Italian researchers investigated the anti-tumour effects of five natural cannabinoids of the cannabis plant (cannabidiol, cannabigerol, cannabichromene, cannabidiol-acid and THC-acid) in breast cancer. Cannabidiol (CBD) was the most potent cannabinoid in inhibiting the growth of human breast cancer cells that had been injected under the skin of mice. CBD also reduced lung metastases deriving from human breast cancer cells that had been injected into the paws of the animals.
Researchers found that the anti-tumour effects of CBD were caused by induction of apoptosis (programmed cell death). They concluded that their data “support the further testing of cannabidiol and cannabidiol-rich extracts for the potential treatment of cancer.”
These observations are supported by investigations of US scientists who found out that exposure of leukaemia cells to CBD led to a reduction in cell viability and induction of apoptosis. In living animals CBD caused a reduction in number of leukaemia cells. The scientists noted that CBD “may be a novel and highly selective treatment for leukemia.”
(Sources: Ligresti A, Schiano Moriello A, Starowicz K, Matias I, Pisanti S, De Petrocellis L, Laezza C, Portella G, Bifulco M, Di Marzo V. Anti-tumor activity of plant cannabinoids with emphasis on the effect of cannabidiol on human breast carcinoma. J Pharmacol Exp Ther. 2006 May 25; [electronic publication ahead of print]; McKallip RJ, Jia W, Schlomer J, Warren JW, Nagarkatti PS, Nagarkatti M. Cannabidiol-induced apoptosis in human leukemia cells: A novel role of cannabidiol in the regulation of p22phox and Nox4 expression. Mol Pharmacol. 2006 Jun 5; [electronic publication ahead of print])