Flavones and lignans from the stems of Wikstroemia scytophylla diels

Background: The genus Wikstroemia has about 70 species, but only a limited number of species have been studied chemically. Wikstroemia indica has long been used as a traditional crude drug in China. However, there is no report about the bioactivity of Wikstroemia scytophylla. Objective: This paper reports the chemical investigation and biological evaluation of the W. scytophylla. Materials and Methods: The EtOAc extraction of W. scytophylla was isolated using chromatographic methods, and the compounds were analyzed by spectroscopic methods. The in vitro antitumor activities against five human cancer cell lines were performed according to the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Results: The chemical investigation of the stems of W. scytophylla resulted in the isolation of 12 compounds mainly including one biflavone (1), five flavones (2-6) compounds, and six lignans (7-12), in which compound 8 was a new natural product. Compounds 1 and 7-12 were evaluated for their antitumor activities while these compounds showed weak cytotoxicity with the half maximal inhibitory (IC₅₀) values more than 40 μM. Conclusion: All of these compounds were isolated from this plant for the first time, and compounds 2-12 were first reported from genus Wikstroemia, in which compound 8 was a new natural product. Compounds 1 and 7-12 exhibited weak antitumor activities (IC₅₀>40 μM). The chemotaxonomic significance of all the isolations was summarized.