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The molecular modification of chlorogenic acid (1) through γ-irradiation resulted in the formation of five new products: chlorogenosins A (2), B (3), C (4), D (5), and E (6) along with known compounds rosmarinosin B (7), protocatechuic acid (8), and protocatechuic aldehyde (9). The structures of the new compounds were elucidated using spectroscopic methods, including one-dimensional and two-dimensional nuclear magnetic resonance, high-resolution electrospray ionization mass spectroscopy, and circular dichroism spectroscopy. The potential anti-inflammatory activities of all the isolated compounds were determined by evaluating their inhibitory effects on the nitric oxide production in lipopolysaccharide-induced RAW 264.7 macrophages. Notably, compounds 2 and 3, which contained two hydroxymethyl functionalities instead of the trans-olefinic moiety present in the original chlorogenic acid, exhibited stronger inhibitory effects on NO production than that of the original compound. These findings suggest that the predominant chemical changes induced in chlorogenic acid by γ-irradiation may enhance its anti-inflammatory properties.

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In this study, we investigated the effects of gamma irradiation on the antioxidant activity and metabolite profiles of Euphorbia maculata calli (PC3012). Gamma irradiation at various doses (0, 0.05, 0.5, and 10 kGy) significantly enhanced the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS+) radical scavenging activities of the callus extracts of PC3012 in a dose-dependent manner. High-performance liquid chromatography (HPLC) and ultra-performance liquid chromatography-quadrupole time-of-flight/mass spectrometry (UPLC-Q-TOF/MS) analyses revealed that irradiation increased the lysophospholipid content, although no new antioxidant compounds were formed. Furthermore, a PLS-DA analysis revealed evident metabolic differences between non-irradiated and irradiated samples, which were further verified by statistical validation. These findings suggest that gamma irradiation induces specific biochemical modifications that enhance the bioactive properties of PC3012 calli. This technology exhibits potential for utilization in the natural product and food sectors, particularly in the development of functional foods and nutraceuticals with improved health benefits.

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The modulation of macrophage polarization is a promising strategy for maintaining homeostasis and improving innate and adaptive immunity. Low-dose ionizing radiation has been implicated in macrophage immunomodulatory responses. However, studies on the relationship between exosomes and regulation of macrophage polarization induced by ionizing radiation are limited. Therefore, this study investigated the alterations in macrophages and exosomes induced by gamma irradiation and elucidated the underlying mechanisms. We used the mouse macrophage cell line RAW 264.7 to generate macrophages and performed western blot, quantitative reverse transcription-PCR, and gene ontology analyses to elucidate the molecular profiles of macrophage-derived exosomes under varying treatment conditions, including 10 Gy gamma irradiation. Exosomes isolated from gamma-irradiated M1 macrophages exhibited an enhanced M1 phenotype. Irradiation induced the activation of NF-κB and NLRP3 signaling in M1 macrophages, thereby promoting the expression of pro-inflammatory cytokines. Cytokine expression was also upregulated in gamma-irradiated M1 macrophage-released exosomes. Therefore, gamma irradiation has a remarkable effect on the immunomodulatory mechanisms and cytokine profiles of gamma-irradiated M1 macrophage-derived exosomes, and represents a potential immunotherapeutic modality.

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The huge diversity of secondary bioactive metabolites, such as antibiotic and anticancer compounds produced by Micromonospora sp., makes it an attractive target for study. Here, we explored the anti-proliferative activities of Micromonospora sp. M2 extract (MBE) in relation to its pro-oxidative activities in A549 and MCF7 cell lines. Anti-proliferative effects were assessed by treating cells with MBE. We found that treatment with MBE decreased cell proliferation and increased intracellular reactive oxygen species, and that these observations were facilitated by the suppression of the PI3K-AKT pathway, alterations to the Bcl/Bad ratio, and increased caspase activity. These observations also demonstrated that MBE induced apoptotic cell death in cell lines. In addition, the phosphorylation of P38 and c-Jun N-terminal kinase (JNK) were upregulated following MBE treatment in both cell lines. Collectively, these results indicate that MBE acts as an anticancer agent via oxidative stress and JNK/mitogen-activated protein kinase pathway activation, enhancing apoptotic cell death in cell lines.

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Nialamide is a non-selective monoamine oxidase inhibitor that was widely used as an antidepressant. However, it has been prohibited for decades in the depressive medicine market due to the adverse hepatotoxic side effects. The re-use of drugs that have been withdrawn from the market represents a promising approach for the development of novel incrementally modified drugs and, in this context, ionizing radiation can serve as a powerful tool for producing new drug candidates. The present study exposed nialamide to γ radiation at 50 kGy to obtain the novel cyclized benzylamide, nialaminosin (compound 2), along with five known compounds, 3-amino-N-benzylpropanamide (compound 3), 3-methoxy-N-benzylpropanamide (compound 4), 3-hydroxy-N-benzylpropanamide (HBPA; compound 5), N-benzylpropanamide (compound 6) and isonicotinamide (compound 7). Among the isolated compounds, HBPA was established to inhibit the lipopolysaccharide-induced overproduction of pro-inflammatory mediators, including nitric oxide (NO) and prostaglandin E2 and cytokines including TNF-α, IL-6 and IL-10, without causing cytotoxicity to both RAW 264.7 and DH82 cells. Furthermore, HBPA was found to reduce the protein expression of inducible NO synthase and cyclooxygenase-2 in macrophages and compared with nialamide, it was established to have more potent radical scavenging activity. The present study therefore suggested the application of HBPA for the improvement of anti-inflammatory properties using ionizing radiation technology on the withdrawn drug nialamide.

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A representative naturally occurring coumarin, 4-methylumbelliferone (5), was exposed to 50 kGy of gamma ray, resulting in four newly generated dihydrocoumarin products 1-4 induced by the gamma irradiation. The structures of these new products were elucidated by interpretation of spectroscopic data (NMR, MS, [α]D, and UV). The unusual bisdihydrocoumarin 4 exhibited improved tyrosinase inhibitory capacity toward mushroom tyrosinase with IC50 values of 19.8 ± 0.5 µM as compared to the original 4-methylumbelliferone (5). A kinetic analysis also exhibited that the potent metabolite 4 had non-competitive modes of action. Linkage of the hydroxymethyl group in the C-3 and C-4 positions on the lactone ring probably enhances the tyrosinase inhibitory effect of 4-methylumbelliferone (5). Thus, the novel coumarin analog 4 is an interesting new class of tyrosinase inhibitory candidates that requires further examination.

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Baicalin, a glucuronic flavone, is the major active component in the medicinal plant Scutellaria baicalensis. Herein, baicalin was irradiated by γ-rays to afford four unusual flavanones, baicalinols A (2), B (3), and C (4) and peroxybaicaleinol (5), and two known flavones, oroxylin A (6) and baicalein (7). The structures of the hydroxymethylated products were elucidated using nuclear magnetic resonance spectroscopy and mass spectrometry, and their absolute configuration was established using electronic circular dichroism spectroscopy. Novel hydroxymethylated flavanones 2 and 3 suppressed both nitric oxide (NO) production and the expression of inducible NO synthase and showed significantly higher anti-inflammatory activities in lipopolysaccharide-stimulated macrophages than the parent compound. These newly generated hydroxymethylated flavanones can be potentially used for treating inflammatory diseases.

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Radiation molecularly transforms naturally occurring products by inducing the methoxylation, hydroxylation, and alkylation of parent compounds, thereby affecting the anti-inflammatory capacities of those compounds. Minaprine (1) modified by ionizing radiation generated the novel hydroxymethylation hydropyridazine (2), and its chemical structure was determined based on NMR and HRESIMS spectra. Compared to the original minaprine, the novel generated product showed a highly enhanced anti-inflammatory capacity inhibited nitric oxide (NO) and prostaglandin E2 (PGE2) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 and DH82 macrophage cells. In addition, minaprinol (2) effectively inhibited cyclooxygenase-2 (COX-2) and inducible NO synthase (iNOS) at the protein level and pro-inflammatory cytokine (tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-10) production in macrophages.

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Rotenone, isolated from Derris, Lonchocarpus, and Tephrosia from the family Fabaceae, has been shown to have a variety of biological properties and is used in various agricultural industries as a potent biopesticide. However, recent reports have demonstrated that rotenone has the potential to cause several adverse effects such as a neurodegenerative disease. This study aimed to induce thermolysis of the biopesticide rotenone and enhance the functionality of the degraded products. Rotenone (1) was degraded after autoclaving for 12 h, and the thermolytic reactants showed enhanced anti-inflammatory capacity against nitric oxide (NO) production. The structures of the newly modified products were spectroscopically determined. The thermal reaction products included various isoflavonoid derivatives 2-6, whose structures were characterized as being produced via chemical reactions in rotenone at the C-12 positions. Among the degraded products, (-)-tubaic acid (6) exhibited significantly improved anti-inflammatory effects compared to the original rotenone. Quantitative LC-MS analysis of the major thermolysis products generated in Derris extract containing rotenone was performed using isolate 2-5 purified from autoclaved rotenone. These results suggest that the thermal transformation of rotenone can improve the functionality of anti-inflammatory agents.

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Chlamydomonas reinhardtii is a eukaryotic, unicellular photosynthetic organism and a potential algal platform for producing biomass and recombinant proteins for industrial use. Ionizing radiation is a potent genotoxic and mutagenic agent used for algal mutation breeding that induces various DNA damage and repair responses. In this study, however, we explored the counterintuitive bioeffects of ionizing radiation, such as X- and γ-rays, and its potential as an elicitor to facilitate batch or fed-batch cultivation of Chlamydomonas cells. A certain dose range of X- and γ-rays was shown to stimulate the growth and metabolite production of Chlamydomonas cells. X- or γ-irradiation with relatively low doses below 10 Gy substantially increased chlorophyll, protein, starch, and lipid content as well as growth and photosynthetic activity in Chlamydomonas cells without inducing apoptotic cell death. Transcriptome analysis demonstrated the radiation-induced changes in DNA damage response (DDR) and various metabolic pathways with the dose-dependent expression of some DDR genes, such as CrRPA30, CrFEN1, CrKU, CrRAD51, CrOASTL2, CrGST2, and CrRPA70A. However, the overall transcriptomic changes were not causally associated with growth stimulation and/or enhanced metabolic activities. Nevertheless, the radiation-induced growth stimulation was strongly enhanced by repetitive X-irradiation and/or subsequent cultivation with an inorganic carbon source, i.e., NaHCO3, but was significantly inhibited by treatment of ascorbic acid, a scavenger of reactive oxygen species (ROS). The optimal dose range of X-irradiation for growth stimulation differed by genotype and radiation sensitivity. Here, we suggest that ionizing radiation within a certain dose range determined by genotype-dependent radiation sensitivity could induce growth stimulation and enhance metabolic activities, including photosynthesis, chlorophyll, protein, starch, and lipid synthesis in Chlamydomonas cells via ROS signaling. The counterintuitive benefits of a genotoxic and abiotic stress factor, i.e., ionizing radiation, in a unicellular algal organism, i.e., Chlamydomonas, may be explained by epigenetic stress memory or priming effects associated with ROS-mediated metabolic remodeling.

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To investigate the CGE on hair growth and to explore the mechanism that is involved in the acceleration of anagen induction, we investigated the effects of CGE studied on cell proliferation and molecular mechanism in human hair dermal papilla cells (hDPCs) and keratinocytes (HaCaT cells). Additionally, hair growth evaluation was carried out following topical treatment of the dorsal skin of telogen C57BL/6 mice with CGE for 14 days. As result, CGE increased cell viability and ALP activity in hDPCs. Moreover, CGE increased the expression of catenin beta 1 (CTNNB1), ALP, sex-determining region Y-box 2 (SOX2), insulin-like growth factor 1 (IGF1), and vascular endothelial growth factor A (VEGFA) genes in hDPCs. CGE increased the expression of proteins such as ALP, ß-catenin, and phosphorylation of glycogen synthase kinase 3ß (pGSK3ß), and protein kinase B (pAKT) in hDPCs. Furthermore, CGE induced the proliferation of HaCaT cells and up-regulated AKT-ERK-GSKß-ß-catenin signaling in HaCaT cells. Additionally, the anagen induction effects of CGE were confirmed on the telogen-anagen transition mice model. these findings demonstrated that CGE promoted the entering the growth phase of hair follicle via activation of ß-catenin signaling pathways in vivo. Thus, this study suggests that CGE might be a potential therapeutic reagent for hair growth.

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Due to lifespan extension and changes in global climate, the increase in mycoses caused by primary and opportunistic fungal pathogens is now a global concern. Despite increasing attention, limited options are available for the treatment of systematic and invasive mycoses, owing to the evolutionary similarity between humans and fungi. Although plants produce a diversity of chemicals to protect themselves from pathogens, the molecular targets and modes of action of these plant-derived chemicals have not been well characterized. Using a reverse genetics approach, the present study revealed that thymol, a monoterpene alcohol from Thymus vulgaris L., (Lamiaceae), exhibits antifungal activity against Cryptococcus neoformans by regulating multiple signaling pathways including calcineurin, unfolded protein response, and HOG (high-osmolarity glycerol) MAPK (mitogen-activated protein kinase) pathways. Thymol treatment reduced the intracellular concentration of Ca2+ by controlling the expression levels of calcium transporter genes in a calcineurin-dependent manner. We demonstrated that thymol decreased N-glycosylation by regulating the expression levels of genes involved in glycan-mediated post-translational modifications. Furthermore, thymol treatment reduced endogenous ergosterol content by decreasing the expression of ergosterol biosynthesis genes in a HOG MAPK pathway-dependent manner. Collectively, this study sheds light on the antifungal mechanisms of thymol against C. neoformans.

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Ascorbate peroxidase (APX) is an important reactive oxygen species (ROS)-scavenging enzyme, which catalyzes the removal of hydrogen peroxide (H2O2) to prevent oxidative damage. The peroxidase activity of APX is regulated by posttranslational modifications (PTMs), such as S-nitrosylation, tyrosine nitration, and S-sulfhydration. In addition, it has been recently reported that APX functions as a molecular chaperone, protecting rice against heat stress. In this study, we attempted to identify the various functions of APX in Arabidopsis and the effects of PTMs on these functions. Cytosol type APX1 from Arabidopsis thaliana (AtAPX1) exists in multimeric forms ranging from dimeric to high-molecular-weight (HMW) complexes. Similar to the rice APX2, AtAPX1 plays a dual role behaving both as a regular peroxidase and a chaperone molecule. The dual activity of AtAPX1 was strongly related to its structural status. The main dimeric form of the AtAPX1 protein showed the highest peroxidase activity, whereas the HMW form exhibited the highest chaperone activity. Moreover, in vivo studies indicated that the structure of AtAPX1 was regulated by heat and salt stresses, with both involved in the association and dissociation of complexes, respectively. Additionally, we investigated the effects of S-nitrosylation, S-sulfhydration, and tyrosine nitration on the protein structure and functions using gel analysis and enzymatic activity assays. S-nitrosylation and S-sulfhydration positively regulated the peroxidase activity, whereas tyrosine nitration had a negative impact. However, no effects were observed on the chaperone function and the oligomeric status of AtAPX1. Our results will facilitate the understanding of the role and regulation of APX under abiotic stress and posttranslational modifications.

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Transcriptome-based dose-response curves were recently applied to the phytodosimetry of gamma radiation in a dicot plant, Arabidopsis thaliana, as an alternative biological assessment of genotoxicity using DNA damage response (DDR) genes. In the present study, we characterized gamma ray-responsive marker genes for transcriptome-based phytodosimetry in a monocot plant, rice (Oryza sativa L.), and compared different phytodosimetry models between rice and Arabidopsis using gamma-H2AX, comet, and quantitative transcriptomic assays. The transcriptome-based dose-response curves of four marker genes (OsGRG, OsMutS, OsRAD51, and OsRPA1) were reliably fitted to quadratic or exponential decay equations (r2 > 0.99). However, the single or integrated dose-response curves of these genes were distinctive from the conventional models obtained by the gamma-H2AX or comet assays. In comparison, rice displayed a higher dose-dependency in the comet signal and OsRAD51 transcription, while the gamma-H2AX induction was more dose-dependent in Arabidopsis. The dose-dependent transcriptions of the selected gamma-ray-inducible marker genes, including OsGRG, OsMutS, OsRAD51, and OsRPA1 in rice and AtGRG, AtPARP1, AtRAD51, and AtRPA1E in Arabidopsis, were maintained similarly at different vegetative stages. These results suggested that the transcriptome-based phytodosimetry model should be further corrected with conventional genotoxicity- or DDR-based models despite the high reliability or dose-dependency of the model. In addition, the relative weighting of each gene in the integrated transcriptome-based dose-response model using multiple genes needs to be considered based on the trend and amplitude of the transcriptional change.

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Prednisolone is an anti­inflammatory drug used to treat a number of conditions, including liver disease and cancer. Numerous studies have demonstrated that glucocorticoids such as prednisolone modified by ionizing radiation can promote anticancer activity in cancer cells. To the best of our knowledge, however, the effect of ionizing radiation on prednisolone structure and cancer cells has not yet been identified. The present study created a novel prednisolone derivative using γ­irradiation, and its anticancer properties were investigated in liver cancer cells. The present study confirmed the structure of the new prednisolone derivative using liquid chromatogram­mass spectrometry. MTT assays determined the cytotoxic effects of γ­irradiated (IR)­prednisolone in liver cancer cells. Flow cytometry analysis evaluated apoptosis, mitochondrial membrane potential and cell cycle distribution. Western blotting was used to analyze the proteins associated with apoptosis. The chromatogram profile revealed that IR­prednisolone produced a number of peaks compared with the single peak of the original prednisolone. In contrast to prednisolone, the MTT results showed that IR­prednisolone significantly prevented the growth of liver cancer cells. IR­prednisolone promoted apoptosis and arrested the cell cycle at the G0/G1 stage in Huh7 cells. IR­prednisolone also altered the mitochondrial membrane potential and activated caspase­associated proteins, which activated the intrinsic apoptotic signaling pathway. In conclusion, IR­prednisolone promoted anticancer effects in liver cancer cells via apoptosis activation. The present study demonstrated that IR­prednisolone may be a potential anticancer agent against liver cancer, although specific molecules have yet to be identified.

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Centipedegrass originates from China and South America, and has been reported to contain several C-glycosyl flavones and phenolic compounds, including maysin and luteolin. The present study aimed to investigate the radioprotective activity of centipedegrass extract (CGE) in radiation exposed-fibroblasts and to assess the affected molecular pathway. The radioprotective effects of CGE were determined in NIH-3T3 cells using Cell Counting Kit-8 and morphological changes were observed. Reactive oxygen species (ROS) levels and the apoptotic profile of NIH-3T3 cells were also measured. The expression levels of B-cell lymphoma-2 (Bcl-2) family proteins [Bcl-2, Bcl-2 like protein 4 (Bax), Bcl-2-associated death promoter (Bad), caspase-3, poly(ADP-ribose) polymerase (PARP)], AKT and MAPK family proteins (ERK, p38 and JNK) were measured in vitro. The results demonstrated that when 3T3 fibroblasts pretreated with CGE were subjected to H2O2-induced cell damage, their viability was significantly decreased. Additionally, CGE pretreatment decreased ROS levels and the protein expression levels of cleaved PARP upon H2O2 treatment, indicating that CGE induced cytoprotective effects against H2O2-induced oxidative stress. Moreover, significant protective effects of CGE against intracellular ROS, induced upon exposure to ionizing radiation (IR), were observed. The protective effects of CGE pretreatment were also determined by morphological observation of NIH-3T3 cells following exposure to IR. CGE pretreatment increased the expression levels of anti-apoptotic signals (Bcl-2, p-BAD) and decreased the levels of pro-apoptotic signals (Bax, Bad), and led to cleavage of PARP and caspase-3 proteins. Additionally, in cells pretreated with CGE, the phosphorylation of AKT and ERK was increased and that of p38 and JNK was decreased compared with in cells subjected only to IR. These results indicated that CGE may act as a radioprotector due to its anti-oxidative activity, restoring cell homeostasis and redox balance in radiation-exposed fibroblast cells. Therefore, it could be suggested that CGE may be an effective candidate in the treatment of oxidative stress-related diseases and in radioprotection.

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Chemotherapy for cancer treatment has therapeutic limitations, such as drug resistance, excessive toxic effects and undesirable adverse effects. Therefore, efforts to improve the safety and efficacy of chemotherapeutic agents are essential. Ionizing radiation can improve physiological and pharmacological properties by transforming structural modifications of the drug. In this study, in order to reduce the adverse effects of rotenone and increase anticancer activity, a new radiolytic rotenone derivative called rotenoisin A was generated through radiolytic transformation. Our findings showed that rotenoisin A inhibited the proliferation of breast cancer cells and increased the rate of apoptosis, whereas it had no inhibitory effect on primary epidermal keratinocytes compared with rotenone. Moreover, rotenoisin A-induced DNA damage by increasing reactive oxygen species (ROS) accumulation. It was also confirmed not only to alter the composition ratio of mitochondrial proteins, but also to result in structural and functional changes. The anticancer effect and molecular signalling mechanisms of rotenoisin A were consistent with those of rotenone, as previously reported. Our study suggests that radiolytic transformation of highly toxic compounds may be an alternative strategy for maintaining anticancer effects and reducing the toxicity of the parent compound.

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Melanoma is aggressive, highly metastatic, and potentially fatal. In the case of patients with advanced melanoma, it is difficult to expect a good prognosis, since this cancer has low sensitivity to chemotherapy and radiation therapy. The use of natural ingredients may enhance existing therapies. Centipedegrass extract (CGE) which contains phenolic structures and C-glycosyl flavones, has been shown to have anti-inflammatory effects and anti-cancer effects. The purpose of this study was to evaluate the radio sensitizing effects of CGE in combination with ionizing radiation (IR). Two melanoma cell lines were exposed to IR after treatment with CGE at concentrations that were not toxic alone. The effects of CGE + IR on cell survival, cell cycle, and apoptotic cell death were examined using MTT and Muse® Cell Analyzer, and fluorescence microscopy. Molecular signaling mechanisms were explored by western blots. Our findings showed that co-treatment of CGE + IR reduced the survival of melanoma cells more than IR alone. Also, cell cycle arrest in CGE-treated cells was enhanced and these cells became more radiosensitive. CGE + IR increased apoptotic cell death more than IR alone. Western blot results showed that the effect of CGE + IR involved MAPKs (ERK1/2, p38, and JNK) pathway. Our study suggests that CGE + IR treatment enhanced radio-sensitization and cell death of melanoma cells via cell cycle arrest and the MAPKs pathway.

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Delphinidin is a major anthocyanidin compound found in various vegetables and fruits. It has anti-oxidant, anti-inflammatory, and various other biological activities. In this study we demonstrated the anti-cancer activity of delphinidin, which was related to autophagy, in radiation-exposed non-small cell lung cancer (NSCLC). Radiosensitising effects were assessed in vitro by treating cells with a subcytotoxic dose of delphinidin (5 µM) before exposure to γ-ionising radiation (IR). We found that treatment with delphinidin or IR induced NSCLC cell death in vitro; however the combination of delphinidin pre-treatment and IR was more effective than either agent alone, yielding a radiation enhancement ratio of 1.54 at the 50% lethal dose. Moreover, combined treatment with delphinidin and IR, enhanced apoptotic cell death, suppressed the mTOR pathway, and activated the JNK/MAPK pathway. Delphinidin inhibited the phosphorylation of PI3K, AKT, and mTOR, and increased the expression of autophagy-induced cell death associated-protein in radiation-exposed NSCLC cells. In addition, JNK phosphorylation was upregulated by delphinidin pre-treatment in radiation-exposed NSCLC cells. Collectively, these results show that delphinidin acts as a radiation-sensitizing agent through autophagy induction and JNK/MAPK pathway activation, thus enhancing apoptotic cell death in NSCLC cells.

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Peroxynitrite (ONOO-), a highly reactive oxygen species generated by the reaction of nitric oxide and superoxide radical anion, is involved in numerous physiological and pathological processes in the human body. To identify important pathogenic mechanisms, it is crucial to develop a reliable tool for detecting peroxynitrite in living systems. In the present study, a new difluoroboron ß-diketonate-based fluorescent probe for detecting exogenous and endogenous peroxynitrite in living systems was designed. The red emitting fluorophore can be synthesized in a simple three-step procedure. This probe reacts quickly and selectively with peroxynitrite and its detection limit is determined to be as low as 19.8 nM. It allows for clear imaging of peroxynitrite in RAW 264.7 cells and was successfully applied to visualize changes of intracellular peroxynitrite induced by reactive oxygen species inhibitors. This designed probe is an effective tool for investigating the physiological and pathological role of peroxynitrite in living cells.

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