Designer drugs in herbal aphrodisiacs.

In the presented case three herbal aphrodisiacs (Libidfit, Satibo and Viamax) were investigated for the presence of regular pharmaceuticals against erectile dysfunction. However, high-performance liquid chromatography with diode array detection and mass spectrometry (HPLC-DAD-MS) and nuclear magnetic resonance (NMR) analyses revealed the presence of ingredients, having a molecular structure strongly resembling those of sildenafil (Viagra) and vardenafil (Levitra). The health risk posed by these analogous substances is high because they were found to be potent phosphodiesterase 5 (PDE5) inhibitors used in pharmacologically relevant quantities having no known safety profile.

Screening suspected counterfeit Viagra and imitations of Viagra with near-infrared spectroscopy.

We describe a near-infrared spectroscopy (NIRS) method for fast-screening Viagra tablets, counterfeit Viagra tablets, and imitations of Viagra. The method can (1) check the homogeneity of a batch; (2) distinguish counterfeits and imitations from authentic Viagra; (3) screen for the presence of sildenafil citrate, the pharmacologically active substance in Viagra, irrespectively of the excipients present; (4) and detect whether similar samples have been previously analysed. We applied the method to 103 samples with a diversity of appearance, chemical composition, and origin.

Structure elucidation of sildenafil analogues in herbal products.

The structure of unknown compounds present in herbal products was elucidated using liquid chromatography-electrospray ionization-mass spectrometry, direct-infusion electrospray ionization-mass spectrometry, and nuclear magnetic resonance. Compounds 1-3 were identified as sildenafil analogues, 1 bearing an N-ethylpiperazine moiety instead of an N-methylpiperazine, and an acetyl group instead of the sulfonyl group, named acetildenafil, 2 bearing an N-ethylpiperazine moiety instead of an N-methylpiperazine (homosildenafil), and 3 bearing an N-hydroxylethylpiperazine moiety instead of an N-methylpiperazine, named hydroxyhomosildenafil. When analysing products marketed for penile erectile dysfunction or marketed as aphrodisiacs, attention should be given to the possible presence of these components.

Analysis of optically active compounds using conventional chromatography with a circular dichroism detector.

Analysis of optically active compounds in complex samples is often based on chiral chromatography or capillary electrophoresis in order to separate the enantiomers. This requires a chiral reagent, when using conventional chromatography, or an expensive chiral column, or a chiral selector, when using capillary electrophoresis. The type of column, reagent, or additive depends highly on the compound to be analysed.

Mass spectrometric analysis of lipo-chitin oligosaccharides--signal molecules mediating the host-specific legume-rhizobium symbiosis.

Lipo-chitin oligosaccharides (LCOs) are novel bacterial glycolipid signal molecules that mediate the species--specific symbiosis between rhizobial bacteria and leguminous plants. Nodulation of the legume roots and nitrogen-fixation in the resulting nodules by Rhizobia is controlled by the bacterial nodulation genes that encode the LCO biosynthetic enzymes. The length of the LCO chitin backbone, the length and degree of unsaturation of the fatty acyl chain attached to it, and the combination of different chemical substituents on the reducing- and nonreducing-terminal residues all contribute to the species--specificity of the signal.