Anti-Hypochlorite, Antioxidant, and Catalytic Activity of Three Polyphenol-Rich Super-Foods Investigated with the Use of Coumarin-Based Sensors

Abstract

The anti-hypochlorite activity of açaí (Euterpe oleracea Mart.), goji (Lycium barbarum L.) and schisandra (Schisandra chinensis) fruit extracts were assessed by determining the reactive chlorine species (RCS)-scavenging ability of these three “super-food” berries. In addition, the aqueous extracts obtained were employed as both the media and the catalyst in a green chemistry approach to the synthesis of a coumarin-based fluorescence turn-off sensor, which was then used for anti-hypochlorite activity testing. The aqueous extracts were also assessed for total phenolic content (TPC), using the Folin–Ciocalteu method, and the antioxidant activity using the ABTS+• assay. Moreover, the main water-soluble polyphenolic constituents of the extracts were identified by the HPLC-PDA-ESI-MS technique. Among the extracts tested, açaí demonstrated the highest anti-hypochlorite and antioxidant activities, while the highest TPC value was found for the goji extract. All extracts demonstrated modest catalytic activity as Knoevenagel condensation catalysts.

Structural Features of 1,3,4-Thiadiazole-Derived Ligands and Their Zn(II) and Cu(II) Complexes Which Demonstrate Synergistic Antibacterial Effects with Kanamycin

“…The fully acetylated compound 3 showed the highest IC 50 and compared to 1 and 2 was considered inactive. These findings are consistent with our previous studies [34,35] and with numerous other reports evidencing the polyphenolic moieties as mandatory for high antioxidant potency [36][37][38].…”

Novel Coumarin-Thiadiazole Hybrids and Their Cu(II) and Zn(II) Complexes as Potential Antimicrobial Agents and Acetylcholinesterase Inhibitors

“…Our previous works evidenced a wide variety of coumarin-derived ligands and their transition metal complexes as potential antimicrobial and antitumor agents [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. Moreover, we established a fluorescence quenching-based mechanism of interaction between a number of fluorescent coumarins and the hypochlorite ion [ 24 ], which was then successfully applied for the determination of anti-hypochlorite activity in a number of plant extracts [ 25 , 26 ]. More recently, a series of 1,3,4-thiadiazole derivatives acting as effective ligands in the synthesis of transition metal complexes with biologically important Cu(II) and Zn(II) ions was reported by our group [ 27 , 28 ].…”

A Simple ICT-Based Fluorescent Probe for HOCl and Bioimaging Applications

“…The solvent was removed under reduced pressure, and the crude product was further purified by chromatography on silica gel using petroleum ether/ethyl acetate, v/v = 2:1, as an eluent to obtain a white solid product (yield, 74%). 1 H NMR (600 MHz, DMSO) δ 7.92 (dd, J = 19.0, 8.4 Hz, 4H), 7.79 (d, J = 8.5 Hz, 2H), 7.21 (d, J = 8.5 Hz, 2H), 3.38 (s, 3H), 3.34 (s, 3H). 13…”

“…Hypochloric acid (HClO) is known as an extremely important reactive oxygen species (ROS) and endogenous messenger in various physiological processes [1][2][3]. Cellular HClO is mainly generated by the biological oxidation reaction of hydrogen peroxide (H 2 O 2 ) and chloride ions (Cl − ) induced by reduced nicotinamide adenine dinucleotide phosphate (NADPH) on the mitochondrial membrane of neutrophils, which is catalyzed by myeloperoxidase (MPO) [4].…”