Isolierung eines neuen Lignans (Yangambin) und mögliche Korrelation zur Piperinführung

Abstract

A new lignan, named yangambin, for which the struc-ture of (+)-2, 6-bis-(2, 3, 4-trimethoxyphenyl)-3, 7-dioxabicyclo-[3, 3, 0] octane was determined, was isolated (0. 2%) from the fruits of Piper guineense. From a comparison of the nuclear magnetic resonance spectra in combination with the optical rotation it was found that yangambin shows the same steric structure as (+)-sesamin. The lignan formation appears to be correlated with the occurrence of piperine, which was isolated from the fruits in a yield of 0. 33%; piperine-free fruits contained no yangambin but contained (+)-sesamin (=pseudocubebin) and aschantin. This striking intraspecific variability of chemical characteristics is discussed with regard to attempts of other authors to subdivide the sp. P. guineense from a morphological point of view.