Uchiyama Nahoko, Kim Ik Hwi, Kikura-Hanajiri Ruri, Kawahara Nobuo, Konishi Tenji, Goda Yukihiro
National Institute of Health Sciences, Tokyo 158-8501, Japan.
J Pharm Biomed Anal. 2008 Apr 14;46(5):864-9. doi: 10.1016/j.jpba.2007.04.004. Epub 2007 Apr 8.
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.
黄酮醇苷，如柚皮苷和新橙皮苷，分布于一些柑橘属植物中，且在黄酮醇部分的C-2位具有一个手性中心。使用多糖衍生的手性固定相（CSPs）CHIRALPAK IB，通过正相高效液相色谱法将柚皮苷和新橙皮苷（2S-型）与相应的C-2差向异构体（2R-表型）分离。对市售柚皮苷样品的分析表明，柚皮苷与C-2差向异构体的相对比例为29%-89%。对于市售新橙皮苷样品，新橙皮苷（2S-型）的相对比例为84%。对日本用作药材的柑橘属植物（枳实、枳壳和橙皮）进行的高效液相色谱分析表明，枳实中柚皮苷与C-2差向异构体的相对比例为75%-93%，枳壳中为74%-79%，橙皮中为54%-64%。然而，柑橘属植物中（2R）-表新橙皮苷的比例相当小。这一结果表明，柑橘属植物中（2S）-柚皮苷的相对比例平均值会随着果实成熟度降低（枳实<枳壳<橙皮）。由于5种汉方制剂（包括枳实或枳壳）干提取物中（2S）-柚皮苷的相对比例降至42%-54%，在制剂煎煮过程中，柚皮苷向（2R）-差向异构体的转化可能会增强。
