著者

中村 泰彦 山藤 一雄

出版者

九州大学

雑誌

九州大學農學部學藝雜誌 (ISSN:03686264)

巻号頁・発行日

vol.23, no.3, pp.119-125, 1968-03

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In vivo ascorbic acid exists in two forms of oxidized dehydroascorbic acid and reduced ascorbic acid. It is reported that ascorbic acid decreases the mortality of mice bearing Ehrlich ascites tumor, but we have no information as to dehydroascorbic acid. We synthesized dehydroascorbic acid by improved method of Kenyon et al. and isolated it as crude crystal. Aqueous solution immediately after dissolution showed no selective absorption in ultraviolet wave length, and it came to have a peak at 295 mμ with the lapse of time. By means of hydrazine method, crude crystal was calculated to be composed of 2% ascorbic acid, 66% dehydroascorbic acid, 1.0% 2, 3-diketogulonic acid and 22% others. Crude crystal solution kept at 30℃ for 70 hours (70-hrs-solution) consisted of 25% dehydroascorbic acid, 58% 2, 3-diketogulonic acid and 17% others. There was similar tendency in paperchromatography. Crude crystal and 70-hrs-solution inhibited the growth of transplantable mouse tumor Sarcoma 180, solid type and the inhibition rates were 45% and 51% respectively with the dose of 150 mg/kg/day for 6 days. With the same dosage, ascorbic acid showed weak antitumor activity. Although crude crystal and 70-hrs-solution went by contraries on the content of dehydroascorbic acid and 2, 3-diketogulonic acid, both inhibited the growth of tumor to similar extent. So we presumed that dehydroascorbic acid and 2, 3-diketogulonic acid had antitumor activities respectively.1. Kenyonらの方法を一部変えてアスコルビン酸よりデヒドロアスコルビン酸を調成し粗結晶として分離した.粗結晶の溶解直後の水溶液は紫外部にほとんど選択的吸収を示さないが,時間がたつにつれて295mμに吸収極大を持つようになり別の物質に変化することを示した.この変化はペーパークロマトグラフィーによつて確かめられた.ヒドラジン法によると粗結晶の組成はデヒドロアスコルビン酸66%, 2,3-ジケトグロン酸10%,アスコルビン酸2%,その他22%であり,70時間放置水溶液はデヒドロアスコルビン酸25%, 2,3-ジケトグロン酸58%,その他17%であつた. 2. 粗結晶およびその70時間放置水溶液は,可移植性マウス腫瘍Sarcoma 180に対して抗腫瘍性を示し,腫瘍の増殖は粗結晶投与群では対照群の55%,70時間放置水溶液投与群では対照群の49%に抑えられた.この抗腫瘍性はデヒドロアスコルビン酸,2,3-ジケトグロン酸によるものと推定した.