Plant and microbial sources of antioxidants

Abstract

In recent years there has been growing interest in substances with antioxidative properties, which reduce or prevent harmful effects of free radicals on living tissues, and inhibit aging processes and the development of certain diseases. The objective of this paper is to review new methods of obtaining antioxidants of plant origin and new trends in research aiming to improve their quality and profitability on an industrial scale. Among the issues discussed, there are the methods that use techniques of plant and microbial genetic engineering. A brief description of antioxidants and natural sources of their occurrence is also presented in this paper. In view of the fact that the biosynthesis of flavonoids and isoflavonoids is probably the best-known metabolic pathway of natural plant products, the review of achievements of recent years in the field of metabolic engineering was shown with the example of flavonoids. The modifications of flavonoid biosynthetic pathways were related to changes in the expression level of structural or regulatory genes, silencing of competitive genes or modifying catalytic properties of enzymes using techniques of protein engineering. The paper also presents the achievements of microorganism engineering in the field of application of fermentation processes as a source of specific flavonoid compounds, which was possible by designing the phenylpropanoid biosynthetic pathway in cells of microorganisms such as the bacterium E. coli or S. cerevisiae, baker's yeast. Both approaches can be used in the production of flavonoids attractive in terms of application.

Molecular mechanisms associated with microbial biostimulant-mediated growth enhancement, priming and drought stress tolerance in maize plants

“…Secondary (also termed specialized) metabolites are widely distributed in plants and are usually classified based on their biosynthetic pathways, and three major families are generally considered: alkaloids, terpenes/steroids and phenolics 41 . Flavonoids have been reported to have diverse functions that include control of respiration and photosynthesis 42 , antioxidant and chelating capacity 43 , and drivers of symbiosis between plants and rhizobacteria 44 . Thus, the observed increased levels of apigenin, apigetrin and vicenin in maize plants treated with PGPR (Fig.…”

Uncovering the evolutionary origin of blue anthocyanins in cereal grains

“…They also protect against UV radiation and strong light, which has facilitated the establishment of vascular plants on land from the original marine environments (Agati et al, 2013;Mouradov and Spangenberg, 2014). As defence mechanisms, anthocyanins act as potent antioxidants (Stolarzewicz et al, 2013), and some also demonstrate antiviral, antibacterial and fungicidal activities cooperating in plant-pathogen interactions (Chalker-Scott 1999;Gould, 2004;Lev-Yadun and Gould, 2009;Buer et al, 2010;Hafidh et al, 2011;Petroni and Tonelli, 2011). In the health sector the antioxidant capacities of anthocyanins have recently spurred increasing interest for their use in the prevention of cancer, diabetes and inflammation (Wang and Stoner, 2008;Lee et al, 2017;Rozanska and Regulska-Ilow, 2018).…”

Flavonoids: a metabolic network mediating plants adaptation to their real estate

“…Physiological functions of flavonoids and the reasons for their ubiquitous existence have been widely discussed. A short list of these functions includes: (i) protection against insect predation and defense against microbes ( Kliebenstein, 2004 ; Bidart-Bouzat and Kliebenstein, 2008 ); (ii) action as sunscreens to absorb UV radiation and strong light, thus replacing mycosporine-like amino acids usually detected in algae ( Guo et al, 2008b ; Agati et al, 2013 ); (iii) attraction of insect pollinators through production of colorful anthocyanins, absorbing different spectra of visible light ( Winkel-Shirley, 2001a , b ); (iv) action as antioxidants, inhibiting the generation of reactive oxygen species (ROS), by maintaining their concentration within a sub-lethal range ( Blokhina et al, 2003 ; Agati et al, 2012 , 2013 ; Stolarzewicz et al, 2013 ); (v) involvement in pollen germination ( Tanaka and Ohmiya, 2008 ; Tanaka et al, 2008 ; Ferreyra et al, 2012b ); (vi) involvement in biological communication in the rhizosphere ( Cesco et al, 2012 ; Weston and Mathesius, 2013 ) and action as (vii) developmental regulators, involved in auxin transport and catabolism ( Friml and Jones, 2010 ).…”