Institute of Microbiology, Laboratory of Biotransformation, Czech Academy of Sciences , Vídeňská 1083, CZ 142 20 Prague, Czech Republic.
Stolařská 601/4 , CZ 747 14 Ludgeřovice, Czech Republic.
J Nat Prod. 2016 Dec 23;79(12):3086-3092. doi: 10.1021/acs.jnatprod.6b00750. Epub 2016 Nov 22.
Silychristin is the second most abundant flavonolignan (after silybin) present in the fruits of Silybum marianum. A group of compounds containing silychristin (3) and its derivatives such as 2,3-dehydrosilychristin (4), 2,3-dehydroanhydrosilychristin (5), anhydrosilychristin (6), silyhermin (7), and isosilychristin (8) were studied. Physicochemical data of these compounds acquired at high resolution were compared. The absolute configuration of silyhermin (7) was proposed to be identical to silychristin A (3a) in ring D (10R,11S). The preparation of 2,3-dehydrosilychristin (4) was optimized. The Folin-Ciocalteau reduction and DPPH and ABTS radical scavenging assays revealed silychristin and its analogues to be powerful antioxidants, which were found to be more potent than silybin and 2,3-dehydrosilybin. Compounds 4-6 exhibited inhibition of microsomal lipoperoxidation (IC 4-6 μM). Moreover, compounds 4-8 were found to be almost noncytotoxic for 10 human cell lines of different histogenetic origins. On the basis of these results, compounds 3-6 are likely responsible for most of the antioxidant properties of silymarin attributed traditionally to silybin (silibinin).
水飞蓟宾是水飞蓟果实中第二丰富的类黄酮木脂素（仅次于水飞蓟素）。一组含有水飞蓟宾（3）及其衍生物的化合物，如 2,3-脱水水飞蓟宾（4）、2,3-去水无水水飞蓟宾（5）、无水水飞蓟宾（6）、水飞蓟亭（7）和异水飞蓟宾（8）被研究。对这些化合物在高分辨率下获得的物理化学数据进行了比较。提出水飞蓟亭（7）的绝对构型与 D 环中的水飞蓟宾 A（3a）相同（10R，11S）。优化了 2,3-脱水水飞蓟宾（4）的制备。福林-希科莱特还原和 DPPH 和 ABTS 自由基清除试验表明，水飞蓟宾及其类似物是强大的抗氧化剂，其效力强于水飞蓟素和 2,3-脱水水飞蓟素。化合物 4-6 表现出抑制微粒体脂质过氧化（IC 4-6 μM）。此外，化合物 4-8 对 10 个人类不同组织起源的细胞系几乎没有细胞毒性。基于这些结果，化合物 3-6 可能是水飞蓟素传统上归因于水飞蓟素（水飞蓟宾）的大部分抗氧化特性的主要原因。
