Modern HPTLC--a perfect tool for quality control of herbals and their preparations

Herbals and herbal preparations are complex mixtures with numerous natural compounds in an uncharacterized matrix--truly multicomponent systems. This is in contrast to most of the samples of the pharmaceutical and, in part, the food industry, where primarily single compounds have to be analyzed. Recently, models for the characterization of multicomponent systems with near-IR, NMR, and MS combined with chemometric tools have been developed. However, the complexity and sophistication of such methods still prevent their general applicability to the QC of herbals. On the other hand, modern TLC is a well-established method with a long tradition. The typical chromatograms visualize even complex multicomponent systems in a special manner. The technique is rapid, comparatively simple, robust, and extremely versatile. HPTLC can not only confirm but also establish identity. It is also an ideal screening tool for adulterations and is highly suitable for evaluation and monitoring of cultivation, harvesting, and extraction processes and testing of stability. To substantiate these claims, several examples taken from daily work are provided and discussed in this paper.