title: HPLC separation of naringin, neohesperidin and their C-2 epimers in commercial samples and herbal medicines.
abstract: Flavanone glycosides, such as naringin and neohesperidin, are distributed in some Citrus species and have a chiral center in the C-2 position of the flavanone moiety. Naringin and neohesperidin (2S-form) were separated from the corresponding C-2 epimers (2R-epi-form) by normal-phase HPLC using a polysaccaride-derived chiral stationary phases (CSPs), CHIRALPAK IB. The analyses of commercial samples of naringin revealed that the relative ratios of naringin to the C-2 epimer were 29-89%. In the case of a commercial sample of neohesperidin, the relative ratio of the neohesperidin (2S-form) is 84%. The HPLC application to Citrus species used as crude drugs in Japan (Kijitsu, Kikoku and Tohi) showed that the relative ratios of naringin to the C-2 epimer were 75-93% in Kijitsu, 74-79% in Kikoku and 54-64% in Tohi. However, there is a quite small ratio of the (2R)-epi-neohesperidin in Citrus. This result suggested that the averages of relative ratio of (2S)-naringin in Citrus species reduced according to the maturity of fruits (Kijitsu<Kikoku<Tohi). Since the relative ratios of (2S)-naringin of dry extracts of 5 Kampo formulations (including Kijitsu or Kikoku) decreased to 42-54%, the conversion from naringin to the (2R)-epimer might be enhanced during the decoction process of the formulations.
authors.affiliation: National Institute of Health Sciences, Tokyo 158-8501, Japan.
authors.forename: Nahoko
authors.initials: N
authors.lastname: Uchiyama
authors.forename: Ik Hwi
authors.initials: IH
authors.lastname: Kim
authors.forename: Ruri
authors.initials: R
authors.lastname: Kikura-Hanajiri
authors.forename: Nobuo
authors.initials: N
authors.lastname: Kawahara
authors.forename: Tenji
authors.initials: T
authors.lastname: Konishi
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Goda
mesh_terms: D002482:Cellulose / Q000031:analogs & derivatives / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D002957:Citrus; D044950:Flavanones / Q000737:chemistry / Q000302:isolation & purification*; D006569:Hesperidin / Q000031:analogs & derivatives / Q000737:chemistry / Q000302:isolation & purification*; D020835:Medicine, Kampo; D048448:Phenylcarbamates / Q000737:chemistry; D028321:Plant Preparations / Q000737:chemistry*; D013237:Stereoisomerism; D013678:Technology, Pharmaceutical / Q000379:methods*
chemical_list: D044950:Flavanones; D048448:Phenylcarbamates; D028321:Plant Preparations; C065943:cellulose tris-3,5-dimethylphenyl-carbamate; D002482:Cellulose; D006569:Hesperidin; C005274:naringin