Quercitrin protects against ultraviolet B-induced cell death in vitro and in an in vivo zebrafish model

BAK and ARG Have Moisturizing, Anti-Inflammatory, Antioxidant, and Antioxidant Bioactivities, in the Zebrafish Model

BACKGROUND

Bakuchiol (BAK) and acetyl hexapeptide-8 have favorable biological activities and have promising applications in the cosmetic industry. However, the evaluation of the biological activity of both alone or in combination has not been reported.

AIMS

The biological activity of both alone or in combination was evaluated based on the zebrafish model.

METHODS

Zebrafish embryos were induced to form models using different methods. Add BAK and Argireline YOUth peptide oil solution MB (ARG, containing 0.125% acetyl hexapeptide-8) to treat zebrafish embryos, and they were evaluated for their restorative effects on preexisting damage in zebrafish embryos.

RESULTS

BAK and ARG were able to reduce water loss from the caudal fin of zebrafish induced by 0.9% NaCl solution. They were able to alleviate the UVB-induced decrease in the expression level of the skin tightness-related gene (ELN/COL1a1b) in zebrafish embryos, and BAK or ARG effectively reversed the increase in β-galactosidase activity induced by exposure to H2O2 solution and restored telomerase activity in zebrafish embryos. In addition, both were able to counteract oxidative stress and mitochondrial damage in zebrafish embryos as a result of LPS treatment. Finally, BAK and ARG were also effective in suppressing the increase in neutrophil counts and inflammatory cytokine levels in zebrafish embryos due to LPS exposure. Notably, BAK and ARG were more effective when used in combination.

CONCLUSIONS

Acetyl hexapeptide-8 promotes the bioactivity of BAK in zebrafish embryos (Danio rerio). BAK and ARG have moisturizing, anti-inflammatory, antioxidant, and antioxidant bioactivities in the zebrafish model.

Novel peptide inhibitor of matrix Metalloproteinases-1 from pufferfish skin collagen hydrolysates and its potential Photoprotective activity via the MAPK/AP-1 signaling pathway

Takifugu bimaculatus, a pufferfish species farmed in Fujian Province, is known for its non-toxic flesh and collagen-rich skin. We identified a novel collagen-derived matrix metalloproteinase 1 (MMP-1) inhibitory peptide, from T. bimaculatus skin with potent anti-photoaging properties. Using multistage membrane and gel filtration chromatography, we purified low-molecular-weight collagen peptides from T. bimaculatus skin (TBSCH-L). Nano-HPLC-MS/MS and virtual molecular docking screening were employed to identify peptides targeting MMP-1. Four anti-photoaging peptide sequences, GDRGFPGE, GPAGPRGA, FPGGPGAK, and RGFPGGDGAA, were identified by assessing the viability of UVB-induced L929 cells. GPAGPRGA (GP8) exhibited the highest MMP-1 inhibitory activity and cellular photoprotection. Surface plasmon resonance confirmed high-affinity binding between MMP-1 and GP8. GP8 significantly reduced intracellular reactive oxygen species (ROS) levels and enhanced superoxide dismutase activity at concentrations of 100-200 μM in UVB-exposed L929 cells. At 200 μM, GP8 significantly decreased malondialdehyde content. GP8 also accelerated migration of L929 cells, demonstrating its wound-healing potential, markedly reduced intracellular β-galactosidase levels, and downregulated phosphorylation levels of extracellular signal-regulated kinases, c-Jun N-terminal kinases, p38 proteins, and c-Jun protein expression within the MAPK/AP-1 signaling pathway, thereby lowering MMP expression in L929 cells. Exposure of zebrafish to 25-100 μM GP8 effectively mitigated UVB-induced damage, restoring up to 31.2 % of caudal fin integrity, while significantly reducing ROS levels, lipid peroxidation, and cellular apoptosis. GP8, a novel marine-derived anti-photoaging peptide, holds promise for applications in cosmetic and functional food sectors.

Protective role of 2-aminothiazole derivative against ethanol-induced teratogenic effects in-vivo zebrafish

Teratology investigates the origins of congenital disabilities, often linked to environmental factors such as ethanol (EtOH) exposure. Ethanol at 150 μM has been associated with teratogenic effects, oxidative stress, immunological responses, and endocrine disruptions. Fetal alcohol spectrum disorder (FASD) arises from maternal alcohol consumption during pregnancy, leading to developmental delays and cognitive impairment. Due to their diverse therapeutic applications, amino thiazole derivatives are crucial in drug development. This study aimed to determine whether the 2-amino thiazole derivative, notably the 1-(4-chlorophenyl)-N-(6-nitrobenzo[d]thiazol-2-yl)ethan-1-imine (N4) compound, reduces teratogenic effects induced by embryonic EtOH exposure in a zebrafish model. Teratogenic effects, mortality, locomotion behaviour, oxidative stress, gene expression, and tissue damage were evaluated in larvae over a 7-day experimental period using three treatment concentrations (50, 100, and 150 μM). Results showed that EtOH induced morphological defects in the head, eyes, and body length of exposed larvae, along with behavioural abnormalities and oxidative damage. N4 effectively mitigated these toxic effects in a concentration-dependent manner, reducing oxidative damage, preventing teratogenic effects, and averting tissue damage induced by EtOH exposure. This study highlights the potential of N4 to enhance antioxidant and anti-inflammatory effects against ethanol-induced oxidative stress, offering promising therapeutic strategies for FASD treatment.

Potential therapeutic agents of Bombyx mori silk cocoon extracts from agricultural product for inhibition of skin pathogenic bacteria and free radicals

Background

Pathogenic bacteria are the cause of most skin diseases, but issues such as resistance and environmental degradation drive the need to research alternative treatments. It is reported that silk cocoon extract possesses antioxidant properties. During silk processing, the degumming of silk cocoons creates a byproduct that contains natural active substances. These substances were found to have inhibitory effects on bacterial growth, DNA synthesis, the pathogenesis of hemolysis, and biofilm formation. Thus, silk cocoon extracts can be used in therapeutic applications for the prevention and treatment of skin pathogenic bacterial infections.

Methods

The extract of silk cocoons with pupae (SCP) and silk cocoons without pupae (SCWP) were obtained by boiling with distilled water for 9 h and 12 h, and were compared to silkworm pupae (SP) extract that was boiled for 1 h. The active compounds in the extracts, including gallic acid and quercetin, were determined using high-performance liquid chromatography (HPLC). Furthermore, the total phenolic and flavonoid content in the extracts were investigated using the Folin-Ciocalteu method and the aluminum chloride colorimetric method, respectively. To assess antioxidant activity, the extracts were evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Additionally, the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of silk extracts and phytochemical compounds were determined against skin pathogenic bacteria. This study assessed the effects of the extracts and phytochemical compounds on growth inhibition, biofilm formation, hemolysis protection, and DNA synthesis of bacteria.

Results

The HPLC characterization of the silk extracts showed gallic acid levels to be the highest, especially in SCP (8.638-31.605 mg/g extract) and SP (64.530 mg/g extract); whereas quercetin compound was only detected in SCWP (0.021-0.031 mg/g extract). The total phenolics and flavonoids in silk extracts exhibited antioxidant and antimicrobial activity. Additionally, SCP at 9 h and 12 h revealed the highest anti-bacterial activity, with the lowest MIC and MBC of 50-100 mg/mL against skin pathogenic bacteria including Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Cutibacterium acnes and Pseudomonas aeruginosa. Hence, SCP extract and non-sericin compounds containing gallic acid and quercetin exhibited the strongest inhibition of both growth and DNA synthesis on skin pathogenic bacteria. The suppression of bacterial pathogenesis, including preformed and matured biofilms, and hemolysis activity, were also revealed in SCP extract and non-sericin compounds. The results show that the byproduct of silk processing can serve as an alternative source of natural phenolic and flavonoid antioxidants that can be used in therapeutic applications for the prevention and treatment of pathogenic bacterial skin infections.

Effects of Fluorinated Functionalization of Linker on Quercetin Encapsulation, Release and Hela Cell Cytotoxicity of Cu-Based MOFs as Smart pH-Stimuli Nanocarriers

Controlled delivery of target molecules is required in many medical and chemical applications. For such purposes, metal-organic frameworks (MOFs), which possess desirable features such as high porosity, large surface area, and adjustable functionalities, hold great potential as drug carriers. Herein, Quercetin (QU), as an anticancer drug, was loaded on Cu2 (BDC)2 (DABCO) and Cu2 (F4 BDC)2 )DABCO) MOFs (BDC=1,4-benzenedicarboxylate and DABCO=1,4-diazabicyclo[2.2.2]octane). As these Cu-MOFs have a high surface area, an appropriate pore size, and biocompatible ingredients, they can be utilized to deliver QU. The loading efficiency of QU in these MOFs was 49.5 % and 41.3 %, respectively. The drug-loaded compounds displayed sustained drug release over 15 days, remarkably high drug loading capacities and pH-controlled release behavior. The prepared nanostructures were characterized by different characterization technics including FT-IR, PXRD, ZP, TEM, FE-SEM, UV-vis, and BET. In addition, MTT assays were carried out on the HEK-293 and HeLa cell lines to investigate cytotoxicity. Cellular apoptosis analysis was performed to investigate the cell death mechanisms. Grand Canonical Monte Carlo simulations were conducted to analyze the interactions between MOFs and QU. Moreover, the stability of MOFs was also investigated during and after the drug release process. Ultimately, kinetic models of drug release were evaluated.

A reduction in temperature induces bioactive red pigment production in a psychrotolerant Penicillium sp. GEU_37 isolated from Himalayan soil

Filamentous fungi are being globally explored for the production of industrially important bioactive compounds including pigments. In the present study, a cold and pH tolerant fungus strain Penicillium sp (GEU_37), isolated from the soil of Indian Himalaya, is characterized for the production of natural pigments as influenced by varying temperature conditions. The fungal strain produces a higher sporulation, exudation, and red diffusible pigment in Potato Dextrose (PD) at 15 °C as compared to 25 °C. In PD broth, a yellow pigment was observed at 25 °C. While measuring the effect of temperature and pH on red pigment production by GEU_37, 15 °C and pH 5, respectively, were observed to be the optimum conditions. Similarly, the effect of exogenous carbon and nitrogen sources and mineral salts on pigment production by GEU_37 was assessed in PD broth. However, no significant enhancement in pigmentation was observed. Chloroform extracted pigment was separated using thin layer chromatography (TLC) and column chromatography. The two separated fractions i.e., fractions I and II with Rf values 0.82 and 0.73, exhibited maximum light absorption, λ_max, at 360 nm and 510 nm, respectively. Characterization of pigments using GC-MS showed the presence of the compounds such as phenol, 2,4-bis (1,1-dimethylethyl) and eicosene from fraction I and derivatives of coumarine, friedooleanan, and stigmasterole in fraction II. However, LC-MS analysis detected the presence of derivatives of compound carotenoids from fraction II as well as derivative of chromenone and hydroxyquinoline as major compounds from both the fractions along with other numerous important bioactive compounds. The production of such bioactive pigments under low temperature conditions suggest their strategic role in ecological resilience by the fungal strain and may have biotechnological applications.

Toward Depth-Resolved Analysis of Plant Metabolites by Nanospray Desorption Electrospray Ionization Mass Spectrometry

Nanospray desorption electrospray ionization (nano-DESI) is one of the ambient desorption ionization methods for mass spectrometry (MS), and it utilizes a steady-state liquid junction formed between two microcapillaries to directly extract analytes from sample surfaces with minimal sample damage. In this study, we employed nano-DESI MS to perform a metabolite fingerprinting analysis directly from a Hypericum leaf surface. Moreover, we investigated whether changes in metabolite fingerprints with time can be related to metabolite distribution according to depth. From a raw Hypericum leaf, the mass spectral fingerprints of key metabolites, including flavonoids and prenylated phloroglucinols, were successfully obtained using ethanol as a nano-DESI solvent, and the changes in their intensities were observed with time via full mass scan experiments. In addition, the differential extraction patterns of the obtained mass spectral fingerprints were clearly visualized over time through selected ion monitoring and pseudo-selected reaction monitoring experiments. To examine the correlation between the time-dependent changes in the metabolite fingerprints and depth-wise metabolite distribution, we performed a nano-DESI MS analysis against leaves whose surface layers were removed multiple times by forming polymeric gum Arabic films on their surfaces, followed by detaching. The preliminary results showed that the changes in the metabolite fingerprints according to the number of peelings showed a similar pattern with those obtained from the raw leaves over time.

Chemistry, pharmacokinetics, pharmacological activities, and toxicity of Quercitrin

Quercitrin is a naturally available type of flavonoid that commonly functions as the dietary ingredient and supplement. So far, a wide spectrum of bioactivities of quercitrin have been revealed, including antioxidative stress, antiinflammation, anti-microorganisms, immunomodulation, analgesia, wound healing, and vasodilation. Based on these various pharmacological activities, increasing studies have focused on the potency of quercitrin in diverse diseases in recent years, such as bone metabolic diseases, gastrointestinal diseases, cardiovascular and cerebrovascular diseases, and others. In this paper, by collecting and summarizing publications from the recent years, the natural sources, pharmacological activities and roles in various diseases, pharmacokinetics, structure-activity relationship, as well as the toxicity of quercitrin were systematically reviewed. In addition, the underlying molecular mechanisms of quercitrin in treating related diseases, the dose-effect relationships, and the novel preparations were discussed on the purpose of broadening the application prospect of quercitrin as functional food and providing reference for its clinical application. Notably, clinical studies of quercitrin are insufficient at present, further high-quality studies are needed to firmly establish the clinical efficacy of quercitrin.

In Vitro Photoprotective, Anti-Inflammatory, Moisturizing, and Antimelanogenic Effects of a Methanolic Extract of Chrysophyllum lucentifolium Cronquist

UVB exposure causes DNA mutation and ROS generation, which lead to skin photoaging, skin wrinkling, skin sagging, and uneven skin pigmentation. ROS activate the NF-κB and MAPK signaling pathways leading to production of inflammatory molecules such as COX-2, collagen-degrading proteins such as matrix metalloproteinases (MMPs), and moisture-deficiency-related proteins such as hyaluronidases (HYALs). UVB exposure also induces irregular skin pigmentation though melanin overproduction, related to CREB transcription factor activity and transcription of melanogenesis genes. Here, we demonstrate that Chrysophyllum lucentifolium methanol extract (Cl-ME) has antioxidant activity; it dose-dependently decreased the expression of COX-2, MMP-1, MMP-9, HYAL-1, and HYAL-4 by downregulating the NF-κB (IKKα/β, IκBα) and MAPK (ERK, JNK, and p38) pathways and increased the expression of Col1a1, which encodes a protein important for maintaining skin elasticity. Cl-ME also showed promising antimelanogenic activity by decreasing the expression of CREB, a transcription factor, which in turn inhibited the expression of genes encoding tyrosinase, MITF, TYRP1, and TYRP2. In summary, a methanol extract of C. lucentifolium exhibited antiphotoaging and antimelanogenic activity and could be useful in the cosmeceutical industry.

The Involvement of the Oxidative Stress Status in Cancer Pathology: A Double View on the Role of the Antioxidants

Oxygen-free radicals, reactive oxygen species (ROS) or reactive nitrogen species (RNS), are known by their "double-sided" nature in biological systems. The beneficial effects of ROS involve physiological roles as weapons in the arsenal of the immune system (destroying bacteria within phagocytic cells) and role in programmed cell death (apoptosis). On the other hand, the redox imbalance in favor of the prooxidants results in an overproduction of the ROS/RNS leading to oxidative stress. This imbalance can, therefore, be related to oncogenic stimulation. High levels of ROS disrupt cellular processes by nonspecifically attacking proteins, lipids, and DNA. It appears that DNA damage is the key player in cancer initiation and the formation of 8-OH-G, a potential biomarker for carcinogenesis. The harmful effect of ROS is neutralized by an antioxidant protection treatment as they convert ROS into less reactive species. However, contradictory epidemiological results show that supplementation above physiological doses recommended for antioxidants and taken over a long period can lead to harmful effects and even increase the risk of cancer. Thus, we are describing here some of the latest updates on the involvement of oxidative stress in cancer pathology and a double view on the role of the antioxidants in this context and how this could be relevant in the management and pathology of cancer.

Antioxidant and Anticholinesterase Activities of Extracts and Phytochemicals of Syzygium antisepticum Leaves

Bioassay-guided separation of young leaves extracts of Syzygium antisepticum (Blume) Merr. & L.M. Perry led to the isolation of four triterpenoids (betulinic acid, ursolic acid, jacoumaric acid, corosolic acid) and one sterol glucoside (daucosterol) from the ethyl acetate extract, and three polyphenols (gallic acid, myricitrin, and quercitrin) from the methanol (MeOH) extract. The MeOH extract of S. antisepticum and some isolated compounds, ursolic acid and gallic acid potentially exhibited acetylcholinesterase activity evaluated by Ellman’s method. The MeOH extract and its isolated compounds, gallic acid, myricitrin, and quercitrin, also strongly elicited DPPH radical scavenging activity. In HEK-293 cells, the MeOH extract possessed cellular antioxidant effects by attenuating hydrogen peroxide (H₂O₂)-induced ROS production and increasing catalase, glutathione peroxidase-1 (GPx-1), and glutathione reductase (GRe). Furthermore, myricitrin and quercitrin also suppressed ROS production induced by H₂O₂ and induced GPx-1 and catalase production in HEK-293 cells. These results indicated that the young leaves of S. antisepticum are the potential sources of antioxidant and anticholinesterase agents. Consequently, S. antisepticum leaves are one of indigenous vegetables which advantage to promote the health and prevent diseases related to oxidative stress.

Zebrafish as a Useful Model to Study Oxidative Stress-Linked Disorders: Focus on Flavonoids

The zebrafish is considered one of the most versatile experimental animal models. The transparency of the embryos, the small size, the rapid development and the homology with higher vertebrates have made the zebrafish a valuable model also for drug screening. Its use is closely related for the determination of bioactivity, toxicity and off-target side effects of novel drug candidates, which also allows a thorough evaluation of new targets; thus, it may represent a suitable model for drug screening and the optimization of novel candidates. Flavonoids are polyphenolic compounds widely present in fruits, vegetables and cereals. Polyphenols are important for both plants and humans, considering their involvement in defense mechanisms, particularly against oxidative stress. They protect plants from biotic and abiotic stressors and prevent or treat oxidative-based human diseases. For these reasons, polyphenols are used as nutraceuticals, functional foods and supplements by the pharmaceutical industry. Therefore, the most relevant findings on zebrafish as a useful experimental model to study oxidative stress-linked disorders, focusing on the biological activities of flavonoids, are here summarized and reviewed.

Characterization of a liposomal copper(II)-quercetin formulation suitable for parenteral use

Quercetin (3,3',4',5,7-pentahydroxyflavone) is a naturally derived flavonoid that is commonly found in fruits and vegetables. There is mounting evidence to suggest that quercetin has potential anticancer effects and appears to interact synergistically when used in combination with approved chemotherapeutic agents such as irinotecan and cisplatin. Unfortunately, quercetin has shown limited clinical utility, partly due to low bioavailability related to its poor aqueous solutions (< 10 μg/mL). In this study, liposomal formulations of quercetin were developed by exploiting quercetin's ability to bind copper. Quercetin powder was added directly to pre-formed copper-containing liposomes (2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and cholesterol (CHOL) (55:45 M ratio)). As a function of time and temperature, the formation of copper-quercetin was measured. Using this methodology, a final quercetin-to-lipid (mol:mol) ratio of 0.2 was achievable and solutions containing quercetin at concentrations of > 5 mg/mL were attained, representing at least a > 100-fold increase in apparent solubility. The resulting formulation was suitable for intravenous dosing with no overt toxicities when administered at doses of 50 mg/kg in mice. Pharmacokinetic studies demonstrated that the copper-quercetin formulations had an AUC_0-24H of 8382.1 μg h/mL when administered to mice at 50 mg/kg. These studies suggested that quercetin (not copper-quercetin) dissociates from the liposomes after administration. The resulting formulation is suitable for further development and also serves as a proof-of-concept for formulating other flavonoids and flavonoid-like compounds. Given that quercetin exhibits an IC₅₀ of >10 μM when tested against cancer cell lines, we believe that the utility of this novel quercetin formulation for cancer indications will ultimately be as a component of a combination product.

Anti-Photoaging and Anti-Melanogenesis Effects of Fucoidan Isolated from Hizikia fusiforme and Its Underlying Mechanisms

Previous studies suggested that fucoidan with a molecular weight of 102.67 kDa, isolated from Hizikia fusiforme, possesses strong antioxidant activity. To explore the cosmeceutical potential of fucoidan, its anti-photoaging and anti-melanogenesis effects were evaluated in the present study. The anti-photoaging effect was investigated in ultraviolet (UV) B-irradiated human keratinocytes (HaCaT cells), where fucoidan effectively reduced the intracellular reactive oxygen species level and improved the viability of the UVB-irradiated cells without any cytotoxic effects. Moreover, fucoidan significantly decreased UVB-induced apoptosis in HaCaT cells by regulating the protein expression of Bax, Bcl-xL, PARP, and Caspase-3 in HaCaT cells in a concentration-dependent manner. The anti-melanogenesis effect of fucoidan was evaluated in B16F10 melanoma cells that had been stimulated with alpha-melanocyte-stimulating hormone (α-MSH), and fucoidan treatment remarkably inhibited melanin synthesis in α-MSH-stimulated B16F10 cells. Further studies indicated that fucoidan significantly suppressed the expression of tyrosinase and tyrosinase-related protein-1 and -2 (TRP-1 and-2) in B16F10 cells by down-regulating microphthalmia-associated transcription factor (MITF) through regulation of the ERK–MAPK (extracellular signal regulated kinase-mitogen activated protein kinase) pathway. Taken together, these results suggest that fucoidan isolated from H. fusiforme possesses strong anti-photoaging and anti-melanogenesis activities and can be used as an ingredient in the pharmaceutical and cosmeceutical industries.

UVB Irradiation Induced Cell Damage and Early Onset of Junbb Expression in Zebrafish

Ultraviolet B (UVB) radiation has drawn more attention over these past few decades since it causes severe DNA damage and induces inflammatory response. Serial gene profiling and high throughput data in UVB-associated phenomenon in human cultured cells or full rack of human skin have been investigated. However, results using different tissue models lead to ambiguity in UVB-induced pathways. In order to systematically understand the UVB-associated reactions, the zebrafish model was used, and whole organism gene profiling was performed to identify a novel biomarker which can be used to generate a new mechanistic approach for further screening on a UVB-related system biology. In this study, detailed morphological assays were performed to address biological response after receiving UVB irradiation at morphological, cellular, and molecular levels. Microarray screening and whole genome profiling revealed that there is an early onset expression of junbb in zebrafish embryos after UVB irradiation. Also, the identified novel biomarker junbb is more sensitive to UVB response than mmps which have been used in mouse models. Moreover, cellular and molecular response chronology after UVB irradiation in zebrafish provide a solid and fundamental mechanism for use in a UV radiation-associated study in the future.

Protective Effect of a Fucose-Rich Fucoidan Isolated from Saccharina japonica against Ultraviolet B-Induced Photodamage In Vitro in Human Keratinocytes and In Vivo in Zebrafish

A fucose-rich fucoidan was purified from brown seaweed Saccharina japonica, of which the UVB protective effect was investigated in vitro in keratinocytes of HaCaT cells and in vivo in zebrafish. The intracellular reactive oxygen species levels and the viability of UVB-irradiated HaCaT cells were determined. The results indicate that the purified fucoidan significantly reduced the intracellular reactive oxygen species levels and improved the viability of UVB-irradiated HaCaT cells. Furthermore, the purified fucoidan remarkably decreased the apoptosis by regulating the expressions of Bax/Bcl-xL and cleaved caspase-3 in UVB-irradiated HaCaT cells in a dose-dependent manner. In addition, the in vivo UV protective effect of the purified fucoidan was investigated using a zebrafish model. It significantly reduced the intracellular reactive oxygen species level, the cell death, the NO production, and the lipid peroxidation in UVB-irradiated zebrafish in a dose-dependent manner. These results suggest that purified fucoidan has a great potential to be developed as a natural anti-UVB agent applied in the cosmetic industry.

Argentine Patagonia barberry chemical composition and evaluation of its antioxidant capacity

An important portion of vitamins, minerals and polyphenols components in human diet are captured from fruit consumption. Argentinean Patagonia Berberis microphylla was characterized with the phenolic content, the proximate composition and the identification and quantification of anthocyanins, not-anthocyanins and proteins. The antioxidant capacity of berberis ethanolic extracts (EB) was determined by the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays. EB was used to reduce production of reactive substances species (ROS) in zebrafish. EB presented a total polyphenols content of 1,035.03 mg GAE/100 g fresh weight (FW). EB presented an ABTS value of 116.25 ± 17 μmol TE/g FW. EB presented a DPPH value of 137.80 ± 1.90 μmol TE/g FW. EB was able of reducing the ROS in zebrafish. Berberies Protein Isolate (BPI) presented proteins with bands from 15 to 62 kDa. BPI presented an ABTS value of 593.11 ± 8.60 μmol TE/g. The BPI duodenal digest presented a value of 641.07 ± 12.60 μmol TE/g digests. PRACTICAL APPLICATIONS: The practical applications of the present study are to increase scientific knowledge for consumers about the quality and benefits of the consumption of the native fruit (Berberis microphylla) from the Patagonia region of Argentine. This work describes the protein profile of berberies, their digestibility and their antioxidant activity. This study allows to better understand the phytonutrients that make up this fruit. Future studies may identify the peptides present in hydrolyzates. The bio-compounds of this fruit could be used as functional ingredients by the food industry for different purposes.

Protective effect of diphlorethohydroxycarmalol isolated from Ishige okamurae against UVB-induced damage in vitro in human dermal fibroblasts and in vivo in zebrafish

Excessive exposure to ultraviolet (UV) irradiation from the sun is the primary environmental factor that causes aging of the skin. Most skin diseases caused by UV are attributed to UVB (280-320 nm). The purpose of this study is to investigate the protective effect of diphlorethohydroxycarmalol (DPHC), isolated from the marine brown alga, Ishige okamurae, against UVB-induced photodamage using both in vitro and in vivo models. Results indicate that DPHC remarkably inhibited commercial collagenase and elastase activities. It also reduced intracellular levels of ROS, improved cell viability and collagen content in UVB-irradiated human dermal fibroblasts (HDF cells). In addition, DPHC significantly inhibited activities of intracellular collagenase and elastase and reduced the expression of matrix metalloproteinases (MMPs) and pro-inflammatory cytokines. These events occurred through regulation of nuclear factor kappa B (NF-κB), activator protein 1 (AP-1), and mitogen-activated protein kinases (MAPKs) signaling pathways in UVB-irradiated HDF cells. Furthermore, DPHC also protected against in vivo photodamage by decreasing cell death through reducing lipid peroxidation and inflammatory response via decreasing ROS levels in UVB-irradiated zebrafish. In conclusion, DPHC has strong in vitro and in vivo photoprotective effects and has the potential to be used as an ingredient in pharmaceutical and cosmeceutical industries.

Supplementation with 5-formyltetrahydrofolate alleviates ultraviolet B-inflicted oxidative damage in folate-deficient zebrafish

Ultraviolet (UV) is an omnipresent environmental carcinogen transmitted by sunlight. Excessive UV irradiation has been correlated to an increased risk of skin cancers. UVB, the most mutagenic component among the three UV constituents, causes damage mainly through inducing DNA damage and oxidative stress. Therefore, strategies or nutrients that strengthen an individual's resistance to UV-inflicted harmful effects shall be beneficial. Folate is a water-soluble B vitamin essential for nucleotides biosynthesis, and also a strong biological antioxidant, hence a micronutrient with potential of modulating individual's vulnerability to UV exposure. In this study, we investigated the impact of folate status on UV sensitivity and the protective activity of folate supplementation using a zebrafish model. Elevated reactive oxygen species (ROS) level and morphological injury were observed in the larvae exposed to UVB, which were readily rescued by supplementing with folic acid, 5-formyltetrahydrofolate (5-CHO-THF) and N-acetyl-L-cysteine (NAC). The UVB-inflicted abnormalities and mortality were worsened in Tg(hsp:EGFP-γGH) larvae displaying folate deficiency. Intriguingly, only supplementation with 5-CHO-THF, as opposed to folic acid, offered significant and consistent protection against UVB-inflicted oxidative damage in the folate-deficient larvae. We concluded that the intrinsic folate status correlates with the vulnerability to UVB-induced damage in zebrafish larvae. In addition, 5-CHO-THF surpassed both folic acid and NAC in preventing UVB-inflicted oxidative stress and injury in our current experimental zebrafish model.

Antioxidant and anti-inflammatory effects of an ethanol fraction from the Schisandra chinensis baillon hot water extract fermented using Lactobacilius paracasei subsp. tolerans

Waste management is a major part of the food industry. The present study was designed to utilize the discarded byproduct of Schisandra chinensis Baillon. The antioxidant and anti-inflammatory effects of a 30% ethanol fraction (RPG-OM-30E) from the fermented hot water extraction of the Schisandra chinensis Baillon byproduct were investigated using RAW 264.7 cells and zebrafish larvae. RPG-OM-30E reduced lipopolysaccharide (LPS)-induced nitric oxide production in the RAW 264.7 cells. Additionally, RPG-OM-30E inhibited mRNA expression and protein secretion of pro-inflammatory cytokines, such as interleukin-6 (Il-6) and interleukin-1β (Il-1β). The anti-inflammatory effects of RPG-OM-30E were tested in Tg(mpx::EGFP) ⁱ¹¹⁴ zebrafish larvae. Neutrophil migration to a wound site was decreased by RPG-OM-30E. Neutrophil aggregation was also inhibited by RPG-OM-30E after induction of an LPS-induced immune response in the yolk. Finally, the antioxidant and hepatoprotective effects of RPG-OM-30E were examined in vivo. Mice with induced oxidative damage recovered from the stress following RPG-OM-30E treatment.

Anti-inflammatory effect of a novel synthetic compound 1-((4-fluorophenyl)thio)isoquinoline in RAW264.7 macrophages and a zebrafish model

The compound, 1-((4-fluorophenyl)thio)isoquinoline (FPTQ), is a synthetic isoquinoline derivative. To test the anti-inflammatory effect of FPTQ, we used neutrophil-specific transgenic zebrafish Tg(mpx::EGFP)ⁱ¹¹⁴ line and lipopolysaccharide (LPS)-stimulated RAW264.7 cells. We also used two different methods, involving tail transection and LPS stimulation in the zebrafish model. Neutrophils translocation in the zebrafish tail-transected model was inhibited by FPTQ. Neutrophil aggregation was also inhibited by FPTQ in the LPS-stimulated zebrafish model. Decreased mRNA expression of the pro-inflammatory cytokine genes, interleukin-1β (il-1β) and interleukin-6 (il-6), was found in zebrafish larvae injected with FPTQ. Additionally, production of nitric oxide was inhibited by FPTQ in RAW264.7 macrophage cells treated with LPS. Moreover, the mRNA expression of Il-1β and Il-6 suppressed by FPTQ treatment in RAW264.7 macrophage cells, and an enzyme immunoassay showed that FPTQ suppressed the secretion of IL-1β and IL-6 in RAW264.7 cells. These results demonstrate that FPTQ reduced inflammatory responses and, therefore, suggest that it may be effective as an anti-inflammatory agent.

Defense potential of secondary metabolites in medicinal plants under UV-B stress

Ultraviolet-B (UV-B) radiation has, for many decades now, been widely studied with respect to its consequences on plant and animal health. Though according to NASA, the ozone hole is on its way to recovery, it will still be a considerable time before UV-B levels reach pre-industrial limits. Thus, for the present, excessive UV-B reaching the Earth is a cause for concern, and UV-B related human ailments are on the rise. Plants produce various secondary metabolites as one of the defense strategies under UV-B. They provide photoprotection via their UV-B screening effects and by quenching the reactive oxygen- and nitrogen species produced under UV-B influence. These properties of plant secondary metabolites (PSMs) are being increasingly recognized and made use of in sunscreens and cosmetics, and pharma- and nutraceuticals are gradually becoming a part of the regular diet. Secondary metabolites derived from medicinal plants (alkaloids, terpenoids, and phenolics) are a source of pharmaceuticals, nutraceuticals, as well as more rigorously tested and regulated drugs. These metabolites have been implicated in providing protection not only to plants under the influence of UV-B, but also to animals/animal cell lines, when the innate defenses in the latter are not adequate under UV-B-induced damage. The present review focuses on the defense potential of secondary metabolites derived from medicinal plants in both plants and animals. In plants, the concentrations of the alkaloids, terpenes/terpenoids, and phenolics have been discussed under UV-B irradiation as well as the fate of the genes and enzymes involved in their biosynthetic pathways. Their role in providing protection to animal models subjected to UV-B has been subsequently elucidated. Finally, we discuss the possible futuristic scenarios and implications for plant, animal, and human health pertaining to the defense potential of these secondary metabolites under UV-B radiation-mediated damages.

Structural characterization of Momordica charantia L. (Cucurbitaceae) oligopeptides and the detection of their capability in non-small cell lung cancer A549 cells: induction of apoptosis

Oligopeptides are rarely reported from Chinese herbal medicine because they are often present in very low concentrations in a complex matrix. Twenty-eight oligopeptides were recently identified by high-performance liquid chromatography and quadrupole-time-of-flight-mass spectrometry (HPLC-Q-TOF-MS) from Momordica charantia L. (Cucurbitaceae), and a septapeptide, FHGKGHE (Phe-His-Gly-Lys-Gly-His-Glu), named MCLO-12, showed the best anticancer activity against the non-small cell lung cancer A549 cell line in vitro, with an IC₅₀ value of 21.4 ± 2.21 mM. The anti-proliferative activity assay results showed that MCLO-12 induced apoptosis of A549 cells in a concentration-dependent manner. Treatment of the cells with MCLO-12 (10.7–42.8 mM mL⁻¹) caused strong intracellular reactive oxygen species (ROS) up-regulating activities and activated caspase expression. MCLO-12 also suppressed the Trx system and subsequently activated a number of Trx-dependent pathways, including the ASK1, MAPK-p38 and JNK pathways. Thus, our research provides a good reference point for anti-NSCLC research into oligopeptides.

MCLO-12 induced apoptosis by up-regulating the ROS, activating the caspases expressions, suppressing the Trx system and subsequently activating a number of Trx-dependent pathways.

Developmental toxicity of penconazole in Zebrfish (Danio rerio) embryos

Penconazole is a widely used fungicide that is toxic to a variety of organisms including fish. In the present study, we investigated the developmental toxicity of penconazole on zebrafish embryos by exposing to different concentrations of penconazole (0.8, 1.6 and 2.4 mg/L) from 4-h post-fertilization (hpf). Hatching, survival, and heart rates, body length, malformation and expression of several genes were detected. The results showed that penconazole exposure induced developmental toxicity, including delayed hatching, reduced survival, and heart rate. In addition to this, exposure to penconazole caused malformations, including pericardial edema, yolk sac edema, axial malformation, tail malformation and spinal curvature. Furthermore, RT-PCR results showed that mRNA levels of antioxidant genes were down-regulated after penconazole exposure. On the other hand, mRNA levels of interleukin 1 beta and interferon in embryos were up-regulated after exposure to penconazole. In summary, our data indicated that penconazole cause embryonic development toxicity on zebrafish embryos.

Topical or oral treatment of peach flower extract attenuates UV-induced epidermal thickening, matrix metalloproteinase-13 expression and pro-inflammatory cytokine production in hairless mice skin

BACKGROUND/OBJECTIVES

Ultraviolet radiation (UV) is a major cause of skin photoaging. Previous studies reported that ethanol extract (PET) of Prunus persica (L.) Batsch flowers (PPF, peach flowers) and its subfractions, particularly the ethylacetate (PEA) and n-butanol extracts (PBT), have potent antioxidant activity and attenuate the UV-induced matrix metalloproteinase (MMP) expression in human skin cells. In this study, we investigated the protective activity of PPF extract against UV-induced photoaging in a mouse model.

MATERIALS/METHODS

Hairless mice were treated with PET or a mixture of PEA and PBT either topically or orally along with UV irradiation. Histological changes and biochemical alterations of mouse skin were examined. Major phenolic compounds in PPF extract were analyzed using an ACQUITY UPLC system.

RESULTS

The overall effects of topical and oral treatments with PPF extract on the UV-induced skin responses exhibited similar patterns. In both experiments, the mixture of PEA and PBT significantly inhibited the UV-induced skin and epidermal thickening, while PET inhibited only the UV-induced epidermal thickening. Treatment of PET or the mixture of PEA and PBT significantly inhibited the UV-induced MMP-13 expression, but not typeⅠ collagen expression. Topical treatment of the mixture of PEA and PBT with UV irradiation significantly elevated catalase, superoxide dismutase (SOD) and glutathione-peroxidase (GPx) activities in the skin compared to those in the UV irradiated control group, while oral treatment of the mixture of PEA and PBT or PET elevated only catalase and SOD activities, but not GPx. Thirteen phytochemical compounds including 4-O-caffeoylquinic acid, cimicifugic acid E and B, quercetin-3-O-rhamnoside and kaempferol glycoside derivatives were identified in the PPF extract.

CONCLUSIONS

These results demonstrate that treatment with PET or the mixture of PEA and PBT, both topically or orally, attenuates UV-induced photoaging via the cooperative interactions of phenolic components having anti-oxidative and collagen-protective activities.

The impact of ultraviolet B (UV-B) radiation in combination with different temperatures in the early life stage of zebrafish (Danio rerio)

Ultraviolet B (UV-B) radiation is an environmental stressor with detrimental effects on many aquatic organisms including fish.

Extraction Optimization of Flavonoids from Hypericum formosanum and Matrix Metalloproteinase-1 Inhibitory Activity

Hypericum formosanum is a valuable herb in Taiwan. In this study, response surface methodology was employed to optimize the ultrasound-assisted extraction of flavonoids from Hypericum formosanum. A central composite design with three variables (ethanol concentration, extraction time, and extraction temperature) was applied. Experimental results were fitted to the second order polynomial model and one-way analysis of variance was used to determine the goodness of fit of the model and the optimal conditions for responses. The optimal conditions for the maximum extraction yield of total flavonoid content (101.1 mg/g) using ultrasound-assisted extraction were ethanol concentration, 73.5%; extraction time, 38.3 min; and extraction temperature, 62.5 °C. The predicted result was consistent with the experimental result obtained under optimal extraction conditions. Hyperoside, astilbin, quercitrin, and quercetin from Hypericum formosanum extract (HFE) were identified by Ultra performance liquid chromatography-diode array detector-mass (UPLC-DAD-MS). HFE significantly reduced matrix metalloproteinase-1 protein expression in human skin keratinocyte cells, induced by advanced glycation end products.

Comparison of the Antioxidant Effects of Quercitrin and Isoquercitrin: Understanding the Role of the 6″-OH Group

The role of the 6″-OH (ω-OH) group in the antioxidant activity of flavonoid glycosides has been largely overlooked. Herein, we selected quercitrin (quercetin-3-O-rhamnoside) and isoquercitrin (quercetin-3-O-glucoside) as model compounds to investigate the role of the 6″-OH group in several antioxidant pathways, including Fe²⁺-binding, hydrogen-donating (H-donating), and electron-transfer (ET). The results revealed that quercitrin and isoquercitrin both exhibited dose-dependent antioxidant activities. However, isoquercitrin showed higher levels of activity than quercitrin in the Fe²⁺-binding, ET-based ferric ion reducing antioxidant power, and multi-pathways-based superoxide anion-scavenging assays. In contrast, quercitrin exhibited greater activity than isoquercitrin in an H-donating-based 1,1-diphenyl-2-picrylhydrazyl radical-scavenging assay. Finally, in a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl assay based on an oxidatively damaged mesenchymal stem cell (MSC) model, isoquercitrin performed more effectively as a cytoprotector than quercitrin. Based on these results, we concluded that (1) quercitrin and isoquercitrin can both indirectly (i.e., Fe²⁺-chelating or Fe²⁺-binding) and directly participate in the scavenging of reactive oxygen species (ROS) to protect MSCs against ROS-induced oxidative damage; (2) the 6″-OH group in isoquercitrin enhanced its ET and Fe²⁺-chelating abilities and lowered its H-donating abilities via steric hindrance or H-bonding compared with quercitrin; and (3) isoquercitrin exhibited higher ROS scavenging activity than quercitrin, allowing it to improve protect MSCs against ROS-induced oxidative damage.

Quercitrin from Toona sinensis (Juss.) M.Roem. Attenuates Acetaminophen-Induced Acute Liver Toxicity in HepG2 Cells and Mice through Induction of Antioxidant Machinery and Inhibition of Inflammation

Quercitrin is found in many kinds of vegetables and fruits, and possesses various bioactive properties. The aim of the present study was to elucidate hepatoprotective mechanisms of quercitrin isolated from Toona sinensis (Juss.) M.Roem. (syn. Cedrela sinensis Juss.), using acetaminophen (APAP)-treated HepG2 cell and animal models. In an in vitro study, quercitrin suppressed the production of reactive oxygen species and enhanced expression of nuclear factor E2-related factor 2 (Nrf2), activity of antioxidant response element (ARE)-reporter gene, and protein levels of NADPH: quinone oxidoreductase 1 (NQO1), catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase 2 (SOD-2) in APAP-treated HepG2 cells. In an in vivo study, Balb/c mice were orally administered with 10 or 50 mg/kg of quercitrin for 7 days and followed by the injection with single dose of 300 mg/kg APAP. Quercitrin decreased APAP-caused elevation of alanine aminotransferase and aspartate aminotransferase levels, liver necrosis, the expression of pro-inflammatory factors including inducible nitric oxide synthase, cyclooxygenase 2 and inerleukin-1β, and phosphorylation of kinases including c-Jun N-terminal kinase and p38. Quercitrin restored protein levels of Nrf2, NQO1 and activities and expressions of CAT, GPx, SOD-2. The results suggested that quercitrin attenuates APAP-induced liver damage by the activation of defensive genes and the inhibition of pro-inflammatory genes via the suppressions of JNK and p38 signaling.

Zebrafish dives into food research: effectiveness assessment of bioactive compounds

Zebrafish ease of use and characteristics reveal it to be an interesting and underused model in food and nutrition research.

Quercetin induces endoplasmic reticulum stress to enhance cDDP cytotoxicity in ovarian cancer: involvement of STAT3 signaling

There is an urgent need to make cisplatin (cDDP) more effective and less toxic in the treatment of ovarian cancer for its systemic side effects and high resistance rate. In this study, we investigated the effect of quercetin (Qu) pretreatment on the potentiation of cDDP in ovarian cancer. We found that Qu pretreatment significantly enhanced cDDP cytotoxicity in an ovarian cancer cell line and primary cancer cells. In addition, we demonstrated that Qu elicited obvious endoplasmic reticulum stress (ERS) and activated all three branches of ERS in ovarian cancer. Specific inhibitors of each ERS pathway, as well as the general ERS stabilizer tauroursodeoxycholic acid, notably diminished such enhancing effects. Furthermore, Qu notably suppressed STAT3 phosphorylation, leading to downregulation of the BCL-2 gene downstream of STAT3. Moreover, blocking ERS restored the protein levels of phosphorylated STAT3 as well as BCL-2 expression, thus abolishing the chemosensitization potency of Qu; these results revealed that Qu affected the STAT3 pathway to enhance cDDP cytotoxicity, and this effect involved ERS signaling. In a xenograft mouse model of ovarian cancer, Qu enhanced the antitumor effect of cDDP. Tumors from mice treated with cDDP in combination with Qu pretreatment had repressed STAT3 phosphorylation, lower BCL-2 and higher apoptosis levels compared with those from the other groups. Meanwhile, Qu markedly reduced the elevation of blood creatinine during cDDP intervention. These data indicate that Qu pretreatment potentiates the antitumor effects of cDDP in ovarian cancer while protecting the kidneys against damage. Therefore the strategy of Qu pretreatment may be beneficial in enhancing the therapeutic efficacy of cDDP against ovarian cancer.

Quercetin and related polyphenols: new insights and implications for their bioactivity and bioavailability

The physiological functions and mechanisms of action of quercetin and its related polyphenols are highlighted, including their effects on brain, blood vessels, muscle, and intestinal microflora.

Inhibition of the flavonoid extract from silkworm cocoons on DMBA/UVB-induced skin damage and tumor promotion in BALB/c mice

Exposure of the skin to ultraviolet B radiation causes oxidative stress that results in sunburn, photoaging, and skin cancer.

Molecular mechanisms of quercitrin-induced apoptosis in non-small cell lung cancer

BACKGROUND AND AIMS

Quercitrin (QR; quercetin-3-O-rhamnoside) has been used previously as an antibacterial agent and has been shown to inhibit the oxidation of low-density lipoproteins and prevent an allergic reaction. Furthermore, it was demonstrated that quercitrin exerts protective effects against H2O2-induced dysfunction in lung fibroblast cells. However, the mechanisms of quercitrin effects on cancer cell proliferation and apoptosis is not well understood. The aim of this study is to investigate the cytotoxic and apoptotic effects of quercitrin and the molecular mechanisms of quercitrin-induced apoptosis in non-small cell lung cancer (NSCLC) cell lines.

METHODS

Time- and dose-dependent antiproliferative and apoptotic effects of quercitrin determined by WST-1 cell proliferation assay, lactate dehydrogenase (LDH) cytotoxicity assay, determination of nucleosome enrichment factor, changes in caspase-3 activity, loss of mitochondrial membrane potential (MMP) and also the localization of phosphatidylserine in the plasma membrane. Changes in whole genome gene expression levels were examined by Illumina Human HT-12v4 beadchip microarrays.

RESULTS

There were significant increases in caspase-3 activity, loss of MMP, and increases in apoptotic cell population in response to quercitrin in A549 and NCI-H358 NSCLC cells in a time- and dose-dependent manner.

CONCLUSION

Our results demonstrated that genes involved in leukocyte transendothelial migration, cell adhesion and phosphatidylinositol signaling system pathways were the most statistically significant pathways in NCI-H358 and A549 cells. These results revealed that quercitrin has antiproliferative and apoptotic effects on lung cancer cells by modulating the immune response. After confirming its anticarcinogenic effects in vivo, quercitrin could be a novel and strong anticancer agent against NSCLC.

Octaphlorethol A isolated from Ishige foliacea prevents and protects against high glucose-induced oxidative damage in vitro and in vivo

We investigated the protective effect of octaphlorethol A (OPA) isolated from Ishige foliacea against high-glucose-induced oxidative damage, as indicated by reactive oxygen species (ROS) generation, lipid peroxidation, and cell death, in human umbilical vein endothelial cells (HUVECs) and in a zebrafish model. OPA treatment significantly and dose-dependently decreased ROS generation, lipid peroxidation, and cell death in HUVECs and in a zebrafish model. Our results show that OPA can protect HUVECs and zebrafish against high glucose by suppressing intracellular ROS generation, lipid peroxidation, and cell death.

Photodynamic effects of 31 different phthalocyanines on a human keratinocyte cell line

Phthalocyanines (Pcs, colored macromolecular compounds with the ability to generate singlet oxygen) represent a promising group of photosensitizers due to their intense absorption in the red and UV portion of the spectrum which leads to their excitation. In order to characterize possible toxic effects associated with eventual practical use and application of these chemicals, we employed an in vitro cell culture model to evaluate cytotoxic effects of 31 different phthalocyanines using neutral red uptake assay. An immortalized human keratinocyte cell line HaCaT was exposed to the tested chemicals for 2 or 24h, either with or without illumination in the last 60 min of the exposure period. After 2- or 24-h exposure without illumination, no cytotoxic effects or weak cytotoxic effects were induced by any Pc under the study and EC50 values could not be obtained within the tested concentration ranges (1.25-20 mg L(-1) or 0.625-10 mg L(-1)). On the other hand, exposure to phthalocyanines under illumination induced a significant cytotoxic effect. The most pronounced cytotoxicity was elicited by Pcs previously shown to have high positive charge densities at peripheral parts of substituent groups, which is most likely the factor responsible for the binding of Pc to negatively charged membranes on the cell surface and thus guaranteeing the tight connection necessary for the singlet oxygen attack on the cell surface.

In vitro and in vivo antioxidant activities of polysaccharide purified from aloe vera (Aloe barbadensis) gel

The in vitro and in vivo antioxidant potentials of a polysaccharide isolated from aloe vera gel were investigated. Enzymatic extracts were prepared from aloe vera gel by using ten digestive enzymes including five carbohydrases and five proteases. Among them, the highest yield was obtained with the Viscozyme extract and the same extract showed the best radical scavenging activity. An active polysaccharide was purified from the Viscozyme extract using ethanol-added separation and anion exchange chromatography. Purified aloe vera polysaccharide (APS) strongly scavenged radicals including DPPH, hydroxyl and alkyl radicals. In addition, APS showed a protective effect against AAPH-induced oxidative stress and cell death in Vero cells as well as in the in vivo zebrafish model. In this study, it is proved that both the in vitro and in vivo antioxidant potentials of APS could be further utilized in relevant industrial applications.

Quercitrin protects skin from UVB-induced oxidative damage

Exposure of the skin to ultraviolet B (UVB) radiation causes oxidative damage to skin, resulting in sunburn, photoaging, and skin cancer. It is generally believed that the skin damage induced by UV irradiation is a consequence of generation of reactive oxygen species (ROS). Recently, there is an increased interest in the use of natural products as chemopreventive agents for non-melanoma skin cancer (NMSC) due to their antioxidants and anti-inflammatory properties. Quercitrin, glycosylated form of quercetin, is the most common flavonoid in nature with antioxidant properties. The present study investigated the possible beneficial effects of quercitrin to inhibit UVB irradiation-induced oxidative damage in vitro and in vivo. Our results showed that quercitrin decreased ROS generation induced by UVB irradiation in JB6 cells. Quercitrin restored catalase expression and GSH/GSSG ratio reduced by UVB exposure, two major antioxidant enzymes, leading to reductions of oxidative DNA damage and apoptosis and protection of the skin from inflammation caused by UVB exposure. The present study demonstrated that quercitrin functions as an antioxidant against UVB irradiation-induced oxidative damage to skin.

Identification of quercitrin as an inhibitor of the p90 S6 ribosomal kinase (RSK): structure of its complex with the N-terminal domain of RSK2 at 1.8 Å resolution

Members of the RSK family of kinases constitute attractive targets for drug design, but a lack of structural information regarding the mechanism of selective inhibitors impedes progress in this field. The crystal structure of the N-terminal kinase domain (residues 45-346) of mouse RSK2, or RSK2(NTKD), has recently been described in complex with one of only two known selective inhibitors, a rare naturally occurring flavonol glycoside, kaempferol 3-O-(3'',4''-di-O-acetyl-α-L-rhamnopyranoside), known as SL0101. Based on this structure, it was hypothesized that quercitrin (quercetin 3-O-α-L-rhamnopyranoside), a related but ubiquitous and inexpensive compound, might also act as an RSK inhibitor. Here, it is demonstrated that quercitrin binds to RSK2(NTKD) with a dissociation constant (K(d)) of 5.8 µM as determined by isothermal titration calorimetry, and a crystal structure of the binary complex at 1.8 Å resolution is reported. The crystal structure reveals a very similar mode of binding to that recently reported for SL0101. Closer inspection shows a number of small but significant differences that explain the slightly higher K(d) for quercitrin compared with SL0101. It is also shown that quercitrin can effectively substitute for SL0101 in a biological assay, in which it significantly suppresses the contractile force in rabbit pulmonary artery smooth muscle in response to Ca(2+).