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Biochemistry

Dandelion chemistry: Diuretics and the tyres of the future

Infographic on dandelion chemistry. The left side of the graphic details some of dandelion's medicinal uses, including as a diuretic, anti-inflammatory, anti-carcinogenic and anti-oxidative. Polyphenols and sesquiterpenes are responsible for many of these and are also responsible for the bitter flavour of dandelion leaves. The right side of the graphic details rubber extraction from Russian dandelions. Bike tyres made from dandelion rubber are now commercially available and consumer tyres are expected to follow within the decade.
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Dandelions: Loved by children, loathed by (most) gardeners. Often dismissed as a weed, dandelions lend themselves to several uses — and might be the solution to making more sustainable car tyres.

The dandelion goes by many names across languages and colloquialisms. The English name comes from the French ‘dent-de-lion’, a reference to the tooth-like serration of the leaf edges. Several languages make similar reference, while some names refer to other characteristics of the plant. But, circling back to French, ‘pissenlit’ is the common name for dandelions. This translates to ‘piss in the bed’, a reference to dandelion’s supposed diuretic properties.

A diuretic is something that increases your body’s production of urine. Caffeine, found in tea and coffee, is a weak diuretic, and alcohol is another example. Evidence for dandelion’s diuretic properties is mixed and limited, despite its use in traditional medicine for centuries. One study found it to have a comparable diuretic activity to the diuretic drug furosemide in mice. Another limited study in humans, which used self-reported data, also found a diuretic effect. However, most studies have been in animals, with limited data for humans, so it’s hard to say what the size of dandelion’s diuretic effect might be.

Because of this uncertainty, it’s unclear which compounds in dandelion might be responsible. Some discussion points to flavonoids and chlorogenic acids, but the research is too sparse for any clear culprit to emerge. What we do know is that, if dandelion is an effective diuretic, it’s got a key benefit: its potassium levels. Dandelion greens have higher levels of potassium than those found in bananas. This is useful because an issue with some diuretics is that they can cause low potassium levels. Even if dandelion doesn’t itself have a diuretic effect, given with existing diuretic drugs it could maintain potassium levels.

Investigation of dandelion compounds goes beyond just determining if they make you wee more. Research has identified anti-inflammatory, anti-carcinogenic and anti-oxidative actions, primarily due to polyphenol and sesquiterpene compounds. These compounds are also responsible for the bitter flavour of dandelion leaves. And if you’ve found that your skin gets a bit irritated or itchy after weeding dandelions in the garden? It’s the sesquiterpene lactones that are partly to blame, as they’re known to be contact allergens.

While pulling up dandelions, you may notice the sticky white liquid that seeps out of their broken stalks. This liquid contains natural latex, from which we can get rubber. The dandelion’s root contains most of the latex. The quantity in common dandelions is too low to make large-scale extraction practical, but a relative, the Russian dandelion (Taraxacum kok-saghyz) contains higher quantities.

Rubber from dandelions isn’t a new discovery. During World War II, rubber shortages led several countries to use dandelions for rubber production. In 1941 30% of the USSR’s rubber came from the Russian dandelion. But as soon as rubber from its primary source, the rubber tree (Hevea brasiliensis), was available again, interest in dandelion rubber waned.

Now, though, efforts to extract and use rubber from dandelions have reemerged. This is partly due to concerns about the sustainability of rubber from the rubber tree and its ability to meet future levels of demand. Rubber trees only grow well in the tropics, and the land required for this leads to deforestation. Russian dandelions can be grown in a much wider range of climates, making scaling up dandelion rubber production a realistic prospect.

Since 2014, Continental, the German tyre manufacturer, has been pursuing the manufacture of dandelion rubber tyres. As of 2019, they have marketed bicycle tyres with a tread made exclusively from dandelion-derived rubber. They have also tested tyres for commercial vehicles and cars. They estimate that dandelion rubber tyres for cars will be available by the end of the decade. Another tyre manufacturer, Goodyear, has announced plans to produce dandelion rubber, initially for military planes but potentially expanding to consumer vehicles in the future.

The best part of all this is that the Russian dandelion can be easily grown in most climates — so you can have a go at extracting rubber from it yourself. This Science in School article presents a couple of different methods for doing so. While you’re unlikely to be able to extract enough rubber for your own tyre, it’s a fun activity to reveal the rubber hidden in the plant’s roots.

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