The 3,7,4′-tri-O-methylated form of quercetin, known as ayanine, has been reported as a potent inhibitor of breast cancer resistance protein (BCRP) [8] and has recently shown promise in the treatment of methicillin-resistant Staphylococcus aureus infections [9]. This evidence concerns the gene ABCG2 and staphylococcus aureus infection.