Thematic Special Issues on Plant Secondary Metabolites

Special Issue on Phenolics and Polyphenolics

Tentative deadline of paper submission for the 2008 edition: 30 November 2008

[Call for Paper] [Editors] [Manuscript Submissions] [Review Papers] [Research Papers] [Published Papers]

Guest Editors:

Prof. Dr. José Alberto Pereira
CIMO/Escola Superior Agrária, Instituto Politécnico de Bragança, Campus Sta Apolónia, Apartado 1 172, 5301-855 Bragança, Portugal
Tel.: +351 273303277; Fax: +351 273325405

Prof. Dr. Paula Andrade
REQUIMTE/Serviço de Farmacognosia, Faculdade de Farmácia, Universidade do Porto, R. Aníbal Cunha, 164, 4050-047 Porto, Portugal

Manuscript submission
Molecules is a synthetic organic and natural product chemistry journal. Another MDPI journal called IJMS at has a new section called "Bioactives and Nutraceuticals" at the website where your paper may be more suitable for publication. Papers should be submitted any time before the deadline and will be processed quickly, and the accepted papers published immediately and continuously. Finally, all papers will be listed together at this special issue website.

Manuscripts should be prepared according to the Instructions for Authors and submitted by e-mail to, with copy to the Guest Editors and the Editor-in-Chief, Dr. Derek J. McPhee, E-mail: The subject title of the message should be "Manuscript for Special Issue on Phenolics and Polyphenolics".

Review papers published or under consideration

Review manuscripts: Before writing their manuscripts, potential authors of review articles should forward the title and a short abstract to, with a copy to the Guest Editors Prof. Dr. José Alberto Pereira (,
Prof. Dr. Paula Andrade (, and Dr. Derek McPhee ( We will then provide feedback on the suitability of the topic.

Open Access
Abbe Maleyki Mhd Jalil and Amin Ismail *
Department of Nutrition and Dietetics, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia 43400, UPM Serdang, Selangor Darul Ehsan, Malaysia
* Author to whom correspondence should be addressed; E-mail:; Tel.: +603- 89472435; Fax: +603-89426769.
Received: 16 August 2006; in revised form: 29 August 2008 / Accepted: 2 September 2008 / Published: 16 September 2008
Review: Polyphenols in Cocoa and Cocoa Products: Is There a Link between Antioxidant Properties and Health?
Molecules 2008, 13, 2190-2219 (PDF format 273 K); DOI: 10.3390/molecules13092190

Molecules Manuscript ID: phenolics-20080606-Schempp-de
Type of the paper: Review
Title: Anti-carcinogenic Effects of luteolin and Other Flavonoids
Authors: Günter Seelinger,  Irmgard Merfort, Ute Wölfle and Christoph M. Schempp*
Dr. Günter Seelinger, Medical and Pharmaceutical Services, Berlin, Germany.
Prof. Dr. Irmgard Merfort, Institute of Pharmaceutical Sciences, Department of Pharmaceutical Biology, University of Freiburg, Germany.
Prof. Dr. Christoph Schempp, Competence center skintegral, Department of Dermatology, University Medical Center Freiburg, Hauptstr. 7, D-79102 Freiburg, Germany
Tel.: +49 761 270 6701; Fax: +49 761 270 6829
Abstract: Luteolin is a flavonoid which is part of our daily nutrition in relatively low amounts (less than 1 mg/day). Nevertheless, some epidemiological studies suggest an inverse correlation between luteolin intake and risk of some cancer types. Luteolin displays specific anti-inflammatory and anti-carcinogenic effects, which can only partly be explained by its anti-oxidant and free radical scavenging capacities. Luteolin can delay or block the development of cancer cells in vitro and in vivo by protection from carcinogenic stimuli, by inhibition of tumor cell proliferation, by induction of cell cycle arrest and by induction of apoptosis via intrinsic and extrinsic signaling pathways. When compared to other flavonoids, luteolin was usually the most effective, or one the most effective ones with IC50 values between 3 and 50 µM in vitro and 0.1 to 30 mg/kg i.p. in vivo. Luteolin is orally bioavailable and can penetrate into human skin, making it a candidate for the prevention and treatment of skin cancer.

Molecules Manuscript ID: phenolics-20080606-Bruni-it
Type of the paper: Review
Title: Factors Affecting Polyphenol Biosynthesis in Wild and Field Grown St. John’s Wort (Hypericum perforatum L.)
Authors: Renato Bruni
Abstract: The steadily increasing diffusion of herbal products is posing new questions: why are the consumer available products often different in their composition and efficacy? Which approach is more suitable and which steps are more relevant in order to increase biochemical productivity of medicinal plants with large-scale, low-cost solutions? Can the phytochemical profile of a medicinal plant be modulated in order to reduce some unwanted substances and increase the accumulation of the most valuable ones? Will medicinal crops ever be traded as commodities? Providing a proactive answer to such questions is an extremely hard task, due to the large number of variables involved: plant breeding, intraspecific chemodiversity, ontogenetic stage, agronomic conditions, climate and latitude, post-harvest handling and exposure to noxious agents, to name a few. An ideal path should include the definition of optimum pre-harvesting and post-harvesting conditions and the availability of specific Good Agricultural Practices centered on secondary metabolism enhancement. The first steps to be taken in this direction are undoubtedly the evaluation and the organization of scattered data regarding the diverse factors involved in the optimization of medicinal plant cultivation, both in terms of biomass and active principles, in order to provide an interdisciplinary overview of main possibilities, weaknesses and drawbacks. This review will provide an overview of the knowledge on this regard focused on Hypericum perforatum L. (Hypericaceae/Guttiferae), summarizing data treating topics directly and indirectly related with factors influencing the production of biomass and phenolic secondary metabolites of St. John’s Wort (dianthrones, flavonoids, cinnamic derivatives) with the aim to provide a reference on the state-of-the-art of its cultivation and to suggest its evolution towards the maximization of bioactive constituents. Factors considered emerge not only from in field agronomic results, but also from physiological, genetical, biotic, abiotic and phytochemical data that can be scaled up to the applicative level. To increase quality for final beneficiaries, growers profit and ultimately transform phenolic-rich medicinal crops into commodities, the emerging trend suggest an integrated and synergic approach. Agronomy and genetics will need to develop their breeding strategies taking account of the suggestions of phytochemistry, pharmacognosy and pharmacology, without lose sight of the economic balance of the production. Indications on possible future developments and needs have been outlined.
Keywords: Hypericum perforatum, hypericins, polyphenols, flavonoids secondary metabolism optimization.

Molecules Manuscript ID: molecules-phenolics-06-Duan
Type of the paper: Review
Title: Biosynthesis and Genetic Regulation of Proanthocyanidins in Plants
Authors: Fei He, Qiu-Hong Pan, Ying Shi, Chang-Qing Duan*
Affiliations: Centre for Viticulture & Enology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China; Tel.: +86 10 62737136; Fax: +86 10 62737136; Email:
Abstract: Proanthocyanidins (PAs), also known as condensed tannins, are a group of polyphenolic secondary metabolites synthesized as oligomers or polymers of flavan-3-ol units via the flavonoid pathway in plants. Due to their structure complexity and composition variety, only in the recent years, has the study on the biosynthesis and regulation of proanthocyanidins in plants been broken through, but some synthetic mechanism remains unclear. The present paper aims to summarize the research status of the structures of proanthocyanidins in plants, the genes encoding key enzymes of biosynthetic pathway, the transport factors, the regulation of proanthocyanidins biosynthesis and genetic manipulation of proanthocyanidins. The problems of this field were also discussed, including the final “enzymes” which catalyze the polymerization reaction of proanthocyanidins and the possible mechanism how the elementary units of flavanols are assembled in vivo.
Keywords: Proanthocyanidins, Condensed Tannins, Structures, Flavonoid Biosynthesis, Regulatory Genes, Transport Factors.

Manuscript ID: phenolics-20080619-Duan-cn
Type of the paper: Review
Title: Chemical Synthesis of Proanthocyanidins in Vitro and Their Reactions in Aging Wines
Authors: Fei He, Qiu-Hong Pan, Ying Shi, Chang-Qing Duan*
Affiliations: Centre for Viticulture & Enology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China; Tel.: +86 10 62737136; Fax: +86 10 62737136; Email:
Abstract: Proanthocyanidins are present in many fruits and plant products like wine, and contribute to their taste and health benefits. In the past decades of years, a series of substantial progresses have been achieved in the identification of composition and structure of proanthocyanidins, but the debate concerning the existence of an enzymatic or nonenzymatic mechanism for proanthocyanidin condensation still goes on. Enough attention has been paid to elucidating the potential forming mechanism by means of biomimetic and chemical synthesis in vitro. The present paper aims to summarize the research status on chemical synthesis of proanthocyanidins, including non-enzymatic synthesis of proanthocyanidin precursors, chemical synthesis of proanthocyanidins with direct condensation of flavanols and stereoselective synthesis of proanthocyanidins. Proanthocyanidin-involved reactions in aging wines are also reviewed such as direct and indirect reactions among proanthocyanidins, flavanols and anthocyanins. The future research objects in this field are put forward.
Keywords: Proanthocyanidins, Condensed Tannins, Chemical Synthesis, Stereoselective Synthesis, Flavanols, Anthocyanins, Wine.

Molecules Manuscript ID: phenolics-20080710-Santana Rodríguez-es
Type of the paper: Review
Title: Micellar Media in the Extraction and Determination of Phenolic Compounds in Environmental Samples: New Approaches
Authors: Cristina Mahugo Santana, Zoraida Sosa Ferrera, M. Esther Torres Padrón, José Juan Santana Rodríguez*
Affiliations: Department of Chemistry, Faculty of Marine Sciences, University of Las Palmas de Gran Canaria, 35017, Las Palmas de Gran Canaria, Spain; Tel.: +34 928452915; Fax: +34 928452922; Email:
Abstract: Phenolic derivatives are some of the most important contaminants present in the environment. These compounds are used in several industrial processes to manufacture chemicals such as pesticides, explosives, drugs and dyes. They also are used in the bleaching process of paper manufacturing. Apart from these sources, phenolic compounds have substantial applications in agriculture as herbicides, insecticides and fungicides. However, phenolic compounds are not only generated by human activity, but they are also formed naturally, e.g., during the decomposition of leaves or wood. As a result of these applications, they are found in soils and sediments and this often leads to wastewater and ground water contamination. Owing to their high toxicity and persistence in the environment, both, the US Environmental Protection Agency (EPA) and the European Union have included some of them in their lists of priority pollutants. Current standard methods of phenolic compounds analysis in water samples are based on liquid¨Cliquid extraction (LLE) while Soxhlet extraction is the most used technique for isolating phenols from solid matrices. However, these techniques require extensive cleanup procedures that are time-intensive and involve expensive and hazardous organic solvents, which are undesirable for health and disposal reasons. In the last years, the use of news methodologies such as solid-phase extraction (SPE) and solid-phase microextraction (SPME) have increased for the extraction of phenolic compounds from liquid samples. In the case of solid samples, microwave assisted extraction (MAE) is demonstrated to be an efficient technique for the determination of these compounds. In this work we review the developed methods in the extraction and determination of phenolic derivatives in different types of environmental matrices such as water, sediments and soils using micellar media. Moreover, we present the new approach in the use of micellar media coupled with SPME process for the extraction of phenolic compounds. The advantages of micellar media over conventional extractants are reduction of organic solvent, low cost, easy handling and shorter time procedures.

Molecules Manuscript ID: phenolics-20080712-Katula-us
Type of the paper: Review
Title: Phytochemical Modulation of NF-kB Activity: the Good and the Bad of it
Author: Karen S. Katula
Affiliations: Dept. of Biology, UNCG. P.O. Box 26174. Greensboro, NC 27402-6174; Tel.: 336-334-4951; Fax: 336-334-5839; Email:
Abstract: NF-kB includes a family of related proteins that in dimeric form function as transcription factors to regulate over 200 different genes. In most cells, NF-kB is maintained in an inactive form in the cytoplasm complexed with IkB. Diverse stimuli due to inflammation, viral and bacterial infection, and other cellular stresses, lead to degradation of IkB and release of NF-kB, which then translocates into the nucleus. The role of NF-kB and inflammation in cancer and other human diseases is well documented. Numerous studies have been published documenting the effects of individual, dietary phytochemicals on NF-kB activity, thus providing in some cases a possible explanation for the anti cancer and other health benefits of these dietary compounds. However, there is contrary data suggesting that certain compounds can negatively impact NF-kB activity. In this review, the results of these studies will be summarized and compared with a particular focus on structural features, concentrations, and assay system. The goal of this review is to provide a summary and generalities regarding phytochemical effects on NF-kB activity.

Molecules Manuscript ID: phenolics-20080720-Meulenberg-nl
Type of the paper: Review
Title: Phenolics: Occurrence and Immunochemical Detection in Environment and Food
Author: Eline P. Meulenberg
Affiliations: ELTI Support VOF, Drieskensacker 12-10, 6546 MH Nijmegen, The Netherlands. E-mail:
Abstract: Phenolic compounds may be of natural or anthropogenic origin and be present in the environment as well as in food. They comprise a large and diverse group of compounds that may be either beneficial or harmful for consumers. In this review first a non-exhausting overview of interesting phenolics is given, in particular with regard to their presence in environment and food. For some of these compounds, beneficial, toxicological and/or optionally endocrine disrupting activities will be presented. Further, immunochemical detection and/or isolation methods developed will be discussed, including advantages and disadvantages thereof in comparison with conventional analytical methods such as HPLC, GC, MS. A short overview of new sensor-like methods will also be included for present and future application.

Molecules Manuscript ID: phenolics-20080717-Medic'-Šaric'-hr
Type of paper: Review
Title: Polyphenols in Propolis and Wines from Croatia
Author: Marica Medic'-Šaric', Vesna Rastija, Mirza Bojic', Željan Maleš
Abstract: Polyphenols, as natural dietary phytochemicals, are the focus of current nutritional and therapeutic interest. Many studies suggest that polyphenols may be involved in cardioprotection and neuroprotection, as well as they play a role as chemopreventive and tumor growth inhibition agents. The protective properties of polyphenols against oxidative stress have been reported to be structure-dependent. Due to these health benefits of propolis and wine polyphenols, it is important to develop techniques for their extraction and analysis.
We have prepared the review paper about our investigation of polyphenols in the propolis and wine samples from Croatia. The review is a compilation of different methodologies and techniques used in the analysis of polyphenols. The results have been grouped mainly in the form of figures and tables.
For this purpose qualitative and quantitative thin-layer chromatography (TLC, 2D TLC, RP-TLC) and high-performance liquid chromatography (HPLC, RP-HPLC, IAM-HPLC, HSA-HPLC) methods were developed. The best mobile phase for the separation of polyphenols in chromatographic analysis was selected using numerical taxonomy methods. The content of polyphenols in thirty-eight propolis samples and twelve samples of wines, collected from different geographic localities in Croatia was reported. The total polyphenolic contents of propolis and wines were determineted by Folin-Ciocalteu method. The antioxidant capacity of polyphenols was measured by ferric reducing antioxidant power (FRAP) and Trolox Equivalent Antioxidant Capacity (TEAC) methods.
Quantitative structure-activity relationship (QSAR) between «two-dimensional» (2D) topological indices, «three-dimensional» (3D) descriptors, calculated physicochemical parameters and antioxidant activity of polyphenols, that are usually present in wines, was also investigated. The results of QSAR study point out that antioxidant activity of polyphenols, as hydrogen donating free radical scavengers, is closely related to their chemical structure, especially with the number and arrangement of free hydroxyl groups of polyphenol skeleton.

Research papers published

Open Access
Neda Mimica-Dukic 1,*, Natasa Simin 1, Jelena Cvejic 2, Emilija Jovin 1, Dejan Orcic 1 and Biljana Bozin 2
1 Department of Chemistry, Faculty of Sciences, Trg D. Obradovica 3, University of Novi Sad, 21000 Novi Sad, Serbia. E-mails:,
2 Department of Pharmacy, Faculty of Medicine, Hajduk Veljkova 3, University of Novi Sad, 21000 Novi Sad, Serbia. E-mails:,
* Author to whom correspondence should be addressed. E-mail:; Tel.: +38121- 4852757; Fax: +38121-454650
Received: 12 June 2008; in revised form: 01 July 2008 / Accepted: 15 July 2008 / Published: 15 July 2008
Phenolic Compounds in Field Horsetail (Equisetum arvense L.) as Natural Antioxidants
Molecules 2008, 131455-1464 (PDF format 292 K); DOI: 10.3390/molecules13071455

Open Access
Yu-Lan Li 1,2, Jun Li 2, Nai-Li Wang 1,* and Xin-Sheng Yao 1,*
1 Department of Natural Products Chemistry, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenhe District, Shenyang, Liaoning 110016, P.R. China; E-mail: (Yu-Lan Li)
2 Shenzhen Institute for Drug Control, 1024, Beihuan Road, Futian District, Shenzhen, Guangdong 518029, P.R. China; E-mail: (Jun Li)
* Authors to whom correspondence should be addressed; E-mails: (Nai-Li Wang); (Xin-Sheng Yao); Tel: 86-20-85225849; Fax: 86-20-85221559.
Received: 20 July 2008; in revised form: 19 August 2008 / Accepted: 26 August 2008 / Published: 28 August 2008
Article: Flavonoids and a New Polyacetylene from Bidens parviflora Willd.
Molecules 2008, 13, 1931-1941 (PDF format 227 K); DOI: 10.3390/molecules13081931

Open Access
Lisa Botes 1, Francois H. van der Westhuizen 2 and Du Toit Loots 1,2,*
1 School for Physiology, Nutrition and Consumer’s Science, Private Bag X6001, Box 594, Potchefstroom, 2531, South Africa; E-mail: (Lisa Botes)
2 School for Physical and Chemical Sciences, North-West University, Private Bag X6001, Box 269, Potchefstroom, 2531, South Africa; E-mails: (Francois H. van der Westhuizen)
* Author to whom correspondence should be addressed; E-mail:; Tel.: +27182991818; Fax: +27182991818.
Received: 10 June 2008; in revised form: 22 August 2008 / Accepted: 23 August 2008 / Published: 11 September 2008
Article: Phytochemical Contents and Antioxidant Capacities of Two Aloe greatheadii var. davyana Extracts
Molecules 2008, 13, 2169-2180 (PDF format 190 K); DOI: 10.3390/molecules13092169

Open Access
Claudio Gardana 1,*, Federico Nalin 2 and Paolo Simonetti 1
1 DiSTAM - Department of Food Science and Microbiology, Division of Human Nutrition, University of Milan, 20133 Milan, Italy; E-mail: (Paolo Simonetti)
2 Specchiasol s.r.l., Via Rizzi 1/3 - 37012 Bussolengo (Vr), Italy; E-mail: (Federico Nalin)
* Author to whom correspondence should be addressed; E-mail:; Tel.: +39 02 50316072; Fax +39 02 50316071.
Received: 1 August 2008; in revised form: 1 September 2008 / Accepted: 9 September 2008 / Published: 18 September 2008
Article: Evaluation of Flavonoids and Furanocoumarins from Citrus bergamia (Bergamot) Juice and Identification of New Compounds
Molecules 2008, 13, 2220-2228 (PDF format 326 K); DOI: 10.3390/molecules13092220

Molecules Manuscript ID: molecules-phenolics-02-Jiang
Type of the Paper: Article
Title: Evaluations of Antioxidant Activity and Antibacterial Ability of Flavonoids from Mulberry Leaf
Authors: Fang Wang, Jianrong Li* and Yueming Jiang
Abstract: Flavonoids play important roles in beneficial effects of human health. The major flavonoids from mulberry leaf were identified as rutin, isoquercitrin, astragalin, morin and kaempferol. Flavonoids were extracted and purified from mulberry leaf and used for the analyses of their antioxidant activity and antibacterial ability. The mulberry flavonoids exhibited a dose-dependent free-radical scavenging activities against α,α-diphenyl-β-picrylhydrazy (DPPH) radicals and lipid oxidation while the bactericidal ability of the extract of mulberry flavonoids was evaluated using the filter paper method, and the minimum inhibitory concentrations of the mulberry flavonoids against Escherichia coli, Staphylococcus aureus and Bacillus subtilis were determined to be 0.025, 0.0125 and 0.05 mg/L, respectively, which suggested that the mulberry flavonoids showed a distinct bactericidal ability. This study could help better utilize mulberry flavonoids, especially as a readily accessible source of natural antioxidants and/or possible antibacterial agents in food or pharmaceutical industry.
Keywords: flavonoids, antioxidant activity, antibacterial ability

Papers published in 2007

See the Special Issue on Phenolics 2007 website.

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Last update: 18 September 2008