Cytotoxicity and Mode of Action of Four Naturally Occuring Flavonoids from the Genus Dorstenia: Gancaonin Q, 4-Hydroxylonchocarpin, 6-Prenylapigenin, and 6,8-Diprenyleriodictyol - Kuete, Victor; Ngameni, Bathelemy; Wiench, Benjamin; Krusche, Benjamin; Horwedel, Cindy; Ngadjui, Bonaventure T.; Efferth, Thomas (Planta Medica, 2011)