A new study, published in PLoS One, reports that the delivery of the naringenin is boosted by its inclusion with cyclodextrin in a nano complex.
The research team, based at both Harvard and the Hebrew University of Jerusalem, found their complex increases the absorption of naringenin by 11 times. They reported that a single dose given to rats before a meal reduced the generation of very low density lipoprotein (VLDL) by 42 per cent, whilst insulin sensitivity was boosted by 64 per cent.
“The complex is special in that it is taken just before a meal, as a preventative measure,” said Dr. Nahmias, lead author of the study.
The authors claim that their research is the first demonstration that a dietary supplement can change the way our body can react beneficially to a meal. They added that the inclusion of sugary cyclodextrin in the nano-complex means that naringenin is “no longer such a bitter pill to swallow.”
Nahmias and his colleagues said that in recent years, polyphenols, and flavonoids in particular, “have emerged as a class of natural products shown to have anti-oxidant, anti-atherogenic, and normolipidemic effects.”
They noted that one of the most abundant flavonoids is the citrus flavonoid-glycoside naringin, which is broken down into naringenin.
Previous research has previously shown that naringenin, responsible for the bitter taste in grapefruits, could potentially be used in the treatment of diabetes, arteriosclerosis and hyper-metabolism. However, the Nahmias and co-workers noted that the absorption of naringenin in its natural form is very low.
They said that the potential for the use of naringenin “is limited by its low solubility and minimal bioavailability, owing to its largely hydrophobic ring structure.”
The authors noted that cyclodextrins have been used to improve the solubility of hydrophobic drugs with similar structures to naringenin.
The new study examined the potential for beta- cyclodextrins to enhance the solubility, and intestinal uptake of naringenin.
Hydroxypropoyl-beta-cyclodextrin was reported to increase the solubility of naringenin by over 400-fold, whilst its transport across a model of the gut epithelium was improved by 11-fold.
“Moreover, when the complex was administered just prior to a meal it decreased VLDL levels by 42% and increased the rate of glucose clearance by 64% compared to naringenin alone,” said Nahmias and colleagues.
“Combined with hydroxypropyl-beta-cyclodextrin's strong safety record, our results suggest that cyclodextrin-naringenin complexes could be used to efficiently deliver the flavonoid,” they added.
The researchers said that patents for further development have been applied for by Harvard University and Yissum, the technology transfer company of the Hebrew University, and clinical tests are now under way in the United States.
Source: PLoS ONE
Published online ahead of print, doi:10.1371/journal.pone.0018033
“Enhancement of Naringenin Bioavailability by Complexation with Hydroxypropoyl-β-Cyclodextrin”
Authors: M. Shulman, M. Cohen, A. Soto-Gutierrez, H. Yagi, H. Wang, et al