toxic

Sea squill, sea squill on the sea shore

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by Jemma

Earlier in the month Rachel went on a trip to Mallorca, with a group of 1st year undergraduates from the University of Manchester (for more information see her blog post: https://herbologymanchester.wordpress.com/2015/04/07/surviving-salt-and-waterlogging-on-the-albuferita-mallorca/). During her time there she saw a number of sea squills (Drimia maritima) so I thought I would write a post about this interesting plant.

Sea squill from Albuferita, Mallorca
Sea squill from Boquer Valley, Mallorca

Drimia maritima is a poisonous plant that grows in rocky coastal habitats across southern Europe, western Asia and northern Africa. It grows from a large bulb that can be up to 20 cm wide and a kilogram in weight. In the spring, the bulb produces a rosette of dark green, leathery leaves that can reach up to a metre long. The leaves die away by autumn, when a shoot containing the flowers grows from the bulb. This flower-bearing shoot can achieve a height of up to 2 metres. Pollination of the Drimia maritima flowers occurs by both insects (specifically the western honey bee, the Oriental hornet, and the paper wasp) and wind.

The flowers and bulb of Drimia maritima Image taken from http://en.wikipedia.org/wiki/Drimia_maritima
The flowers and bulb of Drimia maritima
Image taken from http://en.wikipedia.org/wiki/Drimia_maritima
Drimia maritimia flowers Image taken from http://www.xericworld.com/forums/attachment.php?attachmentid=6344&stc=1&thumb=1&d=1341359115
Drimia maritima flowers
Image taken from http://www.xericworld.com/forums/attachment.php?attachmentid=6344&stc=1&thumb=1&d=1341359115

Drimia maritima has been mentioned as far back as the 16th century BCE in the Ebers Papyrus (an ancient Egyptian medicinal text). In the 6th century BCE the Greek philosopher Pythagoras wrote about the uses of squill and, along with Dioscorides (1st century ACE and author of De Materia Medica), recommended hanging the bulb to protect against evil spirits.

Materia Medica jar containing sea squill bulb
Materia Medica jar containing sea squill bulb

One of the earliest medical applications of the sea squill came from the Greek physician Hippocrates (4th century BCE), who advocated its use to treat jaundice (yellowing of the skin), convulsions and asthma. Over the centuries, Drimia maritima was used as a common treatment for dropsy (abnormal accumulation of fluid in tissues) before the more effective foxglove (Digitalis sp.) became the standard treatment during the 18th century.  The plant has also been used in folk medicine as a laxative and to clear mucus build-up.

Materia Medica jar containing sea squill
Materia Medica jar containing sea squill

In addition to its medicinal use, squill has been employed as a poison. All parts of the plant contain toxic chemicals. Once such compound, called Scilliroside, was shown in 1942 to be an effective rodenticide that is avoided by most other animals. In the 20th century, Drimia maritima began to be experimented on to develop highly toxic varieties for use in rat poison. Though not the most common rodenticide, interest in squill’s rat killing abilities has increased dramatically since many rats became resistant to the coumarin-based poisons previously used.

Specimen of the day – Atropa belladonna

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by Jemma

Atropa belladonna, commonly called deadly nightshade, is a herbaceous perennial (which means it lives for over 2 years and its stems die down back to the soil level at the end of the growing season) in the Solanceae family. This flowering plant produces shiny black berries that are extremely toxic. There is also a second version, Atropa belladonna var. lutea, which produces pale-yellow fruit rather than the iconic black berries.

Belladonna flowers and berries. Image adapted from: https://auntiedogmasgardenspot.wordpress.com/tag/belladonna/ and http://naturephotocloseup.eu/main.php?g2_itemId=1948&g2_jsWarning=true
Belladonna flowers and berries. Image adapted from: https://auntiedogmasgardenspot.wordpress.com/tag/belladonna/ and http://naturephotocloseup.eu/main.php?g2_itemId=1948&g2_jsWarning=true

Toxicity

Atropa belladonna is well known for being one of the most toxic plants in the Eastern Hemisphere. All parts of the plant contain toxic tropane alkaloids that target the nervous system, causing increased heart rate and inhibited movement of skeletal muscle. The symptoms of belladonna poisoning are often slow to appear and include dilated pupils, sensitivity to light, tachycardia (increased heart rate), headache, hallucinations and delirium. The symptoms often last for several days, before coma and convulsions occur, followed by death. Belladonna poisoning is caused by disruptions in the regulation of involuntary activities (such as heart rate) due to the tropane alkaloids.

A Brendel model showing the fruit of a belladonna plant.
A Brendel model showing the fruit of a belladonna plant.

History of belladonna

In the middle ages, belladonna was sometimes used to make Dwale, which was an early form of herbal anaesthetic. Other ingredients in this early anaesthetic included bile, hemlock, lettuce, opium and vinegar. In addition to its use as an anaesthetic, belladonna was said to be one of the key ingredients, along with hemlock and wolfsbane, in the witches flying ointment. This magic potion supposedly allowed witches to fly on their brooms.

Materia Medica jar containing belladonna leaves.
Materia Medica jar containing belladonna leaves.

For centuries, small doses of belladonna have been used as a pain reliever, muscle relaxer and anti-inflammatory. Eye drops made from the plant were also used cosmetically as a method for dilating the pupils, which was considered attractive and seductive in women. To combat the toxicity of the plant, morphine from the opium poppy Papaver somniferum was used. The two plants act against each other, and were used to produce the ‘twilight sleep’. This was a dreamlike state that was utilised as a way to deaden pains and consciousness during labour. Queen Victoria famously used the ‘twilight sleep’ during childbirth. However, despite their pain relief, the drugs could affect the nervous system of the baby, resulting in a poor ability to breathe. Belladonna is still used by pharmaceutical industries today as well as in various homeopathic medicines.

Use as a poison

The most famous use for belladonna throughout history was its use as a poison. In ancient Rome, the Emperor Augustus (who defeated Mark Antony and Cleopatra) was rumoured to have been poisoned by his wife Livia in 14 AD. This resulted in her son Tiberius from a previous marriage to become the next Emperor. Another Roman Emperor supposedly murdered by belladonna was the Emperor Claudius, who was said to be killed by the poisoner Locusta on the orders of his wife Agrippina the Younger. King Macbeth of Scotland, whilst still one of the lieutenants of King Duncan I, used belladonna during a truce in order to stop the troops of the invading Harold Harefoot, who was king of England. Agatha Christie also featured belladonna in a number of her works, including The Caribbean Mystery and The Big Four.

Herbarium sheet depicting belladonna leaves.
Herbarium sheet depicting belladonna leaves.