研究者使用一種長效的合成藥物已經(jīng)治愈了瘧疾感染的小鼠，這種藥物是在一種古老的中國民間草藥的基礎(chǔ)上加工完成的。
 
此研究小組同時研發(fā)了其他幾種藥方，使用這些藥方三次口服劑量后就可治愈嚙齒類動物的發(fā)熱性疾病。這些過氧化物成分，含有關(guān)鍵的氧-氧作用單位，不僅比當今最好的瘧疾治療藥物的效果還要好，而且更加安全。研究團隊領(lǐng)隊Gary Posner解釋道。Posner教授是霍普金斯大學的化學教授。

這種古老的過氧化物抗瘧藥療效很快。這種藥物的主要成分是青縞素。幾千年來，一直用于治療瘧疾和多種發(fā)熱疾病。
 
過氧化物成分中的氧-氧單位導致瘧疾寄生蟲自我破壞。瘧原蟲可以破壞血紅蛋白、紅細胞攜氧單位，破壞后的紅細胞釋放出含鐵血紅素，一種深紅色的含鐵血液色素成分，當含鐵血紅素遇上過氧化物，將會發(fā)生一種劇烈的化學反應，釋放一種無碳的激動劑和氧化物質(zhì)，最終可殺死寄生蟲。

第一代藥物有很多缺點，包括半衰期短于一小時。Posner和其團隊會逐漸改善這些缺點。“我們這種半-合成的藥物已經(jīng)克服了第一代藥物的很多缺點。” Posner教授說，“最重要的是這些成分療效所持續(xù)的時間，但根據(jù)我們的設(shè)計，這些藥物在體內(nèi)具有更長的半衰期。我們在設(shè)計時使這些藥物變得更具親脂性，這意味著藥物在脂肪中的溶解能力更強并且能迅速到達瘧原蟲感染的血紅細胞。”

除外，新的藥物通過代謝不會降解為毒性物質(zhì)，與傳統(tǒng)的配方相比更加具有安全性。 
 

Malaria: Infected Mice Cured By One Dose of New Drug

Researchers have cured malaria-infected mice with single shots of a new series of potent, long lasting synthetic drugs modelled on an ancient Chinese herbal folk remedy.01/06/2007The team also has developed several other compounds which defeated the febrile disease in rodents after three oral doses. These peroxide compounds, containing a crucial oxygen-oxygen unit, promise not only to be more effective than today’s best malaria remedies, but also potentially safer and more efficient, said research team leader Gary Posner, Scowe Professor of Chemistry in the Krieger School of Arts and Sciences at Johns Hopkins. 
"Older drugs in this family of peroxide antimalarials also are known to be fast-acting, but they are unfortunately short-lived and not curative when used by themselves," Posner said. The peroxide compounds, called trioxanes mimic artemisinin, the active agent in a Chinese herbal drug used to treat malaria and other fevers for thousands of years.

The oxygen-oxygen unit in the peroxides causes malaria parasites essentially to self-destruct. The parasites digest hemoglobin, the oxygen-carrying pigment of red blood cells, and, in the process, release a substance called heme, a deep-red iron-containing blood pigment. When the heme encounters peroxides, a powerful chemical reaction occurs, releasing carbon-free radicals and oxidizing agents that eventually kill the parasites.

The first generation of trioxane drugs had a number of shortcomings, including a half-life of less than one hour. Posner and team believe that their new compounds address those disadvantages. "Our semi-synthetic artemisinin-derived compounds successfully overcome the disadvantages of their first-generation predecessors," he said. "Most important is their curative activity after a single, low dose, which is distinctly unusual. But based on our intentional design, they may also have a longer half-life in animals. We also designed them to be more lipophilic, meaning they have an enhanced ability to dissolve in fats and thus to arrive inside malaria-infected red blood cells."

In addition, the new compounds are far less likely to break down into toxic substances when they are metabolized in the test animals’ bodies, making them potentially safer than their predecessors.