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The gram-positive bacterium Deinococcus radiodurans can survive under extreme ionizing radiation environment. This study aims to rationalize the role of redox balance, antioxidant status, and metabolite content on the radiation survival of D. radiodurans. We found that the TrxR inhibitors, i.e., ebselen, auranofin, and epigallocatechin gallate (EGCG) (10 µM) treatment affects the radiation survival of D. radiodurans. The TrxR inhibitors treatment affects the redox status, activities of antioxidant enzymes, increases the intracellular ROS levels and protein carbonylation upon 4 kGy ionizing radiation treatments. Moreover, the alteration in cellular redox status affects the metabolites content of the organism. In addition, we noticed differential metabolomic profiles in sham control, radiation control (4 kGy), and TrxR inhibitors plus radiation-treated D. radiodurans. The TrxR inhibitors plus radiation treated groups exhibit more variation compare to sham control and 4 kGy radiation-exposed D. radiodurans. Further, some novel metabolites can possess the high antioxidant property and involved in vital cellular metabolism were found in sham control and radiation treated cells of D. radiodurans. Thus, the results illustrate the role of intracellular redox status in the survival and metabolomic profile of D. radiodurans. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the photochemopreventive effects of ferulic acid (FA) against chronic ultraviolet-B (290–320 nm) induced oxidative stress, inflammation and angiogenesis in the skin of Swiss albino mice. Chronic UVB exposure (180 mJ/cm 2 for 30 weeks; thrice in a week) induced tumor formation in the mice skin that showed increased expression of carcinogenic and inflammatory markers when compared with the control animals. The intraperitoneal (FAIP) and topical (FAT) administration of FA significantly reduced the incidence of UVB-induced tumor volume and tumor weight in the mice skin. Histopathological studies revealed that both FAIP and FAT administration prevented the UVB-induced hyperplasia, squamous cell carcinoma (SCC) and dysplastic feature in the mice skin. Further, it has been observed that FA treatment reverted chronic UVB-induced oxidative damage (thiobarbituric acid reactive substances, superoxide dismutase, catalase, glutathione peroxidase) accompanied with modulation of vascular endothelial growth factor ( VEGF ), inducible nitric oxide synthase ( iNOS ), TNF-α and IL-6 in the mice skin tumor. FA treatment also modulates mutated p53 , Bcl-2 and Bax expressions in the UVB-induced mice skin tumor. Thus, the results of the present study indicate ferulic acid has potential against UVB-induced carcinogenesis in the Swiss albino mice. [ABSTRACT FROM AUTHOR]

Abstract: Exposure to ultraviolet B (UVB, 280–320) radiation induces the formation of reactive oxygen species (ROS) in the biological system. In this study, we examined the protective effect of ursolic acid on UVB-induced lipid peroxidation and oxidative DNA damage with reference to alterations in cellular antioxidant status in human lymphocytes. Series of in vitro tests (hydroxyl radical, superoxide, nitric oxide, DPPH and ABTS radical scavenging assays) demonstrates antioxidant property of ursolic acid in our study. Treatment of lymphocytes with ursolic acid alone (at 10μg/mL) gave no significant change in cell viability, thiobarbituric acid reactive substances (TBARSs), lipid hydroperoxides (LHPs), % tail DNA and tail moment when compared with normal lymphocytes. UVB-exposure significantly increased TBARS, LHP and % tail DNA, tail moment; decreased % cell viability and antioxidant status in irradiated lymphocytes. Treatment with ursolic acid 30min prior to UVB-exposure resulted in a significant decline of TBARS, LHP, % tail DNA and tail moment and increased % cell viability as ursolic acid concentration increased. Based on our results we conclude that ursolic acid, a dietary antioxidant, mediates its protective effect through modulation of UVB-induced reactive oxygen species. [Copyright &y& Elsevier]

Highlights: [•] Antioxidant potential of Jatropha curcas. [•] UVB-radiation-induced DNA damage in cultured human blood lymphocytes. [•] RB4 fraction and L1 fraction protect UVB-radiation-induced DNA damage in HPBL. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Solar ultraviolet-B radiation (UVB) has severe adverse effects on the structure and functions of the skin. Although, UVB (290–320 nm) represents only 5–10% of UV light reaching earth's surface, its contribution towards photoaging is tremendous. In this present study was investigate the photoprotective effect of methanolic extract of the male flower of J. regia L. (MEJR) against UVB induced photoaging in human epidermal keratinocytes (HaCaT). Cells were exposed to UVB-irradiation at a dose of 20 mJ/cm2, induces the activation of several signaling pathways which are associated with oxidative stress and photoaging. A single dose of UVB irradiation increased the protein and mRNA expression of MAPKs, AP-1, MMPs, Smad7 and decreased expression of TIMP-1/2, TGF-β1, Smad3, procollagen type-1 in HaCaT cells. In contrast, pretreatment of MEJR (80 μg/ml) prior to UVB-irradiation significantly prevented the overexpression of MAPKs, AP-1, MMPs, Smad7 and decreased expression of TIMP-1/2, TGF-β1, Smad3 and procollagen type-1 in HaCaT cells. Moreover, pretreatment of MEJR (80 μg/ml) prior to UVB-irradiation significantly prevents apoptosis in sub G o -phase. Thus, MEJR protects UVB-mediated photoaging in human skin cells, by modulating the expression of photoaging markers. The protection might be because of the presence of the good amount of bioactive compounds in MEJR. [ABSTRACT FROM AUTHOR]

P-glycoprotein, encoded by ATP-binding cassette transporters B1 gene (ABCB1), renders multidrug resistance (MDR) during cancer chemotherapy. Several synthetic small molecule inhibitors affect P-glycoprotein (P-gp) transport function in MDR tumor cells. However, inhibition of P-gp transport function adversely accumulates chemotherapeutic drugs in non-target normal tissues. Moreover, most small-molecule P-gp inhibitors failed in the clinical trials due to the low therapeutic window at the maximum tolerated dose. Therefore, downregulation of ABCB1 -gene expression (P-gp) in tumor tissues seems to be a novel approach rather than inhibiting its transport function for the reversal of multidrug resistance (MDR). Several plant-derived phytochemicals modulate various signal transduction pathways and inhibit translocation of transcription factors, thereby reverses P-gp mediated MDR in tumor cells. Therefore, phytochemicals may be considered an alternative to synthetic small molecule P-gp inhibitors for the reversal of MDR in cancer cells. This review discussed the role of natural phytochemicals that modulate ABCB1 expression through various signal transduction pathways in MDR cancer cells. Therefore, modulating the cell signaling pathways by phytochemicals might play crucial roles in modulating ABCB1 gene expression and the reversal of MDR. [Display omitted] • P-glycoprotein renders multidrug resistance during cancer chemotherapy. • Inhibition of P-gp transport function adversely accumulates drugs in normal tissues. • Downregulation of P-gp expression in tumor tissues seems to be a novel approach. • Phytochemicals modulate cell signaling pathways; reverses P-gp mediated MDR. • Phytochemicals may be considered an alternative for the reversal of MDR. [ABSTRACT FROM AUTHOR]