Toshio Nakabayashi

Paper Chromatography of Tannins

タンニンのpaper chromatographyに影響を及ぼす種種の因子について検討を行つた結果 i. タンニンのスポットの検出には紫外線及び0.5% FeCl3メタノール溶液が用いられる. ii. 濾紙を塩酸で前処理することによりタンニンのスポットのtailingを減少せしめることが出来た. iii. 多数の溶媒系について検討した結果NaHSO3の添加が有効であることより次の溶媒が比較的良好なchromatogramを与える事を知つた. n-BuOH: AcOH: 1% NaHSO3水溶液=4:1:5 (溶比)の上層(I)及び下層(II)並びに1% NaHSO3水溶液飽和フェノール(III)及びフェノール飽和1% NaHSO3水溶液(IV). Fig. 3にみられるようにタンニンのpaper chromatographyは1次元展開のみでは尚不充分であるが上記の4溶媒を適宜組合せて2次元展開を行えば更に良好なchromatogramがえられることは当然予想される処であるので,著者等は本実験で得られた成果に基づいてタンニンの2次元paper chromatographyを行い,ほぼ所期の目的を達することができた.この点については次報に於て述べる.

Studies on the Black Tea Tannin

By the oxidation of tea catechins on the black tea fermentation, black tea tannin is red and weekly astringent. On the two dimensional paper chromatogram of black tea tannin, some catechins, which have not been oxidized, and oxidized tannin are detected (Fig. 1), and it is, therefore. supposed that the black tea tannin contains not only oxidized tannin but also some unoxidized catechins. By the method of the counter current distribution, the black tea tannin is fractionated as follows; ether soluble (I) (unoxidized catechins) and ether insoluble but ethyl acetate soluble (II) (oxidized catechins) and ethyl acetate insoluble fraction (III) (polymerized tannin) (Fig. 2, 3). Of these three fractions, I and II are dialyzable but III is not (Fig, 4, 5). Several qualities of these fractions are detailed in Table 1 and fraction II has good color and taste. From the results of this experiments, it is supposed that the formation of black tea tannin is as follows: Tea catechins oxidation→ Primary products oxidation and→condensation Secondary products↓polymerization Polymers

Quercetin and Isoquercitrin in the Blossom of Tokiwamansaku (Loroptalum chinense olive.)

By the paper chromatographic method, I have detected two spots of flavonoid pigments in the blossoms of Tokiwamansaku (Loroptalum chinense olive.) and obtained quercetin from the ether-extract and isoquercitrin from the ethyl acetate-extract of fresh blossoms.