botany

The Poison Chronicles: Foxglove – The Killer Cure

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Guest Post by Laura Cooper

Foxglove (Digitalis spp) is one of the rare wild plants for which humans found a wide range of uses. It’s most well known as an ornamental plant, but its use in making the heart drugs with a deadly potential (digoxin and digitoxin) comes a close second. For Digitalis, the same cardiac glycosides which strengthen the heart beat and saves a life are the chemicals which can cause death, the epitome of the maxim “the dose makes the poison”.

The Herbarium has a number of specimens of the two Digitalis species most common in the UK, D. purpurea and D. lanata. The photos in the post are all of the Digitalis purpurea from the collection of Charles Bailey. Despite these specimens being over a hundred years old, the flowers still had their scent, though made musty over the years. Though they have both a poisonous and a healing potential, they are very appealing plants.

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Manchester Museum Herbarium specimen of Digitalis purpurea

Digitalis has been used in folk medicine for many centuries for many conditions, but most consistently for dropsy (fluid retention in the tissues). In the 18th century, the medical effects of Digitalis were put under the scientific scrutiny of the pioneering William Withering (1741-1799). Withering was a doctor practicing around Birmingham drawn into botany by the influence of his wife, a botanical artist. He joined the great tradition of botanist-physicians, and was even known as “the English Linnaeus” by publishing works including A Botanical Arrangement of All the Vegetables Naturally Growing in Great Britain in 1776, the first complete Linnaean classification of the flora of Great Britain.

(c) University of Birmingham; Supplied by The Public Catalogue Foundation
Portrait of William Withering with Digitalis Source

Digitalis came to Withering’s attention in 1775 when he was asked to deduce the recipe of on a family treatment of last resort for dropsy, which was kept secret by “an old woman in Shropshire”. Withering discerned that the active ingredient was Digitalis purpurea. Intrigued, Withering trialed giving extract of Digitalis to patients attending his free clinic, but with little success. However, the news that a colleague had treated dropsy with the root of Digitalis spurred him on to continue experimenting with the plant. He obtained the dried leaves and gave this powder to his patients in an early precursor of the modern clinical trial. He meticulously recorded the progression of 163 patients taking the drug and found that the dried leaves were effective at relieving the symptoms of dropsy, adjusting the dose as the trial went on. The results were published in 1785 (including failures) in An Account of the Foxglove. The book was remarkable for showing Withering’s willingness to investigate folk remedies rather than dismiss them, to publish negative results and detail side effects. Withering presumed that Digitalis acted as a diuretic to rid the tissues of fluid, but this was only a consequence of Digitalis correcting the underlying heart condition that caused the edema. 

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Van Gogh’s Portrait of Dr Gachet. Dr Gachet was Van Gogh’s physician, and is pictured here with Digitalis. There is a theory that Van Gogh was suffering chronic Digitalis poisoning at the time of his death, but this hasn’t been sufficiently proved. Source.

Today, the semi-synthetic heart drugs digoxin and digitoxin are derived from Digitalis lanata (rather than  Digitalis purpurea used by Withering). Digoxin is the more widely prescribed of the drugs, being used to treat atrial fibrillation and occasionally heart failure. The safe dose of digoxin is around 8 to 12 micrograms per kg of body weight. Doses much higher than this causes poisoning involving vomiting, delirium, yellow vision and a disturbed heart rhythm, which can kill. However, as digoxin is administered under a doctor’s supervision, accidental overdose of the drug is rare. But chillingly, the availability of the drug and the subtleness of the symptoms makes it a choice drug for an unforgivable but rare crime, the murder of patients by healthcare workers. The person believed to be the most prolific serial killer in American history is the nurse Charles Cullen, who is suspected to have killed several hundred patients using very high doses of digoxin and insulin. This case shows that supplies of all drugs should be carefully monitored to avoid their abuse.

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Poisoning by Digitalis itself do occur, mostly accidentally by uncareful foragers mistaking it for borage or comfrey, but I have found a report of a woman attempting to poison her husband by adding Digitalis purpurea leaves to a salad. Luckily for these people, the strangely bitter leaves cause vomiting, riding some of the material from the body and sending the person to see a doctor. Poisoning by digoxin in any form can be treated by digoxin-specific antibody, a protein which can bind to digoxin and block its effects, but only if it is caught early enough to be effective.

Digitalis is undoubtedly an infamous poisonous plant, but one that has saved many more lives than it has taken, deliberately or accidentally.

 

The Travelling Botanist: Cinnamon, a spice of many tales

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Guest blog by: Sophie Mogg

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Cinnamomum cassia

Cinnamon is a spice that we have all had the opportunity to try, whether in fancy coffees, liqueurs or delicious buns. Whilst the “true” cinnamon species is Cinnamomum verum, the most common source of cinnamon is Cinnamomum cassia. Both species originate in Asia, with C. verum being native to Sri Lanka (formerly known as Ceylon) and C. cassia originating in southern China. In order to distinguish the cinnamon produced by the two species in the spice trade, cinnamon refers to C. verum whilst cassia refers to C. cassia.  This is because, C. verum is  more expensive of the two due to its sweeter taste and aroma as less than 30% of cinnamon exports come from Sri Lanka. 

Cinnamon has been traded for many thousands of years, with the imports into Egypt reported as early as 2000 BCE so it is no surprise that there are countless tales and historical events that surround this spice. From Sieur de Joinville believing cinnamon was fished from the Nile at the end of the world and Herodotus writing about mystical giant birds (such as a phoenix) that used cinnamon sticks to build their nests, the history of cinnamon is rich in legends of its origin as it wasn’t until 1270 that it was mentioned the spice grew in Sri Lanka. However as sweet as this spice may be it also appears to have a bloody history. Aside from the countless wars raged over the right to trade cinnamon, it was also used on the funeral pyre of Poppaea Sabina, the wife of Nero, in 65 AD. It is said that he burned over a years supply as recompense for the part he played in her death.

There are a total of 5 species (C. burmannii, C. cassia, C. citriodorumC. loureiroi and C. verum)  that produce cinnamon however C. verum and C. cassia are where the majority of international commerce is sourced from. Production of cinnamon is fairly straight forward albeit time-consuming. The outer bark of the tree is shaved off exposing the inner bark which is the cinnamon layer. This inner bark is also shaved off and left to dry, naturally curling as it does. By comparison the cinnamon of C. verum has a more delicate flavour than that of C. cassia  as well as having thinner bark that is more easy to crush and produces a much more smooth texture. cinnamon-comparison

Cinnamon is prominent in the practice of Ayurveda medicine as well as traditional Chinese medicine, being one of the 50 fundamental herbs. Traditionally it has been used to treat a wide variety of ailments from digestive problems, respiratory problems, arthritis and infections. In traditional Chinese medicine it is believed that cinnamon is able to treat these ailments through it’s ability to balance the Yin and Wei as well being a counterflow for Qi. These terms are aptly explained here for those who are interested. While there is little scientific evidence for the treatment of digestive and respiratory disorders, cinnamon does appear to possess antibacterial, antifungal and antimicrobial properties which may help to fight infections although at this moment in time it is inconclusive in studies trialled on humans. Cinnamon produced from C. cassia coumarin, which thins the blood, can be toxic to the liver in high concentrations so it is advised that only a few grams per day be consumed.

For those avid tea lovers out there I’ve found instructions to brew your own cinnamon tea.

For more information check out the links below

Cinnamomum verum

Cinnamomum cassia in Chinese medicine

Rainforest Alliance – Cinnamon farms

Leave a comment below to tell me what you think or what you’d like to see next!

The Travelling Botanist: A Berry Good Day!

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Lycium chinense

Guest blog by: Sophie Mogg

Lycium chinese, and its close relative Lycium barbarum, are both native to China although typically found to the Southern and Northern regions respectively. Part of the Solanaceae (Nightshade) family, they are also related to tomatoes, potatoes, eggplants, chili peppers, tobacco and of course belladonna. Both L. chinese and L. barbarum produces the goji berry, or among English folk commonly known as the wolfberry believed to be derived from the resemblance between Lycium and  the greek “lycos” meaning wolf. Both species are decidious woody perennials that typically reach 1-3M tall however L. barbarum is taller than L. chinense.  In May through to August lavendar-pink to light purple flowers are produced with the sepal eventually bursting as a result of the growing berry which matures between August and October. The berry itself is a distinctive orange-red and grape-like in shape.

In Asia, premium quality goji berries known as “red diamonds” are produced in the Ningxia Hui Autonomous Region of North-Central China where for over 700 years goji berries have been cultivated in the floodplains of the yellow river. This area alone accounts for over 45% of the goji berry production in China and is the only area in which practitioners of traditional Chinese medicine will source their goji berries as a result of their superior quality. The goji berry has a long history in Chinese medicine, first being mentioned in the Book of Songs, detailing poetry from the 11th to 7th century BC. Throughout different dynasties master alchemists devised treatments centering around the goji berry in order to improve eyesight, retain youthfulness and treating infertility. However it must be noted that because of the goji berry being high in antioxidants those on blood-thinning medication such as Warfarin are advised not to consume the berries.

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Goji berries and flower

As a result of their long standing history in Chinese medicine and their nutritional quality Goji berries have been nicknamed the “superfruit”. Many studies have linked the berries being high in antioxidants, vitamin A and complex starches to helping reduce fatigue, improve skin condition and night vision as well as age-related diseases such as Alzheimers. However, there has been little evidence to prove these claims and the evidence that is available is of poor quality.

In the 21st century the goji berry is incorporated in to many products such as breakfast biscuits, cereals, yogurt based products as well as many fruit juices. Traditionally the Chinese would consume sun-drief berries with a  wide range of food such as rice congee, tonic soups, chicken and pork. Goji berries would also be boiled alongside Chrysanthemums or tea leaves from Camellia sinensis as a form of herbal tea. How would you like your berries?

I hope you have enjoyed reading about Lycium chinense and Lycium barbarum. Please complete the poll below to tell me more about what you would like to see more of.

For more information follow the links below

Lycium chinense

Lycium barbarum 

Chinese medicine – goji berry

Health benefits and side effects

The Travelling Botanist: There’s always time for EVEN MORE tea!

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baby-chrysanthemum-teaGuest blog by: Sophie Mogg

I know you’re thinking “hasn’t she already covered tea?” and yes you’re correct. I have. However, Camellia sinensis (and all of the wonderful varieties of said species) is not the only plant that tea can be made from.  In a more recent blog post you have seen that tea can be made from winter green (Gaultheria procumbens) and the same can be said for a lot of plants. Today I will be venturing into the world of Chrysanthemums – Chrysanthemum indicum and Chrysanthemum morifolium to be exact.

C. indicum is a perennial that grows to roughly 100cm tall and is native to China. Chrysanthemum originates from the greek “chryos” and “anthos” translating to golden flower.  C. indicum lives up to the name and typically produces a  beautiful array of small yellow flowers that flower from August through to October however a multitude of colours are available amongst varieties. One particular variety, C.indicum var. edule (Kitam), is grown and cultivated as a vegetable in China. C. indicum is also one of the main parents of C. morifolium. C. morifolium is less cold hardy than its parental species, often requiring to be stored in greenhouses in Britain when during the cooler weather. However C.morifolium is far larger than its parental species and so is often favoured as a garden ornamental plant. In 1630 over 500 cultivars were listed and in the centuries since numbers have continued to rise generating plants that range from 30 – 120cm tall, with large blooms again in a range of colours.

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Chrysanthemum indicum

Aside from being beautiful garden plants Chrysanthemums have also been used in Chinese medicine dating back to 475 -221 BCE and the production of tea. The leaves from both species can be used to brew tea, with  cultivars of C. morifolium developed so that leaves are less bitter. The flowers, specifically the petals, of C. morifolium can also be brewed to produce a delicately sweet flavoured tea that is also very beautiful to look at. The tea itself is said to help improve vision by soothing sore eyes and headaches as well as reducing infection and inflammation. Chrysanthemums are said to have antibacterial, antifungal and anti-inflammatory properties and so flowers would often be collected in Autumn and dried so that they could be used later as an infusion. Chrysanthemum tea is also recommended as an alternative to tea from Camellia sinensis for reducing blood pressure.

Flower heads and leaves can also be used in a variety of dishes. Leaves can be battered and turned into fritters and the petals can be pickled or served with soy sauce alongside tofu and salad.  Why not try some Chrysanthemum tea or a sprinkling of petals in your salad next time you’re out in the garden?

As always, let me know in the poll below what you would like to see next and stay tuned for the next Travelling Botanists blog post.

 

If you’d like to find out more about Chrysanthemums check out the links below

Chrysanthemum care

Chrysanthemum indicum

Chrysanthemum morifolium 

Chinese medicine

A Travelling Botanist: #WorldSoilDay

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Guest blog by: Sophie Mogg

I’m taking a break from my travels to celebrate world soil day. World soil day celebrates the importance of soil in our natural environment and contributes enormously to human well-being through providing a place to grow crops and supporting all walks of life.

In many parts of the world soil is now contaminated with heavy metals and radioactive elements as a by product of mining and various other human activities. This renders the soil unusable and unsuitable for feeding livestock, growing crops and restoring natural habitats. However there are many plants, known as hyperaccumulators, that are able to absorb these heavy metals through their roots, often concentrating them in their leaves. This process is known as phytoremediation. These metals can be retrieved from the plants by burning them, a process known as phytomining. By using natural hyperaccumulators we can reclaim those areas affected by mining and hopefully restore some natural habitats in the process.

Here are some of those wonderful plants from our collection, enjoy!

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A Travelling Botanist: Ricecapades

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Guest blog by: Sophie Mogg

I’ll soon be crossing the border into Southeast Asia and exploring the many wonderful plants there but there’s time for one last post!

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Oryza sativa

Oryza sativa, which translates to “rice” and “cultivated”, remains a staple for half of the worlds population. It is a widely cultivated plant, growing in over 100 countries and on all continents with exception of Antarctica. There are currently 40,000 varieties of rice of which over 100 of these are grown globally. Oryza rufipogon grows through South and Southeast Asia, it is the wild relative of Oryza sativa. The earliest recorded cultivation of rice has been documented to be in China around 6000 BC.

Within the species sativa, two subspecies have been classified: japonicaindica.
 Japonica varieties are short-grained and sticky, often grown in higher altitudes such as the uplands of Southeast Asia. Indica on the other hand are long-grained and non-sticky varieties grown in the lowlands and often submerged. Javanica, now known as tropical japonica, is a subgroup to japonica and is made up of broad-grained varieties grown in tropical conditions. However classification of rice has changed numerous times due to differing basis of classification such as the types of enzymes present or short sequence repeats in the DNA.

Oryza sativa can grow either 1M tall in dry conditions or 5M long in submerged conditions.  The stem is composed of several nodes and from each node grows a long, slender leaf. The seeds, like other grass species, grow on long spikes which have the tendency to arch over with the weight of the seed. It is the endosperm of these seeds which we consume. Whilst rice can be found in many colours such as white, brown, red, purple and black we commonly eat either the white or brown rice. White rice is typically polished (milled) to remove the bran layer, where as wholegrain “brown” rice has the bran layer intact. The bran layer, present in all cereal crops, is rich in essential amino acids, dietary fibre and antioxidants.

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Oryza sativa field

96% of the rice that is grown worldwide is consumed by the same countries that grow it however these countries also suffer from Vitamin A deficiency. Scientists have tried to improve the nutritional quality of rice by introducing  enzymes from other plants via genetic modification that are needed to synthesise beta-carotene. Beta-carotene is converted into Vitamin A in the intestines. The Golden Rice Project aims to reduce the incidence of Vitamin A deficiency (VAD) syndrome which is prevalent in these countries.

Generally rice is steamed or boiled however it can also be used to produce several other products. Rice can be pressed in order to produce rice milk, which is an excellent alternative for those avoiding dairy products who may also have a nut allergy however it is rich in carbohydrates and low in protein and so is not necessarily the best option for diabetics or the elderly. In Japan, sake is made from brewing milled rice somewhat similar to beer however the conversion of starch to sugar and then sugar to alcohol occurs simultaneously. Sake is customarily sipped from a small cup known as a sakazuki on special occasions.

Rice is also used in many traditional medicines such as Ayurveda such as in the treatment of diarrhea. Rice would be boiled and then strained, allowing the water to cool. The patient would then drink the rice water which would stop the diarrhoea or ease the stomach upset as well as re-hydrating them. Congee is a traditional dish made using a single grain, often brown rice, and slowly cooking it on low heat with a 1:5 or 1:6 ratio of rice to water. Congee is said to be very beneficial to those with low energy and issues regarding weight loss/gain and is made across India and China. Several studies such those using rice callus and extracts have shown that rice also has anticancer properties by inhibiting growth of human cancer cells.

If you have any suggestions for the types of plants you wish to learn about please fill in the poll below or if you have any specific queries please leave a comment.

 

If you are interested in learning more about rice follow the links below:

Oryza sativa 

Rice association – varieties 

Oldways whole grain council – types of rice (with pictures)

Brown rice in medicine 

Vitamin A Deficiency syndrome (VAD)

A Travelling Botanist: International Year of the Pulses

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Guest blog by: Sophie Mogg

2016 marks the international year of the pulses, decided back in 2013 at the 68th session of the United Nations General Assembly. The Food and Agriculture Organization nominated pulses in the hope that this would raise awareness of their importance in providing a sustainable source of plant protein.

Throughout the the year there have been many conferences, discussions and workshops held in order to promote a better understanding and public awareness on topics surrounding sustainable food production, food security and nutrition as well as improvements in crop rotation and how we can work towards improving trade connections of pulses and utilization of plant based proteins. Whilst none of these events are taking place in the UK many resources are available online at their website including recipes and videos for you to watch.

As with all my other blog posts I have found some specimens within our collection to show you.

The Chick Pea (Cicer arietinum)

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Cicer arietinum

“This interesting little leguminous plant has been an object of cultivation from time immemorial & grows wild at the present day in the cornfields”

C. arietinum is one of the earliest cultivated legumes dating back around 7,500 years ago in the Middle East. Production is rapidly increasing across Asia as superior cultivars are developed and released. Many country farmers depend upon this legume for a source of income however legumes also enrich the soil through the addition of nitrogen.

This small plant, reaching heights of 20-50 cm, may not look like much but the seeds pack a punch. Approximately 100g of these seeds provides ~20% of protein, dietary fibre and other minerals needed, thereby providing a cheaper alternative to those who cannot afford meat or choose not to eat it. Leaves are also consumed providing essential micro-nutrients which are significantly higher than in cabbage and spinach.

A study has also shown that the chickpea can also be used as an animal feed, with many groups of animals benefiting.

The Pigeon Pea (Cajanus cajan)

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Cajanus cajan

The pigeon pea often grows between 1-4M tall with a tap root reaching around 2M. This legume is also a major source of protein for those living in South Asia and has been consumed across Asia, Africa and Latin America since it was first domesticated in India around 3,500 years ago.

It is a perennial plant that is harvested for between 3-5 years however after the second year the yield drops and so annuals are more often used as a means to harvest the seed. Like the chickpea, the pigeon pea is also able to enrich soils with nitrogen and its leaves are often used to feed cattle whilst the woody stem is used for firewood.

 

 

 

 

Black Lentil (Vigna mungo aka Phaseolus mungo L.)

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Vigna mungo

Vigna mungo can be found in various forms ranging from a fully erect plant to one that trails growing between 30-100cm. It produces large leaves which are hairy and seed pods that are approximately 6cm long.

It is very popular in India where the seed is split and made into dal.  The Black Lentil is very nutritionally rich containing 25g of protein per 100g of seed as well as many other important micro-nutrients and therefore plays a huge role in the diets of those from India.