Obtaining hesperetin 7-O-glucosyl 6′′-O-laurate, a high lipophilic flavonoid ester, from Citrus waste

Gustavo Céliz,Mirta Daz,Ramón Díaz

doi:10.1016/j.bcab.2017.10.015

Gustavo Céliz, Mirta Daz + Show 1 more

Open Access

https://doi.org/10.1016/j.bcab.2017.10.015

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Abstract

Abstract A biotechnological process that combines the treatment of Citrus processing waste to extract a high-valuable biomolecule, neohesperidin (NEO), and its further modification by biocatalysis to enhance the lipophilicity of its flavonoic moiety is presented. NEO was extracted from immature fruits of Citrus aurantium and hydrolyzed by a commercial alpha-rhamnosidase to obtain hesperetin 7-glucoside (HG). NEO and HG were mono-acylated with vinyl laurate by using Novozym 435 in their primary OH-groups, but the esterification reaction was substantially faster for HG than NEO. Furthermore, the activation energy of the reaction lowers as solvents’ log-P decreases linearly. Under best conditions, HGL was obtained at gram scale with a simple downstream process. The solubility in n-octanol increased with each biocatalytic step (NEO

Highlights

Neohesperidin (NEO) is a flavonoid unique to Citrus which is found in significant concentrations in some orange varieties from where it can be obtained (Macoritto et al, 2004)
NEO can be enzymatically hydrolyzed with α-rhamnosidases to generate rhamnose, a valuable sugar used as a precursor to diverse organic compounds (Ribeiro, 2011) and as an anti-aging agent in cosmetic products (Asselineau et al, 2011), and hesperetin 7-Oglucoside (HG)
HG can be obtained starting from hesperidin (HES) too, but the partial de-glycosylation is conducted with rhamnosidases in water at mild conditions (50-60 oC), were NEO is 9 times more soluble than HES at 25 °C and this ratio rose up to 32 at 50 °C

Summary

Introduction

Neohesperidin (NEO) is a flavonoid unique to Citrus which is found in significant concentrations in some orange varieties from where it can be obtained (Macoritto et al, 2004). Citrus flavonoids have proven to be quite valuable due to their antioxidant, antiallergy, vasotonic, anti-inflammatory properties ( enavente-Garc a astillo, 2 ) and antimicrobial activity (Tripoli et al, 2007) They are substances Generally Recognized as Safe (GRAS) by the FDA. In the last few years, new characteristics have been determined about NEO It prevents aflatoxin contamination from Aspergillus flavus (Salas et al, 2016), it has antiosteoclastic effects in vitro and in vivo, and it possesses therapeutic potential as a natural anti-catabolic treatment in osteoporosis (Tan et al, 2017). Given these characteristics, this molecule has potential use per se. It is interesting to synthesize a hydrophobic HG ester since lipophilicity, cell membrane penetration, antimicrobial activity and other biological properties could be enhanced, expanding the applications of this molecule in the food, therapeutic and cosmetic industries

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