Search

Quercetin is one of the most promising natural polyphenolic radioprotective compounds. This property is based on its radical-scavenging activity and high antioxidant capacity, in the manifestation of which the products of oxidative degradation of quercetin play a significant role. The formation of specific metabolites during the oxidation of quercetin can determine not only its radioprotective properties, but also toxic manifestations. The purpose of this article is to summarize previously obtained data regarding the reaction pathways of oxidative transformation of quercetin. Materials and methods. We used publicly available scientific publications dedicated to the study of quercetin transformation processes. The method of analysis is descriptive. The discussion of the results. A review of scientific works dedicated to oxygen oxidation, radical-initiated oxidation, electrochemical and enzymatic oxidation is presented, possible transformation products of quercetin and the mechanisms of their formation are given. The most characteristic oxidation pathways of quercetin are determined by the chemical structure of the rings, which exhibit specific reactivity. The influence of the solvent composition on the oxidation products during the autoxidation of quercetin was revealed, while the radical and electrochemical models of oxidation differ in the presence of polymer adducts. Once in a living organism, quercetin can bind free radicals, thereby preventing the harmful effects of radiation, that is, it has the properties of a radioprotector. Conclusions. Quercetin can be considered as a potential radioprotector due to its ability to bind free radicals formed in the biological fluids of living organisms exposed to radiation.

Indigenous people in Bangladesh's Chittagong hill regions use Curcuma longa and Zingiber officinale flowers in their traditional meals due to their vibrant color, exquisite flavor, and fragrant perfume. The induction time of soybean oil enriched with the ethanolic extract of the flower of Curcuma longa (CFE), Zingiber officinale (ZFE), and butylated hydroxytoluene (BHT) was compared to determine the effect on oxidation stability. The study also measured bioactive polyphenolic components, total flavonoid (TFC), total tannin (TTC), total phenolic (TPC), total antioxidant activity (TAA), and IC50 values of ZFE and CFE. The induction time was shorter for both 5 % of CFE (6.97 h) and ZFE (6.85 h) than 0.02 % BHT (7.18 h) but longer than 0.01 % BHT (6.49 h). TPC in CFE (37.57 mg GAE/g) was higher than in ZFE (26.14 mg GAE/g). TAA and IC50 values were not significantly different. TFC in ZFE (28.8 mg QE/g) was higher than in CFE (27.63 mg QE/g). The major polyphenols of CFE and ZFE were trans-cinnamic acid (12,209 and 678 μg/g); catechin hydrate (1758 and 1821 μg/g); p-coumaric acid (1186 and 126 μg/g); and quercetin (1309 and 1773 μg/g), respectively. This study demonstrated that antioxidants in flower extract improve fat and oil oxidation stability.

Wound healing is an intricate process of tissue repair or remodeling that occurs in response to injury. Plants and plant-derived bioactive constituents are well explored in the treatment of various types of wounds. Curcumin is a natural polyphenolic substance that has been used since ancient times in Ayurveda for its healing properties, as it reduces inflammation and acts on several healing stages. Several research studies for curcumin delivery at the wound site reported the effectiveness of curcumin in eradicating reactive oxygen species and its ability to enhance the deposition of collagen, granulation tissue formation, and finally, expedite wound contraction. Curcumin has been widely investigated for its wound healing potential but its lower solubility and rapid metabolism, in addition to its shorter plasma half-life, have limited its applications in wound healing. As nanotechnology has proven to be an effective technique to accelerate wound healing by stimulating appropriate mobility through various healing phases, curcumin-loaded nanocarriers are used for targeted delivery at the wound sites. This review highlights the potential of curcumin and its nanoformulations, such as liposomes, nanoparticles, and nano-emulsions, etc. in wound healing. This paper emphasizes the numerous biomedical applications of curcumin which collectively prepare a base for its antibiofilm and wound-healing action. [ABSTRACT FROM AUTHOR]

The complexity of natural products always leads to the co-elution of interfering compounds with bioactive compounds, which then has a detrimental effect on structural elucidation. Here, a new method, based on selective solid phase extraction combined with 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) spiking and high performance liquid chromatography–diode array detector–quadrupole time-of-flight tandem mass spectrometry (HPLC–DAD–QTOF-MS/MS), is described for sensitive screening, selective extraction and identification of polyphenolic antioxidants in Polygonatum odoratum . First, 25 polyphenolic antioxidants ( 1 – 25 ) were screened by DPPH spiking with HPLC. Second, polydopamine coated Fe 3 O 4 microspheres (Fe 3 O 4 @PDA) were prepared to selectively extract target antioxidants with extraction efficiency from 55% to 100% when the amount of Fe 3 O 4 @PDA, extraction time, desorption solvent and time were 10 mg, 20 min, acetonitrile, and 5 min. Third, 25 antioxidants (10 cinnamides and 15 homoisoflavanones) were identified by HPLC–DAD–QTOF-MS/MS. Furthermore, the DPPH scavenging activities of purified compounds (IC 50 , 1.6–32.8 μg/mL) validated the method. Among the identified antioxidants, four of them ( 12 , 13 , 18 and 19 ) were new compounds, four of them ( 2 , 4 , 8 and 14 ) were first obtained from family Liliaceae, five of them ( 1 , 3 , 5 , 7 and 9 ) were first reported in genus Polygonatum , while one compound ( 24 ) was first identified in this species. The results indicated that the proposed method was an efficient and sensitive approach to explore polyphenolic antioxidants from complex natural products. [ABSTRACT FROM AUTHOR]

Retinal tissue is exposed to oxidative stress caused by visible light. Light-damaged rat used in age-related macular degeneration (AMD) studies clarified that antioxidants decrease retinal light damage. Albino rats were exposed to 5000 Lux light for 12 h with oral administration of the polyphenolic compounds fraction (PF) from the seed shells of Japanese horse chestnut (30 mg/kg, 100 mg/kg, and 300 mg/kg body weight: BW). To evaluate the protective effects against light damage, electroretinograms (ERGs), the outer nuclear layer (ONL) thickness, the antioxidant activity of plasma, oxidized retinal lipids, and the detection of apoptosis were examined. To reveal their active compounds, PF were separated into an A-type proanthocyanidin (PAF) and a flavonol O-glycosides fraction. The protective effects of these fractions against light damage were compared by measuring the thickness of the ERGs and ONL. Compared with the negative control, the PF group (100 mg/kg and 300 mg/kg BW) significantly suppressed the decrease of the ERG amplitudes and ONL thickness. PF (300 mg/kg BW) induced the elevation of in vivo antioxidant activity, and the suppression of retinal lipid oxidation. PF administration also suppressed apoptotic cell death. The protective effects against light damage were attributable to the antioxidant activity of PAF. The light-induced damage of retinas was protected by oral administration of PF and PAF. Taken together, these compounds are potentially useful for the prevention of the disease caused by light exposure. Highlights: The protective effects of retinal damage by light exposure were evaluated using polyphenolic compounds from the seed shells of Japanese horse chestnut (Aesculus turbinata BLUME) as an antioxidant. Decreases in the electroretinographic amplitude and outer nuclear layer thickness were suppressed by the polyphenolic compounds of the seed shells. Polyphenolic compounds from the seed shells of Japanese horse chestnut inhibited the oxidation of retinal lipids. Highly polymeric A-type proanthocyanidin from the seed shells protected the rat retina from light exposure damage by inhibiting oxidative stress and apoptotic mechanisms. [ABSTRACT FROM AUTHOR]