Screening and isolation of natural antioxidants from Ziziphora clinopodioides Lam. with high performance liquid chromatography coupled to a post-column Ce(iv) reduction capacity assay

Abstract

A novel on-line screening method for natural antioxidants was developed with a post-column cerium(IV) reduction reaction after high performance liquid chromatography (HPLC) separation. Under acidic conditions, Ce(IV) sulphate exhibits strong absorption at 320 nm and is reduced to Ce(III) by antioxidants in a post-column reaction coil (no absorbance at this wavelength). The reduction of absorbance at 320 nm affords a negative peak that corresponds to the retention time of an active constituent in the HPLC chromatogram. The proposed method demonstrated different selectivity versus a conventional HPLC-2,2-diphenyl-1-picrylhydrazyl (DPPH) method. This was used to detect the antioxidant constituents from the extract of Ziziphora clinopodioides Lam., which is an indigenous edible plant from north Xinjiang, China. Nine compounds were isolated as major antioxidant compounds by this method. All the isolated compounds were identified by 1 H NMR and 13 C NMR; six of them were isolated from this plant for the first time.

Biological activity, and volatile and phenolic compounds from five Lamiaceae species

“…Similar to the present work, the quality of the different phenolics was determined according to the antioxidant potential 57 . Earlier research disclosed that the phenolic compounds of the ethanol extract of Z clinopodioides were protocatechuic acid, caffeic acid, rosmarinic acid, luteolin, pinocembrin 7‐ O ‐rutinoside, quercetin, apigenin, baicalein and kaempferide 58 . Prior to this study, there has not been any research in the literature taking the phenolic content of the methanol extracts of the five species of the Lamiaceae family as the subject.…”

Natural Flavonoid Derivatives Have Pan-Coronavirus Antiviral Activity

“…Compound 8 (Isosakuranetin or 5,7-dihydroxy-2-(4-methoxyphenyl)chroman-4-one) showed NMR spectra identical to those reported in the literature [ 45 ]. Compound 9 (Baicalein or 5,6,7-trihydroxy-2-phenyl-4 H -chromen-4-one) showed NMR spectra identical to those reported in the literature [ 46 ]. Compound 10 (Hispidulin or 5,7-dihydroxy-2-(4-hydroxyphenyl)-6-methoxy-4 H -chromen-4-one) showed NMR spectra identical to those reported in the literature [ 47 ].…”

Development of an Innovative Pressurized Liquid Extraction Procedure by Response Surface Methodology to Recover Bioactive Compounds from Carao Tree Seeds

“…With regard to flavanones, Peaks 18 and 20 were characterized as pinocembrin-7-neohesperidoside and pinocembrin-7-rutinoside, respectively [ 22 , 23 , 24 , 25 ]. Their chemical structure was a flavanone (pinocembrin) linked to two different disaccharides (neohesperidoside and rutinoside).…”

“…Peaks 36 and 38, both with m/z 431 and the same molecular formula C21H20O10, were proposed as kaempferol-rhamnoside or isomer [20]. Peaks 9,11,16,22,25,40,41,44, 45 and 47 were characterized as flavanols. Peak 9, which was recovered under all extraction conditions, was proposed as theaflavin [19].…”