The potential of PCR-related methods to identify medicinal plants in herbal medicinal products

Methods established and described in pharmacopoeias to test the identity of medicinal plants are generally based on a morphological anatomical analysis or on the analytics of natural products. Nevertheless, in some cases a reliable confirmation of the raw material of medicinal plants and its identity or purity is difficult.

Various molecular biological techniques, including PCR-based methods, have been used for authentication of medicinal plants and herbal drugs during the last years [1,2,3]. However, there is a need not only for reliable authentication of raw plant material but also for suitable methods to verify the medicinal plants used in later steps of production. Our approach is to establish a validated method based on Polymerase Chain Reaction which should be applicable for a broad range of medicinal plant species. As major model for analytical development and validation, we have chosen the genus Matricaria because of the availability of different preparations in the market.

In addition to RAPD techniques we investigated the potential of amplification of specified parts of the nuclear ribosomal DNA-cluster. We were able to demonstrate, that amplifiable DNA could be successfully extracted from herbal preparations such as fluid or dry extracts and finished herbal medicinal products like tablets. However, RAPD-fingerprints were not suitable to identify the raw material: due to the degradation of DNA during processing of the medicinal products data were hardly reproducible. Several fragments of the ETS- and ITS-regions were amplified and sequenced. Thus, comparisons of sequences with data bases may be useful to identify medicinal plants by this method.

References: [1] Joshi, K. et al. (2004). Curr. Sci. India 87(2): 159–165. [2] Slanc, P. et al. (2006). Pharmazie 61(11): 912–915. [3] Techen, N. et al. (2004). Curr. Med. Chem. 11(11): 1391–1401.