Inhibition of crown-gall tumorigenesis with plant extracts

Measurement of the inhibition of crown-gall tumors on potato discs is an antitumor bioassay method for detection of anti-tumor compounds from higher plants. In this study, after surface sterilization, tuber discs were co-cultivated with Agrobacterium tumefaciens B₆S₃ for two days. The discs were then inoculated on MS media with the crude extracts obtained from different parts of various plants – Allium sativum L. (Liliaceae), Salvia verbenaca L., Rosmarinus officinalis L., Ocimum basiculum L., Lavandula stoechas L. (Lamiaceae), Althaea cannabina L. (Malvaceae), Petroselinum sativum Mill. (Apiaceae), Pelargonium radicula L. (Geraniaceaea), Juglans regia L. (Juglandaceae), Platanus orientalis L. (Platanaceae), Laurus nobilis L. (Lauraceae), Ranunculus ficaria L. (Ranunculaceae), and Abies equi-trojani Aschers. et Sint. Ex Boiss (Pinaceae). Tumors appeared after 10-15 days, and tumor inhibition was detected only in six plant extracts of 13 (A. sativum, R. officinalis, P. orientalis, L. nobilis, R. ficaria, and A. equi-trojani) when compared to control material. Constitutive tumor inhibition activities were higher in these plant extracts (63.5%, 56.1%, 61.7%, 54.6%, 69.7%, and 57.9% at 0 min; 58.8%, 54.6%, 58.8%, 48.4%, 62.6%, and 51.6% for 15?min after bacterial inoculation).