ABSTRACT
Boron dipyrromethene (BODIPY) dyes bearing a pyridyl moiety have been used as metal ion sensors, pH sensors, fluorescence probes, and as sensitizers for phototherapy. A comparative study of the properties of the three structural isomers of meso-pyridyl-BODIPYs, their 2,6-dichloro derivatives, and their corresponding methylated cationic pyridinium-BODIPYs was conducted using spectroscopic and electrochemical methods, X-ray analyses, and TD-DFT calculations. Among the neutral derivatives, the 3Py and 4Py isomers showed the highest relative fluorescence quantum yields in organic solvents, which were further enhanced 2-4-fold via the introduction of two chlorines at the 2,6-positions. Among the cationic derivatives, the 2catPy showed the highest relative fluorescence quantum yield in organic solvents, which was further enhanced by the use of a bulky counter anion (PF6-). In water, the quantum yields were greatly reduced for all three isomers but were shown to be enhanced upon introduction of 2,6-dichloro groups. Our results indicate that 2,6-dichloro-meso-(2- and 3-pyridinium)-BODIPYs are the most promising for sensing applications. Furthermore, all pyridinium BODIPYs are highly water-soluble and display low cytotoxicity towards human HEp2 cells.
Subject(s)
Boron Compounds , Water , Boron Compounds/chemistry , Boron Compounds/toxicity , Humans , Molecular Structure , Solvents/chemistryABSTRACT
11,13-Dehydro seco-guaianolides, a particular type of sesquiterpene lactones, were synthesized from the commercially available α-santonin (11) using a facile strategy involving a high-yielding photochemical reaction. Natural products 10 and 17 from Artemisia gorgonum were synthesized in good yields. Specifically, compound 10 was obtained in five steps with an overall yield of 17%. The sesquiterpene lactones were tested in the etiolated wheat coleoptile bioassay, and the most active compounds were assayed on standard target species. Guaianolide 13 showed the highest phytotoxic activities when compared with the known herbicide Logran.
Subject(s)
Artemisia/drug effects , Plants/drug effects , Sesquiterpenes, Guaiane/toxicity , Biological Assay , Cell Line, Tumor , Crystallography, X-Ray , Herbicides/chemistry , Humans , Molecular Structure , Sesquiterpenes, Guaiane/chemistry , Spectrum Analysis/methods , Structure-Activity RelationshipABSTRACT
The discovery of potent natural and ecofriendly pesticides is one of the focuses of the agrochemical industry, and plant species are a source of many potentially active compounds. We describe the bioassay-guided isolation of antifungal and phytotoxic compounds from the ethyl acetate extract of Ambrosia salsola twigs and leaves. With this methodology, we isolated and identified twelve compounds (four chalcones, six flavonols and two pseudoguaianolide sesquiterpene lactones). Three new chalcones were elucidated as (S)-ß-Hydroxy-2',3,4,6'-tetrahydroxy-5-methoxydihydrochalcone (salsolol A), (S)-ß-Hydroxy-2',4,4',6'-tetrahydroxy-3-methoxydihydrochalcone (salsolol B), and (R)-α, (R)-ß-Dihydroxy-2',3,4,4',6'- pentahydroxydihydrochalcone (salsolol C) together with nine known compounds: balanochalcone, six quercetin derivatives, confertin, and neoambrosin. Chemical structures were determined based on comprehensive direct analysis in real time-high resolution mass spectrometry (HR-DART-MS), as well as 1D and 2D NMR experiments: Cosy Double Quantum Filter (DQFCOSY), Heteronuclear Multiple Quantum Coherence (HMQC) and Heteronuclear Multiple Bond Coherence (HMBC), and the absolute configurations of the chalcones were confirmed by CD spectra analysis. Crystal structure of confertin was determined by X-ray diffraction. The phytotoxicity of purified compounds was evaluated, and neoambrosim was active against Agrostis stolonifera at 1 mM, while confertin was active against both, Lactuca sativa and A. stolonifera at 1 mM and 100 µM, respectively. Confertin and salsolol A and B had IC50 values of 261, 275, and 251 µM, respectively, against Lemna pausicotata (duckweed). The antifungal activity was also tested against Colletotrichum fragariae Brooks using a thin layer chromatography bioautography assay. Both confertin and neoambrosin were antifungal at 100 µM, with a higher confertin activity than that of neoambrosin at this concentration.
Subject(s)
Ambrosia/chemistry , Fungicides, Industrial/isolation & purification , Fungicides, Industrial/pharmacology , Herbicides/isolation & purification , Herbicides/pharmacology , Circular Dichroism , Colletotrichum/drug effects , Fungicides, Industrial/chemistry , Herbicides/chemistry , Lactuca/drug effects , Molecular Structure , Plant Extracts/analysis , Plant Leaves/chemistry , Sesquiterpenes/chemistry , Sesquiterpenes/isolation & purification , X-Ray DiffractionABSTRACT
Eragrostis plana (Nees) is an allelopathic plant with invasive potential in South American pastures. To isolate and identify phytotoxic compounds from leaves and roots of E. plana, a bioassay-directed isolation of the bioactive constituents was performed. This is the first report on a new diterpene carbon skeleton, neocassane, and of three new neocassane diterpenes, neocassa-1,12(13),15-triene-3,14-dione, 1; 19-norneocassa-1,12(13),15-triene-3,14-dione, 2; and 14-hydroxyneocassa-1,12(17),15-triene-3-one, 3, identified from the roots. Compounds 1, 2, and 3 inhibited the growth of duckweed by 50% at concentrations of 109 ± 28, 200 ± 37, and 59 ± 15 µM, respectively. Compound 2 was fungicidal to Colletotrichum fragariae, Colletotrichum acutatum, and Colletotrichum gloeosporioides. The compounds identified here could explain the allelopathy of E. plana. The description of the newly discovered compounds, besides contributing to the chemical characterization of the species, may be the first step in the study of the potential of these compounds as bioherbicides.
Subject(s)
Diterpenes/isolation & purification , Eragrostis/chemistry , Herbicides , Agrostis/drug effects , Biological Control Agents , Colletotrichum/drug effects , Diterpenes/chemistry , Diterpenes/pharmacology , Fungicides, Industrial/pharmacology , Herbicides/chemistry , Herbicides/isolation & purification , Herbicides/pharmacology , Lactuca/drug effects , Plant Extracts/chemistry , Plant Extracts/pharmacology , Plant Leaves/chemistry , Plant Roots/chemistryABSTRACT
Stevia rebaudiana and its diterpene glycosides are one of the main focuses of food companies interested in developing novel zero calorie sugar substitutes since the recognition of steviol glycosides as Generally Recognized as Safe (GRAS) by the United States Food and Drug Administration. Rebaudioside A, one of the major steviol glycosides of the leaves is more than 200 times sweeter than sucrose. However, its lingering aftertaste makes it less attractive as a table-top sweetener, despite its human health benefits. Herein, we report the purification of two novel tetra-glucopyranosyl diterpene glycosides 1 and 3 (rebaudioside A isomers) from a commercial Stevia rebaudiana leaf extract compounds, their saponification products compounds 2 and 4, together with three known compounds isolated in gram quantities. Compound 1 was determined to be 13-[(2-O-ß-d-glucopyranosyl-6-O-ß-d-glucopyranosyl-ß-d-glucopyranosyl) oxy]ent-kaur-16-en-19-oic acid-ß-d-glucopyranosy ester (rebaudioside Z), whereas compound 3 was found to be 13-[(2-O-ß-d-glucopyranosyl-3-O-ß-d-glucopyranosyl-ß-d-glucopyranosyl) oxy]ent-hydroxyatis-16-en-19-oic acid -ß-d-glucopyranosy ester. Two new tetracyclic derivatives with no sugar at position C-19 were prepared from rebaudiosides 1 and 3 under mild alkaline hydrolysis to afford compounds 2 13-[(2-O-ß-d-glucopyranosyl-6-O-ß-d-glucopyranosyl-ß-d-glucopyranosyl) oxy]ent-kaur-16-en-19-oic acid (rebaudioside Z1) and 4 13-[(2-O-ß-d-glucopyranosyl-3-O-ß-d-glucopyranosyl-ß-d-glucopyranosyl) oxy]ent-hydroxyatis-16-en-19-oic acid. Three known compounds were purified in gram quantities and identified as rebaudiosides A (5), H (6) and J (7). Chemical structures were unambiguously elucidated using different approaches, namely HRESIMS, HRESI-MS/MS, and 1D-and 2D-NMR spectroscopic data. Additionally, a high-quality crystal of iso-stevioside was grown in methanol and its structure confirmed by X-ray diffraction.
Subject(s)
Diterpenes/chemistry , Plant Extracts/chemistry , Stevia/chemistry , Carbon-13 Magnetic Resonance Spectroscopy , Glycosylation , Proton Magnetic Resonance SpectroscopyABSTRACT
A new schiartane-type nortriterpenoid, micrandilactone H was isolated from Kadsuralongipedunculata Finet et Gagnep. Its 2D (two dimension) structure was elucidated by NMR spectroscopic analysis, and it is similar to that of Kadnanolactones H and the absolute configuration was established through X-ray diffraction and ECD data analysis. This represents the first complete assignment of the absolute configuration of a schiartane-type nortriterpenoid by X-ray diffraction and the ECD method. Micrandilactone H showed moderate hepatoprotective activity against N-acetyl-p-aminophenol (APAP)-induced toxicity in HepG2 cells with cell survival rates of 56.84% at 10 µM.
Subject(s)
Kadsura/chemistry , Triterpenes/chemistry , Triterpenes/pharmacology , Acetaminophen/toxicity , Apoptosis/drug effects , Cell Proliferation/drug effects , Hep G2 Cells , Humans , Magnetic Resonance Spectroscopy , Molecular Structure , Plant Extracts/chemistry , Plant Extracts/pharmacology , X-Ray DiffractionABSTRACT
Phosphorus complexes of corrole have recently attracted increasing interest since these compounds can be easily prepared in good yields, are stable, and show unusual optical properties. For these reasons, phosphorus corroles represent a class of interesting compounds to be exploited in the field of material science or for biomedical investigations and the definition of synthetic pathways for their functionalization is an important step to optimize their properties for various applications. We report here the reactivity of the phosphorus complex of 5,10,15-tritolylcorrole in the nitration or bromination reaction. Both these attempts were successful, allowing the preparation of substituted phosphorus corroles, which can be used as intermediates of more complex architectures endowed with useful properties. Furthermore, the crystallographic characterization of both complexes shows that they have an unusual ruffled geometry of the corrole core, a conformation that has not been considered possible for such a macrocycle.
Subject(s)
Nitrates/chemistry , Phosphorus/chemistry , Porphyrins/chemistry , Halogenation , Molecular StructureABSTRACT
Phytochemical investigation of the roots and rhizomes of Pileostegia viburnoides var. glabrescens led to the isolation and identification of 31 compounds (1-31), 25 of which (1-2, 4-7, 9-12, 15-18, 21-31) were isolated from the Pileostegia genus for the first time. 7α-Hydroxyfriedelan-3-one-26-ol-29-oic acid (1) is a new friedelane-type triterpene. The structure of n-butyl-ß-D-fructopyranoside (2) was determined by single-crystal X-ray diffraction. Compounds 4 and 12 displayed marginal cytotoxicity against the P388 murine leukemia cell line with IC50 values of 13.4 µM and 25.0 µM, respectively. Compound 23 exhibited marginal anti-inflammatory activity by the inhibition of lipopolysaccharide induced nitric oxide production in RAW 264.7 macrophage cells, with an IC50 value of 32.0 µM. Compounds 3, 8-10, 25, and 27 were phytotoxic to the dicot Lactuca sativa (lettuce) and/or the monocot Agrostis stolonifera (bentgrass).
Subject(s)
Plant Roots/chemistry , Rhizome/chemistry , Saxifragaceae/chemistry , Triterpenes/chemistry , Animals , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/pharmacology , Antineoplastic Agents, Phytogenic/chemistry , Antineoplastic Agents, Phytogenic/pharmacology , Cell Line, Tumor , Cell Survival , Computational Biology , Herbicides/chemistry , Herbicides/pharmacology , Lactuca/drug effects , Mice , Molecular Structure , Seeds/drug effects , Triterpenes/pharmacologyABSTRACT
The title compound {systematic name: 4-[(3R)-8,8-dimethyl-3,4-dihydro-2H-pyrano[2,3-f]chromen-3-yl]benzene-1,3-diol, commonly named glabridin}, C20H20O4, is a species-specific biomarker from the roots Glycyrrhiza glabra L. (European licorice, Fabaceae). In the present study, this prenylated isoflavan has been purified from an enriched CHCl3 fraction of the extract of the root, using three steps of medium-pressure liquid chromatography (MPLC) by employing HW-40F, Sephadex LH-20 and LiChroCN as adsorbents. Pure glabridin was crystallized from an MeOH-H2O mixture (95:5â v/v) to yield colorless crystals containing one molecule per asymmetric unit (Z' = 1) in the space group P212121. Although the crystal structure has been reported before, the determination of the absolute configuration remained uncertain. Stereochemical analysis, including circular dichroism, NMR data and an X-ray diffraction data set with Bijvoet differences, confirms that glabridin, purified from its natural source, is found only in a C3 R configuration. These results can therefore be used as a reference for the assignment of the configuration and enantiopurity of any isolated or synthetic glabridin sample.
Subject(s)
Glycyrrhiza/chemistry , Isoflavones/chemistry , Phenols/chemistry , Plant Extracts/chemistry , Plant Roots/chemistry , Circular Dichroism , Isoflavones/isolation & purification , Phenols/isolation & purification , Plant Extracts/isolation & purification , X-Ray DiffractionABSTRACT
Commercially available santonin was used to synthesize seven sesquiterpene lactones using a facile strategy that involved a high-yielding photochemical reaction. Three natural products from Artemisia gorgonum were synthesized in good yields, and in the case of two compounds, absolute configurations were determined from X-ray quality crystals. The structures previously reported for these compounds were revised. Sesquiterpene lactones were tested using the etiolated wheat coleoptile bioassay, and the most active compounds were assayed in standard target species. seco-Guaianolide (4) showed higher phytotoxic activities than the known herbicide Logran. This high activity could be due to the presence of a cyclopentenedione ring. These results suggest that compound 4 should be involved in defense of A. gorgorum, displaying a wide range of activities that allow proposing them as new leads for development of a natural herbicide model with a seco-guaianolide skeleton.
Subject(s)
Artemisia/chemistry , Herbicides/isolation & purification , Herbicides/pharmacology , Lactones/chemistry , Lactones/chemical synthesis , Lactones/pharmacology , Sesquiterpenes, Guaiane/chemistry , Sesquiterpenes, Guaiane/chemical synthesis , Sesquiterpenes, Guaiane/pharmacology , Brassicaceae/drug effects , Crystallography, X-Ray , Herbicides/chemistry , Lactuca/drug effects , Solanum lycopersicum/drug effects , Molecular Conformation , Molecular Structure , Onions/drug effects , Plasmodium falciparum/drug effects , Structure-Activity Relationship , Triticum/drug effectsABSTRACT
CONTEXT: Vernonia amygdalina Del. (VA; Asteraceae or Compositae) is a small tree growing throughout tropical Africa. It is widely used for food and medicinal purposes by local people. It was reported that it had several qualities, including anticancer activity. OBJECTIVE: A sesquiterpene lactone, vernodalinol, was isolated from VA leaves. The first reported source of vernodalinol was in 2009 from a different plant, only (1)H NMR spectrum and no detailed structural analysis were carried out. No whole spectroscopic data were provided. MATERIALS AND METHODS: VA dried leaves were extracted with 85% ethanol followed by further separation into four fractions by liquid-liquid extraction technique using various solvents: hexane, chloroform, and n-butanol. Vernodalinol was separated from the n-butanol fraction by column chromatography. The biological activity of vernodalinol was evaluated in estrogen receptor-positive (ER(+)) human breast carcinoma cells (MCF-7) in vitro. RESULTS: Results indicated that vernodalinol (25 and 50 µg/mL) inhibited breast cancerous cell growth (DNA synthesis) by 34% (P < 0.025) and 40% (P < 0.025), respectively. It is reasonable to expect an LC(50) of 70-75 µg/mL for vernodalinol in MCF-7 cells. DISCUSSION AND CONCLUSION: Vernodalinol structure was confirmed using a battery of spectroscopic methods, 1D and 2D NMR, high-resolution mass spectrometry (HR-MS), UV, IR, and X-ray. These results suggest that vernodalinol, although it has some biological activity, is likely to work in concert with other ingredients responsible for the anticancer activity exhibited of VA.
Subject(s)
Plant Extracts/analysis , Sesquiterpenes/isolation & purification , Vernonia/chemistry , Cell Line, Tumor , Crystallography, X-Ray , DNA/biosynthesis , Humans , Sesquiterpenes/chemistry , Sesquiterpenes/pharmacologyABSTRACT
Phytochemical study of the leaves and stems of Calea zacatechichi Schl. (Asteraceae) led to the isolation of a series of six germacranolides (1-6) with significant antileishmanial activity. The structure of a new compound named by us as calealactone D (1) was determined by NMR and MS, and its absolute configuration by X-ray crystallography. In addition, calealactone E (5) was discovered as a new naturally occurring compound, and the absolute configuration of calealactone C (2) was also determined by X-ray crystallography. All compounds were biologically evaluated in antimicrobial and antiprotozoal assays.
Subject(s)
Asteraceae/chemistry , Sesquiterpenes, Germacrane/isolation & purification , Sesquiterpenes, Germacrane/pharmacology , Anti-Bacterial Agents/pharmacology , Antifungal Agents/pharmacology , Antiprotozoal Agents/chemistry , Antiprotozoal Agents/isolation & purification , Antiprotozoal Agents/pharmacology , Chromatography, High Pressure Liquid , Crystallography, X-Ray , Humans , Lactones/chemistry , Lactones/isolation & purification , Lactones/pharmacology , Microbial Sensitivity Tests , Plant Components, Aerial/chemistry , Plant Extracts/chemistry , Plant Extracts/isolation & purification , Plant Extracts/pharmacology , Sesquiterpenes, Germacrane/chemistryABSTRACT
Chemical constituents of the perennial shrub Calamintha ashei have been characterized as part of our investigation of the allelopathic properties of this plant. Besides the known monoterpenes, (+)-evodone, (-)-calaminthone and (+)-desacetylcalaminthone, fresh aerial parts of C. ashei provided six new menthofurans, two new germacrane sesquiterpenes, and the six, known flavonoids: 5-desmethoxynobiletin, 5-hydroxy-6,7,8,4'-tetramethoxyflavone, 5,4'-dihydroxy-6,7,8,3'-tetramethoxyflavone, thymonin, 5,4'-dihydroxy-6,7-dimethoxyflavone and 6-hydroxy-7,3'-dimethoxyluteolin. The structures of the new compounds were elucidated by spectroscopic methods and comparison of their 1H NMR spectra with those of structurally related compounds. The molecular structures of (+)-evodone, 5-desmethoxynobiletin (5-hydroxy-6,7,8,3',4'-pentamethoxyflavone) and the triacetate of thymonin (7,8,3'-trimethoxy-5,6,4'-triacetoxyflavone), were determined by single crystal X-ray diffraction. Saturated aqueous solutions of menthofuran, (+)-evodone, (-)-calaminthone, (+)-desacetylcalaminthone, 4alpha,5beta-diacetoxymenthofuran, as well as mixtures of (+)-evodone and (+)-desacetylcalaminthone inhibited the germination and root growth of Schizachyrium scoparium and Leptochloa dubia, two native Florida sandhill grasses, as well as Lactuca sativa. (+)-Evodone and (+)-desacetylcalaminthone were the most active. 5-Hydroxy-6,7,8,3',4'-pentamethoxyflavone and 5,4'-dihydroxy-6,7,8,3'-tetramethoxyflavone and mixtures of the two flavonoids in aqueous as well as in saturated aqueous solutions ofursolic acid were tested on the same species, but showed no significant activity.
Subject(s)
Flavonoids/isolation & purification , Furans/isolation & purification , Lamiaceae/chemistry , Plant Components, Aerial/chemistry , Plant Extracts/isolation & purification , Sesquiterpenes, Germacrane/isolation & purification , Flavonoids/chemistry , Flavonoids/toxicity , Florida , Furans/chemistry , Furans/toxicity , Magnetic Resonance Spectroscopy , Molecular Structure , Plant Extracts/chemistry , Poaceae/drug effects , Poaceae/growth & development , Sesquiterpenes, Germacrane/chemistry , Sesquiterpenes, Germacrane/toxicity , X-Ray DiffractionABSTRACT
Roots extract of Rhodiola rosea L. is the source of important commercial preparations widely used throughout Europe, Asia, and the USA. Phytochemical investigation of the roots of Rhodiola rosea afforded 17 compounds, belonging to the phenylalkanoids and monoterpene analogues. Their structures were determined by spectroscopic and chemical methods. Rhodioloside F ( 1) was found to be new. The X-ray crystallographic study on salidroside ( 7) and the complete NMR data of 5 (mongrhoside) and 1A [(-)-rosiridol] are also described.
Subject(s)
Alkanes/chemistry , Monoterpenes/chemistry , Plant Extracts/chemistry , Plant Roots/chemistry , Rhodiola/chemistry , Alkanes/isolation & purification , Magnetic Resonance Spectroscopy , Models, Molecular , Molecular Structure , Monoterpenes/isolation & purification , Plant Extracts/isolation & purification , Plant Extracts/pharmacologyABSTRACT
Three alkamides (1-3) were isolated from the leaves of Zanthoxylum syncarpum. The structures of the new compounds 1 and 2 were established by spectroscopic data and chemical conversion, and by the X-ray crystallography of 1. Compound 3, the racemic form of the known compound syncarpamide, showed moderate antiplasmodial activity, with IC50 values of 4.2 and 6.1 microM against Plasmodium falciparum D6 clone and W2 clone, respectively.