ツバキの葉から(-)―エピカラキンと(+)―カテキンの分離
1967 年 1967 巻 27 号 p. 72-76
詳細
1967 年 1967 巻 27 号 p. 72-76
It has been reported that the shoots of Camellia japonica contain only one catechin identified as (-)-epicatechin from paperchro-matographic studies. However, a predominant presence of a (+)-catechin like substance was noticed in addition to (-)-epicatechin in the shoots of a certain variety i. e. var. Benikarako or var. Soinegawa. The ratios of both substances in the leaf of Camellia japonica are shown in Table 1.
In this paper, the isolation of (-)-epicatechin and (+)-catechin from the leaf of Camellia japonica var. Benikarako and the infra-red spectral comparison of catechin and epicatechin gained from various materials are reported.
The matured leaves of Benikarako were homogenized with ethyl ether. The extracts were filtered and then concentrated under reduced pressure in a current of nitrogen. Then to the residue was added a small volume of water and the precipitated pigments were removed by a super-centrifuger. The aqueous solution was freeze-dried. and the polyphenol mixture containing (-)-epicatechin predominantly was obtained as an orange powder.
The polyphenol mixture in the shoots was obtained by the same procedure as described above. This mixture was consisted mainly of the (+)-catechin like substance and other two polyphenols. Then the (+)-catechin like substance was fractionated in a 50- tube Craig distribution train by the solvent system of ethyl ether and beznene mixture as the upper phase and water as the lower phase.
The crude powder containing (-)-epicatechin or the (+)-catechin like substance was purified by the recrystallization from water, then the final crystals were obtained.
Furthermore both crystals were compared with the authentic catechins from other sources on the infra-red spectral property as shown in Figure 3. The spectrum of the (+)-catechin like substance from Camellia japonica coincided with that of (+)-catechin from Gamnbier. The spectra of (-)-epicatechin from Camellia japonica, Acacia catechu and tea leaf, and (+) epicatechin epimerized from (+)-catechin of Gambier resembled closely one another whether it was (-) or (+) form. Furt her it was supposed that the infra-red spectrum of (-)-epicatechin from Camellia japonica which was reported in the previous paper seemed to be the same as that of (+)-catechin.
