(NaturalNews) The active ingredient in marijuana appears to target cancerous brain cells for destruction while leaving healthy cells alone, according to a study conducted by researchers from the Complutense University in Madrid, and published in theResearchers first conducted an experiment in mice that had been engineered to carry three different grafts of human brain cancer. They injected the mice daily with the molecule tetrahydrocannabinol (THC) near the site of the tumors once each day. The chemical appeared to stimulate the cancerous cells to engage in a process known as autophagy, in which cells initiate their own breakdown."These results may help to design new cancer therapies based on the use of medicines containing the active principle of marijuana and/or in the activation of autophagy," researcher Guillermo Velasco said.THC belongs to a class of chemicals known as cannabinoids, named after the cannabis (marijuana) plant in which they occur. It is the chemical responsible for the psychoactive effects of marijuana consumption.In a followup experiment, the researchers extracted and analyzed brain tissue from two patients with an aggressive form of brain cancer known as "recurrent glioblastoma multiforme." The patients were treated with THC for either 26 or 30 days, then the researchers extracted and analyzed another sample.After examining the brain tissue under an electron microscope, the researchers discovered that THC treatment resulted in death of cancerous cells but had no effect on healthy ones. The researchers were also able to discover the signaling pathway by which THC acts.The research opens up the possibility that cannabinoid research could yield "a new family of potential antitumoral agents," the researchers wrote.Glioblastoma multiforme is the most common and aggressive form of primary brain tumor. Without treatment, the average patient lives only three months after being diagnosed with the cancer. Treatment extends the average life expectancy after diagnosis by less than a year.Sources for this story include: rawstory.com; health.usnews.com.