Open AccessScreening and structural characterization of α-glucosidase inhibitors from hawthorn leaf flavonoids extract by ultrafiltration LC-DAD-MSn and SORI-CID FTICR MS
Author(s) -
Huilin Li,
Fengrui Song,
Junpeng Xing,
Rong Tsao,
Zhiqiang Liu,
Shuying Liu
Publication year - 2009
Publication title -
journal of the american society for mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.961
H-Index - 127
eISSN - 1879-1123
pISSN - 1044-0305
DOI - 10.1016/j.jasms.2009.04.003
Subject(s) - vitexin , chemistry , orientin , isovitexin , tandem mass spectrometry , chromatography , luteolin , flavones , mass spectrometry , electrospray ionization , fourier transform ion cyclotron resonance , quercetin , flavonoid , biochemistry , antioxidant
In vitro alpha-glucosidase inhibition assays and ultrafiltration liquid chromatography with photodiode array detection coupled to electrospray ionization tandem mass spectrometry (ultrafiltration LC-DAD-ESI-MS(n)) were combined to screen alpha-glucosidase inhibitors from hawthorn leaf flavonoids extract (HLFE). As a result, four compounds were identified as alpha-glucosidase inhibitors in the HLFE, and their structures were confirmed to be quercetin-3-O-rha- (1-4)-glc-rha and C-glycosylflavones (vitexin-2"-O-glucoside, vitexin-2"-O-rhamnoside and vitexin) by high-resolution sustained off resonance irradiation collision-induced dissociation (SORI-CID) data obtained by Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS). Several other C-glycosylflavones (vitexin, isovitexin, orientin, isooriention) and their aglycones apigenin and luteolin were evaluated by in vitro assays, and were found to possess strong alpha-glucosidase inhibitory activities as well. Moreover, the substituent groups on the flavones had a great impact on the enzyme inhibition activity. C-3'-OH of the B-ring of flavones in particular increased the alpha-glucosidase inhibition activity, whereas C-glycosylations at C-6 or C-8 of the A ring weakened the inhibition activity.