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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
The biosynthesis of coumarins is complex and involves several different enzymes (see Appendix). Hydroxycinnamic acids and coumarins are phenylpropanoids (58,60), as they contain at least one phenylpropane C6C3 structure. All of these compounds are derived from the aromatic amino acid phenylalanine. Phenylalanine is synthesized by the shikimic acid pathway and is converted by PAL to cinnamic acid, a key intermediate in phenylpropanoid biosynthesis (63,64). From cinnamic acid, derivatives are synthesized by the substitution of hydroxyl and methoxy groups to the aromatic ring. Two such derivatives are o-coumaric acid and sinapic acid.
Structure and Biosynthesis of Lignin
Published in Jean-Luc Wertz, Magali Deleu, Séverine Coppée, Aurore Richel, Hemicelluloses and Lignin in Biorefineries, 2017
Jean-Luc Wertz, Magali Deleu, Séverine Coppée, Aurore Richel
Lignin is the generic term for a large group of aromatic polymers resulting from the oxidative combinatorial coupling of 4-hydroxyphenylpropanoids (monolignols).3–5 It is the only naturally synthesized polymer with an aromatic backbone.6 The name of phenylpropanoids is derived from the phenyl group and the propene tail of cinnamic acid, which is synthesized from the amino acid phenylalanine (Phe) in the first step of phenylpropanoid biosynthesis. The three most abundant monolignols are p-coumaryl (4-hydroxycinnamyl), coniferyl (3-methoxy 4-hydroxycinnamyl), and sinapyl (3,5-dimethoxy 4-hydroxycinnamyl) alcohols (Figure 6.1).1
Explicating the effect of the ozonation on quality parameters of onion (Allium cepa L.) in terms of pungency, phenolics, antioxidant activity, colour, and microstructure
Published in Ozone: Science & Engineering, 2023
Pramod S. Shelake, Debabandya Mohapatra, Manoj Kumar Tripathi, Saroj Kumar Giri
Phenylalanine ammonia-lyase (PAL; EC 4.3.1.5) is known for initiating the phenylpropanoid biosynthesis pathway and is generally found in most of the higher plants. It helps in breaking down of ammonia group from L-phenylalanine, resulting in the formation of trans-cinnamate, initiating the biosynthesis of plant-specific phenylpropanoid derivatives, such as phenolics (Benkeblia 2000). Ozone treatment to onion could be attributed to the activation of PAL (Ali, Ong, and Forney 2014), which resulted in increased phenolic and flavonoids content. Another reason for the increase in phenol might be the cell wall modification during ozone treatment that caused enhanced extractability and release of some conjugated phenolic compounds. At higher concentrations, however, ozone decomposition produces numerous free radicals that scavenge phenolic compounds in commodity, resulting in a decrease in the phenolic and flavonoid contents (Alothman et al. 2010). This might have resulted in a decrease in phenolics after an effective ozone concentration of 400 ppm.
Impact of copper treatment on phenylpropanoid biosynthesis in adventitious root culture of Althaea officinalis L.
Published in Preparative Biochemistry & Biotechnology, 2022
Yun Ji Park, Nam Su Kim, Ramaraj Sathasivam, Yong Suk Chung, Sang Un Park
Phenylpropanoids and their derivatives are a major class of plant secondary metabolites and are commonly present in beverages, cereal grains, fruits, herbs, spices, and vegetables.[16] They are responsible for various aspects of plant growth, structural support, and response to stimuli.[17] These compounds play a crucial role in stress response to light and mineral shortages and are essential mediators of plant interactions with other species.[17] Phenylpropanoids have numerous beneficial biological properties, such as anticancer, antidiabetic, anti-inflammatory, antimicrobial, and antioxidant activities. These compounds also have renoprotective, neuroprotective, cardioprotective, and hepatoprotective effects.[16] Owing to their various biological properties, phenylpropanoids have been applied in a wide range of industries, such as cosmetics, food (edible coating, packaging films, and preservation), pharmaceuticals, and other industries (biofuel, sensors, and textiles).[16]
Exposure of tomato (Lycopersicon esculentum) to silver nanoparticles and silver nitrate: physiological and molecular response
Published in International Journal of Phytoremediation, 2020
Azam Noori, Trevor Donnelly, Joseph Colbert, Wenjun Cai, Lee A. Newman, Jason C. White
Plants produce antioxidants to reduce the harmful effects of ROS. The phenylpropanoid pathway is known to be involved in stress and antioxidative response (Mintz-Oron et al. 2008; Maleki et al. 2017). Flavonoids, the products of the phenylpropanoid pathway, are produced as antioxidants and protectants against heavy metal stress (Keilig and Ludwig-Müller 2009). The oxidation of flavonoids by the enzyme peroxidase promotes H2O2 scavenging (Jabeen et al. 2017; Amin and Bano 2018). Higher concentrations of in planta flavonoids are often detected in species that tolerate environmental stress (Atala et al. 2017; Guo et al. 2018). In our study, in spite of the clear oxidative stress, the total flavonoid concentration did not increase significantly compared to the control group (Figure 3). Considering the role of flavonoids as antioxidants and the elevated amount of H2O2 and MDA (Figure 2), the level of anthocyanins was studied to understand the antioxidative responses. Anthocyanins are a group of water soluble flavonoids and are involved in ROS scavenging (Moustaka et al. 2018; Aghdam et al. 2019). In this study, the level of anthocyanins increased up to three times in plants exposed to AgNPs and 10–20 mg/L of AgNO3. However, exposure to 30 mg/L AgNO3 did not show any significant differences compared to the control. This could be due to high toxicity levels in plants exposed to 30 mg/L AgNO3. Plant growth, antioxidant responses, and overall health was significantly lower in this group indicating an inability in performing metabolic, antioxidative, and defense responses.