Development and validation of thin-layer chromatographic methods for quality control of herbal products

Use of thin-layer chromatography (TLC) for quality control of herbal medicinal products (HMPs) is very useful for determining and comparing the compositions of such products. In Mexico, HMPs are sold as herbal dietary supplements, and there is no legislation regarding their quality control. Heterotheca inuloides, Citrus aurantium, Peumus boldus, Equisetum arvense, Eucalyptus globulus, Ginkgo biloba, Mentha piperita, Aloe vera, Salvia officinalis , and Cassia senna are some of the major commercial products obtained from plants in this region. In this paper we describe the effectiveness of TLC methods for quality control of several commercial products containing plants and their extracts. We used one or several specific markers for each type of plant. In only 20% of the 40 commercial products that were analysed did the chromatographic characteristics of the respective plants match those of the specific respective marker compounds. These results highlighted a problem arising from the lack of regulation of these products. The proposed TLC methods are simple, sensitive, and specific, and can be used for routine quality control of raw herbal products and formulations of the plants tested. The results obtained emphasize the need to develop simple and reliable analytical methods that can be performed in any laboratory for the purpose of quality control of dietary supplements or commercial herbal products sold in Mexico.