Characterization of prenylated xanthones and flavanones by liquid chromatography/atmospheric pressure chemical ionization mass spectrometry

Abstract

Reversed‐phase liquid chromatography with atmospheric pressure chemical ionization mass spectrometry (LC/APCI‐MS) in the positive‐ion mode was utilized to analyze crude ether extracts from the root bark of Maclura pomifera, a tree known to have a high content of prenylated xanthones and flavanones. Identification of three xanthones and two flavanones was based on their unique mass spectra. Under optimum conditions peaks corresponding to the [MH]+ ion and characteristic fragments for each compound were observed. 1H NMR data were used to confirm the identities of two xanthones that had the same molecular mass and similar fragmentation patterns. Fragmentation of the analytes was achieved by application of an electrostatic potential at the entrance of the single quadrupole mass spectrometer. The optimum voltage for fragmentation was found to be related to the class of compounds analyzed and, within each class, to be dependent on the structure of the prenyl moiety. Collision‐induced pathways consistent with precedent literature describing the MS characterization of similar compounds and with the observed fragmentation patterns are tentatively proposed. Copyright © 2000 John Wiley & Sons, Ltd.

Effect of eluent on the ionization efficiency of flavonoids by ion spray, atmospheric pressure chemical ionization, and atmospheric pressure photoionization mass spectrometry

“…The use of APCI and ESI has been widely accepted for the analysis of flavonoids 20–23. Owing to the soft ionization of APCI and ESI, the flavonoid glycosides can be detected as protonated or deprotonated molecules together with diagnostic fragment ions.…”

Natural Products in the Process of Finding New Drug Candidates

“…The relationship between the flavonoid structure, such as the location of the hydroxyl groups as well as sugar moieties, and mass spectra have been studied using ESI-MS [56] and APCI-MS [57]. The limit of detection for flavonoids in full scan MS mode has been reported to vary from 0.1 ng to 40 ng per injection by ESI [58,59], which is reported to be more sensitive than APCI [60]. The mass spectrometric behavior of five flavonoid standards, (+)-catechin, isorhamnetin, vitexin, isoquercitrin and luteolin-3,7-diglucoside, in different HPLC eluent conditions was studied using an LC/MS instrument equipped with three different API interfaces: IS, APCI and APPI [53].…”

Naturally-Occurring Xanthones: Recent Developments

“…The majority of these xanthones has been reported from the Clusiaceae family, while the rest were isolated from plants of the families Annonaceae (Anaxagorea luzonensis [91]) and Moraceae (Cudrania cochinchinensis [173], C. tricuspidata [133], Maclura pomifera [174] and M. tinctoria [18]). …”

“…Calophyllum brasiliense [20] Cudraxanthone S (312) * R 1 =C; R 2 =R 3 =R 4 =H Cudrania cochinchinensis [16] 1,3,5,6-Tetrahydroxy-4-isoprenylxanthone (313) R 2 =A; R 1 =R 3 =R 4 =H Hypericum japonicum [92] Isocudraniaxanthone A (314) R 1 =R 3 =R 4 =H; R 2 =C Garcinia vieillardii [82,98] Montrouxanthone (315) R 1 =R 3 =R 4 =H; R 2 =D Montrouziera sphaeroidea [190] ( [133] Gerontoxanthone I (318) R 1 =A; R 2 =C; R 3 =R 4 =H Cudrania cochinchinensis [173] Macluraxantone C (319) * R 1 =C; R 2 =A; R 3 =R 4 =H Maclura tinctoria [18] Isoalvaxanthone (320) R 1 =C; R 2 = R 4 =H; R 3 =A Cudrania cochinchinensis [173] Alvaxanthone (321) R 1 =C; R 2 = R 3 =H; R 4 =A Cudrania cochinchinensis [173] Maclura pomifera [174] Virgataxanthone A (322) * R 1 =R 3 =H; R 2 =D; R 4 =A Garcinia virgata [198] Garciniaxanthone E (323) R 1 =R 2 =H; R 3 =D; R 4 =A Garcinia subelliptica [19] Garcinia xanthochymus [33] Isogarciniaxanthone E (324) * R 1 =H; R 2 =R 3 =R 4 =A Garcinia subelliptica [19] Garcinia xanthochymus [ Assiguxanthone B (329) R 1 =A; R 2 =R 3 =R 4 =H Hypericum androsaemum [109] Hypericum perforatum [110] Kielmeyera variabilis [15,197] Cudratricusxantone E (330) * R 1 =R 2 =A; R 3 =R 4 =H Cudrania tricuspidata [133] Macluraxanthone B (331) * R 1 =C; R 2 =A; R 3 =R 4 =H Cudrania tricuspidata [133] Maclura tinctoria [18] -Mangostin (332) R 1 =R 4 =A; R 2 =R 3 =H Garcinia mangostana [36,189,191,196] Hypericum androsaemum [84,109] Norcowanin (333) R 1 =A; R 2 =R 3 =H; R 4 =D Garcinia fusca [29] Cudratricusxantone B (334) * R 1 =R 3 =H; R 2 = R 4 =A Cudrania tricuspidata [133] Cudratricusxantone A (335) * R 1 =R 3 =H; R 2 =C; R 4 =A Cudrania tricuspidata …”