Ancient Chinese medicine for malaria could potentially aid in treatment of tuberculosis

In continuation of my update on Artemisinin

A centuries-old herbal medicine, discovered by Chinese scientists and used to effectively treat malaria, has been found to potentially aid in the treatment of tuberculosis and may slow the evolution of drug resistance.

In a promising study led by Robert Abramovitch, a Michigan State University microbiologist and TB expert, the ancient remedy artemisinin stopped the ability of TB-causing bacteria, known as Mycobacterium tuberculosis, to become dormant. This stage of the disease often makes the use of antibiotics ineffective.

The study is published in the journal Nature Chemical Biology.

"When TB bacteria are dormant, they become highly tolerant to antibiotics," Abramovitch said, an assistant professor in the College of Veterinary Medicine. "Blocking dormancy makes the TB bacteria more sensitive to these drugs and could shorten treatment times."

One-third of the world's population is infected with TB and the disease killed 1.8 million people in 2015, according to the Centers for Disease Control and Prevention.

Mycobacterium tuberculosis, or Mtb, needs oxygen to thrive in the body. The immune system starves this bacterium of oxygen to control the infection. Abramovitch and his team found that artemisinin attacks a molecule called heme, which is found in the Mtb oxygen sensor. By disrupting this sensor and essentially turning it off, the artemisinin stopped the disease's ability to sense how much oxygen it was getting.

"When the Mtb is starved of oxygen, it goes into a dormant state, which protects it from the stress of low-oxygen environments," Abramovitch said. "If Mtb can't sense low oxygen, then it can't become dormant and will die."

Abramovitch indicated that dormant TB can remain inactive for decades in the body. But if the immune system weakens at some point, it can wake back up and spread. Whether it wakes up or stays 'asleep' though, he said TB can take up to six months to treat and is one of the main reasons the disease is so difficult to control.

"Patients often don't stick to the treatment regimen because of the length of time it takes to cure the disease," he said. "Incomplete therapy plays an important role in the evolution and spread of multi-drug resistant TB strains."

He said the research could be key to shortening the course of therapy because it can clear out the dormant, hard-to-kill bacteria. This could lead to improving patient outcomes and slowing the evolution of drug-resistant TB.

After screening 540,000 different compounds, Abramovitch also found five other possible chemical inhibitors that target the Mtb oxygen sensor in various ways and could be effective in treatment as well.

"Two billion people worldwide are infected with Mtb," Abramovitch said. "TB is a global problem that requires new tools to slow its spread and overcome drug resistance. This new method of targeting dormant bacteria is exciting because it shows us a new way to kill it."

Ref : http://www.nature.com/nchembio/journal/vaop/ncurrent/full/nchembio.2259.html

Traditional Chinese medicinal plant produces compounds that may help to kill human cancers

New research led by Professor Cathie Martin of the John Innes Centre has revealed how a plant used in traditional Chinese medicine produces compounds which may help to treat cancer and liver diseases.

The Chinese skullcap, Scutellaria baicalensis - otherwise known in Chinese medicine as Huang-Qin - is traditionally used as a treatment for fever, liver and lung complaints.

Previous research on cells cultured in the lab has shown that certain compounds called flavones, found in the roots of this plant, not only have beneficial anti-viral and anti-oxidant effects, but they can also kill human cancers while leaving healthy cells untouched. In live animal models, these flavones have also halted tumour growth, offering hope that they may one day lead to effective cancer treatments, or even cures.

As a group of compounds, the flavones are relatively well understood. But the beneficial flavones found in Huang-Qin roots, such as wogonin and baicalin, are different: a missing - OH (hydroxyl) group in their chemical structure left scientists scratching their heads as to how they were made in the plant.

Professor Cathie Martin, lead author of the paper published in Science Advances, explains: "Many flavones are synthesised using a compound called naringenin as a building block. But naringenin has this -OH group attached to it, and there is no known enzyme that will remove it to produce the flavones we find in Huang-Qin roots."

Working in collaboration with Chinese scientists, Cathie and her team explored the possibility that Huang-Qin's root-specific flavones (RSFs) were made via a different biochemical pathway. Step-by-step, the scientists unravelled the mechanism involving new enzymes that make RSFs using a different building block called chrysin.

"We believe that this biosynthetic pathway has evolved relatively recently in Scutellariaroots, diverging from the classical pathway that produces flavones in leaves and flowers, specifically to produce chrysin and its derived flavones," said Professor Martin.

"Understanding the pathway should help us to produce these special flavones in large quantities, which will enable further research into their potential medicinal uses. It is wonderful to have collaborated with Chinese scientists on these traditional medicinal plants. Interest in traditional remedies has increased dramatically in China since Tu Youyou was awarded the Nobel Prize for Medicine in 2015 for her work on artemisinin. It's exciting to consider that the plants which have been used as traditional Chinese remedies for thousands of years may lead to effective modern medicines."

Traditional Chinese medicinal plant produces compounds that may help to kill human cancers: New research led by Professor Cathie Martin of the John Innes Centre has revealed how a plant used in traditional Chinese medicine produces compounds which may help to treat cancer and liver diseases.

Dual-acting hybrid drug could be a promising new weapon against drug-resistant malaria

A combination of artemisinin and another drug (artemisinin combination therapy, ACT) is currently the best malaria treatment recommended by the World Health Organization. In early 2015, artemisinin-resistant malaria was confirmed in five countries in Southeast Asia: Cambodia, Laos, Myanmar, Thailand, and Vietnam. Even more worrying, malaria cases that are resistant to practically all drugs have begun to emerge along the Thailand-Cambodia border. Such cases do not respond to ACT; thus, new therapies that are effective for resistant malaria are urgently needed.

For a therapy to be effective, it needs to counteract the resistance of malaria to existing drugs. Malaria drugs, such as chloroquine and artemisinin, work within the digestive vacuole of the malaria parasite, which serves as the stomach of the parasite. The killing action of chloroquine is better understood than that for artemisinin. Once chloroquine enters the parasite's "stomach," the stomach membrane traps the drug inside (similar to a window closing and locking) and the high levels of drug can then effectively kill the parasite. However, in a resistant malaria parasite, the stomach membrane is mutated so that it cannot keep the drug inside the stomach, just like a window with a broken lock. Since the drug is no longer concentrated inside the stomach, it can no longer kill the malaria parasite effectively.

Associate Professor Kevin Tan of the Department of Microbiology & Immunology and Associate Professor Brian Dymock of the Drug Development Unit and the Department of Pharmacy have now developed a hybrid drug that combines parts of chloroquine and a chemoreversal agent. This gives the hybrid drug a "dual acting" mechanism: a killing factor (chloroquine-derived) and a second component that acts on that faulty window of the parasite's stomach so it can now close again (the chemoreversal agent). The drug becomes concentrated inside the stomach of the drug-resistant parasite and can kill the parasite.

Dual-acting hybrid drug could be a promising new weapon against drug-resistant malaria: A combination of artemisinin and another drug (artemisinin combination therapy, ACT) is currently the best malaria treatment recommended by the World Health Organization.

Potent parasite-killing mechanism of anti-malarial drug uncovered: New understanding of how artemisinin works could facilitate development of new drugs and therapeutic strategies against malaria -- ScienceDaily

In continuation of my update on artemisinin

A team of researchers has uncovered the mystery behind the potent parasite-killing effect of artemisinin, a drug that is considered to be the last line of defense against malaria. Given the emergence of artemisinin resistance, these findings could potentially lead to the design of new treatments against drug-resistant parasites.

Assistant Professor Lin Qingsong, who is from the Department of Biological Sciences under the NUS Faculty of Science and is one of the scientists who led the study, explained, "Many people may not realise that more human lives are lost to the tiny mosquito, more specifically malaria parasites, each year as compared to ferocious animals such as lions and sharks. After infection, malaria parasites, known for their blood-eating nature, can propagate inside the human body rapidly and consume up to 80 per cent of red blood cells in a short period of time, leading to a series of deadly symptoms."

About 3.2 billion people -- almost half of the world's population -- are considered to be at risk of malaria by the World Health Organization. As of September 2015, there were an estimated 214 million cases of malaria and 438,000 malaria-linked deaths this year alone.

Artemisinin and its derivatives are currently the most potent class of anti-malarial drugs. In recognition of its importance against malaria, the discovery of artemisinin won Chinese scientist Ms Tu Youyou the 2015 Nobel Prize in Physiology or Medicine earlier in October this year. While there have been extensive studies on artemisinin, the mechanism of the drug is not well understood.

Asst Prof Lin, together with Dr Wang Jigang, who was formerly with the NUS Department of Biological Sciences and now with the Singapore-MIT Alliance for Research & Technology, Associate Professor Kevin Tan from the Department of Microbiology and Immunology at the NUS Yong Loo Lin School of Medicine and their research team, discovered over 120 protein targets of artemisinin, and the mechanism that activates its deadly killing effect. The findings of the study are published in the journal Nature Communications on 23 December 2015.

Potent parasite-killing mechanism of anti-malarial drug uncovered: New understanding of how artemisinin works could facilitate development of new drugs and therapeutic strategies against malaria

This Little Known Chinese Herb Kills 12,000 Cancer Cells For Every Healthy Cell | Collective-Evolution

A little known Chinese herb might be eligible for the growing list of cancer killers via alternative methods of treatment. According to  studies published  in Life Sciences, Cancer Letters and Anticancer Drugs, artemesinin, a derivative of the wormwood plant commonly used in Chinese medicine, can kill off  cancer cells, and do it at a rate of 12,000 cancer cells for every healthy cell.

Henry Lai and his team of researchers from the University of Washington synthesized the compound, which uses a cancer cells appetite for iron to make them the target. The great thing about artemisinin is that alone it can selectively kill cancer cells while leaving normal cells unharmed.

“By itself, artemisinin is about 100 times more selective in killing cancer cells as opposed to normal cells. Artemisinin is 34,000 times more potent in killing the cancer cells as opposed to their normal cousins. So the tagging process appears to have greatly increased the potency of artemisinin’s cancer-killing properties.” – Henry Lai

Despite the compound being licensed to Holley Pharmaceuticals, it has yet to be used for cancer treatment in humans.

“We call it a Trojan horse because the cancer cell recognizes transferrin as a natural, harmless protein. So the cell picks up the compound without knowing that a bomb (artemisinin) is hidden inside.”  – Henry Lai

The wormwood extract was used many centuries ago in China for healing purposes. The treatment became lost over time and has now been rediscovered thanks to an ancient manuscript containing medical remedies. It kills 12,000 cancer cells for every healthy cell, which means it could be turned into a drug with minimal side effects.

“The compound is currently being licensed by the University of Washington to Artemisia Biomedical Inc., a company that Lai, Sasaki and Narendra Singh, UW associate professor of bioengineering, founded in Newcastle, Washington for development and commercialization. Human trials are at least several years away. Artemisinin is readily available, Sasaki said, and he hopes their compound can eventually be cheaply manufactured to help cancer patients in developing countries.”

This Little Known Chinese Herb Kills 12,000 Cancer Cells For Every Healthy Cell | Collective-Evolution

Malaria combination drug therapy for children

A drug combination of artemisinin-naphthoquine should be considered for the treatment of children with uncomplicated malaria in settings where multiple parasite species cause malaria according to Tim Davis from University of Western Australia, Fremantle, Australia and colleagues in new research published in this week's PLOS Medicine.

The authors compared the current recommended therapy for uncomplicated malaria in children in Papua New Guinea, artemether-lumefantrine, with a different combination therapy, artemisinin-naphthoquine. Using a randomized, controlled trial study design including 186 children with Plasmodium falciparum infections and 47 children with Plasmodium vivax infections, the researchers found that artemisinin-naphthoquine was non-inferior to (no worse than) artemether-lumefantrine for treating Plasmodium falciparum (a difference of 2.2% [95% confidence interval ?3.0% to 8.4%] for reappearance of infection within 42 days) but was more effective for treating Plasmodium vivax (a difference 70.0% [95% confidence interval 40.9%-87.2%] for reappearance of infection within 42 days).

The authors conclude, "[t]he efficacy, tolerability, and safety of three daily doses of artemisinin-naphthoquine suggest that this regimen should be considered together with other currently available effective [artemisinin combination therapies] for treatment of uncomplicated malaria in [Papua New Guinea] and similar epidemiologic settings with transmission of multiple Plasmodium species."

Ref http://aac.asm.org/content/56/5/2465.full

Malaria combination drug therapy for children 

New low-cost combined therapy shows promise against malaria

Molecular parasitologist Stephen Rich at the University of Massachusetts Amherst has led a research team who report a promising new low-cost combined therapy with a much higher chance of outwitting P. falciparum than current modes. He and plant biochemist Pamela Weathers at the Worcester Polytechnic Institute (WPI), with research physician Doug Golenbock at the UMass Medical School, also in Worcester, have designed an approach for treating malaria based on a new use of Artemisia annua, a plant employed for thousands of years in Asia to treat fever.

"The emergence of resistant parasites has repeatedly curtailed the lifespan of each drug that is developed and deployed," says UMass Amherst graduate student and lead author Mostafa Elfawal. Rich, an expert in the malaria parasite and how it evolves, adds, "We no sooner get the upper hand than the parasite mutates to become drug resistant again. This cycle of resistance to anti-malarial drugs is one of the great health problems facing the world today. We're hoping that our approach may provide an inexpensive, locally grown and processed option for fighting malaria in the developing world."

Currently the most effective malaria treatment uses purified extracts from the Artemisia plant as part of an Artemisinin Combined Therapy (ACT) regime with other drugs such as doxycycline and/or chloroquine, a prescription far too costly for wide use in the developing world. Also, because Artemisia yields low levels of pure artemisinin, there is a persistent worldwide shortage, they add.

The teams's thesis, first proposed by Weathers of WPI, is that locally grown and dried leaves of the whole plant, rich in hundreds of phytochemicals not contained in the purified drug, might be effective against disease at the same time limiting post-production steps, perhaps substantially reducing treatment cost. She says, "Whole-plant Artemisia has hundreds of compounds, some of them not even known yet. These may outsmart the parasites by delivering a more complex drug than the purified form."

Rich adds, "The plant may be its own complex combination therapy. Because of the combination of parasite-killing substances normally present in the plant (artemisinin and flavonoids), a synergism among these constituent compounds might render whole plant consumption as a form of artemisinin-based combination therapy, or what we're calling a 'pACT,' for plant Artemisinin Combination Therapy."

Ref : http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0052746

New low-cost combined therapy shows promise against malaria

Anti-malaria drug synthesised with the help of oxygen and light

In continuation of my update, artemisinin... The most effective anti-malaria drug can now be produced inexpensively and in large quantities. This means that it will be possible to provide medication for the 225 million malaria patients in developing countries at an affordable price. Researchers at the Max Planck Institute of Colloids and Interfaces in Potsdam and the Freie Universität Berlin have developed a very simple process for the synthesis of artemisinin, the active ingredient that pharmaceutical companies could only obtain from plants up to now. The chemists use a waste product from current artemisinin production as their starting substance. This substance can also be produced biotechnologically in yeast, which the scientists convert into the active ingredient using a simple yet very ingenious method..... Look at http://www.mpg.de/4984709/artemisinin_malaria

New malaria drug Artesunate, can save millions of lives....

A landmark trial (AQUAMAT trial) showed that the replacement of the standard malaria drug Quinine with the newer drug Artesunate (Artesunate contains artemisinin, which was discovered by a Chinese researcher in 1972 in a project to follow up advice found in ancient Chinese medicine : see structure) for children with severe malaria could save 100,000 lives a year. The World Health Organisation (WHO) recommended that artesunate derived from a Chinese plant called sweet wormwood, replace the four-century-old remedy of quinine for treating severe malaria in adults in 2006. Similar recommendations were not made for children with further trial results pending.

The trial shows that using artesunate reduced death from severe falciparum malaria among African children by 22.5 per cent compared to quinine. The trial spanned over nine African countries, in which 5,425 badly-infected children aged under 15 were given either artesunate or quinine. There were 230 deaths (8.5 percent) in the artesunate group and 297 deaths (11 percent) in the quinine group, the study authors reported. Artesunate was better tolerated than quinine. There was a lower risk of coma or convulsion or serious dropping of blood sugar as occurred with quinine. Hope this trial (a change in treatment policy from quinine to artesunate) will lead to a solution for severe malaria (most common admission diagnosis in febrile children) and can save thousands of children's lives…...

Ref : http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2810%2961924-1/fulltext

Improved synthetic biology for Artemisinin....

We know that Artemision, is a drug to treat multi-drug resistant strains of falciparum malaria. And also fermenting artemisinin via engineered microbes, such as yeast, can be done at far lower costs than extracting the drug from Artemsisia annua , the sweet wormwood tree, making microbial-based artemisinin a much cheaper but equally effective treatment. However the cost of extracting artemisinin from wormwood trees, which only produce the drug under a narrow set of agricultural and climatological conditions or manufacturing it entirely through chemical synthesis is too high. This encouraged Dr. Keasling and his group to undertake this research and are succesful in achieving an improved method, where in the cost will drastically down. And this research is also of great important by the fact that, the same method can be elaborated to make biofuels.

In 2003, they reported their first success. By transplanting genes from yeast and from the sweet wormwood tree into E. coli bacteria and then bypassing the E. coli's metabolic pathway and engineering a new one based on the mevalonate pathway in yeast, they were able to induce the bacteria to produce amorphadiene, a chemical precursor to artemisinin. Even though the yields were low, they achieved one more significance by res using the re-synthesis and other techniques to improve the yield of amorphadiene in E. coli by a million fold. As the conversion of artemisinic acid to artemisinin in high yields are already known, this finding is of great importance.

The most significant part of their reserach is creating a new metabolic pathway in the yeast, similar to the one created in E. coli, then introduced bacterial and wormwood genes into the yeast's DNA that interacted with the yeast's own genes to produce amorphadiene. Finally, they cloned the gene from the wormwood tree that produces the enzyme P450, which the plant uses to convert amorphadiene to artemisinic acid, and expressed it in the amorphadiene-producing yeast strain. And the group wants to use the same technology to make biofuels.... Congrats Dr.Jay D. Keasling...