Target-guided isolation of polar antioxidants fromAbelmoschus esculentus(L). Moench by high-speed counter-current chromatography method coupled with wavelength switching and extrusion elution mode

Abstract

An off-line two-dimensional high-speed counter-current chromatography strategy combined with the wavelength switching technique and extrusion elution mode was successfully developed and applied to the isolation of polar antioxidants from Abelmoschus esculentus (L).Moench. Target-guided by the result of 2,2-diphenyl-1-picrylhydrazyl screening assay, four antioxidants were obtained with purities over 90% through orthogonal high-speed counter-current chromatography separation. UV spectroscopy, mass spectrometry and H NMR spectroscopy were employed to identify their structures, which were assigned as l-tryptophan, quercetin-3-O-sophoroside, 5,7,3',4'-tetrahydroxyflavonol-3-O-[β-d-rhamnopyranosil-(1→2)]-β-d-glucopyranoside, and quercetin-3-O-glucoside. Each monomer exhibited significant antioxidant activity. The results demonstrated that proposed method could be an effective approach to isolate bioactive compounds from complex natural products.

The anti‐hyperuricemic effect of flavonoid extract of saffron by‐product and its pharmacokinetics in rats after oral administration

“…Most compounds tested in the plasma have been reported to exert anti-inflammatory (for KSG and KS), antioxidant (for QS and KS), and hepatoprotective effects (for KG). KF displays several pharmacological properties, such as antimicrobial, anti-inflammatory, antioxidant, antitumor, cardioprotective, neuroprotective, and antidiabetic activities [58][59][60][61][62][63]. Some biological activities of the compound may also be attributed to the antihyperuricemic activity of the SFB flavonoid extract.…”

Preparative isolation and purification of 12 main antioxidants from the roots of Polygonum multiflorum Thunb. using high‐speed countercurrent chromatography and preparative HPLC guided by 1,1′‐diphenyl‐2‐picrylhydrazyl‐HPLC

“…It is a novel technology which is based on multistage extraction system [12,13]. No irreversible adsorption, high recovery, and a large loading make HSCCC widely applicable to the isolation of compounds from natural products [14–17]. However, sometimes it is challenging to find a perfect solvent system to perform in high purity in a one‐step separation by HSCCC.…”

Preparative isolation of flavonoid glycosides from Sphaerophysa salsula using hydrophilic interaction solid‐phase extraction coupled with two‐dimensional preparative liquid chromatography

“…Above all, the purities of the final products are poor. In recent years, many modern separation techniques have been employed in the isolation of flavonoid glycosides from TCMs, such as high‐speed counter‐current chromatography . Although this approach affords high‐separation efficiency, separations take hours.…”

“…Modern studies have demonstrated that the major bioactive components of S. salsula are flavonoid glycosides [1,2]. Flavonoid glycosides have many biological functions, including anti-hepatitis [3], [9][10][11]. Although this approach affords high-separation efficiency, separations take hours.…”