In times past, ethnobotanist Ermias Lulekal Molla used to collect dingetegna, or Taverniera abyssinica, not far from Ethiopia's capital, Addis Ababa. The shrub, with its reddish flowers, is harvested for its roots to treat sudden illness, fevers, and abdominal pain.
Now, it takes him a couple of days to reach an area of countryside where he can find wild dingetegna, as the local forest habitat where it once grew has been shrinking as a result of land clearing and deforestation.
"These plants are in dire need of conservation attention," Molla told DW, remarking that the species aren't just important for their healing properties, but also in reducing erosion and forming part of an important carbon sink.
Dingetegna is one of at least 60,000 plants and fungi around the globe known to harbor medicinal value. It also belongs to a larger group that risks dying out completely: Over the past four years alone, the number of plants and fungi facing extinction has doubled to 40% . And those are just the species we know about.
Crucial drugs under threat
Researchers like Molla, who is also an associate professor at Addis Ababa University in Ethiopia, say that without these medicinal plants and fungi, the future of human health is seriously at risk.
More than one-third of modern drugs are derived either directly or indirectly from natural products, such as plants, microorganisms and animals, and between 60 and 80% of antibiotics and anticancer drugs originate from chemical compounds found in the natural world.
Far from being the preserve of niche-healing traditions, medicinal plants and fungi are fundamental to modern pharmacology, says Joao Calixto, a retired professor of pharmacology and the director of the not-for-profit Center of Innovation and Preclinical Testing in Brazil (CIEnP).
"If we look at the history of the development of modern medicine, it was almost entirely based on the study of medicinal plants and microorganisms — especially for making anti-infective agents," Calixto told DW.
Morphine and codeine, some of the most widely used painkillers, for example, were derived from the poppy flower. Paclitaxel (taxol) is a commonly used chemotherapy drug from the bark of the Pacific yew tree. Penicillin, one of the first antibiotics, derives from a mold. And cholesterol-lowering drugs are based on properties found in fungus.
Unsustainable use, habitat loss
While concerned conservationists such as Danna Leaman, chair of the IUCN Red List of endangered medicinal plant species, have been sounding the alarm on unsustainable extraction for decades, she says that is only part of the story when it comes to their decline.
"Habitat loss is the primary threat facing these species," Leaman told DW.
Deforestation and land clearing to make way for agriculture and the expansion of cities, in biodiverse-rich areas like Brazil, Ethiopia, India and North America, have decimated large swathes of forest and wild habitats where these plants and fungi are found.
"There has been very, very little awareness of the real and potential threat to the sourcing of these species that these pharmaceutical and herbal companies rely on and that people rely on for their health," Leaman said.
Given that 80% of these plants are harvested in the wild from rapidly depleting sources, one seemingly logical solution is to bring more of them into cultivation.
While that is effective and necessary for a small percentage of the world's high-demand medicinal plants, such as echinacea, Leaman says it is both risky and unrealistic to propose cultivation as a panacea for rising demand and dwindling natural environments.
"If you think of the devastation the conversion of native habitats to agriculture has created, taking so many species that are native to forests and other wild habitats into cultivation would create even more pressure on those habitats," Leaman said, adding that the time and effort it takes to research and rear these species is "enormous" and completely at odds with the current level of global attention being paid to medicinal plants and fungi.
That's not to mention the problems inherent in relying on a limited genetic sample of one species, especially in light of how poorly their wild relatives are looked after, Leaman says.
Public health at risk
Aside from their direct value to human health, many of these medicinal plants play a crucial role in supporting biodiversity — a key determinant of human health.
Prunus africana or the African cherry, a tree native to the mountainous regions of tropical Africa and Madagascar, is one such "keystone" species — responsible for helping a whole host of other plants, animals and organisms to thrive in the immediate ecosystem. Harvested for the bark's medicinal role in treating prostate problems, it's also an endangered plant species.
As the United Nations recently outlined in its landmark assessment of biodiversity, which showed the world had failed to fully achieve any of the 20 global biodiversity targets set 10 years ago, a healthy human population is utterly dependent on healthy, biodiverse-rich ecosystems.
In damaging these ecosystems and the medicinal plant species that live in them, not only is access to raw materials for drug discovery, biotechnology and medical models diminished, but the conditions are created for the spillover of viruses from wildlife to humans.
Protecting healthy environments is "absolutely essential" to the discovery of potential medicines, Leaman says. "Where is the next leukemia treatment going to come from? And the treatment for COVID19?"
"It determines our being able to have access not only to the sources of medicine that we rely on and know of, but the sources we don’t know about yet," she said.