Month: January 2017
For the past few months I’ve been working on a really exciting exhibition opening on the 20th of May: Object Lessons #MMObjectLessons Object Lessons celebrates the scientific model and illustration collection of George Loudon. Each of these finely crafted objects was created for the purpose of understanding the natural world through education, demonstration and display. […]
Last December, Stephen Welsh (Curator of Living Cultures) and I went on a research trip to India for the Courtyard Project, focusing on the South Asia Gallery – a partnership gallery with the British Museum. Neither of us had visited India before, although we were familiar with other parts of South Asia. It was an exciting and hectic schedule and in two weeks we visited Mumbai, Kolkata, Delhi and Kochi – so more or less each compass point of what is an amazing country. The focus of our visit was to meet with museum professionals, artists and to get a real feel for both the historic and archaeological wonders, as well as the contemporary culture of a country that is fast becoming an emerging global superpower. We were joined in Kolkata and Kochi (where we attended the Kochi-Muziris Biennale) by Manchester Museum Director Nick Merriman.
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Guest blog by: Sophie Mogg
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. citriodorum, C. 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 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.
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The Aristolochia genus is particularly close to the heart of the Manchester Herbarium, its name provides us a unique Twitter nom de plume. But it is also a plant with a considerable body count. It contains a carcinogen which may be responsible for a larger number deaths than more notorious plant poisons like cyanide and ricin.
A number of species in the Aristolochia genus are known as birthwort. The genus name is derived from the Greek for “good for childbirth”, so both the common and scientific names suggests its medical use. It was noted by Roman doctors that the flowers of Aristolochia clematitis were somewhat womb-shaped. The Doctrine of Signatures, a major concept within the medicine of the time, stated that plants were designed to resemble the body part they could treat. Therefore A. clematitis roots were used for over two thousand years to trigger delayed menstruation, speed up a labour and help deliver a placenta. The plant continues to be used in Traditional Chinese Medicine and more rarely in homeopathy to treat a wide variety of diseases, despite the risks.
The roots of all Aristolochia sp. contain the carcinogen aristolochic acid, which for anyone can produce more mutations in the genome than tobacco smoke or UV light, but in the 5-10% of people who are genetically susceptible can cause kidney and urinary tract cancers. This was discovered when, in the late 1950s, localised epidemics of kidney disease and urinary tract cancer in certain rural villages in Bulgaria, Yugoslavia and Romania were noted. The condition was described as Balkan Endemic Nephropathy (BEN) but it’s cause was not found. However, in the 1990s a group of women with End Stage Renal Disease were all found to have taken the same herbal mixture for weight loss contaminated with Aristolochia fangchi, and their condition was described by researchers as Aristolochic Acid Nephropathy. When Prof Arthur Grollman from Stony Brook University learned this, he saw the similarities with BEN, and wondered if there was a similar cause. He found A. clematitis in the wheat fields of affected villages and the imprint of aristolachic acid damage in the DNA of BEN patients’ kidneys cells, showing a causal link between chronic exposure to Aristolochia and these cancers.
Aristolochia has been taken by many people as medicine or accidentally throughout history. As recently as between 1997 and 2003, an estimated 8 million people in Taiwan, were exposed to it in herbal medicine. This has lead some to suggest that it may be the most deadly plant in terms of number of fatalities rather than outright toxicity. Whether or not this claim could be quantified, it highlights that plants can be dangerous if used unwisely, so herbal medicines should not be taken blithely.
A. clematitis itself is a common weed, with creeping rhizomes and cordate (heart shaped) leaves. The distinct yellow flowers lack petals and form a tubular structure with a rounded base. Hardly notably uterine. The strange shape of the flower is due to it’s peculiar method of pollination. The hermaphroditic flowers begin first with the female stage and attract and trap flies within the flower, where they feed and spread pollen. In a few days the male stage produces the pollen that covers the trapped flies, which are released to pollinate again.
The native range is around the Mediterranean into central Europe, but was cultivated in the UK and USA. In the UK, it can be found as the survivors of the medicinal gardens of ruined nunneries and monasteries, a reminder of health care’s past and present mistakes.
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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.
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.
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This is a really interesting post on the Awkward Botany blog about alien species and the possibility of plant extinction.
In our current ‘Extinction or Survival?’ exhibition we have illustrated this potential threat to species using the stories of the red squirrel and the white-clawed crayfish in the UK, but of course competition with invasive species is a potential risk for plants too.
One of the concerns about introduced species becoming invasive is that they threaten to reduce the biodiversity of the ecosystems they have invaded. They do this by spreading rampantly, using up resources and space, altering ecosystem functions, and ultimately pushing other species out. In the case of certain invasive animals, species may be eliminated via predation; but plants don’t eat each other (generally), so if one plant species is to snuff out another plant species it must use other means. Presently, we have no evidence that a native plant species has been rendered extinct solely as a result of an invasive plant species. That does not mean, however, that invasive plants are not doing harm.
In a paper published in AoB Plants in August 2016, Paul O. Downey and David M. Richardson argue that, when it comes to plants, focusing our attention on extinctions masks the real impact that invasive…
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Guest Post by Laura Cooper
I remember hearing as a small child the rumour that swallowing a single apple seed would kill you. Whilst I later learnt that this was false, it is true that the cyanide in apple seeds means that theoretically, chewing a large number could cause poisoning.
Cyanide is a simple chemical produced by many organisms, often as an unwanted by-product. But cyanide is found in relatively high levels in many plant species, including the seeds of many common food plants, such as peaches, almonds, and legumes.
The cyanogenic plant I will focus on here is cassava, Manihot esculenta, also known as yucca. It’s tubers are a major carbohydrate source throughout the tropics due to its drought tolerance and ability to thrive in poor soil. It is probably most well known in the UK in the form of tapioca pearls in puddings.
Cyanide is a general defence against herbivores, as at the right dose it can kill anything that respires. There is variation in the levels of cyanide in fresh cassava tubers, “sweet” strains have as little as 20mg/kg whilst “bitter” strains have up to 1g/kg. It has been suggested that when early farmers selected plants with the best insect resistance, they were inadvertently choosing plants containing small amounts of cyanide. This means that sometimes the decision to grow (potentially) dangerous food is not a straightforward one, and higher cyanide cassava is often preferentially planted due their greater pest resistance and drought tolerance.
One of the founding principles of toxicology is an adage derived from Paracelsus: it is the dose that makes the poison. But the case of cyanide in cassava root goes to show that it is not only the dose that matters; the ability of the host to deal with the dose can be the difference between life and death.
The lethal dose of cyanide has been reported as 1mg of cyanide ions per kg of body weight, but it is difficult to ingest this from cassava. At lower levels, chronic cyanide poisoning can have serious effects, especially in people who are already malnourished. For those with diets low in Sulphur containing amino-acids, the body cannot add the Sulphur to cyanide to make it safe. They therefore struggle to remove cyanide at amounts a healthy person could do easily, so cyanide becomes cyanate, which is associated with neurodegenerative diseases. Severe cyanide poisoning can lead to a permanent paralysis of the limbs known as Konzo, which can be fatal. Unfortunately, the hardiness of cassava means it does become relied on when other crops fail and the population is already malnourished.
However, cyanide can be removed from cassava by proper processing. Cassava stores cyanide as a chemical called linamarin, which released cyanide when hydrolysed. This occurs which can occur in the gut if ingested, or when the cassava is soaked and mashed. If done thoroughly, processed cassava is safe to eat. However, if it is done by hand, the person preparing it can inhale a considerable quantity of cyanide gas. Additionally, the water by-products of cassava processing are rich in cyanide so can be an environmental hazard.
A genetically engineered strain of cassava lacking cyanide would be a valuable crop to large agricultural companies, as it would cut down on processing time. However, for small scale farmers with poor soil, drought and no pesticides, the cyanide in cassava acts as a built in pesticide and allows cassava to thrive when little else can. This shows perfectly that poisons are not always villains, but if dealt with carefully can be a vital part of a crops’ survival tool-kit.
For more information, see this excellent article on cyanide in food plants.