John F Fitzloff

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A liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed to distinguish Asian ginseng (Panax ginseng C. A. Meyer) and North American ginseng (Panax quinquefolius L.). The method is based on the baseline chromatographic separation of ginsenoside Rf and 24(R)-pseudoginsenoside F11, two potential chemical markers present in ginseng root(More)
In vitro studies of enantioselective metabolism of R-(+)- and S-(-)verapamil (VER) were conducted using human cDNA-expressed CYP3A isoforms, CYP3A4, CYP3A5, and CYP3A7. N-dealkylated products nor-VER [2,8-bis-(3,4-dimethoxyphenyl)-2-isopropyl-6-azaoctanitrile] and D617 [2-(3,4-dimethoxyphenyl)-5-methylamino-2-isopropylvaleronitrile] were the major(More)
A new triterpene glycoside, 26-deoxyactein (1), along with two known compounds, 23-epi-26-deoxyactein (2), previously designated as "27-deoxyactein", and actein (3), were isolated from the roots/rhizomes of Cimicifuga racemosa. The structures and absolute stereochemistry of 1 and 2 were established by spectroscopic methods (FABMS, (1)H and (13)C NMR) and(More)
A gradient high performance liquid chromatographic method with evaporative light scattering detection (ELSD) for the simultaneous determination of ginkgolide A, ginkgolide B, ginkgolide C, ginkgolide J, bilobalide, quercetin, kaempferol and isorhamnetin in Ginkgo biloba is described. Samples are analyzed by means of a reverse-phase column (Supelco Discovery(More)
Two new flavonoid glycosides, 5-hydroxy-7,8-dimethoxy (2R)-flavanone-5-O-beta-D-glucopyranoside (1) and 5-hydroxy-7,8,2',5'-tetramethoxy-flavone-5-O-beta-D-glucopyranoside (2), and a new diterpenoid, andrographic acid (3), along with andrographidine A (4) were isolated from Andrographis paniculata, and their structures were determined on the basis of(More)
Caffeic acid derivatives occurring in black cohosh [Cimicifuga racemosa (L.) Nutt., Actaea racemosa (Ranunculaceae)], some of which may have pharmacological activity, were analyzed using high-performance liquid chromatography (HPLC) electrospray ionization tandem mass spectrometry (ESI-MS/MS) with the aim of developing a methodology for their rapid(More)
1. Human liver microsomes convert lindane (gamma isomer of 1,2,3,4,5,6-hexachlorocyclohexane) to four major primary metabolites; gamma-1,2,3,4,5,6-hexachlorocyclohex-1-ene (3,6/4,5-HCCH), gamma-1,3,4,5,6-pentachlorocyclohex-1-ene (3,6/4,5-PCCH), beta-1,3,4,5,6-pentachlorocyclohex-1-ene (3,4,6/5-PCCH), and 2,4,6-trichlorophenol (2,4,6-TCP); and two major(More)
A gradient high-performance liquid chromatographic (HPLC) method with evaporative light-scattering detection (ELSD) for the determination of major saponins in a Chinese traditional herbal medicine, Panax notoginseng, is described. Samples were analysed by means of a reverse-phase column (Waters Spherisorb ODS-2, C-18) using acetonitrile and water under(More)