Think licorice and you probably imagine a chewy black rope with a unique sweet flavor. If you get a traditional recipe of this humble confection, it may even contain a cancer-killing chemical.
Scientists from Hong Kong Baptist University (HKBU) recently published findings that a flavonoid in licorice root can inhibit the progression of pancreatic cancer. Researchers showed that this same licorice-based chemical may also enhance the efficacy of chemotherapy drugs used to treat pancreatic cancer.
It’s a vicious cancer that can strike without any clear warning. Patients typically experience little or no symptoms with pancreatic cancer—until it has considerably progressed. When doctors do finally catch it, the disease is very advanced and has spread to other organs.
When most any cancer is caught early enough, a surgeon may be able to remove it. But by the time a patient receives a pancreatic cancer diagnosis, surgical removal is usually no longer an option. Only about 20 percent of pancreatic cancer patients are eligible for surgery (known as a Whipple operation or pancreaticoduodenectomy).
Licorice’s Healing LegacyThese are the realities that a pancreatic cancer patient must face. So why would HKBU scientists study licorice as a source of medicine for such a daunting disease? In part, because of its traditional use. Licorice root has been used as a medicine around the world since ancient times.
In China, licorice root is known as gan cao (which means “sweet herb”) and has been used for a number of health conditions for millennia. Because of its sweet flavor and a long-held reputation for harmonizing combinations of other herbs, licorice is found in a vast array of traditional Chinese herbal formulas.
Licorice root has long been used in the West as well, for treating gastrointestinal, respiratory, and inflammatory diseases. Modern science continues to validate the root’s healing potential.
Understanding ISLWhen modern science analyzes a plant’s healing power and potential, it isolates the chemicals it contains. Licorice root contains several chemicals with medicinal properties. A saponin called glycyrrhizin is the best-known and most frequently studied of these chemicals, but many others remain. The licorice compound at the heart of the HKBU study is known as isoliquiritigenin (ISL).
The team conducted a series of cell experiments to demonstrate that ISL suppressed the growth of pancreatic cancer cells, thereby inhibiting cancer progression.
“ISL possesses a unique property of inhibiting pancreatic cancer progression through the blockade of autophagy, which is a natural process where the body’s cells clean out damaged or unnecessary components. The blockade of late-stage autophagy in our experiments results in cancer cell death,” Mr. Ko said in a statement.
Researchers also looked at tumors in mice to investigate the efficacy of ISL in inhibiting pancreatic cancer cell growth. Mice were divided into groups in which some received chemotherapy with gemcitabine (GEM), a common treatment for pancreatic cancer. Other mice received doses of ISL.
ISL demonstrated treatment effects that were found to be comparable to that of GEM but without the GEM side effects, such as anemia, a drop in white blood cells, and weight loss.
Mr. Ko and his team examined how ISL might help in counteracting chemoresistance. Researchers looked at pancreatic cancer cells treated with chemo drugs alone, compared to cells where the drugs were used in tandem with ISL. They found that ISL combined with GEM inhibited the growth of pancreatic cancer cells 18 percent more compared to the group treated with GEM alone.
ISL combined with 5-fluorouracil was 30 percent more effective than chemo by itself.
Researchers concluded that ISL could considerably enhance conventional treatment.
“The findings in this study open a new avenue for developing ISL as a novel autophagy inhibitor in the treatment of pancreatic cancer," Mr. Ko said. "We hope to collaborate with other research partners to further evaluate the effectiveness and potential clinical application of ISL in treating pancreatic cancer."