Herbacetin
Herbacetin is a flavonol, a type of flavonoid. Glycosides 
Herbacetin diglucoside can be isolated from flaxseed hulls. Rhodionin is a herbacetin rhamnoside found in Rhodiola species. Other related compounds 
Rhodiolin, a flavonolignan, is the product of the oxidative coupling of coniferyl alcohol with the 7,8-dihydroxy grouping of herbacetin. It can be found in the rhizome of Rhodiola rosea. References

Flavonols
Hydroxyquinols