Phebaclavin I, a novel 3-prenylated coumarin, and trichoclin acetate, a new natural furocoumarin, from the aerial parts of Phebalium aff. tuberculosum (Rutaceae)

Phebaclavin I, a novel 3-prenylated coumarin, was isolated from the aerial parts of Phebalium aff. tuberculosum (Rutaceae) together with five known related compounds, Phebaclavin A, B, D, G, H. The structure of phebaclavin I was established by spectroscopic methods. Several other known coumarins were obtained, including trichoclin acetate, a furocoumarin isolated for the first time from a natural source, but previously described from acetylation of trichoclin.     

Two acridones and two coumarins from the roots of Paramignya trimera

Two acridones, paratrimerins C (1) and D (2), and two coumarins, paratrimerins E (3) and F (4), were isolated from the CHCl₃ and EtOAc extracts of Paramignya trimera (Rutaceae), together with twelve known compounds (5–16). Their structures were elucidated on the basis of spectroscopic data. All isolated compounds possessed significant α-glucosidase inhibitory activity in a concentration-dependent manner, and showed more potent inhibitory activity, with IC₅₀ values ranging from 14.6 to 112.2 μM, than the positive control acarbose (IC₅₀, 214.5 μM). The biosynthesis of the isolated coumarins and acridones was proposed.     

A Simple and Efficient Two-Dimensional High-Speed Counter-Current Chromatography Linear Gradient and Isocratic Elution Modes for the Preparative Separation of Coumarins from Roots of Toddalia asiatica (Linn.) Lam.

Toddalia asiatica (L.) Lam. (Rutaceae) has shown a broad spectrum of biological properties, such as anti-inflammatory, antioxidant, antimicrobial, anti-HIV, and anticancer properties. The present study is concerned with the separation of the main components with broad partition coefficients (K_D values) from T. asiatica, using linear gradient high-speed counter-current chromatography (LGCCC) combined with an off-line two-dimensional (2D) mode. Similar to the binary gradient HPLC, the LGCCC mode is operated by the adjustment of the proportion between the mobile phase of 5:5:1:9 (v/v) (pump A) and 5:5:4.5:5.5 (v/v) (pump B) in an n-hexane/ethyl acetate/methanol/water solvent system. The off-line 2D-CCC mode was used in this study for the secondary separation of two similar K_D value compounds with n-hexane/ethyl acetate/methanol/water (5:5:4:6, v/v). Notably, six coumarins, namely, tomentin (1), toddalolactone (2), 5,7,8-trimethoxycoumarin (3), mexoticin (4), isopimpinellin (5), and toddanone (6), were efficiently separated. The structures of the pure compounds were elucidated by spectral techniques and compared with the literature.     

Chemical constituents of Micromelum minutum. Isolation and structural elucidation of new coumarins

The chemical constituents of an acetone extract of the stems of Micromelum minutum Wight et Arn (Rutaceae), collected at Nakorn-Rachasima province in Thailand, were studied. Six new coumarins, named micromarin-A (1), -B (2), -C (3), -F (4), -G (5), and -H (6), were isolated along with six known coumarins, and their structures were elucidated by chemical and spectroscopic methods.     

Complete NMR assignment of 3, 4‐seco‐lup‐20(29)‐en‐3‐oic acid from Decatropis bicolor

Complete ¹H and ¹³C NMR chemical shift assignments for 3,4‐seco‐lup‐20(29)‐en‐3‐oic acid ( 1 ) have been established by means of two‐dimensional COSY, HSQC, HMBC and NOESY spectroscopic experiments as well as by analysis of MS data. Compound 1 was isolated from Decatropis bicolor (Zucc.) Radlk. (Rutaceae) in addition to six coumarins and one alkaloid of known structure. Copyright © 2012 John Wiley & Sons, Ltd.     

In situ visual and content changes analysis of coumarins in Radix Angelicae dahuricae by LSCM combined with LC-MS technology

In this study, a simple, accurate and green localization method of coumarins in Radix Angelicae dahuricae was established with fresh Radix Angelicae dahuricae as research material to reveal the distribution and accumulation of coumarins, based on frozen section and fluorescence imaging technology. The best frozen section conditions were established by comparing the effects of different cryoprotectants on the quality of Radix Angelicae dahuricae's frozen sections, according to the loss of coumarins and the complexity of the operation process. The coumarin components in Radix Angelicae dahuricae at different stages were located and quantitatively analyzed, and coumarin components distribution positions and content changes were identified using fluorescence imaging combined with LC-MS technology. The results showed that 30 μm slice thickness with 15 % glycerin protectant treatment is the best condition for frozen section. Fluorescence imaging showed that coumarins in Radix Angelicae dahuricae were mainly distributed in secretory tissue, the content over different periods showed an “S” curve of growth and coumarins reached their highest content in early September. The distribution and accumulation of coumarins in roots were revealed, which provided a reference for the synthesis and metabolism mechanism of metabolites in medicinal plants and the quality evaluation of traditional Chinese medicine.     

Coumarin’s Anti-Quorum Sensing Activity Can Be Enhanced When Combined with Other Plant-Derived Small Molecules

Coumarins are class of natural aromatic compounds based on benzopyrones (2H-1-benzopyran-2-ones). They are identified as secondary metabolites in about 150 different plant species. The ability of coumarins to inhibit cell-to-cell communication in bacterial communities (quorum sensing; QS) has been previously described. Coumarin and its derivatives in plant extracts are often found together with other small molecules that show anti-QS properties too. The aim of this study was to find the most effective combinations of coumarins and small plant-derived molecules identified in various plants extracts that inhibit QS in Chromobacterium violaceum ATCC 31532 violacein production bioassay. The coumarin and its derivatives: 7-hydroxycoumarin, 7.8-dihydroxy-4-methylcoumarin, were included in the study. Combinations of coumarins with gamma-octalactone, 4-hexyl-1.3-benzenediol, 3.4.5-trimethoxyphenol and vanillin, previously identified in oak bark (Quercus cortex), and eucalyptus leaves (Eucalyptus viminalis) extracts, were analyzed in a bioassay. When testing two-component compositions, it was shown that 7.8-dihydroxy-4-methylcoumarin, 4-hexyl-1.3-benzendiol, and gamma-octalactone showed a supra-additive anti-QS effect. Combinations of all three molecules resulted in a three- to five-fold reduction in the concentration of each compound needed to achieve EC₅₀ (half maximal effective concentration) against QS in C. violaceum ATCC 31532.     

Two New O-terpenoidal Coumarins, Excavacoumarin A and B from Clausena excavata

Cla!tsenaexcavataBurm.f(Rutaceae)isabushwidelydistributedinYunnan,China.Leavesandbarksofthisplanthavebeenusedasfolkrnedicineforthetreatmentofdysentery,enteritis,andurethrainfection1.ClalISenaspeciesareknowntobetherichsourcesofcarbazolealkaloidsandcoumarins=-j.TheconstituentsofCexcavalacollectedinXishuangbannahavebeenstudied'andthispaperdescribestheisolationandstructureelucidationoftwonewO-terpenoidalcoumarins,excavacoumarinA(2)andexcavacoumarinB(3),andthel3CNMRspectraldataassignmentsfora…     

Coumarins from the roots of Cleme Viscosa (L.) antimicrobial and cytotoxic studies

Two coumarins, 7-geranyloxycoumarin (auraptene) and 6′-hydroxy-β-cycloauraptene were isolated from the roots of Cleme viscosa (Capparidaceae). The second compound has never been reported previously from this plant. The isolation process involved extraction with various solvents and separation using column chromatography techniques. The structure of the compounds was assigned on the basis of spectroscopic data Such as IR, UV, ¹H NMR, ¹³C NMR, COSY, HMQC, HMBC, DEPT and MS. However, bioactivity screening showed that the pure isolated compounds possessed no activity on two species of bacteria Bacillus cereus NRRLUI-1447 and Pseudomonas aeruginosa UI-60690 and four species of fungi (Aspergillus ochraceus NRRL 398, Candida lipolytica ATCC 2075, Sacchromyces cereviseae NRRL 2034 and Sacchromyces lipolytica). The cytotoxic test of the compounds against CEM-SS (T-cell lymphoblastic leukemia) cells were also carried out with IC₅₀ values of 14 and 18 μg/ml,respectively.     

The Genus Haplophyllum Juss.: Phytochemistry and Bioactivities—A Review

Herein, a comprehensive review is given focusing on the chemical profiles of the essential oils (EOs), non-volatile compounds, ethnobotany, and biological activities of different Haplophyllum (Rutaceae family) species. To gather the relevant data, all the scientific databases, including Scopus, ISI-WOS (Institute of Scientific Information-Web of Science), and PubMed and highly esteemed publishers such as Elsevier, Springer, Taylor and Francis, etc., were systematically retrieved and reviewed. A wide array of valuable groups of natural compounds, e.g., terpenoids, coumarins, alkaloids, lignans, flavonoids, and organic acids have been isolated and subsequently characterized in different organic extracts of a number of Haplophyllum species. In addition, some remarkable antimicrobial, antifungal, anti-inflammatory, anticancer, cytotoxic, antileishmanial, and antialgal effects as well as promising remedial therapeutic properties have been well-documented for some species of the genus Haplophyllum.     

Palladium-catalyzed carbonylative annulation of terminal alkynes: synthesis of coumarins and 2-quinolones

o-Iodophenols and o-iodoaniline derivatives react with terminal alkynes under 1 atm of CO in the presence of pyridine and catalytic amounts of Pd(OAc)₂ to generate coumarins and 2-quinolones, respectively, as the only products. Terminal alkynes bearing alkyl, aryl, silyl, hydroxyl, ester and cyano substituents are effective in these processes affording the desired products in moderate yields. The formation of coumarins and 2-quinolones in this process is in stark contrast with all previously described palladium-catalyzed reactions of o-iodophenols or o-iodoanilines with terminal alkynes and CO, which have afforded chromones and 4-quinolones. Moreover, under our reaction conditions terminal alkynes insert into the carbonpalladium bond instead of undergoing a Sonogashira-type coupling as confirmed by an isotope labeling experiment.     

Regioselective synthesis of C-prenylated flavonoids via intramolecular [1,3] or [1,5] shift reaction catalyzed by acidic clays

Prenyl side chain and dihydropyrano skeleton exists in many natural and synthetic biologically active flavonoids. A highly efficient and regioselective method for the synthesis of C-prenylated flavonoids via intramolecular [1,3] or [1,5] shift reaction of 5-O-prenylflavonoids catalyzed by Florisil or Montmorillonite clays is described. Florisil catalyzes intramolecular [1,5] shift reaction of 5-O-prenylflavonoids to obtain 8-C-prenylated flavonoids exclusively, Montmorillonite K10 exhibits the superior selectivity to promote intramolecular [1,3] shift reaction to obtain 6-C-prenylated flavonoids compared with Florisil and Montmorillonite KSF. This method provides a practical process to regioselective synthesize biologically important C-prenylated flavonoids in good yields using commercially available and inexpensive catalyst under mild conditions.     

Identification and Quantification of Coumarins by UHPLC-MS in Arabidopsis thaliana Natural Populations

Coumarins are phytochemicals occurring in the plant kingdom, which biosynthesis is induced under various stress factors. They belong to the wide class of specialized metabolites well known for their beneficial properties. Due to their high and wide biological activities, coumarins are important not only for the survival of plants in changing environmental conditions, but are of great importance in the pharmaceutical industry and are an active source for drug development. The identification of coumarins from natural sources has been reported for different plant species including a model plant Arabidopsis thaliana. In our previous work, we demonstrated a presence of naturally occurring intraspecies variation in the concentrations of scopoletin and its glycoside, scopolin, the major coumarins accumulating in Arabidopsis roots. Here, we expanded this work by examining a larger group of 28 Arabidopsis natural populations (called accessions) and by extracting and analysing coumarins from two different types of tissues–roots and leaves. In the current work, by quantifying the coumarin content in plant extracts with ultra-high-performance liquid chromatography coupled with a mass spectrometry analysis (UHPLC-MS), we detected a significant natural variation in the content of simple coumarins like scopoletin, umbelliferone and esculetin together with their glycosides: scopolin, skimmin and esculin, respectively. Increasing our knowledge of coumarin accumulation in Arabidopsis natural populations, might be beneficial for the future discovery of physiological mechanisms of action of various alleles involved in their biosynthesis. A better understanding of biosynthetic pathways of biologically active compounds is the prerequisite step in undertaking a metabolic engineering research.     

A convenient approach to the design and synthesis of indolo[3,2-c]coumarins via the microwave-assisted Cadogan reaction

3-(4,5-Dimethoxy-2-nitrophenyl)coumarins bearing various substituents on the benzene ring of the coumarin system have been prepared from salicylaldehydes and 2-(4,5-dimethoxy-2-nitrophenyl)acetonitrile by means of the Perkin condensation. Further cyclization of these 3-aryl coumarins through the microwave-assisted Cadogan reaction afforded the corresponding indolo[3,2-c]coumarins in good to excellent yields.     

Rapid synthesis of tetrahydroquinolines by indium trichloride catalyzed mono- and bis-intramolecular imino Diels-Alder reactions

A rapid synthesis of mono- and bis-tetrahydropyrazolo[4′,3′:5,6]thiopyrano[4,3-b]quinolines has been achieved by the reaction of aldimines derived from aromatic amines and S-prenylated aldehydes in acetonitrile with InCl₃ as a catalyst, in excellent yields and short reaction times, under mild conditions.     

Application of UPLC-Quadrupole-TOF-MS Coupled with Recycling Preparative HPLC in Isolation and Preparation of Coumarin Isomers with Similar Polarity from Peucedanum praeruptorum

A strategy of ultra performance liquid chromatography-quadrupole-time of flight-mass spectrometry (UPLC-Q-TOF-MS) coupled to recycling preparative HPLC was utilized to sensitively detect the minor constituents and preparatively isolate coumarin isomers from the petroleum ether extract of Peucedanum praeruptorum roots. UPLC-Q-TOF-MS was achieved on an Agilent ZORBAX Extend C-18 analytical column (50 mm × 2.1 mm i.d. 1.8 μm) using methanol:H₂O as the mobile phase, and three pairs of coumarin isomers with similar polarity were detected. Then recycling preparative HPLC was successfully used in one step for the isolation and purification of these six compounds with optimized mobile phases (methanol: H₂O, 73:27, 81:19, 78:22, v/v). The structures of six coumarins including three new coumarins named praeruptorin (F–H) (1, 3 and 6) were identified by spectroscopic analysis.     

Synthesis of functionalized furo[3,2-c]coumarins via a one-pot oxidative pseudo three-component reaction in poly(ethylene glycol)

An efficient and straightforward synthesis of functionalized furo[3,2-c]coumarins via a one-pot oxidative pseudo three-component condensation of aldehydes and 4-hydroxycoumarin (2 equiv) in poly(ethylene glycol) (PEG) as solvent is described. A mixture of I₂ and K₂S₂O₈ in the presence of Na₂CO₃ was used as an oxidative reagent. The structure of the furo[3,2-c]coumarins was established by X-ray single crystal structure analysis.     

Condition-controlled selective synthesis of coumarins and flavones from 3-(2-hydroxyphenyl)propiolates and iodine

2H-Chromen-2-ones (coumarins) and 4H-chromen-4-ones (flavones) were selectively prepared via the reaction of 3-(2-hydroxyphenyl)propiolates with iodine in toluene and N,N-dimethylformide, respectively.     

Simultaneous Determination of Marmin,Skimmianine, Umbelliferone,Psoralene, and Imperatorin in the Root Bark of Aegle Marmelos by High-Performance Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC - Aegle marmelos (Rutaceae) has gained traditional therapeutic importance owing to their coumarins (umbelliferone, psoralene, marmin,...