Introduction of Lycopene2010-02-12
Lycopene (Molecular Formula: C40H56) is a bright red carotene and carotenoid pigment (Figure 1 upper left) and phytochemical found in tomatoes and other red fruits & vegetables, such as watermelon, eggplant, papaya, red guava, cherry, plum, capsicum. There are more than 6000 carotenoids in different colors found in the world, which are the major pigments formed when fruits and vegetables are matured. However, the reason why the fruits and vegetables have to generate large amount of carotenoids is still unrevealed.
The study of Lycopene has been started long time ago.
In 1873, Hartsen isolated the red crystal from berries, but the purity is very low. (Hartsen; Chem. Centr. 1873:204). It is the first time to encounter with lycopene for human.
★ In 1875, Millardet obtained a crude mixture containing lycopene from tomatoes (Millardet; Bull. Soc. Sci. Nancy, 1875; 2: 21), but could not distinguish from other carotenes.
★ Until 1903, tomato pigment was again studied by Schunck who found the red coloring matter clearly distinguishable from carotene in appearance, crystal form, solubility, and absorption spectrum, and named it Lycopene.（Schunck, C.A. Proc. Royal Soc. London, 1903; 72: 165)。
★ In 1910, Willstaller and Escher determined the molecular formula of Lycopene as C40H56 and the molecular weight is 536.85（Willstatter, R. & Escher, H.H.Z.; Physiol. Chem., 1910；64: 47）.
★ By 1930, Karrer et al. had described the structure of the carotene molecule which is loycopene (C40H56), an open-chain highly unsaturated hydrocarbon carotenoid with 11 conjugated double bonds and 2 unconjugated double bonds. Beta-carotene can be formed by cyclization of lycopene. (Karrer, P,et al.; Pflanzenfarbstoffe. XXV. Leber die Konstitution des Lycopins und Carotins. Acta, 1930; 14: 154-162)
The chemical structure of Lycopene has been studied and well understood. However, there was still a long way to go for the biological functions. In 1980s, people started to realize the important role of lycopene for its anti-tumor effect, hypolipidemic effect and other healthcare functions in our daily life.
★ For example, in 1985 the researchers from Harvard University found that the trend of decreased cancer risk with increaseing intake of carotene containing vegetables and fruits is significant. Colditz GA, et al. Increased green and yellow vegetables intake and lowered cancer death in an elderly population. Am.J. Clin. Nutr. 1985；41: 32-36.
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