Flavonols

Flavonols are a class of flavonoids that use the 3-hydroxyflavone backbone (3-hydroxy-2-phenylchromen-4-one (IUPAC)). Their diversity stems from the different positions the phenolic -OH groups.

Some examples include:
 * Quercetin (3,3',4',5,7-pentahydroxy-2-phenylchromen-4-one)
 * Kaempferol (3,4',5,7-tetrahydroxy-2-phenylchromen-4-one)
 * Myricetin (3,,3',4',5',5,7-hexahydroxy-2-phenylchromen-4-one)
 * Fisetin (3,3',4',7-tetrahydroxy-2-phenylchromen-4-one)

Flavonoli