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Oral squamous cell carcinoma, B-cell chronic lymphocytic leukemia, and lung cancer are all difficult to treat with conventional chemotherapy. Researchers have found that extracts from the Magnolia grandiflora plant are effective in fighting these three cancers in laboratory models. The reported mechanism was induction of apoptosis in each case. Honokiol, magnolol, and parthenolide are the compounds believed to be the active ingredients.
Dr. Xi-rui Chen of the University of Toronto, Ontario, Canada, and colleagues tested honokiol on squamous cell carcinoma. This type of cancer has a response rate of only 30 to 40 percent to most commonly used cytotoxic chemotherapy agents in large studies. Earlier research indicates that these cancer cells become resistant to chemotherapy drugs by a mechanism of circumventing apoptosis. The toxicity to peripheral blood mononuclear cells and primary cultured human cells has been reported to be low. Since normal cells have a different physiology from cancer cells, Chen suggested that honokiol's ability to induce apoptosis could make it a novel treatment agent, selectively killing the cancer. Honokiol was effective in killing oral squamous cell carcinoma cells in lab studies by induction of apoptosis in Chen's work.
Dr. Gustavo H. Marin and colleagues at the National University of La Plata, Buenos Aires, Argentina, reported similar results for B-cell chronic lymphocytic leukemia (B-CLL). This type of cancer can be managed, but not cured, as the name suggests. The prognosis has not improved despite years of research. Marin used a water extract of Magnolia seeds to induce apoptosis in B-CLL cells, including cells that were resistant to chlorambucil. From the successful results, he concluded that the herbal extract is a promising therapy strategy.
For lung cancer, Dr. Qi-qi Jiang and colleagues at the West China Medical School reported that honokiol kills lung cancer cells in a lab xenograph model, both alone and in combination with the standard chemotherapy agent cisplatin. The mechanism was apoptosis, as in the other studies.