Development of Free Radical Products during the Greening Reaction of Caffeic Acid Esters (or Chlorogenic Acid) and a Primary Amino Compound
ESR spectra were measured directly on a marked greening reaction mixture of Et-caffeate and a primary amino compound in alkali solution under aeration. A clear hyperfine structure was commonly detected early in the greening reaction with different amino compounds. Its hyperfine spectrum split into seven peaks was analyzed and found to be due to the oxidized free radical product of the Et-caffeate using an authentic sample system. Another type of hyperfine ESR spectrum was observed later in the reaction, and was altered with different amino compounds. The hyperfine structure for n-butylamine split into 12 lines. The latter type of free radical products were assumed to be a semiquinone type radical compounds of the trihydroxy benzacridine derivative, which was identified as the principal structure of the green and yellow pigments formed by this greening reaction system. A formation mechanism of the green pigment and related products involving these free radical products is proposed.
The Greening Reaction of “Gobô” (Arctium Lappa L.) (Part 2)
(1) クロロゲン酸に対するフェニルアラニン或いはロイシンのモル比が10-4モル: 10-4モル; 10-4モル: 2×10-4モル; 2×10-4モル: 10-4モルになる如く両成分を含む6通りのMenzel緩衝溶液20mlを, 50℃で1時間, 105℃, 117℃, 127℃, 138℃, の各温度では2分間加熱反応せしめ, 1時間放置, 24時間放置した各試験液の色をキセノン自動螢光測色計を使用して測色し, その色の主波長並びにマンセル表色系の色相, 明度, 彩度として表し, 各試験液の緑変反応の変化を追究した。(2) 加熱温度50～117℃の範囲では, 各試験液は緑変反応を生じるが, 緑変反応は加熱温度の上昇と共に弱化し, 127℃においては緑変反応はロイシン区においてのみ生じ, フェニルアラニン区では生じない。138℃では各試験液はいずれも赤褐色となり緑変反応を示さない。(3) 加熱温度50～117℃の範囲では, 放置時間による各試験液の緑変反応を比較すると, 24時間放置の場合が1時間放置のものより著しく強い。(4) クロロゲン酸対アミノ酸のモル比が1: 1のとき, 加熱温度50～127℃において, フェニルアラニン区, ロイシン区の緑変反応はほぼ等しく, わずかにロイシン区が強い。1: 2のとぎ, ロイシン区が著しく強い。2: 1の時, フェニルアラニン区が強いが, 127℃ではロイシン区のみ緑変反応を示す。(5) クロロゲン酸に対するモル比が異なる同種アミノ酸の各溶液の緑変反応を比較すると, 加熱温度50～117℃において, モル比1: 1, 2: 1のフェニルアラニン区の緑変反応はほぼ等しく, かつ1: 2の場合より緑変反応が強い。モル比1: 1, 1: 2のロイシン区の緑変反応はほぼ等しく, 2: 1の場合より緑変反応が強い。
Interaction of Diclofop-Methyl and MCPA on Wild Oats (Avena fatua)
Diclofop-methyl {methyl 2-[4-(2,4-dichlorophenoxy)phenoxy] propanoate} loses part of its activity on wild oats (Avena fatua L.) when it is applied in combination with ester or amine formulations of MCPA {[4-chloro-o-tolyl)oxy] acetic acid.} Uptake of diclofop-methyl is reduced in the presence of commercial formulations of MCPA, particularly amine formulations, which are only partly compatible with the diclofop-methyl formulation. With added MCPA, regardless of formulation, hydrolysis of diclofop-methyl to the acid diclofop is slowed down, both in intact wild oat plants and in a crude leaf extract. At the same time, conversion of any acid formed to inactive conjugates is accelerated in the presence of MCPA. It is concluded that the loss of activity of diclofop-methyl by MCPA can be accounted for by the effects of MCPA on uptake and metabolic conversion of diclofop-methyl.