The findings, based on laboratory research, were initially presented at a conference in 2002. However they have not gained widespread media attention until this week, following a spotlight on leading medicinal plants researcher Professor Peter Houghton based at King's College London.
The researcher says the work, which lends support to the traditional use of galangal in Indo-China and the Malay Peninsula against stomach cancer, could be published in a journal in the future.
"We have in a way gone back and tested anti-cancer activity already seen in animals. But no-one had looked at the biological activitiy of the plant and sought to explain it," he told NutraIngredients.com.
Houghton's PhD student Dr CC Lee isolated and purified several compounds from a lesser galangal (Alpinia officinarum) extract, two of which could activate the GST enzyme when added on their own to the liver cells.
GST, or glutathione S-transferases, is a detoxifying enzyme involved in excreting carcinogens from cells. Other research groups have already demonstrated that substances which increase the activity of GST prevent cells becoming cancerous.
These two compounds, which are also present in greater galangal, were more effective than the others at killing breast and lung cancer cells grown in culture.
"These laboratory experiments show that there is some basis to the claim that galangal could be used to treat cancer," said Professor Houghton.
Further tests indicated that a healthy cell type was more resilient to the chemicals than the cancerous cell types tested. One of the isolated chemicals was about three times more effective at killing the cancer cells than the healthy cells.
Furthermore, the effect of this chemical on the healthy cells seemed to be reversible, unlike its effect on the cancerous cells.
Professor Houghton added that the plant's dual action on cells is rare among traditional medicines.
"Normally extracts are able to kill cancer cells or boost healthy cells' natural defences against cancer but galangal seems to do both," he said.
He added that the results do not support recommendations for consumption of the plant to fight cancer.
"We would need to carry out further tests, such as looking to see whether people who eat galangal on a daily basis are less likely to suffer from cancer than those who do not," said Professor Houghton.
The ginger-like root is also thought to help indigestion, colic and dysentery, as well as some skin conditions. In powdered form or as an alcoholic extract, galangal reportedly acts as a stimulant and an aphrodisiac.