Quality control of phytomedicines – is the herbal medicine industry facing a crisis?

The enormity of the herbal medicines industry is emphasised by the fact that 80% of the world's population use herbal medicines. However, due to country-specific legislation (or lack thereof) herbal medicines are often not closely regulated and quality and safety cannot be guaranteed. Herbal medicines are notoriously phytochemically complex mixtures, complicating the of quality control process which is a daunting and intricate task. The quality of herbal medicines is assessed both qualitatively through species authentication as well as quantitatively through the quantification of specific biomarkers which are used to determine the quality of raw materials and products. Established, methodical processes are necessary to standardise herbal medicines to produce consistent and reproducible products. Unfortunately the industry remains plagued by the unscrupulous practices of some suppliers and producers of herbal medicines. The quality of a wide range of commercial products (n = 100) was assessed using various analytical techniques such as single point vibrational spectroscopy, hyperspectral imaging, HPTLC and LC-MS etc. in combination with chemometric data analysis where appropriate. This paper suggests simple and practical quality assurance protocols for medicinally and commercially important plant species. It will demonstrate the effectiveness of these methods to solve significant practical problems such as discriminating between closely related plant species (e.g. Pelargonium, Harpagophytum and Sceletium spp.), uncovered alarming analytical results where the claimed active ingredients were not detected at all (e.g. Hoodia and Ginseng spp.), demonstrated that the raw material does not meet set Pharmacopoeial standards (e.g. Harpagophytum) and revealed several errors in labeling and packaging information. The advantages and limitations of various analytical techniques including the novel application of hyperspectral imaging will be highlighted.