◎ science and Technology Daily reporter Fu Lili
April 25 is World Malaria Day. Speaking of malaria, people naturally think of artemisinin and its discoverer Tu youyou.
This year coincides with the 50th anniversary of artemisinin. Once, people talked about malaria. Some figures showed that before artemisinin was discovered, about 400 million people were infected with malaria every year and at least 1 million people died of the disease.
On June 30, 2021, the World Health Organization announced that China had passed the certification of eliminating malaria. From the 1940s, about 30 million malaria cases were reported every year to the present, it is a great feat. In the world, there are still 91 countries and regions with malaria prevalence. The most serious area is sub Saharan Africa, accounting for 90% of the global proportion. However, global malaria mortality has halved since 2000. Among them, “Chinese god grass” artemisinin has made great contributions.
Artemisinin antimalarial drugs are a gift of traditional Chinese medicine to the world
Since the advent of artemisinin in the 1970s, countless malaria patients have been cured. Artemisinin antimalarial drugs have become life-saving drugs in malaria endemic areas.
“This is a gift of traditional Chinese medicine to the world.” Tu Youyou, lifelong researcher and chief researcher of the Chinese Academy of traditional Chinese medicine and director of the artemisinin Research Center, said.
The stories of Tu youyou and artemisinin are well known in China and around the world. For half a century, artemisinin, dihydroartemisinin, compound artemether, dihydroartemisinin piperaquine tablets… Artemisinin and its derivatives have been widely used in anti malaria clinic, went abroad and finally affected the world.
Tu youyou always talks about this sentence: “artemisinin is the result of the national system. On the battlefield of global malaria control, the strength of individuals is small. Only organized and targeted large teams can gradually defeat malaria.”
Liao Fulong, a colleague of Tu youyou and a researcher at the Institute of traditional Chinese medicine of the Chinese Academy of traditional Chinese medicine, also believes that the discovery of artemisinin not only reflects the originality of Chinese medicine in the field of international medical and health, but also reflects the spiritual outlook of a generation of Chinese researchers, that is, their responsibility and responsibility for national tasks.
“Now this spirit has been summed up as the ‘artemisinin spirit’: Thinking of the motherland, daring to take responsibility, unity and cooperation, inheritance and innovation, caring for the common people, indifferent to fame and wealth, enhancing self-confidence and climbing the peak.” Liao Fulong said.
Progress has been made in the study of artemisinin resistance and other indications
Needless to say, after half a century, artemisinin has made great contributions to global malaria control, but its deep mechanism for malaria treatment is still unclear. In particular, artemisinin resistance has always been a concern of Tu Youyou, and it is also the biggest challenge facing malaria resistance in the world.
Inspired by this spirit, Tu youyou and the team members have been working hard. “What we have been doing is to find out the mechanism of action of artemisinin, crack its drug resistance, and how to expand the indications of artemisinin drugs.” Liao Fulong said.
Fortunately, on June 17, 2019, Tu youyou’s team announced that its artemisinin resistance research had made phased progress. Wang Jigang, a member of Tu youyou’s team and researcher of artemisinin research center of Chinese Academy of traditional Chinese medicine, used chemical biological methods to study the process of heme activating artemisinin. It was found that the activated artemisinin can covalently bind and alkylate with more than 100 proteins of Plasmodium, destroy many life processes of Plasmodium and kill Plasmodium. This heme activated multi-target theory has been recognized by the international antimalarial academic community. It is of great significance to reveal the deep mechanism and drug resistance of artemisinin antimalarial and promote more effective clinical medication.
Wang Jigang introduced that according to the research, the half-life of artemisinin in the human body is very short, only 1 to 2 hours, while the course of artemisinin combined therapy (ACT) recommended clinically is 3 days, and the truly efficient insecticidal window of artemisinin is only limited to 4 to 8 hours. The existing drug-resistant strains make full use of the short half-life of artemisinin to change the life cycle or temporarily enter the dormant state, so as to avoid the sensitive insecticidal period. At the same time, the malaria parasite can also produce obvious resistance to the auxiliary drug “antimalarial formula” in the artemisinin combination therapy, which makes the artemisinin combination therapy “ineffective”.
In response to this, the team proposed a new treatment plan: first, appropriately extend the medication time from 3-day therapy to 5-day or 7-day therapy; The second is to replace the drug-resistant adjuvant drugs in artemisinin combination therapy. “In the foreseeable future, continued rational and strategic application of artemisinin combination therapy is the best solution to deal with treatment failure, and may also be the only solution.” Wang Jigang stressed.
In addition to the antimalarial research of artemisinin, the team is also very concerned about the anticancer and other effects of artemisinin. The anticancer mechanism of artemisinin is similar to the antimalarial mechanism, that is, compared with normal somatic cells, the synthesis of heme in tumor cells is more vigorous, which activates artemisinin or its derivatives, and then the activated artemisinin kills tumor cells in a multi-target manner. However, team members said that the anticancer effect of artemisinin is still in the basic research stage, and its effectiveness does not mean that it can be made into a drug. Whether artemisinin can become an anticancer drug still needs a lot of follow-up research.
Then there is the concern about artemisinin drugs in the treatment of lupus erythematosus. Dihydroartemisinin has a unique effect on lupus erythematosus with high variability. “Under the auspices of Kunming Pharmaceutical Group, phase II clinical trials are currently being carried out, and it is expected that blindness can be uncovered in September.” Liao Fulong said that previous trials have shown that artemisinin has an effective trend in the treatment of lupus erythematosus. However, the mechanism of dihydroartemisinin in the treatment of lupus erythematosus needs to be further studied.