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Flavonoids from Quercus Genus: Applications in Melasma and Psoriasis
Published in Tatjana Stevanovic, Chemistry of Lignocellulosics: Current Trends, 2018
Esquivel-García Roberto, Velázquez-Hernández María-Elena, Valentín-Escalera Josué, Valencia-Avilés Eréndira, Rodríguez-Orozco Alain-Raimundo, Martha-Estrella García-Pérez
The flavonoid classification depends on their degree of hydroxylation, presence of substitutions, conjugations and polymerization degree (Kumar and Pandey 2013). Flavonoid chemical structures are based upon a fifteen-carbon skeleton consisting of two benzene rings linked via a heterocyclic pyrane ring (C6C3C6). This structure forms an oxygenated heterocycle except in the cases of chalcones and dihydrochalcones (Kumar and Pandey 2013, Routray and Orsat 2012, Stalikas 2007). The various classes of flavonoids differ in the level of oxidation and pattern of substitution of the C ring, while individual compounds within a class differ in the pattern of substitution of the A and B rings (Kumar and Pandey 2013). Major classes of flavonoids based on abundance in food are: flavonols, flavones, isoflavones, flavanones, flavandiols, anthocyanins, proanthocyanidins, and catechins (Bravo 1998). Other classes of flavonoids include flavan-3-ols, anthocyanidins, chalcones and other biosynthetic intermediates of the flavonoid biosynthesis such as aurones, biflavonoids, and dihydrochalcones (Rice-Evans et al. 1996, Routray and Orsat 2012, Stalikas 2007). The first flavonoid isolated in 1930 from oranges was the rutin and now between 4,000 and 6,000 varieties of these compounds have been identified (Kumar and Pandey 2013, Stevanovic et al. 2009).
Biological System as Reactor for the Production of Biodegradable Thermoplastics, Polyhydroxyalkanoates
Published in Devarajan Thangadurai, Jeyabalan Sangeetha, Industrial Biotechnology, 2017
Akhilesh Kumar Singh, Nirupama Mallick
In photoautotrophic host system, synthesis of PHAs in agricultural crops has been regarded as a promising alternative (Poirier et al., 1995; Poirier, 1999, 2002). The first PHA synthesized in plants was a homopolymer of PHB. Expression of the last two enzymes, for example, an acetoacetyl-CoA reductase and a PHA synthase, from the bacterium C. necator into the cytoplasm of Arabidopsis thaliana cells steered to production of PHB as intracellular inclusions up to 0.1% of shoot dry weight (Table 11.3). Growth of this transgenic plant was harshly reduced, probably triggered by the limitation of the acetyl-CoA pool available in the cytoplasm for isoprenoid and flavonoid biosynthesis (Poirier, 2002).
Ecological Consequences of Enhanced UV Radiation on the Phenolic Content of Brassica Oleracea: a Review
Published in Donald L. Wise, Debra J. Trantolo, Edward J. Cichon, Hilary I. Inyang, Ulrich Stottmeister, Remediation Engineering of Contaminated Soils, 2000
Jeffrey M. Lynch, Alicja M. Zobel
Levitt (27) and Bornman (41) reported that epidermal cells, which typically accumulate plant pigments, absorb approximately 90% of the incident UV. Levitt (27) attributed the high absorbance to the flavonoid compounds. Zobel and Lynch (34) found an increase in UV-absorbing phenolics in two Acer species following enhanced UV-A. Research by Flint et al. (42), Caldwell et al. (43), and Day et al. (40) found that UV-absorbing phenolics, specifically the flavonoids, increased in plant tissues in response to enhanced UV-B. Rhodes (22) stated that flavonoids increase in plant tissues following UV radiation treatment as UV increases the activity of phenylalanine ammonia lyase (PAL) as well as the other enzymes involved in flavonoid biosynthesis. Therefore, it would seem that most plant species respond to enhanced irradiation, regardless of whether the irradiation is UV-A or UV-B, by synthesizing flavonoids.
Enhanced production of total flavones from Inonotus baumii by multiple strategies
Published in Preparative Biochemistry & Biotechnology, 2018
Hui Li, Xue Jiao, Wanlong Zhou, Yajie Sun, Wei Liu, Weiping Lin, Ao Liu, Aihuan Song, Hu Zhu
The second method is the addition of key precursors or elicitors to regulate the synthesis of many secondary metabolites based on their biosynthetic pathway or physiological function. Previous studies have shown that the supplementation of precursors in flavonoid biosynthesis or some abiotic elicitors could enhance the production of flavonoids in the callus culture of some plant cells such as Anthocephalus indicus[9] and Maytenus emarginata.[10] However, there has been no report on the effects of precursors and elicitors on flavonoid production by I. baumii.
Flavonoids – flowers, fruit, forage and the future
Published in Journal of the Royal Society of New Zealand, 2023
Nick W. Albert, Declan J. Lafferty, Sarah M. A. Moss, Kevin M. Davies
The biosynthesis of flavonoids begins with the aromatic amino acid phenylalanine, and is part of the larger phenylpropanoid biosynthesis pathway, which produces lignin, phenolic acids and volatiles, in addition to flavonoids. The first committed step to flavonoid biosynthesis (Figure 1B, refer for enzyme abbreviations) is catalysed by CHS, after which a series of isomerisation (CHI), hydroxylation (F3H, F3′H, F3′5′H), reduction (DFR, LAR, ANR) or oxidation (FLS, ANS) reactions occur to generate various flavonoid compounds, which are further modified or ‘decorated’ by glycosylation, methylation or acylation. Martin and Gerats (1993) coined the term ‘early’ and ‘late’ flavonoid biosynthesis genes. The ‘early biosynthetic genes’ were steps that did not show substantially reduced expression in anthocyanin regulatory mutants (typically CHS, CHI, F3H), while the ‘late biosynthetic genes’ showed substantial or a complete loss of expression (DFR, ANS, UFGT). This term has been widely adopted in the literature, but is often misinterpreted to suggest the early biosynthetic genes are not targeted by regulators of anthocyanin biosynthesis. More recently, studies have identified genes encoding non-enzymatic biosynthetic proteins, such as CHI-Like and the PR10 proteins, which are necessary for efficient production of flavonoids (Muñoz et al. 2010; Morita et al. 2014; Ban et al. 2018; Clayton et al. 2018; Berland et al. 2019), possibly by binding metabolite intermediates and channelling them to enzymes (e.g. CHS) efficiently, with correct stereochemistry (Dastmalchi 2021). The regulation of different branches of flavonoid production is complex, nuanced, and involves redundant regulation of some biosynthetic genes, particularly genes common to multiple pathways. Central to the regulation of flavonoids are R2R3-MYB transcription factors, which have diversified into sub-groups that have specialised in regulating the production of different metabolites (Figure 2A).