One by one, the many mysterious secrets of traditional Chinese medicine are slowly being revealed.
Western health experts are already familiar with acupuncture and acupressure. The ancient practice of qi gong is becoming ever more popular among Americans.
Now it’s the turn of Chang Shan, an herbal medicine that has been used for thousands of years in China to treat fevers caused by malaria. Its secret action has finally been uncovered, thanks to a high-resolution structural analysis carried out at The Scripps Research Institute.
Described in the journal Nature, the new data shows in atomic detail how halofuginone, a compound derived from Chang Shan, works in cells. Scientists have known for a while now that halofuginone can suppress the immune system, but they didn’t know how.
It turns out halofuginone acts to jam the gears of a molecular machine that carries out protein synthesis, a crucial biological process necessary for life.
For proteins to be made, DNA first needs to be ‘transcribed’ or chemically converted into a similar molecule called RNA. Next, this RNA is ‘translated’ into proteins, which are chemically very different; made up of chains of amino acid molecules strung together in a strict order laid out in the original DNA.
It turns out another set of biological molecules known as transfer RNAs (tRNAs) are critically necessary for translation. Their job is to grab hold of each amino acid and add them like pearls to the growing protein chain…and enzymes known as aminoacyl-tRNA synthetases help attach each amino acid to its respective tRNA.
Interestingly, this new analysis shows for the first time that halofuginone interferes with the specific tRNA synthetase enzyme that attaches the amino acid proline to its appropriate tRNA. According to the research team who carried out this study, nothing like this has been seen before in the field of biochemistry.
Experts believe the reason Chang Shan is so effective in treating malarial fevers is because traces of a halofuginone-like chemical in the herb interfere with protein synthesis in malarial parasites, killing them in an infected person's blood.
These results appear to have finally solved a centuries-old mystery about how Chang Shan actually works; and while halofuginone has been tested in clinical trials for cancer, it now seems halofuginone may be a useful starting point to try and make new drugs for other diseases as well.