Lycopene

lycopene foodsLycopene is a member of the carotenoid family, specifically carotenes. It is a soluble red pigment found mainly in tomatoes but also in other red fruits, watermelon, elaeagnus umbellata, grapefruit. It owes its name to the Latin name for tomato (Solanum lycopersicum), which has the highest concentration in it’s natural form but only when cooked: 27 mg per 125 ml tomato puree, 17 mg per 125 ml of tomato sauce. In raw tomato lycopene values are lower but similar to those of the watermelon, which contains 3.5 mg to 8 mg depending on the crop for a portion of 125 ml.

Chemical structure and properties

Lycopene is a tetraterpene which consists of eight isoprene molecules. It’s formula is: C40H56.

It’s color is due to the eleven double bonds carbon-carbon covalent bonds: each double bond reduces the energy required for an electron to move to a higher energy level, which allows the molecule to absorb light at long wavelengths¬† (bathochromic shift). Lycopene absorbs most of the visible light spectrum apart from red.

Lycopene subjected to an oxidation reaction breaks the carbon=carbon double bonds to give smaller molecules, each twice linked to an oxygen atom. Although the C = O bonds also give a pigment, these molecules are too short to absorb enough light to appear coloured. Similarly, a reduction reaction can cause it to lose it’s colour by saturating the carbon atoms (turning the double bonds into single bonds).

Lycopene is fat-soluble and water-insoluble.

Sources of Lycopene

Fruits that contain the most lycopene are cooked tomatos, raw watermelon, pink grapefruit, guava, and papaya.

Unlike other nutrients in fruits and vegetables whose quantity decreases during cooking (eg vitamin C), cooking increases the amount of bioavailable lycopene in tomatoes. For this reason, the more common foods containing the most bioavailable lycopene are processed tomato-based soup, juice, sauce, paste and puree concentrate including ketchup. However, this is not the case for other fruits.

Medicinal Properties

Lycopene is the most powerful carotenoid for the elimination of intracellular oxygen atoms (oxidizing free radicals). Its effectiveness is due to its lipophilicity, free radicals formed in the lipid cells.

According to research, lycopene present in grapefruit (and also other fruits, including tomatoes) has a preventative effect against prostate cancer. Taking supplements such as Ateronon which contain high levels of bioavailable lycopene has a similar effect as the regular consumption of foods containing lycopene. This is associated with a reduced risk of cardiovascular disease, diabetes, osteoporosis, and even male fertility problems, and perhaps other cancers including those of the esophagus, colon and mouth.