Lycopene the structure of the molecule was determined by 1931. In its natural, all-"trans" form, the molecule is long and straight, constrained by its system of 11 conjugated double bonds. Each extension in this conjugated system reduces the energy required for electrons to transition to higher energy states, allowing the molecule to absorb visible light of progressively longer wavelengths. Lycopene absorbs all but the longest wavelengths of visible light, so it appears red. Plants and photosynthetic bacteria naturally produce all-"trans" lycopene. When exposed to light or heat, lycopene can undergo isomerization to any of a number of "cis"-isomers, which have a
Lycopene pressure, interactions with drugs that affect blood pressure may occur. Lycopene may affect the immune system, the nervous system, sensitivity to sunlight, or drugs used for stomach ailments. Lycopenemia is an orange discoloration of the skin that is observed with high intakes of lycopene. The discoloration is expected to fade after discontinuing excessive lycopene intake. In a review of literature on lycopene and its potential role as a dietary antioxidant, the European Food Safety Authority concluded that evidence was insufficient for lycopene having antioxidant effects in humans, particularly in skin, heart function, or vision protection from ultraviolet light. Although lycopene