title: Sensitive and rapid method to quantify icaritin and desmethylicaritin in human serum using gas chromatography-mass spectrometry.
abstract: The prenyl-flavones, icaritin and desmethylicaritin, are bioactive compounds from the traditional Chinese medicinal herb, Epimedium, extracts of which can enhance bone health in animal models. In order to examine their bioavailability in humans, we have developed and validated a sensitive method to quantify icaritin and desmethylicaritin in human sera, using gas chromatography-mass spectrometry. The serum samples were extracted with ethyl acetate and then derivatized with BSTFA in pyridine (4:1). With genistein as internal standard, calibration curves with good linearity (R(2)>0.99) within the concentration range of 0.15-10nM in the selective ion monitoring mode were obtained. The limits of detection and quantization were 11 and 33 pM for icaritin, and 23 and 70 pM for desmethylicaritin, respectively; inter- and intra-assay variabilities were <15%, and accuracies were between 89 and 110%. Icaritin, but not desmethylicaritin, was detected from 1h, increasing to a peak at 8h (1.51+/-1.6 nM) in sera of human volunteers after ingestion of an aqueous decoction of Epimedium. This sensitive method can be used to quantify serum levels of icaritin and desmethylicaritin for pharmacokinetic studies.
authors.affiliation: Department of Obstetrics & Gynecology, National University Hospital, Yong Loo Lin School of Medicine, National University of Singapore, Republic of Singapore.
authors.forename: Ping
authors.initials: P
authors.lastname: Shen
authors.forename: Shih Peng
authors.initials: SP
authors.lastname: Wong
authors.forename: E L
authors.initials: EL
authors.lastname: Yong
mesh_terms: D000284:Administration, Oral; D001682:Biological Availability; D002138:Calibration; D004365:Drugs, Chinese Herbal / Q000032:analysis* / Q000737:chemistry / Q000493:pharmacokinetics; D034181:Epimedium / Q000737:chemistry*; D005240:Feasibility Studies; D005419:Flavonoids / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D008401:Gas Chromatography-Mass Spectrometry; D019833:Genistein / Q000592:standards; D006801:Humans; D008593:Menopause / Q000187:drug effects; D015394:Molecular Structure; D008517:Phytotherapy; D010946:Plants, Medicinal / Q000737:chemistry; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D014297:Trimethylsilyl Compounds / Q000737:chemistry
chemical_list: D004365:Drugs, Chinese Herbal; D005419:Flavonoids; D014297:Trimethylsilyl Compounds; C499404:desmethylicaritin; C047270:N,N-bis(trimethylsilyl)-2,2,2-trifluoroacetamide; D019833:Genistein; C499403:icaritin