Methodologies for the quality assessment of medicinal plants and phytopharmaceuticals

The abundant consumption of herbal medicines is often associated with toxicity problems due to the presence of pesticide residues, bacterial contaminations and confusions between plant species. Thus besides efficacy, safety represents an important issue in phytotherapy, because many plants are used as dietary supplements. In this respect, different cases of intoxication, mostly renal failure, have been reported after consumption of slimming regimens containing nephrotoxic and carcinogenic aristolochic acids [1]. Hepatotoxicity problems have also been reported for different plants containing pyrrolizidine alkaloids such as Petasites hybridus or Tussilago farfara (Asteraceae) [2]. Other toxicity issues have also been reported for edible plants which can be botanically confused and cases are known in which leaves of the autumn crocus (Colchicum autumnale, Liliaceae) have been consumed instead of ramsons (Allium ursinum, Liliaceae). Ginkgo biloba can also present some safety problems related to its content in allergenic alkylphenols [3]. Such hazardous compounds are present only in very low concentrations in phyto-pharmaceutical preparations and European regulation requires that their content do not exceed 5 ppm. In order to solve some of the issues concerning the quality control and standardisation of plant preparations, analytical strategies based on the use of LC-UV-MS, UPLC-TOF-MS and LC-NMR have been developed for a rapid profiling of the extracts [4]. Different examples of analyses in relation with toxicity assessment and quality control will be discussed. The use of these methods for dereplication purposes in the search of new lead compounds from plants will also be treated.

References: 1. Ioset, J.R. et al. (2003) Food Chem. Toxicol. 41:29.

2. Ndjoko, K. et al. (1999) Planta Med. 65:562.

3. Ndjoko, K. et al. (2000)J. Chromatogr. B 744:249.

4. Hostettmann, K. et al. (2005) Chimia 59:291.