Medicinal Herbs from Indian Ocean Island Found to Stop Growth of Cancer Cells

Mauritian plant
The Mauritius herb L. glauca which researchers studied. FEFU press office

Medicinal herbs found only on an island in Mauritius could one day form the basis of a treatment for one of the most deadly forms of cancer, scientists believe.

Chemicals present in the leaves of the Acalypha integrifolia, Eugenia tinifolia and Labourdonnaisia glauca plants were found to stop esophageal squamous carcinoma cells in a lab. The plants were found to contain a chemical that switches on the signaling pathway of the AMPK protein, and in turn prevent cancer cells from growing.

The disease is aggressive, and only about 20 percent of patients with esophageal cancer survive five years after being diagnosed, compared with 90 percent for breast cancer, for example. Most esophageal cancer patients don't live longer than a year past diagnosis. Scientists are therefore trying to find new, effective treatments.

In this instance, they looked to Mauritius. Thanks to the location, age and isolated nature of the Indian Ocean island, it is home to a range of endemic plants and wildlife. As many as 39 percent of its plants, 80 percent of nonmarine birds and reptiles, as well as 40 percent of its bat species are unique to Mauritius. About a third of the island's local plants are used in traditional medicine, Alexander Kagansky, study co-author and head of the Center for Genomic and Regenerative Medicine of the School of Biomedicine FEFU, explained in a statement.

The researchers took extracts from five plants: Acalypha integrifolia, Labourdonnaisia glauca, Dombeya acutangula Cav. subsp. rosea Friedmann, Gaertnera psychotrioides Baker, Eugenia tinifolia. Then, they dosed cell lines from two types of malignant esophageal tumors with the chemicals.

Of the five, three were found to not only inhibit the growth of the cancer cells but also kill them. The team hopes these plants could one day be turned into drugs to treat this form of cancer.

Alexander Kagansky, study co-author and head of the Center for Genomic and Regenerative Medicine of the School of Biomedicine Far Eastern Federal University, Russia, told Newsweek his team was surprised to find that three plants from the same island appeared to fight cancer in a similar way.

"[They stopped growth by] arresting these cells on a particular stage of their cell cycle, just before the division, or in other words at birth of a new cancer cell from a mother cell," he explained. "Now the effects of the plant molecules can be studied on various cancers, and the precise molecules will hopefully be elucidated to save people."

Kagansky, in speaking to Newsweek cautioned that "much more research" was needed before the compounds were turned into medicines. As well as having medical importance, the study also showed the urgency of the need to preserve diverse habitats such as those on Mauritius, he said.

Not many of the tested plants are left and "we need to take care to know what we need to synthesize without killing these amazing species," he said. "We also need to learn to cultivate these plants, and here we may need the attention of medicinal plants gardeners and traditional healers."

Caroline Geraghty, information nurse for the charity Cancer Research U.K., who did not work on the study, told Newsweek: "Some plants and plant extracts have been found to have anti-cancer properties and have been made into cancer treatments. But this is early stage research, and we need scientific evidence from large human trials to see if these plants could one day be used to treat cancer safely and effectively.

"There's no strong evidence that herbal or natural based remedies can treat, prevent or cure any type of cancer, and we don't advise patients use any alternative therapies that have not been approved by their cancer specialist doctor."

Earlier this month, a separate team of scientists looked at how a more common plant could be used to fight cancer: the chili.

Scientists believe capsaicin, which gives chili its kick, could one day be developed into a drug to treat lung cancer. The study focused on the effects of the compound capsaicin on the lung disease adenocarcinoma, which accounts for around 40 percent of all cases of lung cancer. The findings were presented at the American Society for Investigative Pathology annual meeting during the 2019 Experimental Biology meeting. The research therefore hasn't been published in a peer-reviewed journal.