The researchers found that dibenzoylmethane nanemulsions (derived from liquorice) in the range of 50nm to 200nm could enhance oral availability threefold over conventional emulsions in the 1μm to 100μm range
Bipolymer micelles (derived from amphiphiles, which have both hydrophilic and hydrophobic properties) functional groups demonstrated improved water solubility/dispersibility and in vitro anti-cancer activity of phytochemicals.
But the researchers from the Food Science Department at Rutgers University in New Jersey said more investigation was required into nano impacts, especially in in vivo, “to address public concerns”.
The scientific review, supported by US Department of Agriculture National Research Initiative Program, noted there was increased demand for, “functional food ingredients with improved water solubility, thermal stability, oral bioavailability, sensory attributes, and physiological performance.”
Phytochemicals are an example of a nutrient type that is poorly absorbed by the human body and which have been the subject of encapsulation research to boost their performance, via methods such as introducing other nutrients including polysaccharides, proteins and emulsifiers.
These controlled-release approaches can be assisted with nanotechnology methods.
“Although many different delivery systems are now available to delivery bioactive components in nutraceuticals and functional foods, clear in vitro or in vivo evidences of their biological efficacies are still limited,” the researchers wrote.
Phytochemical lipophilia
They noted the problem with the majority of phytochemicals, such as polyphenols and carotenoids, is their poor solubility, or the fact they were lipophilic compounds.
“To overcome instability, poor water solubility, and to enhance the bioavailability of nutraceuticals, one option to entrap the compound of interest into a food matrix is to use nanoemulsion,” the wrote.
“Compared with conventional methods, such as co-solvent addition, micronizing/milling, spray drying, and salt formation, the use of lipid based delivery systems, such as micro/nanoemulsions and micelles, offers many advantages...”
These include high kinetic or thermodynamic stability; the ability to combine hydrophilic or lipophilic phytochemicals in the same nanoemulsions; the ability to more easily transport droplets through cell membranes.
The researchers noted that while the use of polyphenols in capsules and tablets is common, “their biological effects are frequently diminished or even lost due to incomplete absorption and first-pass metabolism.”
The researchers said that nanoencapsulation could benefit CoQ10, omega-3s and curcumin among others.
In conclusion they observed: “Nanoemulsions-based delivery systems have been proved to be one of the best platforms to enhance the oral bioavailability and biological efficacies (that is, antiinflammation, anti-cancer, and so on) of different phytochemicals.”
“Similarly, polymer micelles also show promise to improve the water dispersibility of many crystalline phytochemicals, such as β-carotene and curcumin, and also show improved in vitro anti-cancer activity. A wide variety of delivery systems with different structures are now available, and their design principles are quite clear now.”
But questions remained: “For example, why nanoencapsulated phytochemicals have better oral bioavailability? How are the cellular signal transduction pathways different for nanoencapsulated phytochemicals compared with the nonencapsulated forms? Are the nanoencapsulated phytochemicals toxic?
"Therefore, more efforts should be devoted to the development of novel value-added food-grade or GRAS (generally recognized as safe) materials from biomass, as well as the understanding of the potential impacts of these nanoencapsulated nutraceuticals to human body and environment to address the public concerns.”
Source: Journal of Food Science
10.1111/j.1750-3841.2009.01457.x
‘Bioavailability and Delivery of Nutraceuticals Using Nanotechnology’
Authors: Qingrong Huang; Hailong Yu; Qiaomei Ru