Natural Sources of Citrus Bioflavonoids:    

Citrus fruits and rinds (orange, grapefruit, lemon, lime).


Standardized citrus bioflavonoid extracts used in antioxidant products and multivitamin and mineral supplements.

Therapeutic Uses:    

– Aches (lower extremities)
– Anti-aging
– Anti-inflammatory
– Antioxidant
– Cancer
– Cataracts
– Cellular Regeneration
– Circulatory Disorders
– Cleansing/Detoxifying
– Cramps (legs)
– Eyesight Disorders
– Free Radical Related Diseases
– Immune System
– Lower LDL Cholesterol
– Nocturnal Leg Cramps
– Pain (lower extremities)
– Prevention of abnormal growths
– Sun Burn
– Vascular Disorders
– Wrinkles


Citrus bioflavonoids are polyphenolic compounds found in the fruits and rinds of citrus plants such as oranges, grapefruits, lemons and limes that are powerful antioxidants. The term “bioflavonoid” as opposed to flavonoid refers to the strong biological activity of these compounds. Bioflavonoids are often responsible for the attractive colors of fruits and vegetables and function within the plant world to protect against ultraviolet light damage from the sun and to attract insects and mammals for pollination and seed dispersal. Bioflavonoids, in general, are essential for the processing of vitamin C within the body and the maintenance of capillary walls. A deficiency of hesperidin in the diet, an abundant citrus bioflavonoid, has also been linked with abnormal capillary leakiness as well as pain in the extremities causing aches, weakness and night leg cramps. Additionally, bioflavonoids modulate the activity of various enzymes that positively influence normal as well as malignant cells and this contributes to the beneficial effects of citrus bioflavonoids in humans. Recent studies also suggest that nobiletin, another citrus bioflavonoid, may be a candidate anti-metastatic drug for preventing the spread of gastric cancer. Citrus bioflavonoids were first identified by Albert Szent-Gyorgyi in 1936, winner of The Nobel Prize for the discovery of vitamin C. He reported that citrus bioflavonoids strengthened blood vessel walls and prevented capillary permeability in ways that vitamin C did not. Indeed, he called these bioflavonoids ‘vitamin P’ after the Permeability factor because they prevented the permeability of capillaries. Later studies disputed his findings and these compounds never actually attained full vitamin status. This is because there are over 4,000 different flavonoids with different properties and biological activities. Later studies done by Dr. Jacques Masquelier of France found that certain bioflavonoids called oligomeric proanthocyanidins (concentrated in grape seeds) are the vitamin P that Szent-Gyorgyi spoke of.

Side Effects:   

The furanocoumarins within fresh citrus peels can cause photosensitivity in people exposed to high levels of UV, especially in people with fair skin. No signs of toxicity have been observed with the normal intake of hesperidin, nobiletin or other citrus flavonoids.

External References:

Garg A, Garg S, Zaneveld LJ, Singla AK. 2001. Chemistry and pharmacology of the Citrus bioflavonoid hesperidin.
Phytother Res 2001 Dec; 15(8): 655-69. Hakim IA, Harris RB, Ritenbaugh C. 2000. Citrus peel use is associated with reduced risk of squamous cell carcinoma of the skin.
Nutr Cancer 2000; 37(2): 161-8. Horowitz, R.M., and B. Gentili. 1977. Flavonoid constituents of Citrus. In S. Nagy, P.E. Shaw, and M.K. Veldhuis, eds., Citrus Science and Technology, vol. 1, pp. 397–426.
Avi Publishers, Westport, CT. Manthey JA, Grohmann K. 2001. Phenols in citrus peel byproducts. concentrations of hydroxycinnamates and polymethoxylated flavones in citrus peel molasses. J Agric Food Chem. 2001 Jul; 49(7): 3268-73.
Minagawa A, Otani Y, Kubota T, Wada N, Furukawa T, Kumai K, Kameyama K, Okada Y, Fujii M, Yano M, Sato T, Ito A, Kitajima M. 2001. The citrus flavonoid, nobiletin, inhibits peritoneal dissemination of human gastric carcinoma in SCID mice. Jpn J Cancer Res 2001 Dec; 92(12): 1322-8.