Differences in antioxidant potential of chalcones in human serum: In vitro study

Isolation and biological activity of natural chalcones based on antibacterial mechanism classification

Bacterial infection, which is still one of the leading causes of death in humans, poses an enormous threat to the worldwide public health system. Antibiotics are the primary medications used to treat bacterial diseases. Currently, the discovery of antibiotics has reached an impasse, and due to the abuse of antibiotics resulting in bacterial antibiotic resistance, researchers have a critical desire to develop new antibacterial agents in order to combat the deteriorating antibacterial situation. Natural chalcones, the flavonoids consisting of two phenolic rings and a three-carbon α, β-unsaturated carbonyl system, possess a variety of biological and pharmacological properties, including anti-cancer, anti-inflammatory, antibacterial, and so on. Due to their potent antibacterial properties, natural chalcones possess the potential to become a new treatment for infectious diseases that circumvents existing antibiotic resistance. Currently, the majority of research on natural chalcones focuses on their synthesis, biological and pharmacological activities, etc. A few studies have been conducted on their antibacterial activity and mechanism. Therefore, this review focuses on the antibacterial activity and mechanisms of seventeen natural chalcones. Firstly, seventeen natural chalcones have been classified based on differences in antibacterial mechanisms. Secondly, a summary of the isolation and biological activity of seventeen natural chalcones was provided, with a focus on their antibacterial activity. Thirdly, the antibacterial mechanisms of natural chalcones were summarized, including those that act on bacterial cell membranes, biological macromolecules, biofilms, and quorum sensing systems. This review aims to lay the groundwork for the discovery of novel antibacterial agents based on chalcones.

Different Strategies to Attenuate the Toxic Effects of Zinc Oxide Nanoparticles on Spermatogonia Cells

Zinc oxide nanoparticles (ZnO NPs) are one of the most used nanoparticles due to their unique physicochemical and biological properties. There is, however, a growing concern about their negative impact on male reproductive health. Therefore, in the present study, two different strategies were used to evaluate the recovery ability of spermatogonia cells from the first stage of spermatogenesis (GC-1 spg cell line) after being exposed to a cytotoxic concentration of ZnO NPs (20 µg/mL) for two different short time periods, 6 and 12 h. The first strategy was to let the GC-1 cells recover after ZnO NPs exposure in a ZnO NPs-free medium for 4 days. At this phase, cell viability assays were performed to evaluate whether this period was long enough to allow for cell recovery. Exposure to ZnO NPs for 6 h and 12 h induced a decrease in viability of 25% and 41%, respectively. However, the recovery period allowed for an increase in cell viability from 16% to 25% to values as high as 91% and 84%. These results strongly suggest that GC-1 cells recover, but not completely, given that the cell viability does not reach 100%. Additionally, the impact of a synthetic chalcone (E)-3-(2,6-dichlorophenyl)-1-(2-hydroxyphenyl)prop-2-en-1-one (1) to counteract the reproductive toxicity of ZnO NPs was investigated. Different concentrations of chalcone 1 (0-12.5 µM) were used before and during exposure of GC-1 cells to ZnO NPs to mitigate the damage induced by NPs. The protective ability of this compound was evaluated through viability assays, levels of DNA damage, and cytoskeleton dynamics (evaluating the acetylated α-tubulin and β-actin protein levels). The results indicated that the tested concentrations of chalcone 1 can attenuate the genotoxicity induced by ZnO NPs for shorter exposure periods (6 h). Chalcone 1 supplementation also increased cell viability and stabilized the microtubules. However, the antioxidant potential of this compound remains to be elucidated. In conclusion, this work addressed the main cytotoxic effects of ZnO NPs on a spermatogonia cell line and analyzed two different strategies to mitigate this damage, which represent a significant contribution to the field of male fertility.

The green chemistry of chalcones: Valuable sources of privileged core structures for drug discovery

The sustainable use of resources is essential in all production areas, including pharmaceuticals. However, the aspect of sustainability needs to be taken into consideration not only in the production phase, but during the whole medicinal chemistry drug discovery trajectory. The continuous progress in the fields of green chemistry and the use of artificial intelligence are contributing to the speed and effectiveness of a more sustainable drug discovery pipeline. In this light, here we review the most recent sustainable and green synthetic approaches used for the preparation and derivatization of chalcones, an important class of privileged structures and building blocks used for the preparation of new biologically active compounds with a broad spectrum of potential therapeutic applications. The literature here reported has been retrieved from the SciFinder database using the term “chalcone” as a keyword and filtering the results applying the concept: “green chemistry”, and from the Reaxys database using the keywords “chalcone” and “green”. For both databases the time-frame was 2017–2022. References were manually selected based on relevance.

Fast Inverted Photoprotective o/w Emulsions Loaded With Dihydroquercetin and β-Carotene: An Innovative Approach to In Vitro Assessment of Antioxidant Activity in a Bioenvironment

Fast inverted, oil-in-water (o/w) emulsions, also known as SWitch-Oil-Phase (SWOP) emulsions, express the performances of both o/w and water-in-oil (w/o) emulsions during application to the skin, favoring their use as cosmetic carriers in sunscreen products. The objective of this study was to investigate the antioxidant potential (by 2 different methods) and the ultraviolet (UV) absorption ability of SWOP emulsion (S) with incorporated plant-based antioxidants dihydroquercetin (DHQ) and β-carotene (βC), using quercetin (Q) in a reference emulsion, in addition to the evaluation of their physicochemical properties and stability. A new biochemical extracellular model for in vitro assessment of antioxidative properties for the SWOP emulsions (S, SQ, SDHQ, and SDHQβC) was developed and compared with the results of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay. The analyses were performed at 20 °C and 37 °C, and oxidative stress parameters were monitored and statistically analyzed. The sun protection factor (SPF) of the samples was determined in vitro. Q and DHQ incorporated into the SWOP emulsion exhibited a strong DPPH radical scavenging ability. Neither incorporated nor pure βC showed DPPH radical scavenging ability at the tested concentrations. Contrary to that, in the bioenvironment conditions, SDHQβC showed minor antioxidative effects increase and also a significant decrease in exogenous pro-oxidative effects, caused by pro-oxidant, when compared to SDHQ. The obtained SPFs of SDHQβC, SDHQ, and SQ were 5.19, 4.65, and 3.35, respectively. The physicochemical stability of the emulsions was satisfactory during 1 month storage. The presented results demonstrated that the SWOP emulsion is a suitable carrier for antioxidants with a photoprotective ability. The novel biochemical approach could be used in addition to DPPH assay with several advantages, relevant for the testing of antioxidant activity of potential active ingredients in cosmetic products.

Chalcones reverse the anxiety and convulsive behavior of adult zebrafish

In the treatment of anxiety and seizures, drugs of the benzodiazepine (BZD) class are used, which act on the Central Nervous System (CNS) through the neurotransmitter gamma-aminobutyric acid (GABA). Flavonoids modulate GABAA receptors. The aim of this study was to evaluate the anxiolytic and anticonvulsant effects of synthetic chalcones and their mechanisms of action via the GABAergic system, using adult zebrafish (ZFa). The animals were treated with chalcones (4.0 or 20 or 40 mg/kg; 20 µL; i.p) and submitted to the open field and 96 h toxicity test. Chalcones that cause locomotor alteration were evaluated in the light and dark anxiolytic test. The same doses of chalcones were evaluated in the anticonvulsant test. The lowest effective dose was chosen to assess the possible involvement in the GABAA receptor by blocking the flumazenil (fmz) antagonist. No chalcone was toxic and altered ZFa's locomotion. All chalcones had anxiolytic and anticonvulsant effects, mainly chalcones 1, where all doses showed effects in both tests. These effects were blocked by Fmz (antagonist GABAA), where it shows evidence of the performance of these activities of the GABA system. Therefore, this study demonstrated in relation to structure-activity, that the position of the substituents is important in the intensity of activities and that the absence of toxicity and the action of these compounds in the CNS, shows the pharmacological potential of these molecules, and, therefore, the insights are designed for the development of new drugs.