[Identification of Descarbonsildenafil in an Adulterated Dietary Supplement and Evaluation of Its Inhibitory Activity for Phosphodiesterase Type 5 (PDE5)].

Some illegal dietary supplements contain phosphodiesterase type 5 (PDE5) inhibitors, such as sildenafil, for exerting "therapeutic" effects in erectile dysfunction. This is apparently dangerous, and thus, should be appropriately regulated. Identification of descarbonsildenafil was first reported in Singapore in a coffee sample labeled to exert male sexual performance enhancement effects. However, it is unclear whether the compound possesses PDE5 inhibitory activity. We encountered during our survey of dietary supplements, a sexual enhancement product commercially available in Tokyo, in which a peak presumed to be of descarbonsildenafil was detected by LC-UV and electrospray ionization-tandem MS (ESI-MS/MS). The compound was isolated and identified as descarbonsildenafil with liquid chromatography-quadrupole time-of-flight-mass spectrometry (LC-QTOF-MS), NMR, and X-ray crystal structural analysis. In addition, descarbonsildenafil showed PDE5 inhibitory activity in PDE5 inhibition assay, and its IC50 value for PDE5A1 was found to be 30 nmol/L. The results of INADEQUATE NMR and X-ray crystal structural analysis in this study provide information for the identification of descarbonsildenafil. Since this study indicates that this compound is a PDE5 inhibitor having adequate activity, it is regulated as a drug component in Japan.

Euphorins A-H: bioactive diterpenoids from Euphorbia fischeriana.

Phytochemical investigation of the roots of Euphorbia fischeriana resulted in the isolation of 23 diterpenoids (1-23), which were classified into five subtypes, namely, ent-rosane (1-9), ent-abietane (10-16), ent-kaurane (17), ingenane (18-22), and lathyrane (23). The chemical structures of eight new compounds, namely, euphorin A (4), B (5), C (7), D (9), E (13), F (14), G (15), and H (16), were elucidated on the basis of extensive 1D and 2D NMR spectroscopic analyses, as well as single crystal X-ray structure analysis. A number of compounds (2, 6, 7, 10, 11, 13, 16, 19, 20, 22, and 23) showed inhibitory activity on the formation of mammospheres in human breast cancer MCF-7 cells at a final concentration of 10 µM, suggesting the potential of these bioactive diterpenoids for further investigation of the action targeting cancer stem cells.