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Wormwood and Artemisinin - A Malaria Medicine from Nature

Updated on January 6, 2016
AliciaC profile image

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

A female Anopheles albimanus engorged with human blood; this species of mosquito transmits malaria
A female Anopheles albimanus engorged with human blood; this species of mosquito transmits malaria | Source

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. Artemisinin 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, anise, fennel, other spices and herbs, 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. | Source

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 to 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.

Key Facts about Malaria from WHO

According to the latest WHO estimates, released in September 2015, there were 214 million cases of malaria in 2015 and 438,000 deaths.

— World Health Organization

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.

Life Cycle of the Malaria Parasite

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.

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 | Source

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 wormword relieved fever and used it as a medicinal plant.

A young sweet wormwood plant
A young sweet wormwood plant | Source
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. | Source

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.

Structure of an artemisinin molecule
Structure of an artemisinin molecule | Source

Tu Youyou and a Nobel Prize for Physiology or Medicine

Tu Youyou discovered the effect of 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 miore 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.

A sporozoite of the malarial parasite moving through the lining of a mosquito's gut; false colour has been added to the photo
A sporozoite of the malarial parasite moving through the lining of a mosquito's gut; false colour has been added to the photo | Source

Between 2000 and 2015, malaria incidence (the rate of new cases) fell by 37% globally. In that same period, malaria death rates fell by 60% globally among all age groups.

— World Health Organization

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, is necessary because in some places the malaria parasite is becoming resistant to artemisinin. This is a worrying discovery. ACT provides both artemisinin and a second drug that works by a different mechanism. The goal is for the second drug to kill the parasite cells that survive the artemisinin attack.

At the moment, in most areas ACT is a good treatment for all types of malaria. It's especially useful for malaria caused by P. falciparum. In general, we seem to be winning the war against the disease. If ACT loses its effectiveness, however, the parasite may get the upper hand. There are other medications for malaria, but the parasite is developing resistance to them, too. 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

Malaria Fact Sheet from the World Heath Organism

Artemisinin Discovery, Structure and Action from the Royal Society of Chemistry

© 2016 Linda Crampton

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    • Mel Carriere profile image

      Mel Carriere 16 months ago from San Diego California

      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!

    • AliciaC profile image
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      Linda Crampton 16 months ago from British Columbia, Canada

      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!

    • DDE profile image

      Devika Primić 16 months ago from Dubrovnik, Croatia

      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.

    • Jodah profile image

      John Hansen 16 months ago from Queensland Australia

      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.

    • AliciaC profile image
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      Linda Crampton 16 months ago from British Columbia, Canada

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

    • AliciaC profile image
      Author

      Linda Crampton 16 months ago from British Columbia, Canada

      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.

    • billybuc profile image

      Bill Holland 16 months ago from Olympia, WA

      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!

    • AliciaC profile image
      Author

      Linda Crampton 16 months ago from British Columbia, Canada

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

    • chef-de-jour profile image

      Andrew Spacey 16 months ago from Near Huddersfield, West Yorkshire,UK

      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.

    • AliciaC profile image
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      Linda Crampton 16 months ago from British Columbia, Canada

      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!

    • drbj profile image

      drbj and sherry 16 months ago from south Florida

      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!

    • AliciaC profile image
      Author

      Linda Crampton 16 months ago from British Columbia, Canada

      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.

    • whonunuwho profile image

      whonunuwho 16 months ago from United States

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

    • AliciaC profile image
      Author

      Linda Crampton 16 months ago from British Columbia, Canada

      Thank you very much for the kind comment, whonu!

    • bdegiulio profile image

      Bill De Giulio 16 months ago from Massachusetts

      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.

    • AliciaC profile image
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      Linda Crampton 16 months ago from British Columbia, Canada

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

    • sujaya venkatesh profile image

      sujaya venkatesh 16 months ago

      a dire need here and now

    • Buildreps profile image

      Buildreps 16 months ago from Europe

      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!

    • AliciaC profile image
      Author

      Linda Crampton 16 months ago from British Columbia, Canada

      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.

    • AliciaC profile image
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      Linda Crampton 16 months ago from British Columbia, Canada

      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.

    • FlourishAnyway profile image

      FlourishAnyway 16 months ago from USA

      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.

    • AliciaC profile image
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      Linda Crampton 16 months ago from British Columbia, Canada

      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.

    • aviannovice profile image

      Deb Hirt 16 months ago from Stillwater, OK

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

    • AliciaC profile image
      Author

      Linda Crampton 16 months ago from British Columbia, Canada

      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.

    • profile image

      RoselinSojan 16 months ago

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

    • AliciaC profile image
      Author

      Linda Crampton 16 months ago from British Columbia, Canada

      Thank you very much, RoselinSojan.

    • RandaHandler profile image

      Randa Awn Handler 16 months ago from USA

      Thanks so much for all this informative research!

    • AliciaC profile image
      Author

      Linda Crampton 16 months ago from British Columbia, Canada

      Thanks, RandaHandler. I appreciate your visit!

    • Larry Rankin profile image

      Larry Rankin 16 months ago from Oklahoma

      Always educational.

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

    • AliciaC profile image
      Author

      Linda Crampton 16 months ago from British Columbia, Canada

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

    • pstraubie48 profile image

      Patricia Scott 16 months ago from sunny Florida

      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

    • AliciaC profile image
      Author

      Linda Crampton 16 months ago from British Columbia, Canada

      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.

    • truthfornow profile image

      truthfornow 16 months ago from New Orleans, LA

      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.

    • AliciaC profile image
      Author

      Linda Crampton 16 months ago from British Columbia, Canada

      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.

    • Vellur profile image

      Nithya Venkat 16 months ago from Dubai

      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.

    • AliciaC profile image
      Author

      Linda Crampton 16 months ago from British Columbia, Canada

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

    • MartieCoetser profile image

      Martie Coetser 14 months ago from South Africa

      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!

    • AliciaC profile image
      Author

      Linda Crampton 14 months ago from British Columbia, Canada

      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!

    • fpherj48 profile image

      Paula 14 months ago from Beautiful Upstate New York

      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!

    • AliciaC profile image
      Author

      Linda Crampton 14 months ago from British Columbia, Canada

      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.

    • Peggy W profile image

      Peggy Woods 14 months ago from Houston, Texas

      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.

    • AliciaC profile image
      Author

      Linda Crampton 14 months ago from British Columbia, Canada

      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.

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