3′,4′,5,7-Tetra-O-methylquercetin

3′,4′,5,7-Tetra-O-methylquercetin (also known as 3-hydroxy-3′,4′,5,7-tetramethoxyflavone) is a methylated version of quercetin, the Molecule of the Week for December 9, 2013. Both molecules are members of the ever-expanding flavonoid family that are touted to have medical and dietary benefits.

Flavonoids occur in a wide variety of plants, including many food crops. In the past 30 years, flavonoids and other polyphenols contained in red wines have been offered as one explanation of the “French paradox”, the observation that, despite a high intake of saturated fats, French people are not widely diagnosed with coronary heart disease.

In 2009, Randall S. Alberte and colleagues at the HerbalScience Group (Naples, FL), the University of Miami School of Medicine (FL), and HerbalScience Singapore reported that an elderberry fruit (Sambucus nigra) extract inhibited infection by the human influenza A virus (H1N1) in vitro. They identified 3′,4′,5,7-tetra-O-methylquercetin as one of two major compounds that were isolated from the extract.

Subsequent synthesis of the compound gave similar results, which compared favorably to those obtained with the commercial flu medicine oseltamivir (Tamiflu). A search of the US Food and Drug Administration and HerbalScience Web sites, however, turned up no evidence that 3′,4′,5,7-tetra-O-methylquercetin was ever submitted for drug approval.