Magnetic Ligand Fishing as a Targeting Tool for HPLC-HRMS-SPE-NMR: α-Glucosidase Inhibitory Ligands and Alkylresorcinol Glycosides from Eugenia catharinae

Abstract

A bioanalytical platform combining magnetic ligand fishing for α-glucosidase inhibition profiling and HPLC-HRMS-SPE-NMR for structural identification of α-glucosidase inhibitory ligands, both directly from crude plant extracts, is presented. Magnetic beads with N-terminus-coupled α-glucosidase were synthesized and characterized for their inherent catalytic activity. Ligand fishing with the immobilized enzyme was optimized using an artificial test mixture consisting of caffeine, ferulic acid, and luteolin before proof-of-concept with the crude extract of Eugenia catharinae. The combination of ligand fishing and HPLC-HRMS-SPE-NMR identified myricetin 3-O-α-l-rhamnopyranoside, myricetin, quercetin, and kaempferol as α-glucosidase inhibitory ligands in E. catharinae. Furthermore, HPLC-HRMS-SPE-NMR analysis led to identification of six new alkylresorcinol glycosides, i.e., 5-(2-oxopentyl)resorcinol 4-O-β-d-glucopyranoside, 5-propylresorcinol 4-O-β-d-glucopyranoside, 5-pentylresorcinol 4-O-[α-d-apiofuranosyl-(1→6)]-β-d-glucopyranoside, 5-pentylresorcinol 4-O-β-d-glucopyranoside, 4-hydroxy-3-O-methyl-5-pentylresorcinol 1-O-β-d-glucopyranoside, and 3-O-methyl-5-pentylresorcinol 1-O-[β-d-glucopyranosyl-(1→6)]-β-d-glucopyranoside.

Screening of lipase inhibitors from Scutellaria baicalensis extract using lipase immobilized on magnetic nanoparticles and study on the inhibitory mechanism

“…Magnetic nanoparticles (MNPs) are ideal solid supports for the target proteins immobilization due to their high specific surface areas and excellent convenience for magnetic separation, which have been widely used in biological and medical applications [19][20][21]. Cyclooxygenase-2, α-glucosidase, and lipase-functionalized MNPs for identification of bioactive compounds from plant extracts have been investigated as reported previously [22][23][24].…”

Magnetic beads-based neuraminidase enzyme microreactor as a drug discovery tool for screening inhibitors from compound libraries and fishing ligands from natural products

“…According to the bioaffinity chromatography theory, the protein-functionalized magnetic beads are immersed directly into the extract and any compounds with an affinity for the immobilized protein are retained while non-binders remain in the supernatant [13,19–22]. The combination of this technique with chromatographic and MS/MS techniques allows for the detection and identification of new potential lead compounds is known as ligand fishing.…”

“…In a pioneering work, human serum albumin immobilized magnetic beads were employed for isolating active compounds from a mixture of binders and non-binders [19]. It was quickly expanded to the screening of plant extracts, such as AChE inhibitors isolated from meldoinus fusiformis [20]; a number of novel SIRT6 inhibitors isolated from fenugreek seed extract [21]; α-Glucosidase inhibitors discovered from Eugenia catharinae [22] and three ligands isolated from oolong tea for pancreatic lipase [23]. These examples illustrate the potential application of magnetic beads-based NA-inhibitory assays for identifying novel NAIs from plant extracts.…”

Ligand fishing using new chitosan based functionalized Androgen Receptor magnetic particles

“…A novel technique that has been successfully used for the identification of active components from a complex mixture is ligand fishing [13–15]. In these studies, the targeted protein is immobilized onto magnetic particles surface and the resulting stationary phase is used to “fish” out potential active compounds from different mixtures [11,13,16–18].…”

“…In these studies, the targeted protein is immobilized onto magnetic particles surface and the resulting stationary phase is used to “fish” out potential active compounds from different mixtures [11,13,16–18]. This has been previously demonstrated with its application for the isolation of active compounds from natural products from different matrixes including plant and cell extracts [12,15,19–21]. …”