The Accumulated Effect of the Number of Ethylene Oxide Units and/or Carbon Chain Length in Surfactants Structure on the Nano-Micellar Extraction of Flavonoids.

Karolina Śliwa,Paweł Śliwa

doi:10.3390/jfb11030057

Abstract

Classical extraction methods used for isolation of active substances from plant material are expensive, complicated and often environmentally unfriendly. The ultrasonic assistance micelle-mediated extraction method (UAMME), based on green chemistry principles, seems to be an interesting alternative. This work aimed to find a connection between the chemical structure of non-ionic surfactants and the efficiency of the extraction process. The effect of hydrophobic chain length and number of ethoxy groups on the quality of Bidens tripartite extracts was investigated. Several ethoxylated fatty alcohols were used: Ceteareth-20, Steareth-20, Oleth-20, Oleth-10, Oleth-5, C12-C13 Pareth-12, C12-C15 Pareth-12 and Ceteareth-12. The bioflavonoid compositions with the HPLC method was determined. The hydrophilic lipophilic balance (HLB) of studied surfactants, as well as the surface tension of surfactant solutions, were compared, to determine the explanation for the obtained differences in bioflavonoids concentration. The structural changes influenced by polyphenol extraction were monitored using Dynamic Light Scattering (DLS) measurements. In this work, probably for the first time, the connection between the chemical structure of non-ionic surfactants and the efficiency of the extraction process was found. The experimental and theoretical approach rationalized the choice of an appropriate eluent. We propose some structurally dependent factors, whose optimal value gave a high efficiency to the UAMME.

Highlights

Solubilization is the spontaneous formation of a stable, isotropic solution of an insoluble or slightly water-soluble substance in an aqueous micellar solution
The solubility of the active substance is low when the surfactant concentration is below its critical micellar concentration (CMC)
The results revealed that the dicaffeoylquinic acid, the most hydrophobic compound, was easiest solubilized into the surfactant pseudo-phase, compared to other polyphenols

Summary

Introduction

Solubilization is the spontaneous formation of a stable, isotropic solution of an insoluble or slightly water-soluble substance in an aqueous micellar solution. The micellar solubilization is very useful, for example, in pharmacy, because many active substances do not dissolve or dissolve very poorly in water. This method protects active substances against degradation, increases their bioavailability and minimizes their side effects. The solubility of the active substance is low when the surfactant concentration is below its critical micellar concentration (CMC). The solubilization process, often called micellar-mediated extraction (MME), occurs mainly through hydrophobic interactions between the extracted substance and surfactant molecules. Electrostatic interactions, especially the formation of hydrogen bonds are important [4,5,6]

Objectives

Methods

Results