University of Michigan researchers led by Dr. Ayyalusamy Ramamoorthy, Associate Professor of Chemistry, have discovered that curcumin, the main active ingredient in turmeric, acts as a disciplinarian, introducing itself into cell membranes and making them more orderly, this improving cells’ resistance to infection and malignancy, according to findings published March 3 in the online Journal of the American Chemical Society.
The colourful spice known as turmeric is revered in India as “holy powder.” It has been used for centuries in treating infections, wounds, and other health problems. In more recent years, research into the healing properties of turmeric’s main ingredient, curcumin, has grown, and its surprising range of antioxidant, antiviral, anti-cancer, antibiotic, and other abilities has been made known. Until now, not much has been known concerning how curcumin works within the body.
“The membrane goes from being crazy and floppy to being more disciplined and ordered, so that information flow through it can be controlled,” said Ramamoorthy.
As a child in India, he was given turmeric-laced milk to drink when he had a cold, and breathed steam infused with turmeric for relief of congestion. Now as researcher in America, he is spellbound by proteins associated with biological membranes. Using a technique known as solid-state nuclear magnetic resonance (NMR) spectroscopy, he has revealed atom-level details of these important molecules and the membranous environment they operate in.
Messy Membranes Surmounted
“Probing high-resolution intermolecular interactions in the messy membrane environment has been a major challenge to commonly-used biophysical techniques,” says Ramamoorthy. The research team he works in recently developed the two-dimensional solid-state NMR technique that they used to probe curcumin-membrane communication in this study.
NMR spectroscopy is a technique which makes use of the magnetic properties of certain nuclei. When placed in a magnetic field, NMR active nuclei absorb at a frequency characteristic of the isotope. The resonant frequency, energy of the absorption and the intensity of the signal are proportional to the strength of the magnetic field.
Scientists have theorized that curcumin promotes health by interacting directly with membrane proteins, but the current study’s findings dispute that notion. Rather, the UM researchers found that curcumin regulates the action of membrane proteins indirectly, by changing the physical properties of the membrane.
Ramamoorthy’s group now is collaborating others to study an assortment of curcumin derivatives, some of which have enhanced potency. “We want to see how these various derivatives interact with the membrane, to see if the interactions are the same as what we have observed in the current study,” Ramamoorthy said. “Such a comparative study could lead to the development of potent compounds to treat infection and other diseases.”
In related research, Ramamoorthy’s team is using the NMR spectroscopy method to study the effects of curcumin on the formation of amyloids; these are clumps of fibrous protein proposed to be involved in Alzheimer’s disease, type 2 diabetes, Parkinson’s disease, and other conditions.
In addition, the researchers are looking to see whether other natural products, such as polyphenols (compounds found in many plant foods that are known to have antioxidant properties) and capsaicin (a pain reliever derived from hot peppers), interact with membranes in the same way as curcumin.
Image by Carol Mitchell, Creative Commons Attribution License.