Isolation and characterisation of N-benzyl tadalafil as a novel adulterant in a coffee-based dietary supplement.

A new tadalafil analogue was detected via high-performance liquid chromatography (HPLC)-diode array detection (DAD) during routine screening of health foods suspected of adulteration with erectile dysfunction drugs. The UV absorption spectrum of the unknown was almost identical to that of tadalafil. The analogue was purified by preparative HPLC and structural elucidation carried out by mass spectrometric and NMR spectroscopic experiments. The spectral data revealed that this tadalafil analogue bears a benzyl group instead of the methyl group. The isolated compound was identified as N-benzyl tadalafil. Considering the risk it poses to public health, this new PDE-5 analogues for ED should be included on the inspection list for illegal products.

[Application of quantitative evaluation on multicomponent drug interaction in anti-HIV research].

OBJECTIVE: To quantitatively evaluate mutual relations of 4 component drugs in anti-HIV action. METHODS: The effect of TCM four components on cell growth was detected using MTT assay. The antiviral effects of 4 components were observed at the maximal nonvenomous dose. The combination index (CI) value of combined two or four components were calculated using median-effect principle. The mutual relations of two or four components for antiviral actions were assessed using CI. RESULTS: Synergism was dominant in combination of A and B, and the effect was dose-dependent. Antagonism was dominant in combination of C and D, and the effect was dose-dependent. But the combination of A, B, C, and D was synergistic when the inhibition rate was over 10%. CONCLUSION: Median-effect principle can be used to quantitatively assess the anti-HIV effect of four components.