Zhang W G, Weng M, Pang S Z, Zhang M H, Yang H Y, Zhao H X, Zhang Z Y
Institute of Biophysics, Academia Sinica, Beijing, China.
J Photochem Photobiol B. 1998 Jun 15;44(1):21-8. doi: 10.1016/S1011-1344(98)00101-8.
The reaction of hypocrellin A (HA) with n-butylamine in pyridine under reflux leads to the formation of 2-butylamino-2-demethoxy-hypocrellin A (2-BA-2-DMHA), which is illustrated by ultraviolet-visible absorption spectra, proton nuclear magnetic resonance spectra, infrared spectra and mass spectra. The product exhibits stronger red-light absorption and has a much higher photopotentiation factor than HA (i.e., more than 200 versus four at a dose of 4 J cm-2 of red light on human gastric adenocarcinoma MGC803 cells). The mechanism of phototoxicity of 2-BA-2-DMHA on MGC803 cells irradiated with red light (lamada = 600-700 nm) has also been studied. An examination of extracted cellular DNA by agarose gel electrophoresis shows that the DNA has degraded into fragments with lengths which are multiples of approximately 180-190 base pairs (i.e., oligonucleosome size), a biochemical marker of apoptosis. Transmission electron microscopy reveals chromatin condensation around the periphery of the nucleus, which is also characteristic of apoptosis. This study suggests that 2-BA-2-DMHA is a potential photosensitizer and that its photoxicity to MGC803 cells proceeds via apoptosis.
竹红菌甲素（HA）与正丁胺在吡啶中回流反应生成2-丁基氨基-2-去甲氧基竹红菌甲素（2-BA-2-DMHA），通过紫外可见吸收光谱、质子核磁共振光谱、红外光谱和质谱对其进行了表征。该产物表现出更强的红光吸收，并且与HA相比具有更高的光增强因子（即在人胃腺癌MGC803细胞上以4 J/cm²的红光剂量照射时，分别为200以上和4）。还研究了2-BA-2-DMHA对用红光（波长=600 - 700 nm）照射的MGC803细胞的光毒性机制。通过琼脂糖凝胶电泳对提取的细胞DNA进行检测表明，DNA已降解为长度约为180 - 190个碱基对倍数的片段（即寡核小体大小），这是细胞凋亡的生化标志物。透射电子显微镜显示细胞核周边染色质浓缩，这也是细胞凋亡的特征。该研究表明2-BA-2-DMHA是一种潜在的光敏剂，其对MGC803细胞的光毒性是通过细胞凋亡进行的。
