Molecular modeling, NOESY NMR, and the structure of nicandrenone isolated from Nicandra physalodes (Solanaceae).

The configuration and conformation of nicandrenone, isolated from Nicandra physalodes, are described using molecular modeling and NMR NOESY techniques. Amsterdam Density Functional (ADF) software was used, and the structures were those reduced to minimum energy molecular models, utilizing B3LYP executions and Density Functional Theory (DFT). The first spectral proof that this withanolide has a 22-R configuration is also provided.

Cytotoxic withanolides from Acnistus arborescens.

Three cytotoxic withanolides, two with new structures, were isolated from the leaves of Acnistus arborescens and their structures determined by a combination of 1D and 2D NMR, mass spectral, and molecular modeling studies. Dereplication analysis of the ethyl ether extract was useful for evaluating the components showing significant cytotoxic activity.