Antioxidant activity of flavonoids

Flavonoids are polyphenolic compounds widely found in fruits, vegetables, tea, and wine, and are well known for their potent antioxidant activity, primarily through free radical scavenging, hydrogen atom/electron donation, metal chelation, and modulation of endogenous antioxidant enzymes. Their bioactivity extends to anti-inflammatory, anticancer, antimicrobial, hepatoprotective, and cardioprotective properties, largely attributed to their capacity to reduce oxidative stress. The antioxidant effectiveness depends on specific molecular features such as the number and position of hydroxyl groups and conjugation in the flavonoid structure. Despite promising preclinical and epidemiological data, clinical translation is limited by poor bioavailability and uncertain pharmacokinetics. "Antioxidant activity of flavonoids" denotes a functional mechanism rather than a discrete molecular or receptor target; flavonoids themselves are studied as bioactive compounds rather than targetable entities.

Other names

FlavonoidPolyphenolic flavonoid

Flavonoids exert their biological effects primarily through free radical scavenging (neutralizing reactive oxygen and nitrogen species, ROS/RNS) via hydrogen atom and electron donation. They also chelate transition metals, such as iron, thereby preventing their role in free radical generation. Furthermore, flavonoids can inhibit free radical-generating enzymes (e.g., microsomal monooxygenase, glutathione S-transferase), modulate receptor and kinase activity (including Aryl hydrocarbon Receptor (AhR), tyrosine kinases, and G protein-coupled receptors (GPCRs)), and upregulate endogenous antioxidant enzymes.