No Plants No Medicine

From tea tree oil to morphine, over 28,000 different species of plants, as well as many species of fungi, are used for medicinal purposes.

From the discovery of Penicillin, produced by a species of Penicillium mould in 1928, right up to today’s cutting-edge research into the Blushwood tree’s potential to treat cancer - plants and fungi keep us alive.

Director of Science and Conservation at the Royal Botanic Garden Sydney, Dr Brett Summerell, is featured in 'No Plants No Medicine', the debut episode of our new podcast: Branch Out.

Have you heard of the Black Bean tree? 

“The rainforest is particularly rich in plants that produce chemicals with healing properties and about one quarter of all medicines contain natural ingredients derived in some way from rainforest plants,” Dr Summerell said. 

“In fact, we’ve got a stunning rainforest species growing here at the Royal Botanic Garden Sydney called Castanospermum austral, more commonly known as the Black Bean or the Moreton Bay Chestnut,” he said.

This grand tree with stunning red and yellow flowering displays can reach a height of 40 metres at maturity, however, its impressive outward beauty tends to overshadow its incredible healing properties.

“The Black Bean contains a toxic chemical called castanopermine in its leaves and large green seed pods, which weigh up to half a kilogram,” Dr Summerell said.

How do some plants heal us?   

But why do only some plants contain these deadly and remarkable healing properties? Dr Brett Summerell said it all comes down to if they contain a ‘secondary metabolite’.

“All plants contain phytochemicals, which are divided into primary metabolites, such as sugars and fats, and secondary metabolites,” Dr Summerell said.

“Secondary metabolites serve a more specific function in plants, such as deterring a predator or attracting insects for pollination.

“If a secondary metabolite can be isolated from a plant and the dosage rate fine-tuned, it can have beneficial effects on long-term human health and can be used to treat and cure human diseases,” Dr Summerell said.

The unexpected discovery of penicillin is testament to the importance of observation, research and discovery, and the more we delve into the dense ecosystems of our rainforests, the more we realise just how little we know.

“Humans may have explored a lot of the planet, with around 400,000 plants known to science, but every year approximately 2000 species of plants are still being discovered by botanists around the world,” Dr Summerell said. 

The Royal Botanic Garden Sydney’s dedicated team of ecologists, horticulturalists and botanists are working together to build one of the most valuable and broad libraries of knowledge about Australia and by extension, the environment at large.

Branch Out & subscribe to our podcast 

Go deeper into the fascinating world of dangerous and life-saving plant chemicals with Dr Brett Summerell in the debut episode of our Branch Out podcast - 'No Plants No Medicine.'

Please subscribe to Branch Out on Apple Podcasts or any podcasting app. If you like the show, please leave a rating, review and share it with your followers on social media. 

If you want to know more about how world leading scientists are developing solutions to the world’s most critical environmental and biodiversity issues, please head to our science page.