A compound in garlic slows the spread of human lung cancer cells, according to researchers in Penn State's College of Health and Human Development.
Kazuko Sakamoto, a Penn State research associate in nutrition, reported that diallyl trisulfide (DATS), a compound in processed garlic oil, slowed the growth of -- or even killed -- human lung tumor cells grown in culture. Lung cancer is the leading cause of cancer death in the United States.
Sakamoto described her findings at Experimental Biology '96, a meeting of 18 scientific societies.
"We found DATS to be extremely effective in reducing the growth of human lung carcinoma cells in culture," says John Milner, professor and head of Penn State's Department of Nutrition and a co-researcher on the study. The study, funded by the American Institute for Cancer Research, was conducted in Milner's laboratory.
The effectiveness of DATS was comparable to that of 5-fluorouracil, a widely used chemotherapy agent, Milner says. In addition, while DATS was effective against the lung cancer cells, it was considerably less toxic to healthy cells.
"The results have profound implications, both for diet and for drug therapy," Milner says.
The findings are the latest in a growing body of evidence that garlic can suppress human cancer cells, both in laboratory cultures and in test animals.
In the current study, treatment with 10 micrograms of DATS for 24 hours reduced cancer cell growth by 47 percent. A larger dose (50 micrograms) for the same length of time reduced cell growth by 72 percent, and an even more powerful treatment (100 micrograms) killed the cancer cells outright within 24 hours.
In previous studies, Milner and his colleagues reported that two other compounds in garlic -- S-allylcysteine or SAC, and diallyl disulfide or DADS -- have anti-carcinogenic properties as well. They found that SAC interfered with the formation of breast tumor cells in rats, while DADS inhibited the growth of human cancer cells (colon, skin, and lung) grown in lab cultures. The new study is especially promising because it found DATS to be 10 times as effective as DADS.
"Clearly we are learning that there is more than one mechanism by which garlic can reduce cancer," Milner says. "Our studies and others have shown that compounds in garlic can block the initiation phase of cancer as well as the subsequent promotion phase."
DATS and DADS can be found in ordinary clove garlic. They also are found in garlic oil preparations, which are available (usually in capsule form) in many health food stores. Deodorized garlic products, on the other hand, typically do not contain DATS and DADS, although they do contain SAC.