Capsaicin-loaded nanoemulsions as a functional-ingredient delivery system and its biological evaluation

Abstract

Capsaicin is widely consumed as a spice and food additive, and is also utilized in medical applications. Capsaicin (N-[4-hydroxy-3- methoxyphenyl] methyl-8-methyl-non-6-enamide) and dihydrocapsaicin (N-[4-hydroxy-3-methoxy-phenyl]methyl-8-methyl-non-6-nonanamide) are two members of the family of naturally occurring capsaicinoids, which make up the pungent components of hot pepper. Capsaicin has been obtained in the oleoresin capsicum form through the industrial extraction of the dried ripe fruits of capsicums, and it contains a complex mixture of essential oils, waxes, colored materials, and several capsaicinoids. Capsaicin is one of the carotenoids, such as capsanthin, cryptoxanthin, carotene and zeaxanthin, which contribute to the yellow to red colours of many foods. However, there are several limitations for its use in food systems, such as lipophilicity and the structure of carotenoids, which affect their distribution in the cellular systems in vivo, and high melting point, making them crystalline at food storage and body temperatures. One of the promising nanotechnologies is the nanometersized emulsion delivery system, which offers the potential to improve the solubility and bioavailability of many bioactive ingredients such as carotenoids, polyunsaturated fatty acids, phytosterols, antioxidants, vitamin, minerals, and other natural compounds. Bioactive ingredients can be encapsulated in nanometer-sized structures, which function as the transport systems. These nanometer-sized structures have sizes ranging from 20-500 nm, and provide the necessary physical properties, such as solubility, stability, and bioavailability. A nanopolymeric system can be applied to the formulation of nanoemulsions through self-assembly emulsification for the development of a bioactive ingredient delivery system. The incorporation of alginate and chitosan to form multi-layer nanoemulsions can be expected to improve the stability of nanoemulsions, and this system holds promise for use in the production of functional foods containing bioactive ingredients. The nanoemulsions of capsaicin which incorporated with alginate (AN) were found to reduced the body weight and adipose tissue mass, whereas capsaicin extract (CE) did not. CE and AN reduced the levels of mRNA of adipogenic genes, including peroxisome proliferator-activated receptor-γ, sterol regulatory element-binding protein-1c, and fatty acid-binding protein in white adipose tissue. The mRNA levels of genes related to β- oxidation or thermogenesis, including PPAR-α, palmitoyltransferase-1α, and uncoupling protein-2, were increased by supplementation with CE and AN relative to the high fat control group. In particular, the expression of PPAR-α, CPT-1α, and UCP2 was well as the activity of AMPK were significantly increased in the AN group compared to those in the OC group. © 2015 by Nova Science Publishers, Inc. All rights reserved.