Pub Date : 2021-09-08DOI: 10.5772/intechopen.96783
Samantha Drouet, Christophe Hano
Mature fruits (achenes) of milk thistle (Silybum marianum (L.) Gaertner, Asteraceae) accumulate high amounts of silymarin, a complex mixture of bioactive antioxidant flavonolignans deriving from taxifolin. Their biological activities in relation with human health promotion and disease prevention have been well described. The conditions of their biosynthesis in planta, however, have long been elusive and thus tend to be a limiting factor for their future applications. Significant advances in understanding their biosynthesis and regulation have been made over the last decade and are outlined in the current chapter.
{"title":"Biosynthesis and Regulation of Antioxidant Flavonolignans in Milk Thistle","authors":"Samantha Drouet, Christophe Hano","doi":"10.5772/intechopen.96783","DOIUrl":"https://doi.org/10.5772/intechopen.96783","url":null,"abstract":"Mature fruits (achenes) of milk thistle (Silybum marianum (L.) Gaertner, Asteraceae) accumulate high amounts of silymarin, a complex mixture of bioactive antioxidant flavonolignans deriving from taxifolin. Their biological activities in relation with human health promotion and disease prevention have been well described. The conditions of their biosynthesis in planta, however, have long been elusive and thus tend to be a limiting factor for their future applications. Significant advances in understanding their biosynthesis and regulation have been made over the last decade and are outlined in the current chapter.","PeriodicalId":8028,"journal":{"name":"Antioxidants - Benefits, Sources, Mechanisms of Action","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89743927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-21DOI: 10.5772/INTECHOPEN.95504
A. Eddaikra, N. Eddaikra
Oxidative stress is an important component of various diseases. It manifests as an imbalance caused by an excessive production of reactive oxygen species (ROS) which are associated with a deficit of antioxidant activity. This deficit can be the consequence of genetic factors, environmental ones, metabolic imbalance, toxicity or direct attacks by the accumulation of free radicals. These can induce metabolic dysfunction affecting biological macromolecules in their structures or activities. From a physiological perspective, the neutralization of free radicals is ensured by enzymatic, antioxidant and non-enzymatic defense systems. In the present chapter, we will focus on the endogenous enzymatic antioxidant defense system such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPxs), thioredoxin (Trx) and paraxonase which play an important role in homeostatic redox balance. Also, we will review this set of antioxidants enzymes within different pathological states such as diabetes, cancer, autoimmune diseases, cardiovascular, Alzheimer’s, Parkinson’s or parasitic diseases such as Leishmaniasis and Malaria.
{"title":"Endogenous Enzymatic Antioxidant Defense and Pathologies","authors":"A. Eddaikra, N. Eddaikra","doi":"10.5772/INTECHOPEN.95504","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.95504","url":null,"abstract":"Oxidative stress is an important component of various diseases. It manifests as an imbalance caused by an excessive production of reactive oxygen species (ROS) which are associated with a deficit of antioxidant activity. This deficit can be the consequence of genetic factors, environmental ones, metabolic imbalance, toxicity or direct attacks by the accumulation of free radicals. These can induce metabolic dysfunction affecting biological macromolecules in their structures or activities. From a physiological perspective, the neutralization of free radicals is ensured by enzymatic, antioxidant and non-enzymatic defense systems. In the present chapter, we will focus on the endogenous enzymatic antioxidant defense system such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPxs), thioredoxin (Trx) and paraxonase which play an important role in homeostatic redox balance. Also, we will review this set of antioxidants enzymes within different pathological states such as diabetes, cancer, autoimmune diseases, cardiovascular, Alzheimer’s, Parkinson’s or parasitic diseases such as Leishmaniasis and Malaria.","PeriodicalId":8028,"journal":{"name":"Antioxidants - Benefits, Sources, Mechanisms of Action","volume":"76 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80807850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-19DOI: 10.5772/INTECHOPEN.95658
Chanjae Lee, Min K. Bae, Sung-Jae Lee
A radiation-resistant bacterium, Deinococcus geothermalis has various stress response mechanisms, including antioxidation. Features that maintain vitality at high radiation doses include the following: enzymatic scavengers of ROS such as catalase, SOD, and peroxidase; strain-specific DNA repair systems such as Deinococcal unique proteins; non-enzymatic responses such as manganese complexes, carotenoids, and DNA-binding proteins. This chapter summarizes the primary response mechanism by redox balance centered on the cystine transporter. It also reviews action characteristics of DNA-binding protein Dps and a putative LysR family protein, and effects on loss of function of the carotenoid biosynthesis genes by transposition of insertion sequences. Environmental adaptation and molecular evolution of radiation-resistant bacterium are also considered to explain the potentials of molecular behavior induced by oxidative stress.
{"title":"An Antioxidant Defense System in Radiation-Resistant Bacterium Deinococcus geothermalis against Oxidative Stress","authors":"Chanjae Lee, Min K. Bae, Sung-Jae Lee","doi":"10.5772/INTECHOPEN.95658","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.95658","url":null,"abstract":"A radiation-resistant bacterium, Deinococcus geothermalis has various stress response mechanisms, including antioxidation. Features that maintain vitality at high radiation doses include the following: enzymatic scavengers of ROS such as catalase, SOD, and peroxidase; strain-specific DNA repair systems such as Deinococcal unique proteins; non-enzymatic responses such as manganese complexes, carotenoids, and DNA-binding proteins. This chapter summarizes the primary response mechanism by redox balance centered on the cystine transporter. It also reviews action characteristics of DNA-binding protein Dps and a putative LysR family protein, and effects on loss of function of the carotenoid biosynthesis genes by transposition of insertion sequences. Environmental adaptation and molecular evolution of radiation-resistant bacterium are also considered to explain the potentials of molecular behavior induced by oxidative stress.","PeriodicalId":8028,"journal":{"name":"Antioxidants - Benefits, Sources, Mechanisms of Action","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78739936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-11DOI: 10.5772/INTECHOPEN.95489
I. Yumoto, Yoshiko Hanaoka, Isao Hara
Enzymatic evolutionary strategies for adaptation to a high H2O2 environment have been evaluated using catalases with high catalytic efficiency isolated from two H2O2-tolerant bacteria, Exiguobacterium oxidotolerans and Psychrobacter piscatori. The entrance size of the narrow main channel in catalase has been estimated by determining the formation rate of the intermediate state of peracetic acid (b), which is a larger substrate than H2O2 versus that of catalase activity with H2O2 (a) (calculated as b/a). The ratio of b/a in E. oxidotolerans catalase (EKTA) is much higher than that of P. piscatori catalase (PKTA). To elucidate the structural differences between the catalases, the amino acids present in the main channel have been compared between the two catalases and other catalases in the database. The combination of amino acid residues, which contribute high catalytic efficiency in the narrow main channel of EKTA were different from those in PKTA. In this review, we discuss strategic differences in the elimination of high concentration of H2O2 owing to differences in the phylogenetic positions of catalases. In addition, we describe the relationships between the environmental distributions of genera involved in H2O2-resistant bacteria and their catalase functions based on the main channel structure of catalase.
{"title":"Evolutionary Strategies of Highly Functional Catalases for Adaptation to High H2O2 Environments","authors":"I. Yumoto, Yoshiko Hanaoka, Isao Hara","doi":"10.5772/INTECHOPEN.95489","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.95489","url":null,"abstract":"Enzymatic evolutionary strategies for adaptation to a high H2O2 environment have been evaluated using catalases with high catalytic efficiency isolated from two H2O2-tolerant bacteria, Exiguobacterium oxidotolerans and Psychrobacter piscatori. The entrance size of the narrow main channel in catalase has been estimated by determining the formation rate of the intermediate state of peracetic acid (b), which is a larger substrate than H2O2 versus that of catalase activity with H2O2 (a) (calculated as b/a). The ratio of b/a in E. oxidotolerans catalase (EKTA) is much higher than that of P. piscatori catalase (PKTA). To elucidate the structural differences between the catalases, the amino acids present in the main channel have been compared between the two catalases and other catalases in the database. The combination of amino acid residues, which contribute high catalytic efficiency in the narrow main channel of EKTA were different from those in PKTA. In this review, we discuss strategic differences in the elimination of high concentration of H2O2 owing to differences in the phylogenetic positions of catalases. In addition, we describe the relationships between the environmental distributions of genera involved in H2O2-resistant bacteria and their catalase functions based on the main channel structure of catalase.","PeriodicalId":8028,"journal":{"name":"Antioxidants - Benefits, Sources, Mechanisms of Action","volume":"603 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77412451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：