Special Issue "Coumarins and Xanthones"

Guest Editor
Prof. Dr. Pascal Richomme
SONAS-UFR Sciences Pharmaceutiques, 16 Bd Daviers, F-49100 Angers, France
Website: http://www.univ-angers.fr/labo/sonas
E-Mail:
Phone: +33 (0) 241226658
Interests: natural products; (hemi)synthesis; biological screening

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• coumarins
• xanthones

Type of Paper: Article
Title: Optically Active Coumarin Photodimers
Author: Koichi Tanaka
Affiliation: Kansai University, Osaka, Japan
Corresponding Author; E-Mail: ktanaka@ipcku.kansai-u.ac.jp
Abstract: The article describes the synthesis, structure and applications of optically active coumarin dimmers. 1) enantioselective photodimerization of coumarins, 2) enantiomeric resolution of coumarin dimmers, 3) optically active coumarin dimmers for chiral catalyst, and 4) optically active coumarin dimmers for chiral polmers.

Type of Paper: Article
Title: Anti-cancer and chempreventive effects of Xanthones
Author: Yukihiro Akao
Affiliation: Department of Medical Oncology, Gifu International Institute of Biotechnology, 1-1 Naka-Fudogaoka, Kakamigahara, Gifu 504-0838, Japan
E-Mail: yakao@giib.or.jp
Abstract: Our recent study focused on the mechanism of xanthone-induced growth inhibition in human colon cancer DLD-1 cells. It was shown that the anti-proliferative effects of the prenylated xanthones were associated with cell-cycle arrest by affecting the expression of cyclins, cdc2, and p27; G1 arrest by α-mangostin and β-mangostin, and S arrest by γ-mangostin. α-Mangostin found to induce apoptosis through the activation of intrinsic pathway following the down-regulation of signaling cascades involving MAP kinases and the serine/threonine kinase Akt. Synergistic effects by the combined treatment of α-mangostin and anti-cancer drugs was to be noted. Furthermore, 5-FU resistant cell line of DLD-1 cells was sensitive to α-mangostine. α-Mangostin was found to have a cancer preventive effect in rat carcinogenesis bioassay and the extract from pericarps (Panaxanthone), which contains mainly α-mangostin and γ-mangostin, exhibited an enhancement of NK cell activity in a mouse model. Recent clinical trials of Panaxanthone indicated no overt side effect and elevated NK cell activity in cancer patients. These findings could provide a relevant basis for the development of xanthones as an agent for cancer prevention and the supportive combination therapy with anti-cancer drugs.

Type of Paper: Review
Tentative title: Synthesis and Application of Novel Phosphorus Ligands Derived from Coumarin Dimer in Asymmetric Catalysis
Authors: Dongbo Zhao ¹ and Kuiling Ding ²
Affiliations: ¹ Bayer Technology & Engineering (Shanghai) Co., Ltd., F3 Area, Mu Hua Road, Shanghai Chemical Industry Park, Shanghai 201507, P. R. China
² State Key laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, 200032, P. R., China; E-Mail: kding@mail.sioc.ac.cn
Abstract: Based on a highly efficient and practical optical resolution of anti-head-to-head racemic coumarin dimer by molecular complexation with TADDOL, a series of novel bisphosphorus and tetraphosphorus chiral ligands with cyclobutane backbone were designed and synthesized from this chiral coumarin dimer. Those phosphorus chiral ligands turned out to be efficient and exhibited their potential utilities as recyclable catalysts in asymmetric Pd-catalyzed allylic substitution and Rh-catalyzed hydrogenation reactions as well. In addition, the dense functionality of this chiral coumarin dimer would facilitate its applications as self-polymerized chiral ligands or in asymmetric multifunctional catalysis. This article will review recent development of novel phosphorus ligands derived from coumarin dimer in asymmetric catalysis.

Type of Paper: Review
Title: Thin-Layer Chromatography of Coumarins
Authors: Miroslaw A. Hawryl and Monika Waksmundzka-Hajnos
Affiliation: Department of Inorganic Chemistry, Medical University of Lublin, 20-081 Lublin, Poland; E-Mail: monika.hajnos@am.lublin.pl (M.W.-H.)
Abstract: The methods of thin-layer determination and analysis in plant material are presented. Coumarins can be divided into four groups: basic coumarins, isocoumarins, furanocoumarins and pyranocoumarins. They appear in plants as free molecules and as glycosides and have various pharmacological activities: antitrombotic, anticoagulative, spasmolitic, photosensibilized, bacteriostatic and antifungal, analgesic, antiphlogistic and antipyretic, cytostatic or cytotoxic, sedative and hypnotic. Some of them like aflatoxines have toxic properties. Some methods of isolation of coumarins from plant material are described like: classic extraction, SFE, MPSLE, MPLC, USAE, MASE, ASE and SPE. Thin-layer chromatographic techniques are often used in the analysis of coumarins. Normal phase (NP-TLC) or reversed phase (RP-TLC) systems were applied. Some special techniques were also described like: 2D-TLC, coupled HPLC-TLC methods and forced flow TLC techniques.

Type of Paper: Article
Title: Accelerated Solvent Extraction of Coumarins from Fruits of Heracleum leskovii with Application of Solvents with Different Polarity
Authors: Krystyna Skalicka-Woźniak and Kazimierz Głowniak
Affiliation: Department of Pharmacognosy with Medicinal Plant Unit, Medical University in Lublin, 1 Chodzki, 20-093 Lublin, Poland; E-Mail: kskalicka@pharmacognosy.org
Abstract: Coumarins are nowadays an important group of organic compounds from natural sources that are useful in a number of fields. Because they possess different pharmacological properties, finding of proper extraction condition for their separation from plant matrix is a very important step. In this report Accelerated Solvent Extraction (ASE) under different temperature conditions and with different types of extraction solvents were tested. As a matrix fruits of Heracleum leskovii have been used. A simple high-performance liquid chromatographic method (RP-HPLC) coupled with a photodiode array detector (DAD) has been developed for separation and quantitative analysis of the major coumarins. Umbelliferone, angelicin, xanthotoxin, xanthotoxol, isopimpinellin, bergaptene, imperatorin and isoimperatorin were investigated. Bergaptene and imperatorin were dominant in almost all extracts in the range of 9.92±0.02 – 20.93± 0.06 and 12.19±0.98 – 19.07±0.03 mg/100g, respectively. Dichloromethane and methanol were chosen as the most proper solvents for extraction of coumarins. Increasing of temperature didn’t caused any important changes in extraction efficiency.