ijms-logo

Journal Browser

Journal Browser

Special Issue "Flavonoids"

A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Molecular Plant Sciences".

Deadline for manuscript submissions: closed (28 June 2021).

Special Issue Editors

Prof. Dr. Marcello Iriti
E-Mail Website
Guest Editor
Department of Agricultural and Environmental Sciences, Milan State University, Milan, Italy
Interests: environmental pollution; agrochemicals; mycotoxins; biomonitoring
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

Flavonoids are the largest group of polyphenols, plant secondary metabolites arising from the essential aromatic amino acid phenylalanine (or more rarely from tyrosine) via the phenylpropanoid pathway. The flavan nucleus is the basic 15-carbon skeleton of flavonoids (C6-C3-C6), which consists of two phenyl rings (A and B) and a heterocyclic ring (C). The main classes of flavonoids (flavonols, flavanols, flavones, flavanones, isoflavones and anthocyanidins) differ in the level of oxidation and saturation of the C ring, while individual compounds within a class vary in the substitution pattern of the A and B rings. In planta, they exert a plethora of ecological roles as variously colored pigments and signaling molecules, being involved in pollinator attraction and root symbioses, just to name a few examples. In addition, flavonoids protect plant from abiotic and biotic stressors, such as UV radiation and pathogen attack (in this context, they represent a group of phytoalexins). Health-promoting effects of traditional food and medicinal plants have been ascribed to their content in bioactive phytochemicals including flavonoids, also known as nutraceuticals. A huge number of in vitro/in vivo studies on animal and cell experimental models highlighted their preclinical efficacy as antioxidant, antimicrobial, anticancer/chemopreventive, antidiabetic, vasoprotective and vasodilating agents, in addition to their cardio- and neuroprotective effects. The flavonoid mechanism of action is directed toward multiple molecular and biochemical targets in prokaryotic and eukaryotic cells. Therefore, plant foods and herbal remedies are multitarget agents containing hundreds of flavonoids (including aglycones and glycosides) and other different phytochemicals. In this context, given the global threat of antimicrobial resistance, these phytotherapeutics have a low risk of selecting chemoresistant microbial and cancer cells. Flavonoids can also reverse chemoresistance (including multidrug resistance) modulating efflux pumps, and hence they can be used as adjuvant (or chemosensitizer) agents in conventional antimicrobial and anticancer therapies. Not least, flavonoids can mitigate age-associated cellular damage and extend lifespan as epigenetic modulators and by mimicking calorie restriction. Finally, oral bioavailability of flavonoids represents another relevant issue. Indeed, after ingestion, they are metabolized by phase I and II enzymes like other xenobiotics before reaching the target cells and tissues.

In this very wide context, we invite investigators to submit both original research and review articles that explore all these aspects.

Prof. Dr. Marcello Iriti
Dr. Elena Maria Varoni
Prof. Dr. Sara Vitalini
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. International Journal of Molecular Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. There is an Article Processing Charge (APC) for publication in this open access journal. For details about the APC please see here. Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Flavonoid biosynthesis
  • Flavonoid gene expression
  • Plant abiotic stresses
  • Plant biotic stresses
  • Phytoalexins
  • Chemoecology
  • Ecophysiology
  • Functional foods
  • Medicinal plants & herbal remedies
  • Nutraceuticals
  • Antioxidant activity
  • Antimicrobial activity
  • Antimicrobial resistance
  • Anticancer activity
  • Cancer chemoprevention
  • Antidiabetic activity
  • Vasoprotection
  • Cardioprotection
  • Neuroprotection
  • Antiaging agents
  • Sirtuins
  • Oral diseases
  • Oral bioavailability
  • In human studies & randomized clinical studies

Published Papers (7 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Jump to: Review

Article
Photoprotective Role of Photosynthetic and Non-Photosynthetic Pigments in Phillyrea latifolia: Is Their “Antioxidant” Function Prominent in Leaves Exposed to Severe Summer Drought?
Int. J. Mol. Sci. 2021, 22(15), 8303; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22158303 (registering DOI) - 02 Aug 2021
Abstract
Carotenoids and phenylpropanoids play a dual role of limiting and countering photooxidative stress. We hypothesize that their “antioxidant” function is prominent in plants exposed to summer drought, when climatic conditions exacerbate the light stress. To test this, we conducted a field study on [...] Read more.
Carotenoids and phenylpropanoids play a dual role of limiting and countering photooxidative stress. We hypothesize that their “antioxidant” function is prominent in plants exposed to summer drought, when climatic conditions exacerbate the light stress. To test this, we conducted a field study on Phillyrea latifolia, a Mediterranean evergreen shrub, carrying out daily physiological and biochemical analyses in spring and summer. We also investigated the functional role of the major phenylpropanoids in different leaf tissues. Summer leaves underwent the most severe drought stress concomitantly with a reduction in radiation use efficiency upon being exposed to intense photooxidative stress, particularly during the central hours of the day. In parallel, a significant daily variation in both carotenoids and phenylpropanoids was observed. Our data suggest that the morning-to-midday increase in zeaxanthin derived from the hydroxylation of ß-carotene to sustain non-photochemical quenching and limit lipid peroxidation in thylakoid membranes. We observed substantial spring-to-summer and morning-to-midday increases in quercetin and luteolin derivatives, mostly in the leaf mesophyll. These findings highlight their importance as antioxidants, countering the drought-induced photooxidative stress. We concluded that seasonal and daily changes in photosynthetic and non-photosynthetic pigments may allow P. latifolia leaves to avoid irreversible photodamage and to cope successfully with the Mediterranean harsh climate. Full article
(This article belongs to the Special Issue Flavonoids)
Article
Physiological Response of Maize Plants (Zea mays L.) to the Use of the Potassium Quercetin Derivative
Int. J. Mol. Sci. 2021, 22(14), 7384; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22147384 - 09 Jul 2021
Viewed by 322
Abstract
Plant production technologies based solely on the improvement of plants themselves face obstacles resulting from the natural limitations of the biological potential of varieties. Therefore, new substances are sought that positively influence the growth and development of plants and increase resistance to various [...] Read more.
Plant production technologies based solely on the improvement of plants themselves face obstacles resulting from the natural limitations of the biological potential of varieties. Therefore, new substances are sought that positively influence the growth and development of plants and increase resistance to various biotic and abiotic stresses, which also translates into an increase in obtained yields. The exogenous application of various phytoprotectants shows great promise in terms of cost effectiveness compared to traditional breeding methods or transgenic approaches in relation to increasing plant tolerance to abiotic stresses. Quercetin is a strong antioxidant among phenolic compounds, and it plays a physiological and biochemical role in plants. As such, the aim of this research was to assess the effect of an aqueous solution of a quercetin derivative with potassium, applied in various concentrations (0.5%, 1.0%, 3.0% and 5.0%), on the efficiency of the photosynthetic apparatus and biochemical properties of maize. Among the tested variants, compared to the control, the most stimulating effect on the course of physiological processes (PN, gs, ci, CCI, Fv/Fm, Fv/F0, PI) in maize leaves was found in 3.0 and 5.0% aqueous solutions of the quercetin derivative. The highest total antioxidant capacity and total content of polyphenolic compounds were found for plants sprayed with 5.0% quercetin derivative solution; therefore, in this study, the optimal concentration could not be clearly selected. Full article
(This article belongs to the Special Issue Flavonoids)
Show Figures

Figure 1

Article
In Vitro Metabolism of Six C-Glycosidic Flavonoids from Passiflora incarnata L.
Int. J. Mol. Sci. 2021, 22(12), 6566; https://doi.org/10.3390/ijms22126566 - 18 Jun 2021
Viewed by 468
Abstract
Several medical plants, such as Passiflora incarnata L., contain C-glycosylated flavonoids, which may contribute to their efficacy. Information regarding the bioavailability and metabolism of these compounds is essential, but not sufficiently available. Therefore, the metabolism of the C-glycosylated flavones orientin, isoorientin, schaftoside, isoschaftoside, [...] Read more.
Several medical plants, such as Passiflora incarnata L., contain C-glycosylated flavonoids, which may contribute to their efficacy. Information regarding the bioavailability and metabolism of these compounds is essential, but not sufficiently available. Therefore, the metabolism of the C-glycosylated flavones orientin, isoorientin, schaftoside, isoschaftoside, vitexin, and isovitexin was investigated using the Caco-2 cell line as an in vitro intestinal and epithelial metabolism model. Isovitexin, orientin, and isoorientin showed broad ranges of phase I and II metabolites containing hydroxylated, methoxylated, and sulfated compounds, whereas schaftoside, isoschaftoside, and vitexin underwent poor metabolism. All metabolites were identified via UHPLC-MS or UHPLC-MS/MS using compound libraries containing all conceivable metabolites. Some structures were confirmed via UHPLC-MS experiments with reference compounds after a cleavage reaction using glucuronidase and sulfatase. Of particular interest is the observed cleavage of the C–C bonds between sugar and aglycone residues in isovitexin, orientin, and isoorientin, resulting in unexpected glucuronidated or sulfated luteolin and apigenin derivatives. These findings indicate that C-glycosidic flavones can be highly metabolized in the intestine. In particular, flavonoids with ortho-dihydroxy groups showed sulfated metabolites. The identified glucuronidated or sulfated aglycones demonstrate that enzymes expressed by Caco-2 cells are able to potentially cleave C–C bonds in vitro. Full article
(This article belongs to the Special Issue Flavonoids)
Show Figures

Figure 1

Article
Flavonoid and Phenolic Acids Content and In Vitro Study of the Potential Anti-Aging Properties of Eutrema japonicum (Miq.) Koidz Cultivated in Wasabi Farm Poland
Int. J. Mol. Sci. 2021, 22(12), 6219; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22126219 - 09 Jun 2021
Viewed by 634
Abstract
Skin aging is a natural, unavoidable, and complex process caused by oxidative stress. As a consequence, it leads to an increase in the activation of extracellular matrix disruption enzymes and DNA damage. The search for natural sources that inhibit these mechanisms can be [...] Read more.
Skin aging is a natural, unavoidable, and complex process caused by oxidative stress. As a consequence, it leads to an increase in the activation of extracellular matrix disruption enzymes and DNA damage. The search for natural sources that inhibit these mechanisms can be a good approach to prevent skin aging. The purpose of our study was to evaluate the composition of flavonoids and phenolic acids in the extracts obtained from the flowers, roots, and leaves of Eutrema japonicum cultivated in Poland. Then, the resultant extracts were subjected to an assessment of antioxidant, anti-collagenase, anti-elastase, anti-hyaluronidase, antibacterial, and cytotoxic properties. It was demonstrated that the extract from the flowers had the highest content of flavonoid glycosides (17.15 mg/g DE). This extract showed the greatest antioxidant, anti-collagenase, anti-elastase, and anti-hyaluronidase activities compared to the other samples. Importantly, the collagenase inhibitory activity of this extract (93.34% ± 0.77%) was better than that of positive control epigallocatechin gallate (88.49% ± 0.45%). An undeniable advantage of this extract was also to possess moderate antibacterial properties and no cytotoxicity towards normal human skin fibroblasts. Our results suggest that extracts from E. japonicum flowers may be considered as a promising antiaging compound for applications in cosmetic formulations. Full article
(This article belongs to the Special Issue Flavonoids)
Show Figures

Figure 1

Article
Anti-Platelet Properties of Phenolic and Nonpolar Fractions Isolated from Various Organs of Elaeagnus rhamnoides (L.) A. Nelson in Whole Blood
Int. J. Mol. Sci. 2021, 22(6), 3282; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22063282 - 23 Mar 2021
Viewed by 520
Abstract
Sea buckthorn (Elaeagnus rhamnoides (L.) A. Nelson) is a shrub growing in coastal areas. Its organs contain a range of bioactive substances including vitamins, fatty acids, various micro and macro elements, as well as phenolic compounds. Numerous studies of sea buckthorn have [...] Read more.
Sea buckthorn (Elaeagnus rhamnoides (L.) A. Nelson) is a shrub growing in coastal areas. Its organs contain a range of bioactive substances including vitamins, fatty acids, various micro and macro elements, as well as phenolic compounds. Numerous studies of sea buckthorn have found it to have anticancer, anti-ulcer, hepatoprotective, antibacterial, and antiviral properties. Some studies suggest that it also affects the hemostasis system. The aim of the study was to determine the effect of six polyphenols rich and triterpenic acids rich fractions (A–F), taken from various organs of sea buckthorn, on the activation of blood platelets using whole blood, and to assess the effect of the tested fractions on platelet proteins: fraction A (polyphenols rich fraction from fruits), fraction B (triterpenic acids rich fraction from fruits), fraction C (polyphenols rich fraction from leaves), fraction D (triterpenic acids rich fraction from leaves), fraction E (polyphenols rich fraction from twigs), and fraction F (triterpenic acids rich fraction from twigs). Hemostasis parameters were determined using flow cytometry and T-TAS (Total Thrombus-formation Analysis System). Additionally, electrophoresis was performed under reducing and non-reducing conditions. Although all tested fractions inhibit platelet activation, the greatest anti-platelet activity was demonstrated by fraction A, which was rich in flavonol glycosides. In addition, none of the tested fractions (A–F) caused any changes in the platelet proteome, and their anti-platelet potential is not dependent on the P2Y12 receptor. Full article
(This article belongs to the Special Issue Flavonoids)
Show Figures

Figure 1

Review

Jump to: Research

Review
Chirality Matters: Biological Activity of Optically Pure Silybin and Its Congeners
Int. J. Mol. Sci. 2021, 22(15), 7885; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22157885 - 23 Jul 2021
Viewed by 249
Abstract
This review focuses on the specific biological effects of optically pure silymarin flavo-nolignans, mainly silybins A and B, isosilybins A and B, silychristins A and B, and their 2,3-dehydro derivatives. The chirality of these flavonolignans is also discussed in terms of their analysis, [...] Read more.
This review focuses on the specific biological effects of optically pure silymarin flavo-nolignans, mainly silybins A and B, isosilybins A and B, silychristins A and B, and their 2,3-dehydro derivatives. The chirality of these flavonolignans is also discussed in terms of their analysis, preparative separation and chemical reactions. We demonstrated the specific activities of the respective diastereomers of flavonolignans and also the enantiomers of their 2,3-dehydro derivatives in the 3D anisotropic systems typically represented by biological systems. In vivo, silymarin flavonolignans do not act as redox antioxidants, but they play a role as specific ligands of biological targets, according to the “lock-and-key” concept. Estrogenic, antidiabetic, anticancer, antiviral, and antiparasitic effects have been demonstrated in optically pure flavonolignans. Potential application of pure flavonolignans has also been shown in cardiovascular and neurological diseases. Inhibition of drug-metabolizing enzymes and modulation of multidrug resistance activity by these compounds are discussed in detail. The future of “silymarin applications” lies in the use of optically pure components that can be applied directly or used as valuable lead structures, and in the exploration of their true molecular effects. Full article
(This article belongs to the Special Issue Flavonoids)
Show Figures

Graphical abstract

Review
A Comprehensive Review on Chemotaxonomic and Phytochemical Aspects of Homoisoflavonoids, as Rare Flavonoid Derivatives
Int. J. Mol. Sci. 2021, 22(5), 2735; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms22052735 - 08 Mar 2021
Cited by 1 | Viewed by 589
Abstract
Homoisoflavonoids (3-benzylidene-4-chromanones) are considered as an infrequent flavonoid class, possessing multi-beneficial bioactivities. The present study gives an overview on phytochemical aspects of homoisoflavonoids, including utilized plant species, parts, extracts, and separation techniques. Overall, these compounds have mainly been isolated and identified from bulbs [...] Read more.
Homoisoflavonoids (3-benzylidene-4-chromanones) are considered as an infrequent flavonoid class, possessing multi-beneficial bioactivities. The present study gives an overview on phytochemical aspects of homoisoflavonoids, including utilized plant species, parts, extracts, and separation techniques. Overall, these compounds have mainly been isolated and identified from bulbs and rhizomes of the plants belonging to Asparagaceae and Fabaceae families, particularly the genera of Ophiopogon, Dracaena, Scilla, Polygonatum, and Caesalpinia. Full article
(This article belongs to the Special Issue Flavonoids)
Show Figures

Figure 1

Back to TopTop