Anti-malaria effect of artemisinin

[Overview]
Artemisinin (QHS) is a novel sesquiterpene lactone containing a peroxy bridge isolated from the Chinese herbal medicine Artemisia annua L. Artemisinin has unique structure, high efficiency and low toxicity. It has anti-tumor, anti-tumor, anti-bacterial, anti-malarial, and immune-enhancing pharmacological effects. It has special effects on brain-type abuse and malignant abuse. It is the only internationally recognized anti-malarial drug in China. It has become the ideal drug for the treatment of malaria recommended by the World Health Organization.
[Physical and chemical properties]
Artemisinin is a colorless needle crystal with a melting point of 156~157 ° C. It is easily soluble in chloroform, acetone, ethyl acetate and benzene. It is soluble in ethanol, ether, slightly soluble in cold petroleum ether, and almost insoluble in water. Because of its special peroxy group, it is unstable to heat and is easily decomposed by the influence of wet, hot and reducing substances.
[Pharmacological action]
1. Anti-malarial effect Artemisinin has special pharmacological properties and has a very good therapeutic effect on malaria. In the antimalarial action of artemisinin, artemisinin causes complete disintegration of the structure of the worm by interfering with the membrane-mitochondrial function of the malaria parasite. The main analysis of this process is as follows: the peroxy group in the molecular structure of artemisinin generates free radicals by oxidation, and the free radicals bind to the malaria protein, thereby acting on the membrane structure of the parasitic protozoa, destroying the membrane, nuclear membrane and plasma membrane. The mitochondria are swollen and the inner and outer membranes are detached, eventually destroying the cellular structure and function of the malaria parasite. In this process, the chromosomes in the nucleus of the malaria parasite are also affected. Optical and electron microscopy observations show that artemisinin can directly enter the membrane structure of Plasmodium, which can effectively block the nutrient supply of Plasmodium-dependent host red blood cell pulp, and thus interfere with the membrane-mitochondrial function of Plasmodium ( Rather than disturbing its folate metabolism, it eventually leads to the complete collapse of the malaria parasite. The application of artemisinin also greatly reduces the amount of isoleucine ingested by Plasmodium, thereby inhibiting the synthesis of proteins in Plasmodium.
In addition, the antimalarial effect of artemisinin is also related to oxygen pressure, and high oxygen pressure will reduce the effective concentration of artemisinin on P. falciparum cultured in vitro. The destruction of malaria parasite by artemisinin is divided into two types, one is to directly destroy the malaria parasite; the other is to damage the red blood cells of the malaria parasite, which leads to the death of the malaria parasite. The antimalarial effect of artemisinin has a direct killing effect on the erythrocyte phase of Plasmodium. There is no significant effect on the pre- and extra-erythrocytic phases. Unlike other antimalarials, the antimalarial mechanism of artemisinin relies primarily on peroxyl in the molecular structure of artemisinin. The presence of peroxyl groups plays a decisive role in the antimalarial activity of artemisinin. If there is no peroxide group, artemisinin will lose its antimalarial activity. Therefore, it can be said that the antimalarial mechanism of artemisinin is closely related to the decomposition reaction of peroxyl groups. In addition to its good killing effect on malaria parasites, artemisinin also has a certain inhibitory effect on other parasites.
2. Anti-tumor effect Artemisinin has obvious inhibitory effects on the growth of various tumor cells such as liver cancer cells, breast cancer cells and cervical cancer cells. A number of studies have shown that artemisinin has the same mechanism of action against malaria and anticancer, namely, anti-malarial and anti-cancer by free radicals generated by peroxy bridge breaks in the molecular structure of artemisinin. And the same artemisinin derivative is selective for the inhibition of different types of tumor cells. The action of artemisinin on tumor cells relies on the induction of cell apoptosis to complete the killing of tumor cells. In the same antimalarial effect, dihydroartemisinin inhibits the activation of hypoxia inducing factors by increasing the reactive oxygen group. For example, after acting on the cell membrane of leukemia cells, artemisinin can increase the intracellular calcium concentration by changing the permeability of its cell membrane, which not only activates calpain in leukemia cells, but also promotes the release of apoptotic substances. Speed ​​up the process of apoptosis.
3. Immunomodulatory effects Artemisinin has a regulatory effect on the immune system. Under the condition that the dosage of artemisinin and its derivatives does not cause cytotoxicity, artemisinin can inhibit T lymphocyte mitogen well, and thus can induce the increase of spleen lymphocytes in mice. Artesunate can increase the total complement activity of mouse serum by enhancing the effect of non-specific immunity. Dihydroartemisinin can directly inhibit the proliferation of B lymphocytes and reduce the secretion of autoantibodies by B lymphocytes, thereby inhibiting the humoral immune response.
4. Antifungal action The antifungal action of artemisinin is reflected in its inhibition of fungi. Artemisinin slag powder and decoction have strong inhibitory effects on Staphylococcus epidermidis, Bacillus anthracis, diphtheria and catarrhalis, and also have certain effects on Pseudomonas aeruginosa, Shigella, Mycobacterium tuberculosis and Staphylococcus aureus. Inhibition.
5. Anti-Pneumocystis carinii pneumonia effect Artemisinin mainly destroys the structure of Pneumocystis carinii membrane system, causing vacuoles in the cytoplasm and package of sporozoite trophozoites, mitochondria swelling, nuclear membrane rupture, swelling of endoplasmic reticulum, Intracapsular problems such as dissolution and destruction of ultrastructural changes.
6. Anti-pregnancy effect Artemisinin drugs have high selective toxicity to embryos. Lower doses can cause embryos to die and cause miscarriage. It may be developed as abortion drugs.
7. Anti-Schistosomiasis The anti-schistosomiasis active group is a peroxy bridge, and its medicinal mechanism is to affect the sugar metabolism of the worm.
8. Cardiovascular effects Artemisinin can significantly prevent arrhythmia caused by ligation of coronary artery, which can significantly delay the onset of arrhythmia caused by calcium chloride and chloroform, and significantly reduce ventricular fibrillation.
9. Anti-fibrosis It is related to inhibiting fibroblast proliferation, reducing collagen synthesis, and anti-histamine-induced collagen decomposition.
10. Other effects Dihydroartemisinin has a significant inhibitory effect on Leishmania donovani and is dose-related. Artemisia annua extract also kills Trichomonas vaginalis and lysate amoeba trophozoites.


Post time: Jul-19-2019
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