- Aloe vera gel contains compounds that reduce inflammation, prevent bacterial infection, and speed healing when applied to sunburnt skin. It hydrates and protects the skin while the body heals itself. - Olwen Grace is investigating whether other plants related to aloe vera also contain the healing properties in aloe vera gel. - The sausage tree grows across Africa and all parts have traditional medicinal uses, including using the fruit to treat skin conditions and cancer. Preliminary research shows the fruit contains compounds toxic to tumor cells.

1. 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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2. 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

3. 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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4. 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

5. 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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6. 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.

7. 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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8. 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

9. 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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10. 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.

11. 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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12. 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

13. 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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14. 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.