Enhancing the Membranolytic Activity of Chenopodium quinoa Saponins by Fast Microwave Hydrolysis

Abstract

Saponins are plant secondary metabolites. There are associated with defensive roles due to their cytotoxicity and are active against microorganisms. Saponins are frequently targeted to develop efficient drugs. Plant biomass containing saponins deserves sustained interest to develop high-added value applications. A key issue when considering the use of saponins for human healthcare is their toxicity that must be modulated before envisaging any biomedical application. This can only go through understanding the saponin-membrane interactions. Quinoa is abundantly consumed worldwide, but the quinoa husk is discarded due to its astringent taste associated with its saponin content. Here, we focus on the saponins of the quinoa husk extract (QE). We qualitatively and quantitively characterized the QE saponins using mass spectrometry. They are bidesmosidic molecules, with two oligosaccharidic chains appended on the aglycone with two different linkages; a glycosidic bond and an ester function. The latter can be hydrolyzed to prepare monodesmosidic molecules. The microwave-assisted hydrolysis reaction was optimized to produce monodesmosidic saponins. The membranolytic activity of the saponins was assayed based on their hemolytic activity that was shown to be drastically increased upon hydrolysis. In silico investigations confirmed that the monodesmosidic saponins interact preferentially with a model phospholipid bilayer, explaining the measured increased hemolytic activity.

Microwave-Assisted Desulfation of the Hemolytic Saponins Extracted from Holothuria scabra Viscera

“…An elegant strategy to address such a puzzling task is to specifically modify targeted chemical functions and to evaluate the influence of the performed modifications using a standard biological system, such as red blood cells to evaluate hemolytic activities [22]. As for an example, we recently modulated the membranolytic activity of Chenopodium quinoa saponins by fast microwave hydrolysis, transforming the native bidesmosidic saponins into their monodesmosidic analogues [30]. The induced structural modification drastically increases the saponin Hemolytic Activity (HA), which not only makes it possible to obtain saponins of modulated activity, but also to build the SAR of this important family of molecules [30].…”

“…As for an example, we recently modulated the membranolytic activity of Chenopodium quinoa saponins by fast microwave hydrolysis, transforming the native bidesmosidic saponins into their monodesmosidic analogues [30]. The induced structural modification drastically increases the saponin Hemolytic Activity (HA), which not only makes it possible to obtain saponins of modulated activity, but also to build the SAR of this important family of molecules [30]. Other studies have been conducted to better understand the SAR of saponins, including the esterification of tea saponins [31], the action of various enzymes on Centella asiatica saponins [32], or the derivatization of hederagenin [33].…”

Lipid Flip-Flop-Inducing Antimicrobial Phytochemicals from Gymnema sylvestre are Bacterial Membrane Permeability Enhancers

“… 16 Monodesmosidic saponins exhibit enhanced membranolytic potential compared to di- and tri-desmosidic due to their stronger membrane association. 26 …”

Microwave technology: a novel approach to the transformation of natural metabolites

“…Membranolytic activity in saponins is related to the interaction between saponins and cell membranes, and the toxic effect of saponins on cell membranes contributes its antibacterial properties. Some studies have shown that the membranolytic activity in saponins increases sharply after hydrolysis [ 129 ]. Microwave radiation also has a selective heating effect on ester bonds.…”