Mori Mihoko, Kondo Tadao, Toki Kenjiro, Yoshida Kumi
Graduate School of Human Informatics, Nagoya University, Chikusa, Nagoya 464-8601, Japan.
Phytochemistry. 2006 Mar;67(6):622-9. doi: 10.1016/j.phytochem.2005.12.024. Epub 2006 Feb 7.
The dicaffeoyl anthocyanin, phacelianin, was isolated from blue petals of Phacelia campanularia. Its structure was determined to be 3-O-(6-O-(4'-O-(6-O-(4'-O-beta-d-glucopyranosyl-(E)-caffeoyl)-beta-d-glucopyranosyl)-(E)-caffeoyl)-beta-d-glucopyranosyl)-5-O-(6-O-malonyl-beta-d-glucopyranosyl)delphinidin. The CD of the blue petals of the phacelia showed a strong negative Cotton effect and that of the suspension of the colored protoplasts was the same, indicating that the chromophores of phacelianin may stack intermolecularly in an anti-clockwise stacking manner in the blue-colored vacuoles. In a weakly acidic aqueous solution, phacelianin displayed the same blue color and negative Cotton effect in CD as those of the petals. However, blue-black colored precipitates gradually formed without metal ions. A very small amount of Al(3+) or Fe(3+) may be required to stabilize the blue solution. Phacelianin may take both an inter- and intramolecular stacking form and shows the blue petal color by molecular association and the co-existence of a small amount of metal ions. We also isolated a major anthocyanin from the blue petals of Evolvulus pilosus and revised the structure identical to phacelianin.
从钟花紫筒草的蓝色花瓣中分离出二咖啡酰花青素——天蓝绣球素。其结构被确定为3 - O -（6 - O -（4'- O -（6 - O -（4'- O -β - D -吡喃葡萄糖基 -（E）-咖啡酰）-β - D -吡喃葡萄糖基）-（E）-咖啡酰）-β - D -吡喃葡萄糖基）-5 - O -（6 - O -丙二酰基 -β - D -吡喃葡萄糖基）飞燕草素。钟花紫筒草蓝色花瓣的圆二色光谱显示出强烈的负科顿效应，有色原生质体悬浮液的圆二色光谱也是如此，这表明天蓝绣球素的发色团可能在蓝色液泡中以逆时针堆积方式进行分子间堆积。在弱酸性水溶液中，天蓝绣球素呈现出与花瓣相同的蓝色和圆二色光谱中的负科顿效应。然而，在没有金属离子的情况下，会逐渐形成蓝黑色沉淀。可能需要极少量的Al(3+)或Fe(3+)来稳定蓝色溶液。天蓝绣球素可能采取分子间和分子内堆积形式，并通过分子缔合以及少量金属离子的共存呈现出蓝色花瓣颜色。我们还从毛籽旋花的蓝色花瓣中分离出一种主要的花青素，并修正其结构与天蓝绣球素相同。
