Synthesis and antioxidant properties of diphenylmethane derivative bromophenols including a natural product

Abstract

Bromination of bis(3,4-dimethoxyphenyl)methanone (5) gave four products (6-9) with mono, di, tri, and tetra Br under different conditions. Reduction and demethylation reactions of product 9 with tetra Br were performed, consecutively and a natural product, 5,5'-methylene bis(3,4-dibrombenzene-1,2-diol) (1), was obtained with a 53% yield. Five derivatives, (13-17) (bromophenols), of 1 were also synthesised. The antioxidant and radical scavenging activities of bromophenols 1 and 13-17 were determined by employing various in vitro assays such as 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH(*)), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid (ABTS(*+)), N,N-dimethyl-p-phenylenediamine dihydrochloride radical cation (DMPD(*+)), and superoxide anion radical (O(2)(*-)) scavenging, reducing ability determination by the Fe(3+)-Fe(2+) and Cu(2+)-Cu(+) cupric reducing antioxidant capacity (CUPRAC) transformation methods, hydrogen peroxide scavenging, and ferrous ion (Fe(2+)) chelating activities. Moreover, these activities were compared to those of synthetic standard antioxidant compounds such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), alpha-tocopherol, and trolox. The results showed that the synthesised bromophenols had effective antioxidant power.

A comparative study on the antioxidant effects of hesperidin and ellagic acid against skeletal muscle ischemia/reperfusion injury

“…Also, EA and HES have antioxidative effects that attenuated the muscle damage reducing lipid peroxidation levels. Normally, living organisms are protected from the dangerous effects of O 2 À by SOD, which converts O 2 À into H 2 O 2 [68][69][70] . Whereas, during reperfusion of ischemic tissues, these natural defences may not be overcome and H 2 O 2 is converted into OH , this transformation has the capacity to damage a wide range of biomolecules species containing amino acids, membrane proteins and nucleic acids [71][72][73] .…”

Quercetin protects rat skeletal muscle from ischemia reperfusion injury

“…They are naturally present in almost all plant materials, including food products of plant origin. Phenolics are thought to be an integral part of both human and animal diets [35][36][37][38] . The majority of natural antioxidant compounds are phenolics, and the most important groups of natural antioxidants are flavonoids, which include flavanones, flavanols and flavanonols [39][40][41][42][43] .…”

The effects of some bromophenols on human carbonic anhydrase isoenzymes

“…They were frequently isolated from red algae of the family Rhodomelaceae and had some important biological activities [53][54][55] . It was reported that the bromophenol derivatives coordinate to the active site Zn 2+ and to block the reaction catalysis.…”