Illustrated Glossary of Organic Chemistry

Lycopene: A tetraterpene found in many plants. Lycopene is highly conjugated. Its HOMO-LUMO gap is small enough to allow absorption of green light photons, causing lycopene to appear red. Lycopene also has antioxidant properties.

Molecular structure of lycopene.

Lycopene imparts a reddish color to many plants, such as tomatoes.