Aloe vera Aloe vera

Have you ever been on holiday and enjoyed the sun a little too much? There’s nothing more soothing than the cool relief of aloe vera gel on your skin.

This amazing gel is extracted from the centre of the leaf and contains compounds that reduce inflammation, prevent bacteria from infecting the skin, and help produce new cells, speeding up the healing process.

That’s why you can feel relief almost immediately when you put aloe vera on your sunburnt skin. It hydrates and protects the skin, giving your body time to heal itself.

Family: Xanthorrhoeaceae

Sooth yourself with the ‘wonder plant’

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Aloes come from dry habitats so they need very effective ways of saving water. The leaves have a waxy surface that keeps in moisture and reflects the sun’s heat away from the plant. Water is also stored in the leaves, providing a valuable water supply in times of drought.

Kew and Aloe vera

Olwen Grace, a Kew scientist, is working in South Africa investigating whether the healing properties of the leaf gel are also found in plants closely related to aloe vera. Maybe it isn’t the only wonder plant in the aloe family.

Good for us good for the plant

Sausage tree Kigelia africana

Named for its large, sausage-like fruits, this useful tree is sacred to many African communities.

All parts of the tree, which grows across sub-Saharan tropical Africa, are used medicinally. The fruits have been used in traditional medicine as a treatment for many skin conditions, including skin cancer.

Preliminary research shows that the fruit contains compounds that are toxic to certain tumour cells. Research that brings together traditional knowledge and modern science can result in the discovery of new leads for the treatment of cancer.

Family: Bignoniaceae

Under the skin of a sacred tree

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The same properties that are used in skin treatments for us are used by the plant itself as a defence mechanism against disease. Not only this, the bark and leaves are bitter tasting, and so deter passing herbivores from having a snack.

Kew and Kigelia africana

Kew scientists have documented the multitude of uses that communities in Africa make of this plant.

Good for us good for the plant

Dragon’s blood Dracaena cinnabari

Despite its mythical sounding name, the dragon’s blood tree really does exist, and moreover its healing properties have been exploited for centuries.

The blood-red sap or resin of this tree has a number of wound-healing properties. Studies have shown that it stops bleeding, and is an antiseptic and anti-inflammatory agent. It also speeds up the healing process by contracting the edges of the wound, and helps to produce collagen and regenerate skin cells.

This ancient looking tree comes from the Socotra archipelago off the coast of Yemen. It survives in desert and scrubland habitats that have little rainfall. Its unusual shape helps to provide shade and reduces the rate of water loss from its leaves.

Family: Asparagaceae

Here be dragon’s blood

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Good for us good for the plant

The properties of this tree’s sap give it a bitter taste, and the sap may be toxic to some animals and fungi. This can provide the tree with some protection against grazers and disease in an already harsh environment.

Kew and Dracaena cinnabari

Kew’s Economic Botany Collection contains the largest collection of dragon’s blood sap or resins, dating back to the 19th century. This collection is being analysed to find out how useful the sap is medicinally.

As the plant is already threatened in the wild, proven medicinal value could either put further pressure on these populations or provide a compelling reason for ensuring their protection.

Cacao Theobroma cacao

Do you like chocolate? Well you might love it after reading this! We know that eating this sweet treat makes us feel good, and now we can also say that it does us good.

Cacao contains many different compounds, including antioxidants, that have health benefits for the body, particularly the heart. These compounds are found in the raw cacao beans from which chocolate is made.

The compounds in cacao can help our heart in two ways. They reduce the amount of ‘bad’ cholesterol in our blood, and they help to reduce hardening of the arteries. Both of these are major factors contributing to heart disease.

So a small amount of dark chocolate with a high percentage of cocoa really can do you good!

Family: Malvaceae

Sweet medicine

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Like us, some plants use antioxidants for their own benefit. Antioxidants are compounds that plants produce to protect their own cells from exposure to heat, light, air, pathogens and moisture.

Kew and Theobroma cacao

Like any crop, cultivated cacao can be susceptible to disease.

Kew scientists are working with partners in the Amazon rainforest in Brazil to protect the ‘wild cousins’ of the cultivated cacao.

This wild population is more genetically diverse, and therefore more resistant to pests and diseases, which may help us to protect our future supply of chocolate.

Good for us good for the plant

Madagascar periwinkle Catharanthus roseus

This pretty plant holds a life-saving secret within its leaves that has dramatically increased survival rates for some cancer patients.

The Madagascar periwinkle is native to Madagascar, as you might guess, but it also grows in subtropical and tropical regions worldwide, commonly grown as an ornamental garden plant and now cultivated commercially for the pharmaceutical industry.

The leaves of this plant contain chemical compounds called alkaloids.

Two of these, vincristine and vinblastine, are used as chemotherapy drugs to treat a whole range of cancers, including leukaemia and Hodgkin’s disease. Vincristine has helped increase survival rates of childhood leukaemia patients from less than 10% in 1960 to over 90% today.

Family: Apocynaceae

Leukaemia treatment from Madagascar

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The same toxic properties of the alkaloids vincristine and vinblastine that make them powerful anti-cancer drugs also protect the leaves of the plant from being grazed by herbivores.

At Kew we believe that local communities should have a say in how their plant resources are exploited. Plant collecting teams from Kew draw up contracts to ensure that if a profitable discovery is made while they are collecting in a particular region, the local people will have a share in it.

Good for us good for the plant

Kew and Catharanthus roseus

When these alkaloids were first discovered, little of the profit made from the drugs ever reached the people of Madagascar, the plant’s native habitat.

Sacred lotus Nelumbo nucifera

Revered as a divine symbol for more than 5,000 years, the sacred lotus has been grown not only for its cultural and ornamental value, but also for its medicinal uses.

All parts of the plant have various traditional medicinal uses. You can find out more about these in our Waterlily House. Here, we focus on the seeds.

The sacred lotus seed contains bitter chemical compounds called alkaloids. These have an antispasmodic effect on the muscles of the intestines, which helps to reduce the symptoms of diarrhoea.

Family: Nelumbonaceae

Nature’s Imodium

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Because the alkaloids found in the sacred lotus have a bitter taste, they also protect the seeds by deterring herbivores from snacking on them.

Kew and Nelumbo nucifera

Two collections of seeds of the related species, Nelumbo lutea, are stored at subzero temperatures at Kew’s Millennium Seed Bank. Our seed bank aims to save plant life worldwide, especially endangered species and those plants likely to be of most use in the future.

Californian research has recently shown that lotus seeds can survive for well over 1,000 years!

Good for us good for the plant

Laurel clock vine Thunbergia laurifolia

The laurel clock vine (also called the blue trumpet vine) is a vigorous climbing plant native to tropical regions of India and south and south-east Asia, including Malaysia and Burma. It is used medicinally in Malaysia and Thailand.

In Thailand a powder prepared from the dried leaves and flowers is used as an antidote to poisons, and in the treatment of drug addiction.

Certain chemical compounds called iridoids that have been isolated from the leaves have antioxidant, anti-inflammatory, pain-killing, antispasmodic, anti-tumour and antiviral effects, as well as acting on toxins in the liver and supporting the immune system.

Family: Acanthaceae

Round-the-clock detox

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The iridoids produced by the laurel clock vine also protect the plant itself from being eaten by herbivores or infected by microorganisms.

Good for us good for the plant

Research includes identifying compounds such as iridoids, that could provide new medical treatments in the future.

Kew and Thunbergia laurifolia

Kew’s Jodrell Laboratory is home to a team of scientists who use the latest analytical techniques to study plants of economic importance or particular interest, for example medicinal plants.