New research examining the anti-inflammatory potential of curcumin delivered in different ways has found that the use of nano-emulsions could improve bioavailability and lead to a greater immune response.
Led by Nicholas Young from Ohio State University the research team noted that their previous work has already suggested that nano-emulsions increase bioavailability – showing that concentrations of the emulsified curcumin in blood were more than 10 times higher than of curcumin powder suspended in water.
The new study used a mouse model to examine whether the different delivery formats had any effects on anti-inflammatory responses by measuring whether the curcumin blocked activation of NF-kB - a protein that is known to play an important role in the immune response.
Writing in PLOS ONE, they revealed that while plain curcumin powder had little effect on NF-kB activation, the nano-emulsion curcumin blocked almost all activation – with mice showing ‘minimal’ signs of NF-kB activation resulting from a 22-fold reduction in activation that also blocked the ‘recruitment’ of immune cells called macrophages that contribute to inflammation.
“These data demonstrate that curcumin can suppress inflammation by inhibiting macrophage migration via NFκB and MCP-1 inhibition and establish that NEC [nano-emulsion curcumin] is an effective therapeutic formulation to increase the bioavailability of curcumin in order to facilitate this response,” wrote the team.
"This study suggests that we have identified a better and more effective way to deliver curcumin and know what diseases to use it for so that we can take advantage of its anti-inflammatory power," commented Young.
The Ohio State team created the nano-emulsion by mixing curcumin powder with castor oil and polyethylene glycol, to create a fluid filled with microvesicles that contain curcumin.
This process allows the compound to dissolve and be more easily absorbed by the gut to enter the bloodstream and tissues, they said.
Using genetically modified mice that had a special gene that caused NF-kB activation to show up in a bioluminescent imaging system (known as a NF-kB luciferase reporter gene) the researchers found that NF-kB activity was suppressed with nano-emulsion curcumin (NEC) compared to an equivalent amount of curcumin in water alone (aqueous suspension).
“Administration of NEC by oral gavage resulted in a reduction of blood monocytes, decreased levels of both TLR4 and RAGE expression, and inhibited secretion of MCP-1,” the team reported.
“Mechanistically, curcumin blocked LPS-induced phosphorylation of the p65 subunit of NF-kB and IkBa in murine macrophages,” they added.
They also found that NEC significantly reduced macrophage recruitment, but not T-cell or B-cell levels.
"This macrophage-specific effect of curcumin had not been described before," said Young. "Because of that finding, we propose nano-emulsified curcumin has the best potential against macrophage-associated inflammation."
Young and his colleagues now want to know if curcumin in this form can counter the chronic inflammation that is linked to sickness and age-related frailty.
They have started with animal studies testing nano-emulsified curcumin's ability to prevent or control inflammation in a lupus model.
"We envision that this nutraceutical could be used one day both as a daily supplement to help prevent certain diseases and as a therapeutic drug to help combat the bad inflammation observed in many diseases," said Young. "The distinction will then be in the amount given - perhaps a low dose for daily prevention and higher doses for disease suppression."
Inflammation triggered by overactive macrophages has been linked to cardiovascular disease, disorders that accompany obesity, Crohn's disease, rheumatoid arthritis, inflammatory bowel disease, diabetes and lupus-related nephritis.
Source: PLOS ONE
Published online ahead of print, doi: 10.1371/journal.pone.0111559
“Oral Administration of Nano-Emulsion Curcumin in Mice Suppresses Inflammatory-Induced NFκB Signaling and Macrophage Migration”
Authors: Nicholas A. Young, et al