天然色素アントシアニンの合成とその機能の解明

天然色素花青素的合成及其生物学功能的阐明花青素是主要的花卉色素，可能具有基因防晒、嗜虫、自由基清除等多种生物学功能。它被用作食品着色剂和眼部治疗药物。本研究以黄酮醇苷为原料合成了新的(1)酰基化花青素，并证实了酰基化花青素（HBA）对DNA的保护作用(2)。(1)利用金属还原反应实现了黄酮醇苷类化合物芦丁及其衍生物直接转化为花青素。在不同的反应条件下进行了还原。以芦丁为原料，在0℃条件下，以3%的绝对盐酸甲醇为溶剂，用锌汞对芦丁进行处理，得到产率为24%的花青素3-芦丁苷。并将过苯甲酰芦丁还原为相应的花青素，产率为Ox(3E)5%。锌粉代替锌汞得到黄-3-烯-3-芦丁苷，收率65%。因此，我们找到了一种新的高效合成天然黄-3-烯的途径。(2)化学证据表明，天蓝花青素（heavenly blue anthocyanin， HBA）具有UV-A和uv - B的遮光作用，保护DNA。通过纤维素酶处理后分离的蓝色原生质体的显微光度测定，证实了HBA存在于花瓣表皮细胞的10-2M处。我们建立了一个保护DNA免受紫外线照射的花瓣模型系统。采用胸苷二聚体抗体ELISA法分析DNA损伤。浓度（10-3M）的aq. HBA溶液与活细胞浓度相同，完全阻断了紫外线照射下DNA的损伤，说明开放花中的花青素具有保护基因免受阳光照射的功能。

Synthesis of anthocyanin, a natural pigment, and clarification of its biological functionAnthocyanin is major flower pigment and might play role of amount biological functions such as gene protection form sunlight, entomophily, and radical scavenger. It is used for a food colorant and eye therapeutic medicine.We developed the new synthesis (1) of acylated anthocyanins from flavonol glycoside and proven protection (2) of DNA by acylated anthocyanin (HBA) from sunlight, UV-A and B.(1) We realized the direct transformation to anthocyanin from rutin and its derivatives, a flavonol glycoside by using metal reduction reaction. Various reaction conditions were applied to the reduction. Rutin was treated with Zn-Hg in absolute 3% HCl-methanol at 0℃ to give cyanidin 3-rutinoside in 24% yield. And also, perbenzoylrutins were reduced to afford the corresponding anthocyanin in Ox(3E)5% yield. Zn powder in replacing of Zn-Hg gave flav-3-ene 3-rutinoside in 65% yield. Therefore, we found the new efficient synthetic route to a natural flav-3-ene.(2) We provided chemical evidence that heavenly blue anthocyanin (HBA), a pigment of blue petal of Ipomoea tricolor, has a light shielding effect of UV-A and B to protect the DNA. That HBA exists at 10-2M in epidermis cell of the petal, was clarified by micro-photometery of a blue protoplast, which was isolated after treatment of the tissue with cellulase. We built up a model system of the petal for protection of DNA from UV-light exposure. The DNA damage was analyzed by ELISA method using antibody of thymidine dimers. The concentration (10-3M) of an aq. HBA solution just as that of living cell completely blocked the DNA damage under UV-irradiation, indicating that the anthocyanin pigment in open flower has a function of protection of the gene from sun-light.