Month: May 2015
This blog post is going to focus on the genus Cinchona, which is the source of the antimalarial drug quinine.
The Quechua peoples of Peru, Bolivia and Ecuador were the first to realise the medicinal properties of Cinchona. Though now famous as a cure for malaria, the Quechua used the tree’s bark as a muscle relaxant to treat shivering. Since shivering can be one of the symptoms of the disease, the bark was coincidently used to treat malaria. The Quechua’s use of Cinchona was observed by Jesuit missionaries, who introduced the plant to Europe by the 1630s.
In 1677, the use of the bark as a treatment for malaria was first noted in the London Pharmacopoeia, a reference text of different medicines. During his reign, the English King Charles II contracted malaria. He was treated by Robert Talbor, who used Cinchona bark mixed with wine to fight off the disease. He later went on to treat the son of Kind Louis XIV of France of the same disease.
In 1738, Charles Marie de La Condamine produced a paper that identified three separate species of Cinchona from his travels from Ecuador. This paper and a specimen from La Condamine were then used by the Swedish botanist Carl Linnaeus, who named the tree Cinchona. The name was based on a 16th century Spanish Countess of Chinchon, who contracted malaria and was cured with bark from the tree by the Quechua people. Linnaeus’ species was later named as Cinchona officinalis after he established his binomial system for classifying plants.
The bark of the Cinchona tee contains a number of medicinal compounds, including quinine and quinidine. Quinidine is used in pharmaceuticals as an antiarrhythmic agent, suppressing abnormal rhythms of the heart and regulating the heartbeat. Cinchona has been used in folk medicine to stimulate appetite, promote discharge of bile and treat mild influenza infections.
However, the most well-known use of Cinchona is as a source of the antimalarial compound quinine. Quinine is a crystalline salt that has antimalarial, fever-reducing, painkilling and anti-inflammatory properties. Though it is frequently found in antimalarial drugs, the compounds mechanism of action is still not fully understood. Even so, the bitter tasting quinine compound is included in many drugs treating malaria. Cinchona bark is still the most economically viable source of the compound, despite it being possible to synthesise quinine in a laboratory. Quinine has not been the primary treatment for malaria since 2006, when the World Health Organisation (WHO) recommended that the drug artemisinin become the standard cure. Now quinine is used when artemisinin is not available.
Despite being an effective malarial treatment, quinine is not entirely safe. It can cause a condition called cinchonism, which can range from mild to severe. Mild conditions mainly involve reversible symptoms, such as skin rashes, dizziness and vomiting. Severe symptoms of cinchonism can involve temporary deafness, paralysis, blindness and death. Death is usually by pulmonary oedema, which is fluid accumulation in parts of the lungs.
Cinchona and homeopathy
It is said that the birth of homeopathy came about from Cinchona. Homeopathy is a form of alternative medicine in which it is believed that a substance that causes the symptoms of a disease in healthy people will cure similar symptoms in sick people. Samuel Hahnemann (1755-1843), the founder of homeopathy, came across the tree when he was translating William Cullen’s work on the Materia Medica. In it, Cullen documented that the bark could be used to treat intermittent fevers and shivering. Hahnemann began taking a large dose of Cinchona daily for two weeks. He started to develop symptoms that resembled malaria. Though he attributed the symptoms to a hypersensitivity to the bark, this experiment gave Hahnemann the idea that ‘like cures like’, which he later developed into the idea of homeopathy.
Gin and Tonic
Quinine extracted from Cinchona is they key ingredient in tonic water, a carbonated soft drink. The dissolved quinine gives tonic water a distinctive bitter flavour, which is often used to compliment the alcoholic drink gin. The quinine content gives tonic water fluorescent properties under ultraviolet (UV) light. It can even fluoresce in direct sunlight as quinine is extremely sensitive to UV.
Tonic water was first produced in the early 19th century, when British officials stationed in tropical colonial outposts began mixing quinine with carbonated water and sugar to alleviate the bitterness of quinine. They later started mixing this medicinal tonic with gin to create the classic ‘gin and tonic’ combination.
Lemongrass (Cymbopogon citratus) is a dense, clump-forming grass that is found in tropical and subtropical grassland throughout southeast Asia. It can reach a height of around 2 metres with leaves that are white on the top and green on the underside. Lemongrass flowers are red to reddish-brown in colour.
Cymbopogon citratus is abundant in the Philippines and Indonesia, where it is known as tanglad or sereh. Lemongrass leaves are too tough for the body to digest, so they either need to be removed before eating or chopped vary finely. Both the stems and leaves feature in Asian, African and Latin American cuisine in teas, soups and curries. It has a subtle citrus flavour that complements poultry, fish, beef and seafood dishes in particular.
Lemongrass is sometimes used in folk medicine, particularly in India and Brazil. The plant is believed to have a range of medicinal applications with its supposed hypnotic, anticonvulsant, antibacterial and antifungal properties. Though many of these believed effects have not been supported scientifically, some studies have shown that it does have antioxidant, anti-inflammatory and antifungal properties.
Citronellol, one of the essential oils that can be made from the plant, has antihypertensive properties. In other words it can lower blood pressure by relaxing the muscles of blood vessels, which results in increased blood flow and decreased tension. Hydrosol, a by-product of the distillation process used to extract the essential oils from lemongrass, is used in skin care products as a weaker alternative to the oils. In some individuals Cymbopogon citratus oil can cause contact dermatitis, whereby the skin is irritated and becomes swollen and sore.
The oil extracted from Cymbopogon citratus is a popular insect repellent. It is particularly favoured for use against the stable flies that bite domesticated animals. Though it repels most insects, beekeepers are very fond of lemongrass oil as it can be used to attract honey bees when they swarm. In addition to these, lemongrass oil is also used in perfumes and is a popular houseplant as it gives a room a ‘fresh’ fragrance. The plant is also grown on embankments in South and Southeast Asia as a means of soil conservation.
Today’s blog post is going to focus on Matricaria chamomilla, which is more commonly known as chamomile or scented mayweed.
It is a highly aromatic shrub native to Europe and Western Asia. Chamomile grows up to 0.5 metres tall and possesses yellow daisy-like flowers that bloom in early- to mid-summer. Sometimes viewed as a weed, this plant is found near roadsides, landfills and in cultivated fields. It needs open soil to survive.
Chamomile has been used as far back as the ancient Egyptians and Greeks. They used it to treat fevers, digestive and menstrual problems, and as an insecticide.
In herbal medicine today it is used as a mild laxative, a sleep aid, an anti-inflammatory, and to treat digestive problems. In large doses, Matricaria chamomilla can cause nausea and vomiting due to small amounts of the toxin coumarin it contains, though this is extremely rare.
The plant has been studied extensively using pharmacological models, animal experiments and clinical tests. These studies showed that chamomile has anti-inflammatory, muscle relaxing, ulcer-protecting, bactericidal and fungicidal activity. Chamomile’s properties arise from the interaction of many different chemical compounds, such as bisabolol, chamzulene, matricin and apigenin. Bisabolol, a complex alcohol, seems to be partially responsible for the majority of chamomile’s medicinal effects. Recent studies have also reported that Matricaria chamomilla extracts could have some anti-cancer effects.
Other interesting facts
Garlands of this plant were found on Tutankhamun’s mummy along with chamomile traces being found on the body of Rameses II. Chamomile produces a strong yellow dye that has been used to dye textiles and is now a popular all-natural hair dye. Matricaria chamomilla is a relative of ragweed that can cause allergic reactions in some people.
Elder, or Sambucus nigra, if found in woodlands and hedgerows throughout Europe, western Asia and North America. It is a short-lived shrub that can reach up to 6-9 metres tall. The plant has dark green, serrated leaves that possess a distinctive smell and flat-topped yellow-white flowers. These flowers bloom in May-July and are pollinated by insects, especially hoverflies. Following pollination, Sambucus nigra produces dark purple fruit that grow between September-October. These elderberries are mildly poisonous and grow in large clusters that often weigh down the branches of the plant.
For a long time Sambucus nigra has been used for a wide range of medicinal applications. It has been mentioned as far back as the Hippocratic Corpus (a collection of medical works from Ancient Greece) and Pliny (23-79 ACE), who both suggest the use of elderberry as a laxative and diuretic.
The flowers and fruit are still used in herbal medicine today for a wide range of remedies. They are used as a diuretic, to reduce inflammation, and to treat coughs and constipation. Sambucus nigra is also a popular flavouring agent used in laxatives.
Studies have shown that elderberries can be used to boost the immune system. This effect has been suggested to be caused by the high levels of anthocyanidins, which are chemical compounds that are known to stimulate the immune system, found in the berries. Other studies have suggested that the plant is effective against diabetes. Extracts from elderflower has been shown to stimulate the breakdown of glucose and increase secretion of insulin, both of which lower blood sugar levels.
Sambucus nigra has a wide range of culinary uses, despite being toxic in its raw form. The plant contains low concentrations of cyanogenic glycosides, which are toxic, but these are destroyed by heat. Thus the elder is safe to consume after cooking. One of the primary uses of elder is the production of an anise-flavoured Italian liqueur, called Sambuca, which is made from the plants berries. Elder is also involved in the production of cordials, wines and teas. In addition, it is used to make various other products such as jams, jellies, chutneys, elderflower fritters and other baked goods.
Other uses and interesting facts
Elder has been found in prehistoric archaeological sites across Europe. The stems were used by the ancient Greeks to make musical instruments called sambuke, whilst Native Americans used them for whistles and to make arrows. Traditionally, elder has also been included in the production of perfumes and dyes. The leaves are often used as a natural insect repellent. For a long time it was believed to be the tree from which Judas supposedly hanged himself in the Bible. However, this is unlikely since Sambucus nigra is not native to the Palestine region.
One of the most well-known animals in medicine is the leech, Hirudo medicinalis. Found over almost the whole of Europe and part of Asia, the leech has been collected from muddy freshwater pools and ditches for hundreds of years.
Fully mature leeches can reach up to 20 cm in length and are hermaphrodites that reproduce sexually. Leeches have suckers on each end, called the anterior and posterior suckers. The posterior (back) one is mainly used for leverage whilst the anterior (front) sucker has the jaw and teeth for feeding. Large adults can consume 5-15 ml in a single meal, which is about 10 times their body weight. After feeding, they can live up to a year before requiring another feed.
After biting but before sucking out blood, Hirudo medicinalis secrete saliva containing about 60 different proteins. These include anticoagulants (such as hirudin), platelet aggregation inhibitors (to prevent clotting), anaesthetics and vasodilators (to widen blood vessels and increase blood flow).
Bloodletting was used by many ancient peoples, including the Egyptians and Greeks, and is one of the earliest known medical techniques. The first described use of leeches was in 800 BC by the ancient Indian surgeon Sushruta, who recommended their use for skin diseases and muscle pains.
Ancient Greek physicians Nicander, Hippocrates and Galen all advocated the use of bloodletting. Bloodletting was modelled on menstruation as they believed it purged women of bad humours (excess bodily fluid). The humours were blood, phlegm, black bile and yellow bile, and each represented air, water, earth and fire respectively. Those agreeing with this theory believed that any sickness that caused the patient’s skin to become red, such as fever and inflammation, must have been caused by too much blood in the body. Thus, removal of blood was supposed to balance the humours, allowing the body to function properly.
The popularity of bloodletting rose through the centuries until it reached its peak in the early 19th century. In the 1830s, the French imported as many as 40 million leeches a year for medicinal purposes. By this time, bloodletting was used to treat almost every disease, from asthma to cholera, gangrene to epilepsy, smallpox to tuberculosis and beyond. Some of the ailments leeches were employed caused more harm than good. For example, after America’s first president George Washington developed a throat infection in 1799, he was bled for 10 hours and lost 3.75 litres of blood before dying of a throat infection.
The use of leeches fell drastically towards the end of the 19th century as knowledge of the bodies systems increased. However, they made a medical comeback in the 1970s. Leeches began to be used to stimulate circulation following skin grafts, particularly in finger reattachment. The therapeutic value of Hirudo medicinalis was no longer in bloodletting, but rather in the anticoagulants and anaesthetics in the saliva. Leeches are still used today but ‘mechanical leeches’ have been developed that perform the same function, though they are not yet commercially available.
It is time for a new blog post: this time on the tea plant Camellia sinensis. This has been a really interesting plant to research. Thank you to Stephen Welsh (Curator of Living Cultures at the Manchester Museum) for allowing me to use some pictures from his collection.
Camellia sinensis is an evergreen shrub that can reach up to 17 metres in height, but is usually trimmed to below 2 metres when cultivated to facilitate picking of leaves. More commonly known as tea, the leaves of this bush are bright green, shiny and often hairy on the underside. It takes roughly 3 years before a new plant is ready to be harvested. However, once ready to be harvested, the leaves can be picked up to 30 times per year.
Due to the wide variety of habitats available to the plant, there are many different varieties of the tea plant. Of these varieties, there are two commonly grown today: Camellia sinensis var. sinensis (Chinese tea) and Camellia sinensis var. assamica (Assam or Indian tea). Chinese tea tends to be the hardier variety that produces small, narrow leaves used for green tea and China’s black tea. In contrast, the Indian variety possesses larger, leathery leaves that often appear to sag off the branches.
History of tea drinking
The origin of the tea plant is not clear but fossil records show that it has existed for millions of years. Tea is thought to have originated in China and ‘wild’ Camellia sinensis can be found in its forests, though these may only be relics of past cultivation. Either way, the earliest record of tea consumption is in China during the 10th century BCE. Though likely to have been originally drunk for medicinal purposes, by the 4th century ACE the art of tea drinking was deeply ingrained in Chinese culture. According to documents from the Tang dynasty, by 650 ACE Camellia sinensis was being grown in almost all of the Chinese provinces. The ritual of making a drink of tea, as well as the ability to recognise type and quality, became the height of sophisticated society. Around this time, tea was introduced to Japan for the first time by travelling Buddhist priests. It quickly spread among the elite and the Japanese tea culture soon developed. By the 12th century, all social classes in Japan drank tea.
For the most part, tea drinking remained an Eastern tradition until the 16th century. Travelling Portuguese priests and merchants were introduced to tea during their travels to China. They in turn spread Camellia sinensis to Europe and the West. The drink quickly became fashionable in Britain, though it was not widely consumed through the 17th century because it remained an expensive plant to import.
Tea smuggling became big business during over the next century as all social classes in Britain began drinking tea in large quantities. It became so lucrative that, in 1785, the British Government had to abolish tax on tea to try and eliminate the smuggling trade. They even began to break Chinese monopoly on the tea market, by mass cultivating Camellia sinensis in India and other British colonies. At first they tried to grow seeds from the Chinese variety, before discovering that there was a second type endemic to India (Camellia sinensis var. assamica). Tea steadily became more affordable and soon became a permanent fixture within British culture. By the early 18th century, Britain was consuming over nine million cups of tea per year.
Tea is now the most consumed beverage in the world, with the exception of water (Britain alone uses over 3 million tonnes per year). As a general rule, tea is divided into a number of categories based on how it is processed. There are many different social rituals (such as Japanese tea ceremonies and British tea time) associated with the plant and a vast number of different styles and additions (like milk and sugar). Flavourings and seasonings, such as chamomile and mint, can also be added to tea. Over the past decade, tea has even been used to create liqueurs and other beverages, including martinis.
Harvesting Camellia sinensis is a labour intensive process but overproduction of the plant has led to falling prices and poor wages for workers. To combat this, Fair Trade tea producers charge more for their products in order to pay suppliers a higher price, therefore providing better wages for workers.
Before the culture of drinking tea arose, Camellia sinensis was used for medicinal purposes. It is believed that as far back as prehistoric times, people have used the leaves for wound healing. The first definitive use of tea medicinally was around 5,000 years ago in ancient China. Since then, Camellia sinensis has featured heavily in traditional Chinese medicine and is used as a cure for over 200 illnesses. These include for digestive problems, fevers, paralysis, nervousness, insomnia and insect bites. The most common use for tea is as a stimulant, which is due to the caffeine content.
Caffeine makes up approximately 3% of tea’s dry weight and is included in many over-the-counter medicines. It is often combined with pain relieving remedies, like aspirin, to counteract their sedative-like effects. Camellia sinensis also contains small amounts of theobromine and theophylline, which are both stimulants similar to caffeine. Theophylline is used in the treatment of a number of respiratory diseases, including asthma. Tea also possesses a number of flavonoids, which are secondary metabolites (compounds whose absence can cause long-term effects on health). These flavonoids have anti-oxidant, anti-inflammatory and antimicrobial properties.
Although not strictly an effect of Camellia sinensis, the process of making a cup of tea requires boiling water. This destroys pathogenic microorganisms, thereby preventing waterborne diseases from spreading.
Though used extensively in traditional medicines, studies into the compounds within Camellia sinensis have not conclusively shown that they have any effect against human diseases. In addition, tea does not possess any essential nutrients in a significant quantity, with the exception of manganese. Drinking tea also results in large amounts of aluminium in the human body, which has been associated with an increased risk of Alzheimer’s disease. However, there is insufficient evidence to support this and the level of aluminium in tea is still generally regarded as safe.
For the most part, the concentrations of caffeine and other compounds in tea are considered safe. However, there can be negative side-effects if consumed in large quantities. The most common problem is that caffeine can cause headaches and anxiety. It can also inhibit iron absorption in the gut and stimulate the production of urine. Many of the undesired effects of caffeine are mitigated by other compounds, particularly antioxidants, in the tea unless consumed excessively.
When ingested in high doses, Theophylline can have more toxic effects than caffeine. These include heart problems (such as heart palpitations), insomnia and convulsions. Camellia sinensis also contains small amounts of tannins (which have been linked with cancer) and oxalate (which can cause kidney stones). However, prolonged overconsumption is required for them to reach a level that is harmful.
Other uses and interesting facts
In addition to its use as a beverage and in medicine, tea leaves have also been used as an ingredient in some food recipes and in some cosmetic products. Despite being hugely popular as a drink, Camellia sinensis is actually considered a pest species in some areas of the world. There have been reports of the tea plant spreading in Madagascan forests, dampening the regeneration of the native forests that are important lemur habitats.
For the past few days I have been digging through the Museum’s annual reports from the 19th-20th century. During my search one name kept cropping up: Miss Wigglesworth. She was in every report for a long period of time so I decided to look into her.
Grace Wigglesworth was a student at Owens College from 1900 (which became The Victoria University of Manchester in 1904 and would later become the University of Manchester). She graduated with a B.Sc (Hons) in Botany in 1903 and later gained a Master’s degree in palaeobotany.
In 1908 she was admitted as a fellow in the Linnean Society of London, which housed (and still does) the collection and personal library of the father of modern taxonomy Carl Linnaeus. In January 1911, Wigglesworth was appointed Assistant Keeper of botany at the Manchester Museum. Assistant Keepers were in charge of curating the collections. During her time as Keeper, Wigglesworth cared and organised the museum’s collections, worked on gallery displays and lectured at the University.
Wigglesworth was the second female within the Herbarium staff and held the post for 33 years. Even after she retired in 1944, Wigglesworth continued to help around the Herbarium until the 1950’s.