It was a boring green/yellow Earth before 140 million years ago when Flowering plants (Angiosperms) were not born. The entire world as we see today became vibrantly coloredwith red, pink, purple , majenta , violet , blue and all their shades when Angiosperms entered the world with their variously colored flowers and fruits. Anthocyanins are coloring pigments of most flowers and fruits like blueberries, raspberries, currants, grapes, Jamun, dates, red to purplish blue-colored leafy vegetables, grains, roots, and tubers .
Anthocyanins are C15 (C6-C3-C6) polyphenols structurally related to flavonols, consisting of a skeleton in which two benzene (aromatic) rings connected by a propane unit. They occur as glycosides (glycones) dissolved in cell sap. Anthocyanidins are their aglycones (non-sugar part). With acids they become red and with alkalies, blue. The various shades of colors mentioned in the beginning are made by change in pH or metal complexing. There are about 600 anthocyanins (glycosides ) based on 16 anthocyanidins. The most common anthocyanindins are cyanidin, delphinidin and pelargonidin.
In India the known sources of anthocyaninsare red grapes, Jamun fruits, mulberry, and petals of rose, Ixora, Woodfordia etc. But in Europe there are many sources such as fruits belonging to the genus Vaccinium ( such as blueberry, cranberry,and bilberry), Rubus (Black raspberry, red raspberry and blackberry), other fruits like blackcurrant (Ribes nigrum),Red-fleshed peaches, cherry, brinjal, black rice, Concord grape, muscadine grape, red cabbage , violet or red petals, genetically bred/modified tomatoes and ripened olives. The seed coat of black soybean (Glycine max L. Merr. ) and skins and pulp of black chokeberry (Aronia melanocarpa L.) are reported to have the maximum anthocyanin content i.e., about 2,000 mg per 100 g. However, the fruit pulp of açaí palm (Euterpe oleracea) having about 320 mg per 100 g has a single compound, cyanidin-3-glucoside, forming the largest share (approximately 10 mg per 100 g). In addition, the artificial crops such as blue- or red-flesh potatoes and purple or red broccoli, cabbage, cauliflower, carrots, corn also provide edible anthocyanins.
The medical benefits of anthocyanins were recognized during Second World War time when Royal Air Force pilots reported increasing night vision and overall vision during night sorties. As they were solely on bread and blueberry jam continuously for weeks and months, scientists discovered that it was the blue berry jam, containing anthocyanins, responsible for the increase in night vision. It was later experimentally proved that anthocyanins regenerate rhodopsin in retina, protect from retinal inflammation, prevention of glaucoma, cateract (esp. due to diabetes) and oxidative damage of lens epithelial cell and increases and increase ocular blood flows. Therefore extracts of blueberry, raspberry, strawberry , blackberry are recommended for elderly people for delaying cataract and vision related disorders in Europe.
Other benefits of Anthocyanins are as follows
2. Anti-tumor properties
Anthocyanins are well-known for their ability to reduce cancer cell proliferation and to inhibit tumor formation (Hou, 2003), due to their antioxidant properties and inhibition of cyclooxygenase enzymes. They stall growth of pre-malignant cells, accelerate the rate of cell turnover, called apoptosis, effectively making the cancer cells die faster, reduce inflammatory mediators that initiate tumor onset, inhibit growth of new blood vessels that nourish tumors, a process called angiogenesis and minimizing cancer-induced DNA damage.
3. Protection from cardiovascular disease
The antioxidant properties are considered crucial in cardiovascular disease protection exhibited by anthocyanins. They reduce inflammation and enhance capillary strength and permeability, and to inhibit platelet formation and enhance nitric oxide (NO) release causing vasorelaxation in aorta and capillaries. When rats were fed with anthocyanin-rich extracts, significant reduction in indices of lipid peroxidation and DNA damage resulted.
4. Prevention of obesity and diabetes
Hyperglycemia, hyperinsulinemia, and hyperleptinemia are some other clinical problems which can be rectified by an anthocyanin-rich diet.
5. Anti-inflammatory properties
Anti-inflammatory properties of anthocyanins are well-proved. These compounds are found to down-regulate expression of enzymes involved in inflammation in the lung (Rossi et al., 2003).
Anthocyanins from Hibiscus sp. have historically been used in remedies for liver disfunction and hypertension.. It is to be mentioned that anthocyanins of Ixora and Hibiscus are used ad hair dyes.
Source :
Useful Herbs of the Planet Earth, by M. Daniel, (2012), Scientific Publishers,
Jodhpur, Pages 399- 402
Mammen Daniel
