Bengaluru: In a stunningly successful trial, scientists report they cured 18 critically-ill patients suffering from drug-resistant malaria with tablets made from dried leaves of the Chinese plant Artemisia annua (also known as sweet wormwood).
The Dried Leaves Artemisia annua (DLA) trial, which attracted international attention, was carried out a clinic in the Democratic Republic of Congo in central Africa by an international team lead by Pamela Weathers, professor of biology at Worcester Polytechnic Institute (WPI) in Massachusetts.
The patients were originally treated without success using the World Health Organisation-recommended artemisinin-based combination therapy (ACT) -- a blend of "artemisinin", a chemical extracted from Artemisia annua, with one or more anti-malaria drugs.
The patients not only failed to respond to the standard ACT medication, but lapsed into severe malaria. However, they all completely recovered "after just five days of treatment" with the DLA tablets and laboratory tests showed "they had no parasites remaining in their blood", the researchers report in the journal Phytomedicine.
The authors were prompted to examine the potential of the whole dried plant (rather than just a chemical extract) by the fact that traditional Chinese medicine has used Artemisia annua for hundreds of years as a medicine to cure various diseases, including malaria.
According to the researchers, the superior performance of DLA in comparison to ACT, as well as its ability to kill drug-resistant parasites, "is likely due to the synergistic effects of a complex array of phytochemicals contained in the plant's leaves".
In their earlier studies, they had found that dried leaves of the Artemisia annua plant delivers 40 times more artemisinin to the blood than does the drug based on the chemical extract of the plant and is more effective in knocking out the parasite in mice.
According to the researchers, their results suggest that DLA could be a new and inexpensive treatment option for the mosquito-borne disease that affects 212 million people worldwide.
"Successful treatment of all 18 ACT-resistant cases suggests that DLA should be rapidly incorporated into the anti-malarial regimen possibly wherever ACT resistance has emerged, particularly in Southeast Asia," they say.
While ACT is expensive to produce and is in short supply, DLA's advantage is its low cost and the relative simplicity of its manufacture, it is claimed.
"To our knowledge, this is the first report of Dried-Leaf Artemisia annua controlling ACT-resistant malaria in humans," the authors conclude adding that more comprehensive clinical trials on patients with drug-resistant malaria are warranted.
"I hope and wish this (DLA therapy) succeeds in larger trials," G. Padmanabhan, a biochemist at the Indian Institute of Science in Bengaluru and a leading malaria researcher, told this correspondent in an email
"If it really works in larger number of severe malaria patients, it will be great," he said. "But it will be considered as alternate therapy, since the dose of artemisinin, etc., cannot be fixed (when whole plant is used) as is the case when the pure molecule is given."
Padmanabhan said his group had also done some studies in animal models with a combination of dried leaf of Artemisia annua and curcumin (a compound found in turmeric) and the trials "were partially successful".
Then why did he not take this important research work forward considering the country's serious malaria problem?
"One notices how easily the group was able to test (their therapy) in 18 patients in Africa," said Padmanabhan. "However, with the kind of regulations for (clinical) trials that we have In India, it is difficult to take (my) work forward."