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Wormwood and Artemisinin: A Malaria Medicine From Nature

Linda Crampton is a writer and teacher with a first-class honors degree in biology. She often writes about the scientific basis of disease.

Mosquitoes may transmit disease organisms when they bite us. (The tiger mosquito shown above transmits disease, though not malaria.)

Mosquitoes may transmit disease organisms when they bite us. (The tiger mosquito shown above transmits disease, though not malaria.)

Artemisia and Wormwood

Wormwood is the name used for herbaceous plants in the genus Artemisia. The plants are known for their extremely bitter taste. A chemical called artemisinin is extracted from the flowers, leaves, and stems of one species of wormwood. The chemical is an important substance because it acts as an anti-malaria drug. It has been so successful in treating malaria that the scientist who discovered the chemical's effect was awarded a Nobel Prize for Physiology or Medicine in 2015.

The genus Artemisia plays several interesting roles in human life and culture. For example, Artemisia absinthium is an ingredient in the distilled alcoholic beverage known as absinthe. The drink is made from wormwood, fennel, anise, other herbs and spices, alcohol, and water. Wormwood is also mentioned in the Book of Revelation in the Bible. Here its name is given to a star that falls to Earth, filling the waters with bitterness and killing people. There is preliminary evidence that artemisinin may be useful in destroying cancer cells. The most important use of wormwood at the moment is its role in fighting malaria, however.

The sweet wormwood (Artemisia annua) contains artemisinin, which is a malaria medicine.

The sweet wormwood (Artemisia annua) contains artemisinin, which is a malaria medicine.

When scientists write the scientific name for an organism, the genus is often abbreviated to one letter after it's been written in full at least once. For example, Plasmodium vivax may be abbreviated as P. vivax.

Malaria

Malaria is a tropical and subtropical disease that is a risk in a large proportion of the planet. According to WHO (World Health Organization), almost half the world's population lives in an area where malaria is endemic. The disease is not only very unpleasant but is sometimes fatal. The good news is that the death rate is decreasing. The bad news is that the parasite that causes the disease is becoming resistant to anti-malaria drugs in some parts of its range.

Malaria is caused by five species of a one-celled parasite named Plasmodium. The parasite belongs to a group of organisms known as protozoans. Malaria caused by Plasmodium falciparum is more likely to be deadly than the disease caused by other species of its genus. Malaria produced by P. vivax, P. ovale, and P. malariae is generally milder. P. knowlesi causes malaria in certain species of macaques. It was once thought to be unimportant with respect to humans, but it's now known to be a zoonotic species. Zoonotic organisms can infect both animals and humans. Most cases of human malaria are the result of a P. falciparum or P. vivax infection.

According to WHO, in 2018 (the latest year for which statistics are available) there were 288 million cases of malaria around the world and an estimated 405,000 deaths from the disease.

Possible Symptoms of Malaria

The symptoms of uncomplicated malaria generally appear ten to fifteen days after the bite of an infected mosquito but may not develop until as long as thirty days after the bite. Common symptoms include:

  • a high fever
  • chills that produce shaking
  • sweating
  • a headache
  • nausea
  • vomiting
  • diarrhea
  • body aches
  • weakness

Unfortunately, the malaria parasite sometimes produces effects beyond the basic ones. Complicated malaria is a serious condition. Symptoms may include:

  • serious anemia due to loss of red blood cells
  • seizures, confusion, and coma due to a complication known as cerebral malaria
  • difficulty in breathing
  • hypoglycemia (very low blood sugar)
  • low blood pressure and cardiovascular collapse
  • kidney failure

Another problem linked to malaria is that the parasite may stay in the liver in an inactive form after a person has apparently been cured of the disease. The dormant parasite may become active up to a year later, causing malaria symptoms once again.

Someone experiencing any of the above symptoms should visit a doctor for treatment. A diagnosis of malaria must be made by a physician.

The malaria parasite requires both a human and a female mosquito in order to complete its life cycle. Only female mosquitoes suck blood, which is an essential factor in the transmission of the parasite between its two hosts. The females need the nutrients in blood to produce their eggs.

Overview of Plasmodium Life Cycle

Plasmodium exists in different forms, each with a different name. It changes from one form to another during its life cycle. The form of the parasite in a mosquito's saliva is known as a sporozoite.

  1. A female mosquito belonging to the genus Anopheles injects anticoagulant into a human's bloodstream during a bite. Sporozoites from her saliva enter the victim's blood during this process. The sporozoites travel to the liver and infect its cells.
  2. Each sporozoite produces merozoites, which break break out of the liver cells and enter red blood cells.
  3. Merozoites in the red blood cells produce more merozoites. These burst out of the red blood cells, destroying them and releasing toxins produced by the parasite's activities. This stage corresponds with the typical symptoms of malaria.
  4. Some merozoites produce male and female gametocytes instead of producing more merozoites.
  5. When a mosquito bites an infected human and sucks up blood, the red blood cells containing the gametocytes enter the insect's digestive tract.
  6. Inside the insect's gut, the gametocytes leave the red blood cells.
  7. The gametocytes become male and female gametes, which are the reproductive cells.
  8. A male and female gamete join to form a zygote.
  9. The zygote becomes an ookinete, which burrows into the wall of the mosquito's digestive tract and forms oocysts.
  10. The oocysts produce sporozoites, which enter the body cavity of the mosquito. This cavity is known as the hemocoel and contains fluid.
  11. The sporozoites travel to the mosquito's salivary glands. When the mosquito bites a human, the cycle begins again.
The malaria parasite in a human and a female mosquito

The malaria parasite in a human and a female mosquito

Artemisia and Artemisinin

Wormwood plants belong to the daisy family, whose scientific name is the Asteraceae. The family used to be known as the Compositae family because the flowers have a composite structure. Although a flower head of Artemisia looks like a single flower, it's actually an inflorescence consisting of many smaller flowers. The inflorescense of Artemisia is not as big and showy as those of many members of the daisy family, however. The leaves of wormwood are generally deeply divided into leaflets.

Artemisia is a widespread plant that occurs in many parts of the world. The common name used for some members of the genus is sagebrush rather than wormwood. The sagebrush species that is often associated with dry areas of the western United States is Artemisia tridentata.

Artemisinin is obtained from the sweet wormwood, or Artemisia annua. The artemisinin concentration is highest in the young plant. The plant is native to Asia but has been found growing wild in other parts of the world, including North America.

We owe the modern use of artemisinin in malaria treatment to Chinese traditional medicine and a very persistent scientist, as described below. China has a rich tradition of using nature to treat disease. Fourth-century Chinese doctors discovered that sweet wormwood relieved fever and used it as a medicinal plant.

Flowers, seeds, and leaves of Artemisia absinthium are typical of the genus, although some species are not as colourful.

Flowers, seeds, and leaves of Artemisia absinthium are typical of the genus, although some species are not as colourful.

How Does Artemisinin Work?

It's not known for certain how artemisinin cures malaria. There are several theories, most of them relating to the peroxide bridge in the molecule. In the diagram below, the two oxygen atoms joined together inside the first polygon form the peroxide bridge. The bridge is sometimes known as an endoperoxide because it's part of the inner structure of the molecule. ("Endo" means "within".) This type of chemical structure is very unusual in the molecules of living things.

While inside red blood cells, Plasmodium feeds on hemoglobin, the red pigment that carries oxygen from the lungs to the tissue cells. Hemoglobin contains iron. A leading theory for the action of artemisinin states that the iron that is released from the hemoglobin reacts with the peroxide in the artemisinin. This leads to the production of very reactive forms of oxygen known as radicals. Radicals are also known as free radicals and reactive oxygen species, or ROS. The oxygen radicals are believed to damage and kill the parasite.

Tu Youyou's Work and a Nobel Prize

Tu Youyou discovered the effect of the artemisinin obtained from Artemisia (or qinghao as it's known in China) on malaria. She's a Chinese chemist who was born on December 30th, 1930. Her name is written as both Tu Youyou and Youyou Tu in the western literature. Her first or given name is Youyou and her surname or family name is Tu. In China, the surname is written before the first name.

Tu Youyou discovered a modern use of Artemisia rather than the herb itself. At the start of her research, a new malaria medicine was badly needed. Youyou performed a very diligent and comprehensive search of the literature relating to traditional Chinese medicine. She looked for materials with properties that might enable them to attack malaria and then tested them. She realized that sweet wormwood might be a suitable candidate, since it reportedly relieved intermittent fever. In the past, the plant was traditionally gathered early in the growing season, added to water, and pounded in a mortar and pestle to extract the contents.

Youyou and her colleagues tried extracting the active principle of Artemisia (artemisinin or qinghaosu) with hot water, but the resulting liquid had no effect on mice with malaria. They then extracted artemisinin with cold water and were delighted to find that the liquid was a successful malaria cure. Youyou continued to explore the medication and made other significant discoveries.

Today semi-synthetic versions of artemisinin are used to treat malaria. Researchers have discovered ways to make artemisinin more effective, such as by improving its solubility. The natural chemical is still used as a starting point, though.

Two other scientists won a 2015 Nobel Prize for Physiology or Medicine at the same time as Tu Youyou. William C. Campbell and Satoshi Omura received the award and part of the prize money for their discovery of a new therapy for roundworm infections.

Stages in the life cycle of Plasmodium falciparum (stained slide); the round cells are red blood cells

Stages in the life cycle of Plasmodium falciparum (stained slide); the round cells are red blood cells

Artemisinin resistance alone rarely leads to treatment failure. However, resistance of malaria parasites to ACT partner drugs can lead to treatment failure (regardless of the presence of artemisinin partial resistance).

— World Health Organism

Artemisinin Resistance

Artemisinin on its own has treated malaria very successfully for many years and has saved many lives. It's currently given in combination with another drug, however. Artemisinin-based combination therapy, or ACT, provides both artemisinin and a second drug that works by a different mechanism. The artemesin kills parasites during the first three days of treatment and the second drug kills the parasite cells that have survived the artemisinin attack.

In some places the malaria parasite is becoming resistant to artemisinin, which is a worrying discovery. According to the World Health Organization, however, the resistance involves only one stage of the parasite's complex life cycle and is better referred to as "partial resistance". As the quote from WHO shown above indicates, there is concern that resistance to other drugs used in ACT combination therapy might be more serious than the resistance to artemisinin.

At the moment, in most areas ACT is still a good treatment for all types of malaria. It's especially useful for malaria caused by P. falciparum. If ACT loses its effectiveness, however, the parasite may get the upper hand. Other medications for malaria exist, but the parasite is developing resistance to them as well. Searching for new medicines and reducing the incidence of disease by reducing the number of mosquitoes are both very important practices. Malaria is an enemy that needs to be beaten.

References

This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.

© 2016 Linda Crampton

Comments

Linda Crampton (author) from British Columbia, Canada on March 19, 2016:

Hi, Peggy. Yes, I agree. It sounds wonderful to hear that the death rate from malaria is decreasing, until we look at the number of people that still die from the disease. Thank you for the visit. I appreciate your comments and shares a great deal.

Peggy Woods from Houston, Texas on March 19, 2016:

Even though the death rate is falling, that is still a lot of deaths each year due to malaria. It is certainly concerning that malaria is becoming resistant to treatment by currently known means of combating it. Hopefully something new will be found soon that will be effective. Excellent hub per usual! I'll be sharing this far and wide.

Linda Crampton (author) from British Columbia, Canada on March 09, 2016:

Hi, fpherj48. Thank you very much for the comment! It's very unfortunate that malaria is still a major disease and that mosquitoes can be such a serious problem. I hope the incidence of malaria continues to decrease.

Suzie from Carson City on March 09, 2016:

Alicia...Well, I either need to get out more or seriously need to catch up on my reach for continuing education! I am amazed that malaria is still a health issue. I don't know why that is. For some reason, I suppose I believed it had gone the route of polio & whooping cough. Apparently I thought the offending insect had died out.

Fascinating read. Thank you. I'm now up to snuff thanks to you!

Linda Crampton (author) from British Columbia, Canada on March 09, 2016:

I'm glad that your brother survived, Martie. His illness must have been scary for you as well as him. Thanks for the comment. As always, I appreciate it!

Martie Coetser from South Africa on March 09, 2016:

Very interesting and comprehensive article about Malaria and its cure, Artemisinin. We, too, have Malaria regions. Taking anti-malaria medicine in time is absolutely vital. My brother almost died from Malaria, so, this hub hits home! Thank you, Alicia!

Linda Crampton (author) from British Columbia, Canada on January 23, 2016:

Thank you very much, Vellur. I appreciate your comment.

Nithya Venkat from Dubai on January 23, 2016:

Interesting and informative post about Wormwood and Artemisinin. Did not know about Tu Youyou till I read your hub, thank you for sharing. Well researched and presented well, voted up.

Linda Crampton (author) from British Columbia, Canada on January 19, 2016:

Hi, truthfornow. Malaria is a worrying disease. It's been our enemy for a long time, which is a shame. It would be nice to defeat it. Thanks for the visit.

Marie Hurt from New Orleans, LA on January 19, 2016:

Wow I didn't know the parasite can stay in your liver and could come back. That is pretty scary. When I went to Thailand, they had signs in the rural areas warning you about malaria. Nobody seemed very worried, but I was freaked out. At one clinic, they had a lot of patients there with it.

Linda Crampton (author) from British Columbia, Canada on January 19, 2016:

Hi, Patricia. Thank you for the Angels. I always appreciate them. I hope that a way will be found to eradicate malaria, too. It's a very unpleasant disease and it's horrible when it kills someone.

Patricia Scott from North Central Florida on January 19, 2016:

Alicia...You have filled in a LOT of holes in my knowledge of malaria as well as the discovery made by the 2015 Nobel Prize winner. I knew that malaria still existed but had no idea how many cases occur nor did I know of how high the death toll can be.

Hopefully a way will be found to eradicate this illness.

Sending you many Angels this evening. ps

Linda Crampton (author) from British Columbia, Canada on January 17, 2016:

Thank you very much, Larry. Wormwood plants and their applications are interesting topics!

Larry Rankin from Oklahoma on January 17, 2016:

Always educational.

I had some knowledge base concerning wormwood and its applications, but as always, you have gone above and beyond in your analysis.

Linda Crampton (author) from British Columbia, Canada on January 14, 2016:

Thanks, RandaHandler. I appreciate your visit!

Randa Awn Handler from USA on January 14, 2016:

Thanks so much for all this informative research!

Linda Crampton (author) from British Columbia, Canada on January 13, 2016:

Thank you very much, RoselinSojan.

RoselinSojan on January 13, 2016:

Hi Alicia,your article is very good&informative.great work.

Linda Crampton (author) from British Columbia, Canada on January 11, 2016:

Hi, Deb. Quinine is still used to treat malaria, but it's often not the preferred drug. It can cause side effects and is not as effective as some of the other anti-malaria medications.

Deb Hirt from Stillwater, OK on January 11, 2016:

What happened with quinine? Was it never as effective, or did it lose its properties through the mutation of the disease?

Linda Crampton (author) from British Columbia, Canada on January 10, 2016:

Thank you, Flourish. What a scary story about your cousin! I'm glad that he survived. Safety while travelling through areas where malaria is common is definitely something to think about very carefully.

FlourishAnyway from USA on January 10, 2016:

A very comprehensive and informative hub as all of your hubs are. I wonder how the threat of malaria impacts travel to impacted regions, given that medications are not as effective as they have been previously? My cousin joined the Peace Corps but had to come home when he nearly died of malaria.

Linda Crampton (author) from British Columbia, Canada on January 08, 2016:

Thanks for the kind comment and the virtual votes, Buildreps! Thank you for sharing your mother's experience, too. I'm sorry that she experienced malaria. It can be a horrible illness.

Linda Crampton (author) from British Columbia, Canada on January 08, 2016:

Hi, sujaya venkatesh. Thank you for commenting. I hope the problem of malaria is solved soon. It's sad that while the situation is improving, people are still getting sick and dying from the illness.

Buildreps from Europe on January 08, 2016:

As always, a wonderful article. Malaria is a problem I'm very aware of. My mother caught the Tropicana version during one of their travels through dark Africa. You perfectly highlighted the topic, the origin of the medicine, and especially the increasing resistance of the parasite. Many virtual up votes!

sujaya venkatesh on January 07, 2016:

a dire need here and now

Linda Crampton (author) from British Columbia, Canada on January 07, 2016:

Hi, Bill. Thanks for the comment! I appreciate your visit.

Bill De Giulio from Massachusetts on January 07, 2016:

Hi Linda. What a fascinating hub. I had no idea that malaria still affects and kills so many people. Amazing. Thanks again for the education.

Linda Crampton (author) from British Columbia, Canada on January 07, 2016:

Thank you very much for the kind comment, whonu!

whonunuwho from United States on January 07, 2016:

This is very informative and an excellent proposition for helping control mosquito born diseases. Thank you so much for sharing this vital information. whonu

Linda Crampton (author) from British Columbia, Canada on January 07, 2016:

Thank you very much for sharing this information, drbj. I have heard about it before but decided not to add it to the hub. I've very glad that you added it in your comment! It's an interesting and lovely story.

drbj and sherry from south Florida on January 07, 2016:

Thank you, Alicia, for this fascinating and well-written account of the little-known Chinese scientist, Tu Youyou, who discovered the malaria-fighting properties of the plant we know as wormwood.

I remember reading one time that her first name, Youyou, was given to her by her father based on a quote from the Chinese Book of Odes. The quote is translated as "deer bleat 'youyou' while eating wild Hao."

She remarked about that coincidence since artemisia is known as qinghao in China. Truth IS stranger than fiction!

Linda Crampton (author) from British Columbia, Canada on January 07, 2016:

Hi, chef-de-jour. Thank you very much for the interesting comment and the share! I appreciate your visit.

Resistance develops due to genetic variability and genetic changes during a lifetime. By chance, some individuals have a gene (or genes) that gives them the ability to withstand a stress. These individuals survive during the stress while their comrades die. When the survivors reproduce, they send copies of their genes to their offspring, gradually creating a resistant population.

Resistance can be a very worrying problem when it affects humans. It would be wonderful if we were resistant to the malaria parasite, though!

Andrew Spacey from Near Huddersfield, West Yorkshire,UK on January 07, 2016:

A fascinating read, thank you. I know of Mugwort, a common plant that loves waste ground and roadsides here in the UK - in the same family as Wormwood I think - we make a tea out of it but you need plenty of honey to offset the bitterness!

I wonder how the malaria parasites become immune to chemicals after a certain length of time? If only the situation could be reversed and we humans became immune to the parasite?

Votes and a share.

Linda Crampton (author) from British Columbia, Canada on January 07, 2016:

Thank, Bill! I appreciate your comment and your kindness very much.

Bill Holland from Olympia, WA on January 07, 2016:

I hated science in school but I love your articles. Why is that? Perhaps because you make things interesting and easy to understand? Yes, that's it!

Linda Crampton (author) from British Columbia, Canada on January 07, 2016:

Thank you very much, Jodah. It's a great shame that some people in the west don't realize how big a problem malaria can be. I agree with you - malaria needs to be dealt with.

Linda Crampton (author) from British Columbia, Canada on January 07, 2016:

Thank you for the visit and comment, Devika. The malaria parasite could definitely be viewed as a monster!

John Hansen from Queensland Australia on January 07, 2016:

What a fantastic hub Alicia. Malaria has to be the most deadly disease on Earth and the mosquito the deadliest creature. Thank you for sharing this amazing information. Malaria gets very little publicity in the western world, but it needs to be dealt with. It needs to be taken more seriously.

Devika Primić from Dubrovnik, Croatia on January 07, 2016:

I watched a few episodes of ''Monsters Inside Me'' I learned that malaria is the most dangerous to humans. The parasite can live in the individual for years before reappearance. A very interesting insight here.

Linda Crampton (author) from British Columbia, Canada on January 06, 2016:

Hi, Mel. Yes, malaria is still a big problem in some parts of the world, despite the fact that the death rate is decreasing. Thank you very much for the comment!

Mel Carriere from San Diego California on January 06, 2016:

I had no idea malaria killed that many people yearly, but yet we continue to pour money into fighting Ebola, while malaria ravages the globe. Thanks for this great info!

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