Flavonoids or bioflavonoids are non-nitrogenous plant pigments. Its functions in the plant world seems to be to attract pollinators to flowers or animals that eat the fruits with the intention that they can disperse the seeds.
A very distinctive , for example, is that of bromeliads among which we have Tillandsias or Billbergias . These plants develop flowers on a kind of stem that emerges from a number of rosette leaves. This stem is formed by a series of bracts. These bracts have a strong reddish color before or during pollination and then become more green.
Other times flavonoids have the function to attract prey. The same carnivorous plants such as sundew, uses anthocyanins in their flowers to attract insects which it devours.
Many times the flavonoids are the plant adaptive response to intense ultraviolet radiation. These components protect plants from the harmful effects of these noxious rays. Other times these components show unpleasant flavors what would constitute an advantage against herbivores that would reject these kind of food.
Some flavonoids give these components the yellow color and the general name of these principles, since flavus in Latin means "yellow". So, the word flavonoid derives from the latin word flavus. . Other ones t provide the red color of buds, shoots or leaves in autumn. They are also responsible for the colors of many fruits. Many varieties of color in the flowers depend on the acidity of the medium. Acidic conditions provides strong red colors; an alkaline medium, blue color and a neutral environment, provides the violet. These variations explain because the same plant, such as hydrangea , color varies according to where it is planted.
More than 600 flavonoids have been discovered. They all seem to have an important role in human food. They have very interesting medicinal properties . These properties might include:
Antioxidant properties: Most of them, especially catechins of green tea, have a high capacity to neutralize the free radicals and to prevent the pernicious effects these have on the health of our body. Used as supplements , in combination many times with the vitamin C , can be able to neutralize virus like those of herpes.
Anticancerous properties: Many flavonoids have been tremendously effective in the treatment of the cancer. It is known that many inhibit the growth of cancer cells
Cardiotonic properties: They have a tonic effect on the heart , strengthening the heart muscle and improving circulation. Mainly attributed to the flavonoid quercetin, although it appears less intense in others, such as genistein and luteolin.
Capillary fragility: They improve the strength of capillaries, so they prevent them to break, preventing bleeding. Among all the flavonoids, hesperidin , rutin and quercetin should be mentioned in order of importance
Antithrombotic properties: The ability of these components to prevent thrombus formation in blood vessels allows better circulation and prevention of many cardiovascular diseases.
Lowering cholesterol: Its capacity to reduce cholesterol and triglycerides supposes an advantage in the health of the circulatory apparatus.
Protection of the liver: Some flavonoids have demonstrated their protective power against liver diseases. Silymarin from milk thistle has been tested experimentally as a protective and regenerative for the liver in hepatitis. The same flavonoid, together with apigenin and quercetin, are very useful to eliminate certain digestive ailments related to the liver, like the feeling of fullness or vomits.
Protection of the stomach: Certain flavonoids, including quercetin, rutin and kaempferol have properties , anti-ulcer properties which can be useful to protect the gastric mucosa or inner linnen of the stomach.
Anti-inflammatory and analgesic: Hesperidin, from lemons or oranges, and other flavonoids, for its anti-inflammatory and analgesic properties, have been used for the treatment of certain diseases such as arthritis.
Antimicrobial: Most of these principles have proven to have antiviral, antifungal and antibacterial.
Most of flavonoids in fruits are found in the skin , reason why it is better to eat them without peeling them, once we have washed them properly.
Main flavonoids and carotenoids
The most important flavonoids would be the following: