Structure and Analysis of Flavonolignans from Silybum marianum

摘要

The structures and stereochemistry of silybin A, silybin B, isosilybin A, and isosilybin B, diastereoisomers of silybin and isosilybin, were characterized, together with other known flavonolignans isolated from the seeds of Silybum marianum so far. The absolute stereochemistry of each diastereoisomer was unambiguously established through the X-ray crystallographic study of isosilybin A in combination with optical rotation data. Three new flavonolignans, namely, 2,3-cw-silybin A, 2,3-cw-silybin B, and neusilychristin were separated for the first time. The fingerprints of HPLC and 'H NMR of silymarin, standardized extract from the seeds of Silybum marianum were also reported.