Plant Physiology and Biochemistry

Volume 166, September 2021, Pages 10-19
Plant Physiology and Biochemistry

Review
The role of quercetin in plants

https://doi.org/10.1016/j.plaphy.2021.05.023Get rights and content

Highlights

  • •
    Quercetin is a special subclass of flavonoid.
  • •
    Biosynthesis of flavonoids, their signaling pathways, and quercetin's role in plant signaling is discussed.
  • •
    Quercetin's role in increasing several physiological and biochemical processes in under stress and non-stress environments.
  • •
    Quercetin is a powerful antioxidant, so it potently provides plant tolerance against several biotic and abiotic stresses.

Abstract

Flavonoids are a special category of hydroxylated phenolic compounds having an aromatic ring structure. Quercetin is aspecial subclass of flavonoid. It is a bioactive natural compound built upon the flavon structure nC6(ring A)-C3(ring C)–C6(ring B). Quercetin facilitates several plant physiological processes, such as seed germination, pollen growth, antioxidant machinery, and photosynthesis, as well as induces proper plant growth and development. Quercetin is a powerful antioxidant, so it potently provides plant tolerance against several biotic and abiotic stresses. This review highlights quercetin's role in increasing several physiological and biochemical processes under stress and non-stress environments. Additionally, this review briefly assesses quercetin's role in mitigating biotic and abiotic stresses (e.g., salt, heavy metal, and UV stress). The biosynthesis of flavonoids, their signaling pathways, and quercetin's role in plant signaling are also discussed.

Introduction

Plants produce huge amounts of different primary and secondary metabolites. Primary metabolites are directly involved in photosynthesis, the energy expenditure process, the metabolism of fat, protein, carbohydrate, and cells' vital activities. Primary metabolites are used up by plant cells, while secondary metabolites perform several activities in different parts of the plant, either in situ or ex-situ. The synthesis of secondary metabolites is restricted by its location, as every organ has a different need for secondary metabolites. Light, ultraviolet radiations, drought, salinity, and numerous other sorts of stresses also modulate the production of secondary metabolites (Li et al., 2020; Nabavi et al., 2020). Flavonoids can promote nutrient uptake in plants as it help in interacting plants with nitrogen-fixing bacteria and arbuscular mycorrhizal fungi. Flavonoids are supposed to encode the chemical information that influences the outcome of a huge amount of biological interactions, thus controlling large-scale ecological processes like nutrient cycling and community dynamics (Del Valle et al., 2020).
Shikimic acid and glycolytic pathways are the initial steps for secondary metabolite synthesis. The subsequent variations, including the involvement of different enzymes and cell types, are responsible for synthesizing diverse secondary metabolites (Li et al., 2020). Several extrinsic factors also modify the biosynthesis of these metabolites. Developmental factors alter the initiation and differentiation of plant parts responsible for secondary metabolites synthesis and storage. On the other hand, various extrinsic factors also regulate these processes. Sanchita (2018) observed that fluctuating environments greatly influence the gene responsible for secondary metabolites biosynthesis, so these metabolites' quantity and quality get modified. According to their synthesizing pathway, as many as 100,000 secondary metabolites are present in different plant species. They were categorized into three distinct categories, i.e., terpenes (isoprenoids), nitrogen-containing compounds (i.e., alkaloids, cyanogenic glycosides, and glucosinolates), and phenolic compounds (i.e., phenylpropanoids and flavonoids) (Balestrini et al., 2021).
Among several secondary metabolites, flavonoids are broadly recognized as compounds carrying an aromatic ring with a minimum single hydroxyl group. Around 8000 phenolic compounds have been identified so far from various plants, half of which are flavonoids found as glycosides, aglycone, and methylated derivatives. The synthesis of flavonoids is done via the polypropanoid pathway, where phenylalanine acts as a startup molecule. Flavonoids, which were initially named vitamin P, in combination with vitamin C, were reported as valuable for maintaining the integrity of the capillary wall and capillary resistance (Havsteen, 1983). The nature of flavonoids depends on their degree of hydroxylation and polymerization, structural class, other conjugations, and substitutions (Kumar and Pandey, 2013; Ahmed et al., 2016). Flavonoids are classified into several subclasses comprising flavonols (e.g., quercetin, myricetin, fisetin, and kaempferol), flavones (e.g., apigenin, luteolin, and flavones), isoflavonoids, flavanones (e.g., naringenin, flavanone, and hesperetin), isoflavones, catechins, and anthocyanidins. The free radicals scavenging property of flavonoids is considered in medicine (Cook and Samman, 1996; Van Acker et al., 1996).
This review highlights quercetin's role in plants and its biosynthesis and regulation. It also focuses on the role of quercetin in signal transduction, as well as its potential role in providing plant stress tolerance by modulating diverse physio-biochemical traits.

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Section snippets

Occurrence

Quercetin, a plant pigment widely present in tea and onion, works as an antioxidant. The name quercetin derives from the Latin word quercetum, which means Quercus robur (oak). Quercetin has medical properties, including anti-allergy, anti-inflammatory, anticancer, cardiovascular protection, anti-tumor, anti-viral, anti-diabetic, immune-modulatory, anti-hypertensive, and gastroprotective effects (Lakhanpal and Rai, 2007). Quercetin is yellow-colored, a crystalline insoluble solid substance

Biosynthesis of quercetin

Quercetin biosynthesis takes place via the phenylpropanoid metabolic pathway. Initially, cinnamic acid is synthesized from phenylalanine; this reaction is catalyzed by the crucial enzyme phenylalanine ammonia-lyase (PAL) (Fig. 1). In particular, cinnamic acid undergoes the action of chief enzyme cinnamate 4-hydroxylase (C4H) to produce p-coumaric acid. This synthesized p-coumaric acid with carboxylic group undergoes ligation with CoA and produces 4-coumaroyl-CoA. This particular reaction is

Quercetin-derived compounds

Quercetin is a bioactive natural compound built upon the flavon structure: C6(A-ring)-C3(C-ring)-C6(B-ring) (Fig. 1). The structural differences in the various flavonoid are due to the changeover of the differentially located hydrogen ion with other groups, including hydroxyl, methoxyl, and glycosyl. Additional structural variations come about due to the C-ring oxidation and its association with the B-ring. Isoquercetin is a quercetin-derived compound having attached glucose instead of the 3-OH

Quercetin in phytohormone signaling

Several changes have occurred in the past, making the recent flora more adaptive than earlier. One of them is replacing mycosporine-like amino acid (MAA) with flavonol metabolism. Marine flora started producing MAA as a UV-protectant material. Gradual evolution pushed vegetation towards nutrient-poor land, and MAA (being an N-containing compound) became costly for them; this marks the turning point where the flavonol takes over MAA's function. Flavonols proved themselves as powerful in

Role of quercetin in plants

Flavonoids are essential secondary metabolites synthesized in almost all plant parts under different plant-environment communication. They are associated with numerous physiological activities, including the taste and smell of fruits, flowers, and vegetables, and color development, making them that compose them essential compounds in the context of insects, birds, and animal attraction, facilitating seed dispersal. Likewise, flavonoids protect the plants from noxious insects and herbivores (

Quercetin in stress mitigation

Flavonoids are a diverse group of secondary metabolites, performing a vast range of biological functions, including stress protection. The fluctuating environment alters the flavonoid synthesizing pathway, indicating flavonoid's stress protective mechanisms in plants (Chalker-Scott, 1999). Increased flavonols under biotic and abiotic stress indicate their stress-filter function in plants. Having OH-group at the 3-position of flavonoid skeleton makes flavonols more efficient ROS scavengers,

Conclusions and future prospective

Quercetin is the particular class of bioactive flavonoids built upon the flavon structure that plays a remarkable role in facilitating numerous plant functions. However, it is still regarded as an enigmatic compound. It is becoming highly apparent that quercetin is a multifaceted compound in plants. This review gives a better understanding of several key characteristic features related to flavonoids, especially quercetin, including their potential sources in plants. Interestingly, recent

Authors' contributions

SH: an idea of the article; PS, YA: drafting of the article; SH, AB: significant revision and precious intellectual input; all authors: final acceptation. We apologize to the authors whose previous works have not been cited due to space limitations.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

References (150)

  • M.A. Griep et al.

    Myricetin inhibits Escherichia coli DNA B helicase but not primase

    Bioorg. Med. Chem.

    (2007)
  • G.R.M.M. Haenen et al.

    Peroxynitrite scavenging by flavonoids

    Biochem. Biophys. Res. Commun.

    (1997)
  • B. Havsteen

    Flavonoids, a class of natural products of high pharmacological potency

    Biochem. Pharmacol.

    (1983)
  • T. Hirayama et al.

    Perception and transduction of abscisic acid signals: keys to the function of the versatile plant hormone ABA

    Trends Plant Sci.

    (2007)
  • R. Jorgensen

    The origin of land plants: a union of alga and fungus advanced by flavonoids?

    Biosystems

    (1993)
  • K.H. Lee et al.

    Activation of glucosidase via stress-induced polymerization rapidly increases active pools of abscisic acid

    Cell

    (2006)
  • M. Lesjak et al.

    Antioxidant and anti-inflammatory activities of quercetin and its derivatives

    J. Funct. Food.

    (2018)
  • Y. Li et al.

    Quercetin, inflammation and immunity

    Nutrients

    (2016)
  • Y. Li et al.

    The effect of developmental and environmental factors on secondary metabolites in medicinal plants

    Plant Physiol. Biochem.

    (2020)
  • D. Metodiewa et al.

    Quercetin may act as a cytotoxic prooxidant after its metabolic activation to semiquinone and quinoidal product

    Free Radical Biol. Med.

    (1999)
  • M. Michniewicz et al.

    Antagonistic regulation of PIN phosphorylation by PP2A and PINOID directs auxin flux

    Cell

    (2007)
  • B. Mishra et al.

    Effect of O-glycosilation on the antioxidant activity and free radical reactions of a plant flavonoid chrysoeriol

    Bioorgan. Med. Chem.

    (2003)
  • S.M. Nabavi et al.

    Flavonoid biosynthetic pathways in plants: versatile targets for metabolic engineering

    Biotechnol. Adv.

    (2020)
  • K.A. Ohemeng et al.

    DNA gyrase inhibitory and antibacterial activity of some flavones

    Bioorg. Med. Chem. Lett

    (1993)
  • K. Abdel-Lateif et al.

    The role of flavonoids in the establishment of plant roots endosymbioses with arbuscular mycorrhiza fungi, rhizobia and Frankia bacteria

    Plant Signal. Behav.

    (2012)
  • M. Adamowski et al.

    PIN-dependent auxin transport: action, regulation, and evolution

    Plant Cell

    (2015)
  • G. Agati et al.

    Multiple functional roles of flavonoids in photoprotection

    New Phytol.

    (2010)
  • G. Agati et al.

    Flavonoid distribution in tissues of Phillyrea latifolia L. leaves as estimated by microspectrofluorometry and multispectral fluorescence microimaging

    Photochem. Photobiol.

    (2002)
  • G. Agati et al.

    Chloroplast-located flavonoids can scavenge singlet oxygen

    New Phytol.

    (2007)
  • G. Agati et al.

    Mesophyll distribution of 'antioxidant' flavonoid glycosides in Ligustrum vulgare leaves under contrasting sunlight irradiance

    Ann. Bot.

    (2009)
  • S.I. Ahmed et al.

    Pharmacologically active flavonoids from the anticancer, antioxidant and antimicrobial extracts of Cassia angustifolia Vahl

    BMC Compl. Alternative Med.

    (2016)
  • T.A. Akhtar et al.

    Photosynthetic redox imbalance influences flavonoid biosynthesis in Lemna gibba

    Plant Cell Environ.

    (2010)
  • N.S. Alrawaiq et al.

    A review of flavonoid quercetin: metabolism, bioactivity and antioxidant properties

    Int. J. Pharm. Technol. Res.

    (2014)
  • S. Alseekh et al.

    Quantitative trait loci analysis of seed‐specialized metabolites reveals seed‐specific flavonols and differential regulation of glycoalkaloid content in tomato

    Plant J.

    (2020)
  • D.V. Badri et al.

    Altered profile of secondary metabolites in the root exudates of Arabidopsis ATP-binding cassette transporter mutants

    Plant Physiol.

    (2008)
  • R. Balestrini et al.

    Strategies to modulate specialized metabolism in Mediterranean crops: from molecular aspects to field

    Int. J. Mol. Sci.

    (2021)
  • A. Bartwal et al.

    Role of secondary metabolites and brassinosteroids in plant defense against environmental stresses

    J. Plant Growth Regul.

    (2012)
  • U. Bechtold et al.

    Impact of chloroplastic- and extracellular-sourced ROS on high light-responsive gene expression in Arabidopsis

    J. Exp. Bot.

    (2008)
  • C. Becker et al.

    Unlike quercetin glycosides, cyanidin glycoside in red leaf lettuce responds more sensitively to increasing low radiation intensity before than after head formation has started

    J. Agric. Food Chem.

    (2014)
  • F.J. Berli et al.

    Abscisic acid is involved in the response of grape (Vitis vinifera L.) cv. Malbec leaf tissues to ultraviolet-B radiation by enhancing ultraviolet-absorbing compounds, antioxidant enzymes and membrane sterols

    Plant Cell Environ.

    (2010)
  • F.J. Berli et al.

    Solar UV-B and ABA are involved in phenol metabolism of Vitis vinifera L. increasing biosynthesis of berry skin polyphenols

    J. Agric. Food Chem.

    (2011)
  • C. Bhatia et al.

    Low temperature enhanced flavonol synthesis requires light-associated regulatory components in Arabidopsis thaliana

    Plant Cell Physiol.

    (2018)
  • K.M. Brodowska

    Natural flavonoids: classification, potential role, and application of flavonoid analogues

    Eur. J. Biol. Res.

    (2017)
  • D.E. Brown et al.

    Flavonoids act as negative regulators of auxin transport in vivo in Arabidopsis

    Plant Physiol.

    (2001)
  • C. Brunetti et al.

    Modulation of phytohormone signaling: a Primary function of flavonoids in plant-environment interactions

    Front. Plant Sci.

    (2018)
  • C.S. Buer et al.

    Flavonoids: new roles for old molecules

    J. Integr. Plant Biol.

    (2010)
  • I.E. Burbulis et al.

    Interactions among enzymes of the Arabidopsis flavonoid biosynthetic pathway

    P. Natl. Acad. Sci. USA

    (1999)
  • M. Cavia-Saiz et al.

    Antioxidant properties, radical scavenging activity and biomolecule protection capacity of flavonoid naringenin and its glycoside naringin: a comparative study

    J. Sci. Food Agric.

    (2010)
  • S. Cesco et al.

    Plant-borne flavonoids released into the rhizosphere: impact on soil bio-activities related to plant nutrition. A review

    Biol. Fertil. Soils

    (2012)
  • L. Chalker-Scott

    Environmental significance of anthocyanins in plant stress responses

    Photochem. Photobiol.

    (1999)

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