| Popis: |
The volatiles from Calea hispida leaves were analyzed by GC-MS-FID and presented as the main components (E)-nerolidol, beta-cubebene, spathulenol, alfa-cadinol and 6-acetyl-7-hydroxy-2,2-dimethylchromene, the latter being the major component (54.46%), which was crystallized and analyzed by X ray diffraction. Microbiological assays indicated activity of this chromene against Helicobacter pylori (ATCC 26695), what prompts a deeper investigation on this concern. The crystal structure study showed no difference to that reported before for this compound while quantum mechanics optimization indicated that the crystal structure is close to a minimum energy conformation, what includes the relative position of the hydroxyl to the acetyl moiety. In fact, potential energy scan and molecular dynamics showed that the intramolecular hydrogen bond within these two moieties is quite stable, both in gas phase and in solution. |
