Effect of chemical interaction between oleic acid and L-Arginine on oral perception, as a function of polymorphisms of CD36 and OBPIIa and genetic ability to taste 6-n-propylthiouracil.

Melania Melis,Massimiliano Arca,Roberto Crnjar,Iole Tomassini Barbarossa,Mariano Mastinu

doi:10.1371/journal.pone.0194953

Abstract

Oral sensitivity to fats varies in individuals influencing nutritional status and health. Variations in oleic acid perception are associated with CD36 and odorant binding protein (OBPIIa) polymorphisms, and 6-n-propylthiouracil (PROP) sensitivity, which is mediated by TAS2R38 receptor. L-Arginine (L-Arg) supplementation was shown to modify the perception of the five taste qualities. Here we analyzed the effect of three concentrations (5, 10, 15 mmol/L) of L-Arg on oral perception of oleic acid in forty-six subjects classified for PROP taster status and genotyped for TAS2R38, CD36 and OBPIIa polymorphisms. L-Arg supplementation was effective in increasing the perceived intensity of oleic acid in most subjects. The lowest concentration was the most effective, especially in PROP non-tasters or medium tasters, and in subjects with at least an allele A in CD36 and OBPIIa loci. Density Functional Theory (DFT) calculations were exploited to characterize the chemical interaction between L-Arg and oleic acid, showing that a stable 1:1 oleate·ArgH+ adduct can be formed, stabilized by a pair of hydrogen bonds. Results indicate that L-Arg, acting as a ‘carrier’ of fatty acids in saliva, can selectively modify taste response, and suggest that it may to be used in personalized dietetic strategies to optimize eating behaviors and health.

Highlights

Dietary fatty acids play an important role in the regulation of energy and lipid metabolism, and many are their effects on health and illness outcomes of individuals [1]
Quantum-mechanical (QM) calculations at the Density Functional Theory (DFT) level [78] allowed us to optimize the geometry of oleic acid, the oleate anion, L-Arg, and the protonated form of L-Arg (L-ArgH+)
An Natural Bond Orbital level (NBO) analysis was carried out to verify the effect of the solvent variation on the strength of the formed hydrogen bonds, showing that, as expected, the two H-bonds are energetically equivalent (< 5%) and derive from the charge-transfer (CT) interaction of the lone pairs of electrons (LP) on the negatively-charged carboxylate oxygen atoms to the antibonding NBOs localized on the N–H bonds

Summary

Introduction

Dietary fatty acids play an important role in the regulation of energy and lipid metabolism, and many are their effects on health and illness outcomes of individuals [1]. The ability to discriminate dietary fatty acids, selectively and quantitatively, may have crucial implications for nutritional status and human health. Oral sensitivity to dietary fatty acid greatly varies among individuals [2,3,4]. Understanding the range of fatty acid oral sensitivity and how it is influenced by genetic and environmental factors may lead to significant insights on the role of taste in fat-rich food intake regulation and metabolism.

Methods

Results

Discussion

Conclusion