What are the health benefits of flavonoids?

Cancer prevention:

Dietary flavonoid intake is associated with reduced gastric carcinoma risk in women, and reduced aerodigestive tract cancer risk in smokers.

Inflammation Prevention:

Flavonoids have also been proposed to inhibit the pro-inflammatory activity of enzymes involved in free radical production, such as cyclooxygenase, lipoxygenase or inducible nitric oxide synthase, and to modify intracellular signaling pathways in immune cells,or in brain cells after a stroke.

Antibacterial Activity:

Flavonoids has activity to fight against infection and bacteria . It also helps to increase the effect of antibiotics acting against bacterial infection.

Flavonoids have been shown to have  direct antibacterial activity,  synergistic activity with antibiotics, and (c) the ability to suppress bacterial virulence factors in studies.