The terms “bioflavonoids” and “flavonoids” are used interchangeably since they both refer to the yellow plant pigments that give citrus fruits their color. Aside from their antioxidant capacity, these compounds provide visual cues to attract pollinators. Prior to the 1980s, however, bioflavonoids and flavonoids were collectively referred to as vitamin P. Of course, flavonoids are not vitamins, so this name has fallen to the wayside.
Citrus bioflavonoids exist in multiple forms and combinations. Hesperidin, for example, one of the most common citrus bioflavonoids, is a flavanone glycoside first isolated in the early 19th century that is now attributed with deterring inflammation and oxidative stress by modulating the pro-inflammatory cytokines TNF-α, IL-1β, and IL-6.
Quercetin is another bioflavonoid that supports heart health and exerts antioxidant and anti-inflammatory activity. Because it enhances collagen production, it is a popular ingredient in skin care products. However, as a nutrient or therapeutic agent, it is difficult to get enough quercetin from diet alone.
Another potent citrus bioflavonoid is rutin, also known as rutoside or quercetin-3-O-rutinoside because it consists of the flavanol quercetin and the disaccharide rutinose. This compound has demonstrated several pharmacological actions, most notably antinociceptive and neuroprotective effects.
Collectively, citrus bioflavonoids disarm free radicals that damage DNA and RNA by breaking the molecule chain of reactive oxygen species with the donation of one of their electrons.
