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Covering: 1959 to 2013 Silybin, a secondary metabolite isolated from the seeds of the blessed milk thistle (Silybum marianum) was discovered as the first member of a new family of natural compounds called flavonolignans in 1959. Over the years it has received the research attention of many organic chemists. This research has resulted in a number of semisynthetic derivatives prepared in an effort to modulate and better target the biological activities of silybin or to improve its physical properties, such as its solubility. A fundamental breakthrough in silybin chemistry was the determination of the absolute configurations of silybin A and silybin B, and the development of methods for their separation. This review covers articles dealing with silybin chemistry and also summarizes all the derivatives prepared. [ABSTRACT FROM AUTHOR]

Abstract: NMR studies showed that 11-demethylcyclosporin A (cyclosporin E) and 11-demethylcyclosporin B exist as single species both in polar and nonpolar solvents. They adopt the same conformation that was found in the solid state. [ABSTRACT FROM AUTHOR]

Homoisoleucine, an unusual amino acid recently discovered in the structure of the ergopeptine alkaloid ergogaline, was determined in the parasitic fungus Claviceps purpurea Fr. (Tul.). growing on rye Secale cereale (L.) and in its host plant. Free homoisoleucine was detected by gas chromatography-mass spectrometry (GC-MS) in the amino acid pool of sclerotia of all fungal strains examined. Since homoisoleucine was not detected in rye, it seems that the amino acid is synthetized by the fungus. Furthermore, the ratio of leucine/homoisoleucine in the free amino acid pool of sclerotia is in good agreement with the ratio of the corresponding alkaloids α-ergokryptine/ergogaline estimated by high performance liquid chromatography (HPLC). Thus, homoisoleucine is incorporated into the ergopeptines randomly with the similar specificity as leucine. [ABSTRACT FROM AUTHOR]