scholarly journals Reconceptualization of Hormetic Responses in the Frame of Redox Toxicology

2021 ◽  
Vol 23 (1) ◽  
pp. 49
Author(s):  
Zoi Skaperda ◽  
Fotios Tekos ◽  
Periklis Vardakas ◽  
Charitini Nepka ◽  
Demetrios Kouretas

Cellular adaptive mechanisms emerging after exposure to low levels of toxic agents or stressful stimuli comprise an important biological feature that has gained considerable scientific interest. Investigations of low-dose exposures to diverse chemical compounds signify the non-linear mode of action in the exposed cell or organism at such dose levels in contrast to the classic detrimental effects induced at higher ones, a phenomenon usually referred to as hormesis. The resulting phenotype is a beneficial effect that tests our physiology within the limits of our homeostatic adaptations. Therefore, doses below the region of adverse responses are of particular interest and are specified as the hormetic gain zone. The manifestation of redox adaptations aiming to prevent from disturbances of redox homeostasis represent an area of particular interest in hormetic responses, observed after exposure not only to stressors but also to compounds of natural origin, such as phytochemicals. Findings from previous studies on several agents demonstrate the heterogeneity of the specific zone in terms of the molecular events occurring. Major factors deeply involved in these biphasic phenomena are the bioactive compound per se, the dose level, the duration of exposure, the cell, tissue or even organ exposed to and, of course, the biomarker examined. In the end, the molecular fate is a complex toxicological event, based on beneficial and detrimental effects, which, however, are poorly understood to date.

2019 ◽  
Vol 9 (4-A) ◽  
pp. 458-462
Author(s):  
MANIVANNAN - RAJAMANICKAM

The present study describes the isolation and structural elucidation of new alkaloid 3-deoxy-3, 11-epoxy cephalotaxine (1) from the flowers of C. ternatea. It was isolated by careful column chromatographic separation of the crude extract on silica gel 60. The structure was established based on UV, IR, 1HNMR, 13CNMR and GC-MS spectroscopy methods. The antibacterial activity of various bacterial and fungal strains and anti-inflammatory activities of the isolated compound and its crude methanol extract was studied. The highest zone of inhibition (13.0 and 12.0 mm) was shown by 1 at a dose of 200 µg/kg against E. coli and S. aureus strains and (16.0, 12.0 mm) against anti-fungal strains of C. albicans and A. flavus. The results indicated that at both dose levels (100 mg and 200 mg / kg) of isolated compound 1 had significant anti-inflammatory activity from 2nd hour onwards. The bioactive compound isolated from this plant can be employed for antimicrobial activity, also for the treatment of various bacterial and fungal infections and to show pronounced anti-inflammatory effects after three hours of injection. Keywords: Clitoria ternatea, Alkaloid, 3-deoxy-3, 11-epoxy cephalotaxine, Anti-microbial activity, Anti-inflammatory activity 


Antioxidants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1065
Author(s):  
Simone Luti ◽  
Alessandra Modesti ◽  
Pietro A. Modesti

The importance of training in regulating body mass and performance is well known. Physical training induces metabolic changes in the organism, leading to the activation of adaptive mechanisms aimed at establishing a new dynamic equilibrium. However, exercise can have both positive and negative effects on inflammatory and redox statuses. In recent years, attention has focused on the regulation of energy homeostasis and most studies have reported the involvement of peripheral signals in influencing energy and even inflammatory homeostasis due to overtraining syndrome. Among these, leptin, adiponectin, ghrelin, interleukin-6 (IL6), interleukin-1β (IL1β) and tumour necrosis factor a (TNFa) were reported to influence energy and even inflammatory homeostasis. However, most studies were performed on sedentary individuals undergoing an aerobic training program. Therefore, the purpose of this review was to focus on high-performance exercise studies performed in athletes to correlate peripheral mediators and key inflammation markers with physiological and pathological conditions in different sports such as basketball, soccer, swimming and cycling.


Proceedings ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 6 ◽  
Author(s):  
Vanja Todorovic ◽  
Monika Baranowska ◽  
Sladjana Sobajic ◽  
Agnieszka Bartoszek

Cocoa polyphenols play an important role in protection against diseases in which oxidative stress is implicated as a causal or contributing factor. The main aim of this study was to elucidate the influence of different cocoa extracts and main cocoa bioactive compound (–)-epicatechin on cell growth and support of antioxidant cellular barrier in colon adenocarcinoma cell line model (HT29). Results show that the tested cocoa bioactivity results from concerted interactions between epicatechin and other components. Hence, cocoa is a very good example which supports the food synergy concept that is attracting growing interest.


BIOspektrum ◽  
2021 ◽  
Vol 27 (2) ◽  
pp. 142-145
Author(s):  
Andreas Petry ◽  
Agnes Görlach

AbstractReactive oxygen species (ROS) are not only toxic agents but also potent signaling molecules. NADPH oxidases are the sole enzymes to generate ROS playing an important role in redox signaling. They closely interact in several ways with hypoxia-inducible transcription factors of the HIF family. This signaling network is active under normoxic and hypoxic conditions as an important regulator of redox homeostasis. Members of the NADPH oxidases-HIF axis appear as interesting therapeutic targets for various disorders characterized by an impaired redox homeostasis.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Guo-Tian Liu ◽  
Bian-Bian Wang ◽  
David Lecourieux ◽  
Mei-Jie Li ◽  
Ming-Bo Liu ◽  
...  

AbstractWild grapevines can show strong resistance to the downy mildew pathogen P. viticola, but the associated mechanisms are poorly described, especially at early stages of infection. Here, we performed comparative proteomic analyses of grapevine leaves from the resistant genotype V. davidii “LiuBa-8” (LB) and susceptible V. vinifera “Pinot Noir” (PN) 12 h after inoculation with P. viticola. By employing the iTRAQ technique, a total of 444 and 349 differentially expressed proteins (DEPs) were identified in LB and PN, respectively. The majority of these DEPs were related to photosynthesis, respiration, cell wall modification, protein metabolism, stress, and redox homeostasis. Compared with PN, LB showed fewer downregulated proteins associated with photosynthesis and more upregulated proteins associated with metabolism. At least a subset of PR proteins (PR10.2 and PR10.3) was upregulated upon inoculation in both genotypes, whereas HSP (HSP70.2 and HSP90.6) and cell wall-related XTH and BXL1 proteins were specifically upregulated in LB and PN, respectively. In the incompatible interaction, ROS signaling was evident by the accumulation of H2O2, and multiple APX and GST proteins were upregulated. These DEPs may play crucial roles in the grapevine response to downy mildew. Our results provide new insights into molecular events associated with downy mildew resistance in grapevine, which may be exploited to develop novel protection strategies against this disease.


Author(s):  
Peijie Wu ◽  
Wei Gao ◽  
Miao Su ◽  
Edouard C. Nice ◽  
Wenhui Zhang ◽  
...  

Cancer is a disease which frequently has a poor prognosis. Although multiple therapeutic strategies have been developed for various cancers, including chemotherapy, radiotherapy, and immunotherapy, resistance to these treatments frequently impedes the clinical outcomes. Besides the active resistance driven by genetic and epigenetic alterations in tumor cells, the tumor microenvironment (TME) has also been reported to be a crucial regulator in tumorigenesis, progression, and resistance. Here, we propose that the adaptive mechanisms of tumor resistance are closely connected with the TME rather than depending on non-cell-autonomous changes in response to clinical treatment. Although the comprehensive understanding of adaptive mechanisms driven by the TME need further investigation to fully elucidate the mechanisms of tumor therapeutic resistance, many clinical treatments targeting the TME have been successful. In this review, we report on recent advances concerning the molecular events and important factors involved in the TME, particularly focusing on the contributions of the TME to adaptive resistance, and provide insights into potential therapeutic methods or translational medicine targeting the TME to overcome resistance to therapy in clinical treatment.


Nutrients ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1605 ◽  
Author(s):  
Wiramon Rungratanawanich ◽  
Maurizio Memo ◽  
Daniela Uberti

Redox homeostasis may be defined as the dynamic equilibrium between electrophiles and nucleophiles to maintain the optimum redox steady state. This mechanism involves complex reactions, including nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, activated by oxidative stress in order to restore the redox balance. The ability to maintain the optimal redox homeostasis is fundamental for preserving physiological functions and preventing phenotypic shift toward pathological conditions. Here, we reviewed mechanisms involved in redox homeostasis and how certain natural compounds regulate the nucleophilic tone. In addition, we focused on the antioxidant properties of rice and particularly on its bioactive compound, γ-oryzanol. It is well known that γ-oryzanol exerts a variety of beneficial effects mediated by its antioxidant properties. Recently, γ-oryzanol was also found as a Nrf2 inducer, resulting in nucleophilic tone regulation and making rice a para-hormetic food.


2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Aysegul Cort ◽  
Tomris Ozben ◽  
Luciano Saso ◽  
Chiara De Luca ◽  
Liudmila Korkina

Clinical efficacy of anticancer chemotherapies is dramatically hampered by multidrug resistance (MDR) dependent on inherited traits, acquired defence against toxins, and adaptive mechanisms mounting in tumours. There is overwhelming evidence that molecular events leading to MDR are regulated by redox mechanisms. For example, chemotherapeutics which overrun the first obstacle of redox-regulated cellular uptake channels (MDR1, MDR2, and MDR3) induce a concerted action of phase I/II metabolic enzymes with a temporal redox-regulated axis. This results in rapid metabolic transformation and elimination of a toxin. This metabolic axis is tightly interconnected with the inducible Nrf2-linked pathway, a key switch-on mechanism for upregulation of endogenous antioxidant enzymes and detoxifying systems. As a result, chemotherapeutics and cytotoxic by-products of their metabolism (ROS, hydroperoxides, and aldehydes) are inactivated and MDR occurs. On the other hand, tumour cells are capable of mounting an adaptive antioxidant response against ROS produced by chemotherapeutics and host immune cells. The multiple redox-dependent mechanisms involved in MDR prompted suggesting redox-active drugs (antioxidants and prooxidants) or inhibitors of inducible antioxidant defence as a novel approach to diminish MDR. Pitfalls and progress in this direction are discussed.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Adamou Mfopa ◽  
Francine K. Mediesse ◽  
Clémence Mvongo ◽  
Sandrine Nkoubatchoundjwen ◽  
Ambe A. Lum ◽  
...  

Increased consumption of high-calorie foods leads to obesity usually associated with metabolic disorders including diabetes, hyperglycemia, and dyslipidemia. Ganoderma applanatum is a nonedible mushroom traditionally used in West Cameroon for the treatment of many diseases including hypertension, diabetes, and hepatitis. This study was designed to investigate the antidyslipidemic potential of water-soluble polysaccharides of G. applanatum in MACAPOS-2- (maize, cassava, palm oil, and sugar) induced obese rats. For this purpose, obesity was induced on 6–8-week-old male Wistar rats with a local high-fat diet for four months. G. applanatum polysaccharides (GAPs) obtained by hot water extraction were orally administered to obese rats for two months at different dose levels (50, 100, and 150 mg/kg bodyweight), and its potential was investigated on food consumption, bodyweight gain, serum, and tissue lipids parameters. GAP extract increased the bodyweight gain by raising the food intake of obese rats. Furthermore, the administration of GAP extract at different dose levels significantly decreased the total cholesterol, triglyceride, low-density lipoprotein cholesterol levels, and the atherogenic index from 50 to 150 mg/kg bodyweight. Conversely, GAP extract improved the high-density lipoprotein cholesterol level in obese rats compared with untreated rats after two months’ study period. These results indicated that GAP extract may be considered as a novel bioactive compound against dyslipidemia and its associated complications.


Author(s):  
F. G. Zaki

Fetal and neonatal liver injury induced by agents circulating in maternal plasma, even though well recognized, its morphological manifestations are not yet established. As part of our studies of fetal and neonatal liver injury induced by maternal nutritional disorders, metabolic impairment and toxic agents, the effects of two anti-inflammatory steroids have been recently inves tigated.Triamcinolone and methyl prednisolone were injected each in a group of rats during pregnancy at a-dosage level of 2 mgm three times a week. Fetal liver was studied at 18 days of gestation. Litter size and weight markedly decreased than those of control rats. Stillbirths and resorption were of higher incidence in the triamcinolone group than in those given the prednisolone.


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