Lao Rainforests Becoming Laboratory for Cancer Drugs

The emerging field of ethnopharmocology is pinpointing exciting new possibilities in Laos to fight the deadliest cancers.

Djaja D. Soejarto has been trekking through the rain forests of Laos and Vietnam for over two decades in search of cytotoxic molecules—the anticancer drugs of the future.

It’s a quest—a biological prospecting—that depends on carefully-crafted partnerships with national governments, village communities, and local healers.

“The community has to know what we intend to do. They have to permit us to go in there,” Dr Soejarto told The Daily Beast. “When you want to sit down with the [traditional] healer, before you ask any questions, you have to ask permission to the healer whether he or she wishes to be interviewed.”

An emeritus professor of the College of Pharmacy at the University of Illinois at Chicago, Dr Soejarto recently contributed to a paper with first author Joshua Henkin.

It describes two expeditions in Laos during a recent “dry winter season” in Xieng Khouang along with Bolikhamxay, a lowland rain forest recovering from the devastation of past fires and logging. Soejarto’s team collected over 200 samples from nearly 100 species in total.

The report found that, based on intel from traditional healers in Laos, six unique plant extracts from six different species “exhibited notable cytotoxicity” against colon cancer.

Five of these plant extracts killed more than half of HT-29 colon cancer cells—a notoriously hard-to-treat cell line (adenocarcinoma).

“It’s not that you necessarily can translate these results directly to […] a tumor, but at least it gives you some idea that it’s killing these cells to a significant degree,” Henkin told The Daily Beast. “There aren’t more of them. And there are, in fact, [colon cancer cells] that died as a result of this.”

This success rate—a high ‘hit rate’ against colon cancer cells—is exceedingly rare, ethnobotanist and anthropologist Glenn Shepard told The Daily Beast. “They found that plant species derived from traditional medicine had a 6.25 percent success rate in bioassays for some kind of anti-cancer activity.

But how can we be sure that what’s in the lab can actually help cure what’s in the body?

There’s no guarantee that the cell lines you have in the lab really have exactly the same characteristics as the tumor cell line, but there are ways of investigating that further,” Henkin said.

Plant-derived drugs and treatments are becoming more prevalent in allopathic medicine (so-called ‘Western’ or ‘mainstream’ medicine): a 2012 paper estimated over 60 percent of anticancer drugs originate from natural sources.

“Nature is the best source of anti-cancer drugs,” a 2017 index of scientific literature on the topic proclaimed.

Dr Soejarto and Henkin’s paper outlines how the old-school bioprospecting method—collecting a diverse range of wild plants at random testing them in the lab—was actually less successful than a strategy called “ethnobotany,” a culturally- and community-oriented approach that takes folk medicine seriously.

“What I think is really interesting about the plants that we found with active plant parts against the HT-29 cells is that three of the plant parts were in fact used locally for various purposes of medicine,” Mr Henkin said.

For the comple article, click here.

Source: The Daily Beast

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