Try or die for the aff – biodiversity loss makes pharma collapse inevitable

Katherine, October 9, 2021, ‘The Guardian, How biodiversity loss is jeopardising the drugs of the future’, https://www.theguardian.com/environment/2021/oct/09/how-biodiversity-loss-is-jeopardising-the-drugs-of-the-future, Accessed July 16, 2024, CT

Traditionally used as a painkiller for headaches, snowdrops are now known to slow the onset of dementia. In the 1950s, a natural alkaloid called galantamine was extracted from the bulbs. Today, a synthesised version of this is used to treat Alzheimer’s disease and scientists are investigating further to see if snowdrops might also be effective in the treatment of HIV.

However, over-harvesting has resulted in many snowdrop species becoming threatened. The snowdrop isn’t alone – plants are an abundant source of potential new medicines, often providing us with chemical templates for the design of novel drugs. Yet scientists across the globe say unsustainable use of wild medicinal plants is contributing to biodiversity loss and could limit opportunities to source medicines from nature in the future.

Dr Cassandra Quave, medical ethnobotanist and associate professor at Emory University, Atlanta, Georgia, says: “Just at the time we need them most, we are at risk of losing many important species.”

A long history of health

Humans have been using nature to heal since before written language. The first documented evidence was found on a 5,000-year-old slab of clay from Nagpur in India, which refers to more than 250 plants. Traditional Chinese medicine dates back thousands of years, the earliest found writings on pieces of tortoiseshell and bone from the 15th century BC. The Ebers papyrus, a 3,500-year-old Egyptian scroll, mentions willow bark from which aspirin was later developed.

Dr Melanie-Jayne Howes, lead researcher in biological chemistry at Kew Gardens, explains how they take traditional remedies and investigate to see if there is a real scientific basis for their use.

“The antimalarial drug artemisinin, found in sweet wormwood, was developed in this way. Sweet wormwood had been used in traditional Chinese medicine for thousands of years to treat fevers, which can be a symptom of malaria. Artemisinin and its derivatives now play a key role in our fight against malaria.”

Humanity’s biggest killers

Inspired by a traditional Italian remedy, scientists have isolated a molecule found in the leaves of the European chesnut tree that can neutralise drug-resistant staph bacteria.

Penicillin, morphine and some of the most effective cancer chemotherapeutics we have today all derive from natural sources and many of humanity’s biggest killers, including cancer and heart disease, are treated with medicines that originate from plants and fungi. According to the World Health Organization, 11% of the world’s essential medicines derive from flowering plants.

Recent discoveries include farnesol, found in fruits and herbs, used to treat Parkinson’s disease. Water hyssop, used for centuries across Asia to improve brain function, has recently been shown to reduce inflammation in the brain. And a protein isolated from beetroot is being explored as a target for neurodegenerative and inflammatory diseases, such as Alzheimer’s and multiple sclerosis.

In June this year, scientists isolated a molecule, extracted from the leaves of the European chestnut tree, with the power to neutralise dangerous, drug-resistant staph bacteria. They hope to synthesise a drug that will treat methicillin-resistant Staphylococcus aureus (MRSA) despite its resistance to antibiotics.

Quave says: “In the pre-antibiotic era, it was not unusual to die from childbirth and surgery due to infection. Even a simple scratch in the garden could lead to a fatal infection. The threat of antimicrobial resistance is effectively a return to similar conditions: the post-antibiotic era. Today, we lose an estimated 700,000 people across the globe each year due to antimicrobial-resistant (AMR) infections. By 2050, it is estimated that 10 million a year will die due to AMR infections. I believe nature holds the key to battle these and other emerging health threats.”

A deep-sea cure for cancer

The blue blood of horseshoe crabs is sensitive to toxic bacteria and is widely used to detect impurities in vaccines, including those for Covid-19.

The blue blood of horseshoe crabs is sensitive to toxic bacteria and is widely used to detect impurities in vaccines, including those for Covid-19. Photograph: Mike Segar/Reuters

Medicines are found in every corner of the Earth. Fungi growing on the hairs of sloths could be used to fight off parasites, bacteria and cancer. Snake venom-derived drugs treat heart conditions. Scientists have even discovered a marine bacterium living at depths of up to 6,500ft that they hope could provide a cure for aggressive brain cancer.

The bright-blue blood of the horseshoe crab was used in the development of Covid vaccines

Nature’s resources can be used in other ways too, to facilitate research or medical procedures. The bright-blue blood of the horseshoe crab has long been used to detect impurities in medicines and vaccines and was used in the development of Covid vaccines.Micro-algae, known as diatoms, have porous cell-wall structures so can be used as vehicles for drug delivery into the body. They are also being investigated for use in immunotherapy and combination therapy to treat cancer.

Other applications take inspiration from nature. A glue that mimics the natural adhesive made by barnacles helps wounds heal more quickly. A sharkskin-inspired, bacteria-proof material is used in urinary catheters and deep-wound dressings. A hypodermic needle that mimics a mosquito’s proboscis promises to give almost painless injections.

How little we know

However, we are losing species before we are even aware of them. Pollution, over-exploitation of natural resources, introduction of invasive species, change of land use and degradation through urbanisation and agriculture – human activity is the primary cause of biodiversity loss. Now, experts are asking, could biodiversity loss be as great a threat to humans as climate change?

Wildlife populations have fallen by more than two-thirds in less than 50 years

World Wildlife Fund

Howes says: “People have only harnessed the properties of a relatively small number of species. Some of the chemicals that plants and fungi produce are so complex we still can’t produce them synthetically – take vincristine, used in the treatment of children’s leukaemia, and vinblastine, used to treat Hodgkin’s disease.”

The rate of species loss is estimated to be between 1,000 and 10,000 times higher than the natural extinction rate, although it is impossible to know for sure as we have no idea how many species actually live on Earth, with estimates ranging between 5.3m and 1tn. However, we do know that the rate of extinction is accelerating. Wildlife populations have fallen by more than two-thirds in less than 50 years, according to the WWF, while the International Union for Conservation of Nature (IUCN) estimates that almost a third of all species are threatened with extinction.