Absolute Configuration of a Tetrahydrophenanthrene from Heliotropium ovalifolium by LC-NMR of Its Mosher Esters

A new tetrahydrophenanthrene (1, (1R,2R)-1-hydroxy-2-methoxy-6,9-dimethyl-2,3-dihydrophenanthren-4(1H)-one (heliophenanthrone)) has been isolated from the aerial parts of Heliotropium ovalifolium. Its structure was elucidated on the basis of spectroscopic data, and the absolute configuration of the asymmetric centers was determined from LC-NMR data of the Mosher ester derivatives

An LC/DAD-UV/MS method for the rapid detection of aristolochic acid in plant preparations.

A new method using direct on-line coupling between HPLC and UV-DAD/MS was developed for the rapid detection of aristolochic acid I in plant preparations. The use of both UV-DAD and MS detectors enables this method to be very selective. A ng range detection limit was determined for both UV and MS detections. A quantitative determination of aristolochic acid I in plant preparations was achieved using UV and MS detection. A thin layer chromatography assay was also developed for the preliminary detection of aristolochic acid I in complex mixtures

Qualitative and quantitative determination of yohimbine in authentic yohimbe bark and in commercial aphrodisiacs by HPLC-UV-API/MS methods

The development and validation of a rapid qualitative and quantitative method based on an HPLC-UV-MS technique with atmospheric pressure chemical ionisation and electrospray ionisation for the analysis of yohimbine in a number of commercial aphrodisiac products is reported. HPLC with multiple-stage mass spectrometry experiments allowed the identification of the target compound and increased the selectivity of complex analyses such as those involved with multi-botanical preparations. The precision and the robustness of the method were improved by the use of two internal standards: codeine for UV detection and deuterium-labelled yohimbine for MS detection. Twenty commercial aphrodisiac preparations were analysed and the amount of yohimbine measured and expressed as the maximal dose per day suggested on product labels ranged from 1.32 to 23.16 mg. Copyright (C) 2003 John Wiley Sons, Ltd

Synthesis and evaluation of analogs of the phenylpyridazinone NPD-001 as potent trypanosomal TbrPDEB1 phosphodiesterase inhibitors and in vitro trypanocidals.

Trypanosomal phosphodiesterases B1 and B2 (TbrPDEB1 and TbrPDEB2) play an important role in the life cycle of Trypanosoma brucei, the causative parasite of human African trypanosomiasis (HAT), also known as African sleeping sickness. Knock down of both enzymes leads to cell cycle arrest and is lethal to the parasite. Recently, we reported the phenylpyridazinone, NPD-001, with low nanomolar I