scholarly journals Identification of Ellagic Acid Derivatives from Stem Bark of Syzygium Guineense (Myrtaceae)

2007 ◽  
Vol 2 (3) ◽  
pp. 1934578X0700200
Author(s):  
Jules Desire Djoukeng ◽  
Eliane Abou-Mansour ◽  
Leon Azefack Tapondjou ◽  
David Lontsi ◽  
Raffaele Tabacchi
Keyword(s):  
Ellagic Acid ◽  
Radical Scavenging ◽  
2D Nmr ◽  
Stem Bark ◽  
Dpph Assay ◽  
Spectrometric Data ◽  
Esi Ms ◽  
Syzygium Guineense ◽  
Fragmentation Patterns

An LC-DAD-ESI-MSn technique was developed to investigate crude extracts of the stem bark of S. guineense for phenolic compounds. Ellagic acids were detected on the basis of their UV absorption spectra and ESI-MS fragmentation patterns. Six ellagic acid conjugates in the complex extract of S. guineense were identified. With the aim to confirm the structures, further purification of the extract afforded the known 3-O-ellagic acid-4′-O-α-rhampyranonosides (3), two new ellagic acid rhamnopyranosides, 3-O-methylellagic acid-4′-O-α-2″-O-acetylrhamnopyranoside (4) and 3-O-methylellagic acid-4′-O-α-3″-O-acetylrhamnopyranoside (6). The structures were identified on the basis of 1D- and 2D- NMR, IR, and UV spectroscopic and mass spectrometric data. The HMBC and NOESY data of these compounds were most useful for determination of their structures. Radical scavenging activities were evaluated in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. Compounds 3, 4 and 6, with IC50 values of 6.1 ± 0.5, 5.8 ± 0.4, and 6.2 ± 0.4 μM, respectively were as active as ellagic acid (1) (IC50 = 4.9 ± 0.3 μM) and more active than catechin (IC50=10.8 ± 0.3 μM).

Acridone Alkaloids and Coumarins from the Stem Bark of Citropsis articulata (Rutaceae)

2010 ◽  
Vol 65 (4) ◽  
pp. 525-527 ◽  
Author(s):  
Luc Mbaze Meva’a ◽  
Jules Lobe Songue ◽  
Jean Duplex Wansi ◽  
Alain François Kamdem Waffo ◽  
Etienne Dongo ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
2D Nmr ◽  
Stem Bark ◽  
Mass Spectrometric ◽  
Meoh Extract ◽  
Mass Spectrometric Data ◽  
Spectrometric Data ◽  
Acridone Alkaloids ◽  
2D Nmr Spectra ◽  
Acridone Alkaloid

A new acridone alkaloid, citropsine A (1), and thirteen known compounds (2 - 14) were isolated from the MeOH extract of the stem bark of Citropsis articulata. Structures of all compounds were determined by detailed analyses of their 1D and 2D NMR spectra, mass spectrometric data and by comparison with previously known analogs.

scholarly journals Synthesis and characterization of new 4-aryl-2-(2-oxopropoxy)-6-(2,5-dichlorothiophene)nicotinonitrile and their furo[2,3-b]pyridine derivatives: Assessment of antioxidant and biological activity

2018 ◽  
Vol 9 (4) ◽  
pp. 375-381 ◽  
Author(s):  
Mahmoud Al‐Refai ◽  
Mohammad Ibrahim ◽  
Abdullah Al‐Fawwaz ◽  
Armin Geyer
Keyword(s):  
Antioxidant Activities ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
2D Nmr ◽  
Pyridine Derivatives ◽  
Esi Ms ◽  
Scavenging Effect ◽  
Radical Scavenging Effect ◽  
New Compounds

A new series of furo[2,3-b]pyridine derivatives bearing aryl substituents were synthesized in two steps, where, the cyano-(2H)-pyridones (1a-l) were converted to the corresponding nicotinonitriles (2a-l), followed by the Thorpe-Ziegler ring cyclization to the furo[2,3-b]pyridine derivatives (3a-l). All new compounds were characterized by 1D-NMR experiments (1H and 13C) and 2D-NMR experiments (COSY, HMBC and HSQC), as well as ESI-MS and HR-ESI-MS data. The new compounds were screened for their antioxidant activities by 2,2-diphenyl-1-picryl-hydrazylhydrate (DPPH) free radical assay. The highest radical scavenging effect was observed for nicotinonitriles 2d, 2h and 2l and furo[2,3-b]pyridines 3b, 3f and 3j by methanolic solvent at 4.0 mg/mL concentration. Remarkably, all nicotinonitriles and furo[2,3-b]pyridine exhibited a significant radical scavenging activity after 24 and 48 hours compared with 0.5 hour.

A New Chlorine-containing Glucosyl-fused Compound from Curculigo glabrescens

2009 ◽  
Vol 64 (9) ◽  
pp. 1077-1080 ◽  
Author(s):  
Cui-Cui Zhu ◽  
Tian-Ming Wang ◽  
Kai-Jin Wang ◽  
Ning Li
Keyword(s):  
Spectroscopic Analysis ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
2D Nmr ◽  
Free Radical Scavenging ◽  
Scavenging Activity ◽  
Dpph Assay ◽  
Etoh Extract ◽  
Structure Activity ◽  
First Time

A new chlorine-containing glucosyl-fused compound, crassifoside H (1), was isolated from the EtOH extract of the rhizomes of Curculigo glabrescens. The structure was established on the basis of MS, IR, 1D and 2D NMR experiments. In addition, seven known compounds (2 - 8) were isolated and identified by spectroscopic analysis and comparison of their spectral data with those reported previously. All the compounds were isolated from this plant for the first time. The free radical scavenging activity of the isolated compounds was evaluated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. Compounds 1 and 2 showed strong radical scavenging activities. The primary structure-activity relationship is also discussed.

scholarly journals Fruits of Rosa brunonii – A Source of Antioxidant Phenolic Compounds

2017 ◽  
Vol 12 (11) ◽  
pp. 1934578X1701201
Author(s):  
Muhammad Ishaque ◽  
Yamin BiBi ◽  
Karin M. Valant–Vetschera ◽  
Johann Schinnerl ◽  
Markus Bacher
Keyword(s):  
Mass Spectrometry ◽  
Phenolic Compounds ◽  
Biological Activities ◽  
Radical Scavenging ◽  
2D Nmr ◽  
Flavonol Glycosides ◽  
Northern Pakistan ◽  
Dpph Assay ◽  
2D Nmr Spectroscopy ◽  
Kaempferol Glycosides

Phytochemical examination of matured fruits of Rosa brunonii collected in Northern Pakistan led to the isolation of three flavonol glycosides quercetin-3- O-rhamnoside (1), and the kaempferol glycosides astragalin (2) and tiliroside (3). Their structures were elucidated by 1D– and 2D–NMR spectroscopy and mass spectrometry. Radical scavenging activities of the crude extract and isolated compounds were assessed by a DPPH assay. The results show strong antioxidative activities of tiliroside (3) and lower activities of astragalin (2) and quercetin-3- O-rhamnoside (1). These data confirm previous reports and underline the biological activities of flavonol glycosides.

scholarly journals Determination of Polar Compounds in Guava Leaves Infusions and Ultrasound Aqueous Extract by HPLC-ESI-MS

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Elixabet Díaz-de-Cerio ◽  
Vito Verardo ◽  
Ana María Gómez-Caravaca ◽  
Alberto Fernández-Gutiérrez ◽  
Antonio Segura-Carretero
Keyword(s):  
Antioxidant Activity ◽  
Aqueous Extract ◽  
Ellagic Acid ◽  
Polar Compounds ◽  
Optimal Time ◽  
Esi Ms ◽  
Conventional Ultrasound ◽  
Ellagic Acid Derivatives ◽  
Guava Leaves

Literature lacks publications about polar compounds content in infusion or guava leaves tea. Because of that, a comparison between different times of infusion and a conventional ultrasound aqueous extract was carried out. Several polar compounds have been identified by HPLC-ESI-MS and their antioxidant activity was evaluated by FRAP and ABTS assays. Four different classes of phenolic compounds (gallic and ellagic acid derivatives, flavonols, flavanones, and flavan-3-ols) and some benzophenones were determined. The quantification results reported that the order, in terms of concentration of the classes of polar compounds in all samples, was flavonols > flavan-3-ols > gallic and ellagic acid derivatives > benzophenones > flavanones. As expected, the aqueous extract obtained by sonication showed the highest content in the compounds studied. Significative differences were noticed about the different times of infusion and five minutes was the optimal time to obtain the highest content in polar compounds using this culinary method. All the identified compounds, except HHDP isomers and naringenin, were positively correlated with antioxidant activity.

scholarly journals Phytochemical, Antimicrobial and Antiplasmodial Investigations of Terminalia brownii

2013 ◽  
Vol 8 (6) ◽  
pp. 1934578X1300800 ◽  
Author(s):  
Francis Machumi ◽  
Jacob O. Midiwo ◽  
Melissa R. Jacob ◽  
Shabana I. Khan ◽  
Babu L. Tekwani ◽  
...  
Keyword(s):  
Ellagic Acid ◽  
Soluble Fraction ◽  
2D Nmr ◽  
Stem Bark ◽  
Bark Extract ◽  
Spectroscopic Methods ◽  
Group 4 ◽  
Phytochemical Investigation ◽  
Stem Bark Extract ◽  
Ellagic Acid Derivatives

Phytochemical investigation of the ethyl acetate-soluble fraction of stem bark extract of an African medicinal plant Terminalia brownii led to the isolation of a new oleanane-type triterpenoid, along with seven known triterpenoids, seven ellagic acid derivatives, and 3- O-β-D-glucopyranosyl-β-sitosterol. The new compound was identified using spectroscopic methods, notably 1D- and 2D NMR, as 3β,24- O-ethylidenyl-2α,19α-dihydroxyolean-12-en-28-oic acid. The isolated compounds were evaluated for their antimicrobial and antiplasmodial activities. Two compounds with a galloyl group (4 and 6) were found to be active against chloroquine sensitive (D6) and chloroquine resistant (W2) strains of Plasmodium falciparum, whereas three ellagic acid derivatives (5–7) were found active against three species of fungi and one species of bacteria.

scholarly journals GC-MS fragmentation patterns of sprayed endosulfan and its sulphate metabolite in samples of Theobroma cacao L from a field kinetic study

2018 ◽  
Vol 25 (4) ◽  
pp. 362-371 ◽  
Author(s):  
Edebi N Vaikosen ◽  
Lorraine T Gibson ◽  
Christine M Davidson ◽  
Bamidele I Olu-Owolabi ◽  
Kayode Adebowale ◽  
...  
Keyword(s):  
Theobroma Cacao ◽  
Ion Trap ◽  
Stem Bark ◽  
Molecular Ion ◽  
Isotopic Pattern ◽  
Endosulfan Sulphate ◽  
Pattern Characteristic ◽  
Fragmentation Patterns ◽  
Cacao Plantation

Most environmental analytical methods for the determination of organochlorine pesticides (OCPs) are multi-residual with other organic compounds co-extracted and co-eluted. This has been observed in GC spectra using classical detectors like electron-capture detector (ECD) even after appropriate clean-up. This limitation could be resolved by using GC-MS methods which are more specific and selective. Thus, a commercial-grade endosulfan treated Theobroma cacao plantation was sampled. Representative samples comprising leaves, stem bark and pulp were obtained between 0.5 h and 60 days after treatment. Samples were analyzed for residual parent endosulfan ( α- and β-isomers) as well as the metabolite endosulfan sulphate using an ion trap GC-MS. The retention times and chromatogram peaks obtained for various endosulfan were identified and compared with reference standards, and confirmed with National Institute of Standards and Technology library. Results showed that the molecular ion at m/z 407 was exhibited by α- and β-endosulfan, representing the parent molecular ion M+• ([C9H6Cl6SO3]+•). The α-isomer was more thermally stable, hence exhibited more relative abundance. Other predominant peaks were 339, 307, 277, 265, 243, 241, 207, 195, 160, 159, 99 and 75 m/z. The peak at m/z 159 was the base molecular ion. For endosulfan sulphate, the peak at m/z 422 corresponded to parent molecular ion (M+•), while m/z 424 was due to isotopic pattern characteristic of the chlorine atom. The peaks at 387, 357, 289, 272, 229, 206, 170, and 120 m/z were characteristic for the sulphate metabolite. The m/z peak at 272 was the base molecular ion, while m/z 143 may be due to metabolite diol and lactone. These results showed that the various endosulfan species can be identified and confirmed simultaneously using a GC-MS.

Department of Pharmaceutical Care, General Hospital of Chinese PLA, Beijing, 100853, P. R. China

2012 ◽  
Vol 67 (7-8) ◽  
pp. 353-359
Author(s):  
Assem El-Shazly ◽  
Afaf El-Sayed ◽  
Eman Fikrey
Keyword(s):  
Methanolic Extract ◽  
Diclofenac Sodium ◽  
Radical Scavenging ◽  
Ethyl Acetate Fraction ◽  
2D Nmr ◽  
Stem Bark ◽  
Free Radical Scavenging ◽  
Light Petroleum ◽  
Paw Oedema ◽  
Analgesic Activities

Column chromatography of the light petroleum fraction from the methanolic extract of the stem bark of Salix tetrasperma Roxb. (Salicaceae) resulted in the isolation of β-sitosterol acetate, friedelin, 3β-friedelinol, β-amyrin, β-sitosterol, β-sitosterol-O-glucoside in addition to palmitic acid. From the dichloromethane fraction of the leaves, catechol and tremulacin were isolated. Salicin and its derivatives tremuloidin and 2’-O-p-(E)-coumaroyl salicin were isolated from the ethyl acetate fraction of the leaves. The isolated compounds were identified by MS, and 1D NMR (1H and 13C) and 2D NMR (H-H COSY, HSQC, and HMBC) spectral analyses. The total methanolic extract exhibited significant anti-inflammatory activity (rat hind paw oedema). The extract with a content of 120 mg/kg body weight produced 52% inhibition equivalent to the standard diclofenac sodium (54% inhibition). The antioxidant (DPPH free radical scavenging) and analgesic activities, respectively, were also evaluated.

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