Multiple free radical scavenging reactions of aurones

Naringenin, a Functional Food Component, Improves Motor and Non-Motor Symptoms in Animal Model of Parkinsonism Induced by Rotenone

Parkinson's disease (PD) and other age-related neurodegenerative ailments have a strong link to oxidative stress. Bioflavonoid naringenin has antioxidant properties. The effects of pre- and post-naringenin supplementation on a rotenone-induced PD model were examined in this work. Naringenin (50 mg/kg, p.o.) was administered to rats for two weeks before the administration of rotenone in the pre-treatment phase. In contrast, rotenone (1.5 mg/kg, s.c.) was administered for eight days before naringenin (50 mg/kg, p.o.) was supplemented for two weeks in the post-treatment phase. During behavioral investigation, the motor and non-motor signs of PD were observed. Additionally, estimation of neurochemical and biochemical parameters was also carried out. Compared to controls, rotenone treatment substantially increased oxidative stress, altered neurotransmitters, and caused motor and non-motor impairments. Rotenone-induced motor and non-motor impairments were considerably reduced by naringenin supplementation. The supplementation also increased antioxidant enzyme activities and restored the changes in neurotransmitter levels. The findings of this work strongly imply that daily consumption of flavonoids such as naringenin may have a therapeutic potential to combat PD.

Recent Trends in the Antidiabetic Prominence of Natural and Synthetic Analogues of Aurones

Natural products are a boundless source for the development of pharmaceutical agents against a wide range of human diseases. Accordingly, naturally occurring aurones possess various biological benefits, such as anticancer, antioxidant, antimicrobial, antidiabetic, anti-inflammatory, antiviral and neuroprotective effects. In addition, various studies have revealed that aurones are potential templates for the regulation of diabetes mellitus and its associated complications. Likewise, certain aurones and their analogues have been found to be remarkable kinase inhibitors of DARK2, PPAR-γ, PTPM1, AGE, α-amylase and α-glucosidase, which represents a promising approach for the treatment of chronic metabolic disorders such as diabetes. Therefore, in our present study, we provide a detailed account of the advances in aurones as antidiabetic agents over the past decade.

An update of aurones: food resource, health benefit, biosynthesis and application

Aurones are a subclass of active flavonoids characterized with a scaffold of 2-benzylidene-3(2H)-benzofuranone. This type of chemicals are widely distributed in fruit, vegetable and flower, and contribute to human health. In this review, we summarize the natural aurones isolated from dietary plants. Their positive effects on immunomodulation, antioxidation, cancer prevention as well as maintaining the health status of cardiovascular, nervous system and liver organs are highlighted. The biosynthesis strategies of plant-derived aurones are elaborated to provide solutions for their limited natural abundance. The potential application of natural aurones in food coloration are also discussed. This paper combines the up-to-date information and gives a full image of dietary aurones.

Mechanisms of polyphenols on quality control of aquatic products in storage: A review

Aquatic products are easily spoiled during storage due to oxidation, endogenous enzymes, and bacteria. At the same time, compared with synthetic antioxidants, based on the antibacterial and antioxidant mechanism of biological agents, the development of natural, nontoxic, low-temperature, better-effect green biological preservatives is more acceptable to consumers. The type and molecular structure of polyphenols affect their antioxidant and antibacterial effectiveness. This review will describe how they achieve their antioxidant and antibacterial effects. And the recent literature on the mechanism and application of polyphenols in the preservation of aquatic products was updated and summarized. The conclusion is that in aquatic products, polyphenols alleviate lipid oxidation, protein degradation and inhibit the growth and reproduction of microorganisms, so as to achieve the effect of storage quality control. And put forward suggestions on the application of the research results in aquatic products. We hope to provide theoretical support for better exploration of the application of polyphenols and aquatic product storage.

Polymeric Forms of Plant Flavonoids Obtained by Enzymatic Reactions

Naringenin is one of the flavonoids originating from citrus fruit. This polyphenol is mainly found in grapefruit, orange and lemon. The antioxidant and antimicrobial properties of flavonoids depend on their structure, including the polymeric form. The aim of this research was to achieve enzymatic polymerization of naringenin and to study the properties of poly(naringenin). The polymerization was performed by methods using two different enzymes, i.e., laccase and horseradish peroxidase (HRP). According to the literature data, naringenin had not been polymerized previously using the enzymatic polymerization method. Therefore, obtaining polymeric naringenin by reaction with enzymes is a scientific novelty. The research methodology included analysis of the structure of poly(naringenin) by NMR, GPC, FTIR and UV-Vis and its morphology by SEM, as well as analysis of its properties, i.e., thermal stability (DSC and TGA), antioxidant activity (ABTS, DPPH, FRAP and CUPRAC) and antimicrobial properties. Naringenin oligomers were obtained as a result of polymerization with two types of enzymes. The polymeric forms of naringenin were more resistant to thermo-oxidation; the final oxidation temperature T_o of naringenin catalyzed by laccase (poly(naringenin)-laccase) was 28.2 °C higher, and poly(naringenin)-HRP 23.6 °C higher than that of the basic flavonoid. Additionally, due to the higher molar mass and associated increase in OH groups in the structure, naringenin catalyzed by laccase (poly(naringenin)-laccase) showed better activity for scavenging ABTS^+• radicals than naringenin catalyzed by HRP (poly(naringenin)-HRP) and naringenin. In addition, poly(naringenin)-laccase at a concentration of 5 mg/mL exhibited better microbial activity against E. coli than monomeric naringenin.

Thermochemistry of antioxidant action of isoflavones and their deprotonated forms in aqueous solution: hydrogen or electron transfer?

Isoflavones possessing several weak acidic hydroxyl groups can undergo successive deprotonations in aqueous solutions. Therefore, their antioxidant properties cannot be ascribed only to the neutral forms but also to corresponding phenoxide anions. It was already confirmed that isoflavones prefer the formation of dianions in aqueous solution. For eight isoflavones and their preferred (poly)deprotonated forms, thermochemistry of hydrogen atom transfer and electron abstraction was studied in terms of corresponding reaction enthalpies, i.e., O—H bond dissociation enthalpies and ionization potentials. Our results clearly indicate that the increase in negative charge causes significant drop in ionization potential and bond dissociation enthalpy. On the other hand, proton affinities show the opposite trend. Thus, it is unfeasible to find a generally valid trend for dianions — corresponding reaction enthalpies strongly depend on the structure of isoflavone, especially on the number/positions of OH groups.