carotene.

Beta-carotene

© Image: David E. Volk
$\beta$-carotene.