The Biosynthesis of Phenolic Compounds Is an Integrated Defence Mechanism to Prevent Ozone Injury in Salvia officinalis

Abstract

Specialized metabolites constitute a major antioxidant system involved in plant defence against environmental constraints, such as tropospheric ozone (O3). The objective of this experiment was to give a thorough description of the effects of an O3 pulse (120 ppb, 5 h) on the phenylpropanoid metabolism of sage, at both biochemical and molecular levels. Variable O3-induced changes were observed over time among the detected phenylpropanoid compounds (mostly identified as phenolic acids and flavonoids), likely because of their extraordinary functional diversity. Furthermore, decreases in the phenylalanine ammonia-lyase (PAL), phenol oxidase (PPO), and rosmarinic acid synthase (RAS) activities were reported during the first hours of treatment, probably due to an O3-induced oxidative damage to proteins. Both PAL and PPO activities were also suppressed at 24 h from the beginning of exposure, whereas enhanced RAS activity occurred at the end of treatment and at the recovery time, suggesting that specific branches of the phenolic pathways were activated. The increased RAS activity was accompanied by the up-regulation of the transcript levels of genes like RAS, tyrosine aminotransferase, and cinnamic acid 4-hydroxylase. In conclusion, sage faced the O3 pulse by regulating the activation of the phenolic biosynthetic route as an integrated defence mechanism.

Plant Secondary Metabolites Produced in Response to Abiotic Stresses Has Potential Application in Pharmaceutical Product Development

“…Similarly, O 3 treatment (200 nL/L for 10 h) increases both PAL and CHS activities resulting in a 2-fold increase of total leaf furanocoumarins and flavone glycosides in parsley ( Petroselinum crispum ) [ 239 ]. Lignin deposition in O 3 exposed leaves is also linked to increased PAL activity [ 240 ], whereas in sage ( Salvia officinalis ), both PAL and PPO (phenol oxidase) activities were suppressed after 24 h exposure to O 3 [ 241 ]. However, rosmarinic acid synthase (RAS) activity is accompanied by the increased transcription level of genes (e.g., RAS) encoding biosynthesis enzymes, suggesting that the sage plant mediates oxidative damage through synthesizing phenolic compounds.…”

Production of Trans-Cinnamic Acid by Immobilization of the Bambusa oldhamii BoPAL1 and BoPAL2 Phenylalanine Ammonia-Lyases on Electrospun Nanofibers

“…Phenylalanine ammonia-lyase (PAL, 4.3.1.24) catalyzes the deamination of L-phenylalanine to yield trans-cinnamic acid and ammonia, is one of the crucial steps in the general phenylpropanoid pathway (Figure 1) [1,2]. PAL plays a vital role in supplying secondary metabolic products in plants such as flavonoids, lignins, caffeic acid, ferulic acid and so on [3,4].…”

Phenolic Compounds: Classification, Chemistry, and Updated Techniques of Analysis and Synthesis

“…There are two general routes for the biosynthesis of phenolic compounds; shikimic acid pathway and the acetic acid pathway. [12,28] In the shikimic acid pathway (Figure 35), hosphoenolpyruvate and erthrose-4-phosphate react in few steps to provide 3-dehydroquinate. Dehydration with shikimate dehydrogenase gives 3-dehydroshikimic acid.…”

“…[32] Functionalization and expeditious transformation of phenol derivatives into new functional molecules have been made possible with metal-catalyzed C-H bond functionalization. [28,29] The C-H activation science has allowed accessing new and further functionalized phenol derivatives in an expedient and efficient manner (Figure 44). Thus catalysts based on various transition metals such as Pd, Rh, Ru, Ir, Au and Fe have allowed functionalization of inert C-H bonds in simple phenolic compounds and subsequently their transformation into new functionalized molecules.…”