The goal of this doctoral thesis was the phytochemical and pharmacological investigation of Chinese herbs with potential anti-cancer activity. 12 plants were chosen for investigation based on a previous study. The plant material was successively extracted with different solvents and different extraction methods. All extracts were subjected to in vitro viability assays using several cancer cell lines. Six extracts showed high activity, four of them moderate activity. Using activity-guided fractionation, four active shikonin derivatives were isolated from Onosma paniculata. The active extract as well as dimethylacryl- and epoxyshikonin were shown to affect cell morphology, cell cycle distribution and cleavage of caspase-3 in different melanoma cell lines. Dimethylacrylshikonin also changed the mRNA expression levels of several proapoptotic genes. The results suggest that dimethylacrylshikonin can not only lead to caspase-dependent apoptosis but also to caspase-independent. Finally, the activity of the isolated compounds was compared to several other shikonin and alkannin derivatives.Costunolide and dehydrocostus lactone were identified as active principles in Saussurea lappa. Investigations of their effects on several soft tissue sarcomas revealed that they changed cell cycle distribution and inhibited the expression of different metalloproteinases. Dehydrocostus lactone also decreased the expression levels of ABCB1 transporter. However, apoptotic events (disruption of the mitochondrial membrane potential or cleavage of caspase-3) were not observed.From Helianthus angustifolius, four furanogermacranolides (8-methacrylyl-4,15-iso-atriplicolide, 8-isobutyryl-4,15-iso-atriplicolide, 8-(2-methylbutyryl)-4,15-iso-atriplicolide and 8-isovaleryl-4,15-iso-atriplicolide) were isolated and identified as active principles. The last compound has not been reported before. The other three have not yet been reported in this plant species.