| Research Abstract |
Synthesis of anthocyanin, a natural pigment, and clarification of its biological function
Anthocyanin 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.
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