クリプトキサンチン

解説C40H56O(552.85)．クリプトキサンチンは，カロテノイド色素の一つで，ビタミンA活性をもつ．植物の花や果実に遊離あるいはエステルとしてゼアキサンチンに伴って広く存在するが，量的には多くない．ナス科ホオズキPhysalis alkekengiの萼(がく)，パパイヤ科パパイヤCarica papayaの実などを有機溶媒で抽出し，けん化，クロマトグラフィーによりほかの色素と分離精製する．菌類，けいそう類，魚卵などからも見いだされている．紫色の光沢を有する赤褐色の柱状結晶．融点169 ℃．λmax 484，451，423 nm(ヘキサン)．ジクロロメタン，ベンゼンに易溶，石油ベンジン，メタノールに微溶．β-カロテンの約60％ の活性を有するプロビタミンAである．森北出版「化学辞典（第2版）

使用A natural caratenoid pigment that is converted to Vitamin A in the human body. It is an antioxidant and may help prevent free radical damage to cells and DNA, as well as stimulate the repair of oxidative damage to DNA. A potential chemopreventative agent against lung cancer as well as other types of cancer.

一般的な説明β-Cryptoxanthin is an oxygen-containing carotenoid and is a member of the xanthophyll family. It is one of the major sources of vitamin A and is present in fruits such as oranges, tangerines and papayas. In addition, it is also found in corn, peas and some animal products such as egg yolk and butter.

純化方法Purify it by chromatography on MgO, CaCO3 or deactivated alumina, using EtOH or diethyl ether to develop the column. Crystallise it from *C6H6/EtOH (metallic prisms), or needles from *C6H6. Store it in the dark under N2 or Ar at -20o. The acetate has m 117.5o. The racemate is purified through a column of alumina (grade IV), eluted with *C6H6 then EtOAc/*C6H6 (1:9) and recrystallised from pet ether (b 60-80o) with m 172-173o. [Loeber et al. J Chem Soc (C) 404 1971, Goodfellow et al. J Chem Soc Chem Commun 1578 1970, Isler et al. Helv Chim Acta 40 456 1957, Beilstein 6 III 3772, 6 IV 5111.]