Molecular modification of chlorogenic acid via radiolysis with inhibitory effects on NO production.

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.

Anti-cancer effects of plant-derived Micromonospora sp. M2 against A549 and MCF-7 cell lines.

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.

Novel Dihydrocoumarins Induced by Radiolysis as Potent Tyrosinase Inhibitors.

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.

Inhibitory effect of γ-ray-modified hydroxymethylated baicalins on NO production.

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.

Inhibitory Effects of Thermolysis Transformation Products of Rotenone on Nitric Oxide Production.

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.

Centipedegrass extract enhances radiosensitivity in melanoma cells by inducing G2/M cell cycle phase arrest.

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.

Investigation of Antifungal Mechanisms of Thymol in the Human Fungal Pathogen, Cryptococcus neoformans.

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.

SOG1-dependent NAC103 modulates the DNA damage response as a transcriptional regulator in Arabidopsis.

The plant-specific transcription factor (TF) NAC103 was previously reported to modulate the unfolded protein response in Arabidopsis under endoplasmic reticulum (ER) stress. Alternatively, we report here that NAC103 is involved in downstream signaling of SOG1, a master regulator for expression of DNA damage response (DDR) genes induced by genotoxic stress. Arabidopsis NAC103 expression was strongly induced by genotoxic stress and nac103 mutants displayed substantial inhibition of DDR gene expression after gamma radiation or radiomimetic zeocin treatment. DDR phenotypes, such as true leaf inhibition, root cell death and root growth inhibition, were also suppressed significantly in the nac103 mutants, but to a lesser extent than in the sog1-1 mutant. By contrast, overexpression of NAC103 increased DDR gene expression without genotoxic stress and substantially rescued the phenotypic changes in the sog1-1 mutant after zeocin treatment. The putative promoters of some representative DDR genes, RAD51, PARP1, RPA1E, BRCA1 and At4g22960, were found to partly interact with NAC103. Together with the expected interaction of SOG1 with the promoter of NAC103, our study suggests that NAC103 is a putative SOG1-dependent transcriptional regulator of plant DDR genes, which are responsible for DDR phenotypes under genotoxic stress.

Delphinidin enhances radio-therapeutic effects via autophagy induction and JNK/MAPK pathway activation in non-small cell lung cancer.

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.

Site-directed mutagenesis substituting cysteine for serine in 2-Cys peroxiredoxin (2-Cys Prx A) of Arabidopsis thaliana effectively improves its peroxidase and chaperone functions.

BACKGROUND AND AIMS: The 2-Cys peroxiredoxin (Prx) A protein of Arabidopsis thaliana performs the dual functions of a peroxidase and a molecular chaperone depending on its conformation and the metabolic conditions. However, the precise mechanism responsible for the functional switching of 2-Cys Prx A is poorly known. This study examines various serine-to-cysteine substitutions on α-helix regions of 2-Cys Prx A in Arabidopsis mutants and the effects they have on the dual function of the protein. METHODS: Various mutants of 2-Cys Prx A were generated by replacing serine (Ser) with cysteine (Cys) at different locations by site-directed mutagenesis. The mutants were then over-expressed in Escherichia coli. The purified protein was further analysed by size exclusion chromatography, polyacrylamide gel electrophoresis, circular dichroism spectroscopy and transmission electron microscopy (TEM) and image analysis. Peroxidase activity, molecular chaperone activity and hydrophobicity of the proteins were also determined. Molecular modelling analysis was performed in order to demonstrate the relationship between mutation positions and switching of 2-Cys Prx A activity. KEY RESULTS: Replacement of Ser(150) with Cys(150) led to a marked increase in holdase chaperone and peroxidase activities of 2-Cys Prx A, which was associated with a change in the structure of an important domain of the protein. Molecular modelling demonstrated the relationship between mutation positions and the switching of 2-Cys Prx A activity. Examination of the α2 helix, dimer-dimer interface and C-term loop indicated that the peroxidase function is associated with a fully folded α2 helix and easy formation of a stable reduced decamer, while a more flexible C-term loop makes the chaperone function less likely. CONCLUSIONS: Substitution of Cys for Ser at amino acid location 150 of the α-helix of 2-Cys Prx A regulates/enhances the dual enzymatic functions of the 2-Cys Prx A protein. If confirmed in planta, this leads to the potential for it to be used to maximize the functional utility of 2-Cys Prx A protein for improved metabolic functions and stress resistance in plants.

Enhancement of Chaperone Activity of Plant-Specific Thioredoxin through γ-Ray Mediated Conformational Change.

AtTDX, a thioredoxin-like plant-specific protein present in Arabidopsis is a thermo-stable and multi-functional enzyme. This enzyme is known to act as a thioredoxin and as a molecular chaperone depending upon its oligomeric status. The present study examines the effects of γ-irradiation on the structural and functional changes of AtTDX. Holdase chaperone activity of AtTDX was increased and reached a maximum at 10 kGy of γ-irradiation and declined subsequently in a dose-dependent manner, together with no effect on foldase chaperone activity. However, thioredoxin activity decreased gradually with increasing irradiation. Electrophoresis and size exclusion chromatography analysis showed that AtTDX had a tendency to form high molecular weight (HMW) complexes after γ-irradiation and γ-ray-induced HMW complexes were tightly associated with a holdase chaperone activity. The hydrophobicity of AtTDX increased with an increase in irradiation dose till 20 kGy and thereafter decreased further. Analysis of the secondary structures of AtTDX using far UV-circular dichroism spectra revealed that the irradiation remarkably increased the exposure of ß-sheets and random coils with a dramatic decrease in α-helices and turn elements in a dose-dependent manner. The data of the present study suggest that γ-irradiation may be a useful tool for increasing holdase chaperone activity without adversely affecting foldase chaperone activity of thioredoxin-like proteins.

Novel Radiolytic Rotenone Derivative, Rotenoisin B with Potent Anti-Carcinogenic Activity in Hepatic Cancer Cells.

Rotenone, isolated from roots of derris plant, has been shown to possess various biological activities, which lead to attempting to develop a potent drug against several diseases. However, recent studies have demonstrated that rotenone has the potential to induce several adverse effects such as a neurodegenerative disease. Radiolytic transformation of the rotenone with gamma-irradiation created a new product, named rotenoisin B. The present work was designed to investigate the anticancer activity of rotenoisin B with low toxicity and its molecular mechanism in hepatic cancer cells compared to a parent compound, rotenone. Our results showed rotenoisin B inhibited hepatic cancer cells' proliferation in a dose dependent manner and increased in apoptotic cells. Interestingly, rotenoisin B showed low toxic effects on normal cells compared to rotenone. Mitochondrial transmembrane potential has been decreased, which leads to cytochrome c release. Down regulation of anti-apoptotic Bcl-2 levels as well as the up regulation of proapoptotic Bax levels were observed. The cleaved PARP (poly ADP-ribose polymerase) level increased as well. Moreover, phosphorylation of extracellular signal regulated kinase (ERK) and p38 slightly up regulated and intracellular reactive oxygen species (ROS) increased as well as cell cycle arrest predominantly at the G2/M phase observed. These results suggest that rotenoisin B might be a potent anticancer candidate similar to rotenone in hepatic cancer cells with low toxicity to normal cells even at high concentrations compared to rotenone.

Protective effect of centipedegrass against Aß oligomerization and Aß-mediated cell death in PC12 cells.

CONTEXT: Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the abnormal accumulation of ß-amyloid (Aß). Multiple Aß-aggregated species have been identified, and neurotoxicity appears to be correlated with the amount of non-fibrillar oligomers. Potent inhibitors of Aß oligomer formation or Aß-induced cell toxicity have emerged as attractive means of therapeutic intervention. Eremochloa ophiuroide Hack. (Poaceae), also known as centipedegrass (CG), originates from China and South America and is reported to contain several C-glycosyl flavones and phenolic constituents. OBJECTIVE: We investigated whether CG could suppress Aß aggregation, BACE1 activity, and toxicity at neuronal cell. MATERIALS AND METHODS: The inhibitory effect of CG extracts toward aggregation of Aß42 was investigated in the absence and presence of 50 µg/mL CG. We investigated the inhibitory effects of CG (0-5 µg/mL) on BACE1 using fluorescence resonance energy transfer (FRET)-based assay. The effects of CG (0-75 µg/mL) on Aß42-induced neurotoxicity were examined in PC12 cells in the presence or absence of maysin and its derivatives of CG. RESULTS: We isolated EA-CG fraction (70% MeOH fraction from EtOAc extracts) from methanol extracts of CG, which contained approximately 60% maysin and its derivatives. In the present studies, we found that several Aß oligomeric forms such as the monomer, dimer, trimer, and highly aggregated oligomeric forms were remarkably inhibited in the presence of 50 µg/mL of EA-CG. EA-CG also inhibited BACE1 enzyme activity in a dose-dependent manner. EA-CG treatment generated approximately 50% or 85% inhibition to the control at the tested concentrations of 1 or 5 µg/mL, respectively. Moreover, the neurotoxicity induced by Aß42 was significantly reduced by treatment of EA-CG, and the 75 µg/mL EA-CG treatment significantly increased cell viability up to 82.5%. DISCUSSION AND CONCLUSION: These results suggested that the anti-Alzheimer's effects of CG occurred through inhibition of neuronal cell death by intervening with oligomeric Aß formation and reducing BACE1 activity. Maysin in CG could be an excellent therapeutic candidate for the prevention of AD.

Gamma irradiation-engineered macrophage-derived exosomes as potential immunomodulatory therapeutic agents.

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.

Ionizing radiation­induced modification of nialamide as an anti­inflammatory agent against lipopolysaccharide­induced RAW 264.7 and DH82 cells.

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.

Effects of Gamma Irradiation on Changes in Chemical Composition and Antioxidant Activity of Euphorbia maculata Callus.

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.

Radiolytic transformation of rotenone with potential anti-adipogenic activity.

Radiolytic transformation of the isoflavonoid rotenone (1) with γ-irradiation afforded two new degraded products, rotenoisins A (2) and (3). The structures of the two new rotenone derivatives were elucidated on the basis of spectroscopic methods. The new products 2 and 3 exhibited significantly enhanced inhibitory activities against pancreatic lipase and adipocyte differentiation in 3T3-L1 cells when compared to parent rotenone.

Molecular mechanism of apoptosis induction in skin cancer cells by the centipedegrass extract.

BACKGROUND: Centipedegrass extract (CGE) is mainly composed of maysin and its derivatives, which are recognized internationally as natural compounds. Compared to other flavonoids, maysin has a unique structure in that mannose is bound to the flavonoid backbone. CGE exhibits some biological properties in that it can function as an anti-oxidant, anti-inflammatory, anti-adipogenic, and insecticidal. Whether CGE has other biological functions, such as anti-cancer activity, is unknown. METHODS: B16F1 (mouse) and SKMEL-5 (human) cells were treated with CGE, and their subsequent survival was determined using MTT assay. We performed a cell cycle analysis using propidium iodide (PI), and detected apoptosis using double staining with annexin V-FITC/PI. In addition, we examined mitochondrial membrane potentials using flow cytometry, as well as signaling mechanisms with an immunoblotting analysis. RESULTS: CGE inhibited skin cancer cell growth by arresting the cell cycle in the G2/M phase, and increased both early and late apoptotic cell populations without affecting normal cells. Furthermore, we observed mitochondrial transmembrane depolarization, increased cytochrome-c release, caspase-3 and caspase-7 activation, and increased poly ADP-ribose polymerase degradation. CGE also downregulated activation of p-AKT, p-glycogen synthase kinase-3ß (GSK-3ß), and p-BAD in a time-dependent manner. LY294002 inhibition of phosphoinositide 3-kinase (PI3K) significantly sensitized skin cancer cells, which led to an increase in CGE-induced apoptosis. CONCLUSIONS: CGE controlled skin cancer cell growth by inhibiting the PI3K/AKT/GSK-3ß signaling pathway and activating the effector caspases. This study is the first to demonstrate anti-cancer properties for CGE, and that CGE may be an effective therapeutic agent for treating skin cancer.

Application of ionizing radiation as an elicitor to enhance the growth and metabolic activities in Chlamydomonas reinhardtii.

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.

Novel aminopyridazine derivative of minaprine modified by radiolysis presents potent anti-inflammatory effects in LPS-stimulated RAW 264.7 and DH82 macrophage cells.

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.