The belief that herbal remedies are less invasive on the human body than conventional medicine and the return of the consumer to a more natural lifestyle, has led to the development of a multitude of remedies, with many different uses. Because the use of these herbal remedies has increased drastically in the last decade, it is essential that the quality and efficacy of these products are well regulated. One of the objectives in this study includes the investigation of the presence of marker metabolites in five herbal remedies, namely Serenoa repens, Silybum marianum, Hypericum perforatum, Echinacea purpurea and Gingko biloba. Although most of the brands tested contained the active ingredients assayed for, a few exceptions were found. However, because this study used only thin layer chromatography for analysis of products, verification of these results should be obtained using other more modern methods for example high pressure liquid chromatography. Four brands of Serenoa repens were selected and assayed for the presence of β-sitosterol. All four brands tested indicated the presence of β-sitosterol. Five brands of Hypericum perforatum were selected and assayed for the presence of hypericin, rutin and chlorogenic acid. Four of the five products tested indicated the presence of hypericin, while three of five products indicated the presence of rutin and chlorogenic acid. Five brands of Echinacea purpurea were selected and assayed for the presence of β-sitosterol, chlorogenic and caffeic acid. Three of the five products indicated the presence of β-sitosterol, while only one of the five products contained chlorogenic acid. Caffeic acid was present in 3 of the 5 products. Seven brands of Gingko biloba were selected and assayed for the presence of rutin and bilobalide. Five of the seven products indicated the presence of rutin and bilobalide. Four brands of Silybum marianum were selected and assayed for the presence of both taxifolin and sylibin. Only two of the four products contained both taxifolin and silybin. The second objective of this study is to provide a literature review of the five herbal remedies mentioned above. Amongst the topics discussed were uses of these plants, evidence from studies conducted, chemistry and mechanism of action of the active molecules contained in the plants.
Supervisor: Prof AM Viljoen