Screening for ligands of human aromatase from mulberry (Mori alba L.) leaf by using high-performance liquid chromatography/tandem mass spectrometry

Aromatase, a cytochrome P450 (CYP19) enzyme that catalyses the conversion of androgens to oestrogens, is an important target for breast cancer therapy. Flavonoid has been proved to be potential therapeutic agent for breast cancer by inhibiting the activity of aromatase and is one of the main active constituents of mulberry leaves. In this study, twelve flavonoids, 3,5,7,3′,4′-pentahydroxyflavone-3-glucosyl-glucoside/3,5,7,3′,4′-pentahydroxyflavone-3,7-diglucoside, mulberroside F, 3,5,7,3′,4′-pentahydroxyflavone-3-(6″-malonyl)-glucoside, 3,5,7,4′-tetrahydroxyflavone-3-(6″-malonyl)-glucoside, 3,5,7,4′-tetrahydroxyflavone-3-O-(6″-acetyl)-glucoside, 3,5,7,3′,4′-pentahydroxyflavone-3-rutinoside, 3,5,7,3′,4′-pentahydroxyflavone-3-glucoside/3,5,7,2′,4′-pentahydroxyflavone-3-glucoside, kuwanon G, 5,7,3′,4′-tetrahydroxyflavone-7-rutinoside/3,5,7,4′-tetrahydroxyflavone-3-rutinoside, 3,5,7,4′-tetrahydroxyflavone-3-glucoside, 3,5,7,3′,4′-pentahydroxyflavone-3-O-(6″-acetyl)-glucoside and chalcomoracin/mongolicin F, and three fatty acids, 9,12,15-octadecatrienoic acid, compounds 12 and 13, were tentatively identified by HPLC-DAD-ESI-MS/MS method. Seven of the compounds, 3,5,7,3′,4′-pentahydroxyflavone-3-rutinoside, 3,5,7,3′,4′-pentahydroxyflavone-3-glucoside/3,5,7,2′,4′-pentahydroxyflavone-3-glucoside, 3,5,7,4′-tetrahydroxyflavone-3-glucoside, chalcomoracin/mongolicin F and 9,12,15-octadecatrienoic acid, were revealed unequal binding capability for aromatase by HPLC-DAD-ESI-MS/MS.