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Special Issue "Natural Flavonoids: Structure Elucidation, Distribution and Applications"

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Natural Products".

Deadline for manuscript submissions: 30 June 2018

Special Issue Editor

Guest Editor
Prof. Dr. Tsukasa Iwashina

Department of Botany, National Museum of Nature and Science, Amakubo 4-1-1, Tsukuba, Ibaraki 305-0005, Japan
Website | E-Mail
Phone: +81-29-851-5159
Interests: flavonoid distribution in plants; new flavonoid compounds; chemical adaptation of plants against various severe environment using polyphenols; flower colors and flavonoid pigments

Special Issue Information

Dear Colleauges,

Flavonoid is the general name of compounds that have a fifteen-carbon skeleton, which consists of two phenyl rings (A- and B-rings) connected by a three-carbone bridge (C-ring). In general, vascular plants and bryophytes alone possess the biosynthetic ability of the flavonoids, except for a few green alga, fungi, and marine coral. Flavonoids are divided into several classes, e.g., anthocyanins, flavones, flavonols, chalcones, aurones, flavanones, dihydroflavonols, isoflavonoids, flavan and proanthocyanidins, biflavonoids etc. Moreover, numerous sorts of flavonoids occur in plants with additional hydroxyl, methoxyl, methyl and/or glycosyl substitution patterns. Additionally, aromatic and aliphatic acids, sulfate, methylenedioxyl or prenyl groups also attach to flavonoid nucleus and their glycosides. Thus, ca. 9000 kinds of flavonoids have been reported as naturally-occurring compounds. The isolation and identification, structures and distribution of the flavonoids in plants have been reviewed by many authors. Flavonoids, as medicinal resources, were also reviewed. Especially, the pigments, anthocyanins, were recently observed as having effects including antioxidant, antitumor, astringents, etc. However, the secondary metabolites involved in flavonoids were considered to be waste products of plant metabolism in the early days of the 20th century. One of the most important functions of flavonoids may be to serve as an ultraviolet filter in land plants. It has been shown by surveys of some plants that flavonoids act as a UV shield. The occurrence of anthocyanins as pollinator attractants is well-known as a function of flavonoids in plants. Additionally, it is known that flavones and flavonols, which can hardly be seen by the human eye, also act as pollinator attractants in addition to visible anthocyanins. Recently, other functions, e.g., oviposition stimulants, feeding attractants, feeding deterrents, allelopathy and phytoalexins of naturally-occurring flavonoids, have been reported by many authors. However, although almost vascular plants have synthesize abilities of the flavonoids, the presence of flavonoids may be known in ca. 25% of all plants on the Earth, and, moreover, the function of flavonoids in plants are hardly reported.

In this Special Issue, we will publish papers on new flavonoids, new flavonoid resources, flavonoid functions in plants, including as a UV shield, phytoalexins, allelopathy, oviposition stimulants, feeding attractants, feeding deterrent, and contribution of flavonoids, including anthocyanins to flower colors, and so on.

Prof. Dr. Tsukasa Iwashina
Guest Editor

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. Molecules is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). 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.


  • flavonoid distribution in plants
  • new flavonoid resources
  • new compounds
  • chemical ecology
  • chemical adaptation
  • medicinal resources
  • phytoalexins
  • allelopathy
  • plant pigments
  • flower colors

Published Papers (1 paper)

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Open AccessArticle Protective Mechanism of the Antioxidant Baicalein toward Hydroxyl Radical-Treated Bone Marrow-Derived Mesenchymal Stem Cells
Molecules 2018, 23(1), 223; doi:10.3390/molecules23010223
Received: 5 December 2017 / Revised: 16 January 2018 / Accepted: 17 January 2018 / Published: 20 January 2018
Cited by 1 | PDF Full-text (6979 KB) | HTML Full-text | XML Full-text | Supplementary Files
Our study explores the antioxidant and cytoprotective effects of baicalein and further discusses the possible mechanisms. A methyl thiazolyl tetrazolium (MTT) assay revealed that baicalein could considerably enhance the viability of hydroxyl radical-treated bone marrow-mesenchymal stem cells (bmMSCs) at 37–370 µM. The highest
[...] Read more.
Our study explores the antioxidant and cytoprotective effects of baicalein and further discusses the possible mechanisms. A methyl thiazolyl tetrazolium (MTT) assay revealed that baicalein could considerably enhance the viability of hydroxyl radical-treated bone marrow-mesenchymal stem cells (bmMSCs) at 37–370 µM. The highest viability rate was 120.4%. In subsequent studies, baicalein was observed to effectively scavenge hydroxyl radical and PTIO• radicals, reducing Fe3+ and Cu2+ ions. In the Fe2+-chelating UV-vis spectra, mixing of baicalein with Fe2+ yielded two evident redshifts (275 → 279 nm and 324 → 352 nm) and a broad absorption peak (λmax ≈ 650 nm, ε = 1.6 × 103 L mol−1·cm−1). Finally, we compared the Fe2+-chelating UV-vis spectra of baicalein and its analogues, including 5-hydroxyflavone, 6-hydroxyflavone, 7-hydroxyflavone, catechol, pyrogallol, and chrysin. This analysis revealed that the 4-keto group of the C-ring played a role. The 5,6,7-trihydroxy-group (pyrogallol group) in the A-ring served as an auxochrome, enhancing the absorbance of the UV-vis spectra and deepening the color of the Fe2+-complex. We concluded that baicalein, as an effective hydroxyl radical-scavenger, can protect bmMSCs from hydroxyl radical-mediated oxidative stress. Its hydroxyl radical-scavenging effects are likely exerted via two pathways: direct scavenging of hydroxyl radicals, possibly through electron transfer, and indirect inhibition of hydroxyl radical generation via Fe2+ chelation through the 4-keto-5,6,7-trihydroxy groups. Full article

Figure 1

Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Type of paper: Article
Title: Green tea quality evaluation based on the catechins and metals composition in combination with chemometric analysis
Authors: Wojciech Koch
Abstract: Green tea infusions are one of the most popular beverages consumed across the world, especially is Asian countries. Extracts from this plant possess a broad spectrum of biological activities, including anticancer, antioxidant, antidiabetic and weight reducing properties, which was proved in numerous in vitro, in vivo and clinical studies. Green tea quality is primarily based on catechin content, however, the concentration of elements could also significantly influence its biological properties and thus quality. The main purpose of the present study was the evaluation of catechin and metal content (K, Na, Ca, Mg, Fe, Mn, Cu, Zn, Cr, Pb, Cd and Ni) in 9 different green tea types cultivated in Japan, Sri Lanka, South Korea, India, China and Japan. Chemical analysis was performed using LC-ESI-Q-TOF-MS for organic and atomic absorption spectrometry (flame and electrothermal) method for inorganic constituents. The obtained results were subjected to chemometric elaboration, which revealed interesting correlations between catechin concentration, metal content, antioxidant properties (DPPH, FC and ABTS tests) and origin of the investigated samples. Literature review revealed that such a study, including so many chemical parameters, have not yet been conducted for green teas.

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