Molecules

200 KiB

Open AccessArticle

Synthesis and Biological Evaluation of Some Novel Schiff’s Bases from 1,2,4-Triazole

by Xiao-Xia Ye, Zhen-Fei Chen, An-Jiang Zhang and Li-Xue Zhang

Molecules 2007, 12(6), 1202-1209; https://doi.org/10.3390/12061202 - 5 Jul 2007

Cited by 32 | Viewed by 9227

We have synthesized a number of novel Schiff’s bases from 4-amino-3-(D-glucoheptonic-hexitol-1-yl)-1H-1,2,4-triazole-5-thione. By attaching D-glucoheptonic-hexitol-1-yl residues to 1,2,4-triazole at the 3-position, the solubility of the title compounds has been improved greatly. All the products have been characterized by elemental analysis, IR, ¹H-NMR, ¹³C-NMR and MS. The plant-growth regulating effects of the title compounds were examined. From the biological activity results, we found that most compounds showed weak to moderate activities. Full article

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140 KiB

Open AccessArticle

Synthesis and Antibacterial Properties of New 8-Nitrofluoroquinolone Derivatives

by Yusuf M. Al-Hiari, Inas Saleh Al-Mazari, Ashok K. Shakya, Rula M. Darwish and Rana Abu-Dahab

Molecules 2007, 12(6), 1240-1258; https://doi.org/10.3390/12061240 - 30 Jun 2007

Cited by 57 | Viewed by 10686

Abstract

The objective of this research was the preparation of new 8-nitrofluoroquinolone models and investigation of their antibacterial properties. The work initially involved large scale preparation of the synthon 7-chloro-1-cyclopropyl-6-fluoro-8-nitro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid (3), followed by introduction of substituted primary amine appendages at the C-7 position to give derivatives 9a-g, in which the amino group is appended to substituted benzenes or aromatic heterocycles, is part of a primary α-amino acid or just a simple primary aliphatic amine. This nucleophilic aromatic substitution step was a very simple procedure since the 8-nitro group of the above synthon facilitated the addition of weak nucleophiles at C-7. All compounds prepared were fully identified and characterized using NMR, IR, EA and MS, and were consistent with expected structures. The prepared targets and the intermediates have shown interesting antibacterial activity against gram positive and/or gram negative strains. In particular, the p-toluidine, p-chloroaniline and aniline derivatives showed good activity against S. aureus with MIC range ≈ 2-5 μg/mL. In conclusion, more lipophilic groups seem to enhance activity against gram positive strains. Full article

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52 KiB

Open AccessCommunication

Composition and Enantiomeric Analysis of the Essential Oil of the Fruits and the Leaves of Pistacia vera from Greece

by Anastasia Tsokou, Katerina Georgopoulou, Eleni Melliou, Prokopios Magiatis and Eugenia Tsitsa

Molecules 2007, 12(6), 1233-1239; https://doi.org/10.3390/12061233 - 30 Jun 2007

Cited by 54 | Viewed by 9709

Abstract

The essential oils of the fruits and the leaves of pistachio (Pistacia vera L.) were analyzed by GC and GC/MS. Fresh unripe pistachio fruits were richer in essential oil (0.5 %, w/w) than the leaves (0.1 %, w/w). Twenty one compounds were identified in the essential oil of the fruits and the major components were (+)-α-pinene (54.6 %) and terpinolene (31.2 %). The enantiomeric ratio of the major constituents of the essential oil of the fruits was determined using chiral GC/MS and it was found that the (+)/(-)-α-pinene ratio was 99.5:0.5, (+)/(-)-limonene 80:20, (+)/(-)-β-pinene 96:4, and (+)/(-)-α-terpineol 0:100. Thirty three compounds were identified in the essential oil of the leaves and the major components were found to be α-pinene (30.0 %), terpinolene (17.6 %) and bornyl acetate (11.3 %). Full article

96 KiB

Open AccessArticle

Solar Ultraviolet-B Radiation Increases Phenolic Content and Ferric Reducing Antioxidant Power in Avena sativa

by Christopher T. Ruhland, Mitchell J. Fogal, Christopher R. Buyarski and Matthew A. Krna

Molecules 2007, 12(6), 1220-1232; https://doi.org/10.3390/12061220 - 29 Jun 2007

Cited by 41 | Viewed by 12979

Abstract

We examined the influence of solar ultraviolet-B radiation (UV-B; 280-320 nm) on the maximum photochemical efficiency of photosystem II (F_v/F_m), bulk-soluble phenolic concentrations, ferric-reducing antioxidant power (FRAP) and growth of Avena sativa. Treatments involved placing filters on frames over potted plants that reduced levels of biologically effective UV-B by either 71% (reduced UV-B) or by 19% (near-ambient UV-B) over the 52 day experiment (04 July - 25 August 2002). Plants growing under near-ambient UV-B had 38% less total biomass than those under reduced UV-B. The reduction in biomass was mainly the result of a 24% lower leaf elongation rate, resulting in shorter leaves and less total leaf area than plants under reduced UV-B. In addition, plants growing under near-ambient UV-B had up to 17% lower F_v/F_m values early in the experiment, and this effect declined with plant age. Concentrations of bulk-soluble phenolics and FRAP values were 17 and 24% higher under near-ambient UV-B than under reduced UV-B, respectively. There was a positive relationship between bulk-soluble phenolic concentrations and FRAP values. There were no UV-B effects on concentrations of carotenoids (carotenes + xanthophylls). Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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278 KiB

Open AccessArticle

Antiradical Activity of Paulownia tomentosa (Scrophulariaceae) Extracts

by Karel Smejkal, Pavla Holubova, Ales Zima, Jan Muselik and Margita Dvorska

Molecules 2007, 12(6), 1210-1219; https://doi.org/10.3390/12061210 - 27 Jun 2007

Cited by 31 | Viewed by 13365

Abstract

Paulownia tomentosa is a large indecidous tree planted mostly for its fast growing wood and decoratative purposes. The tree is also used in traditional Chinese medicine. As a part of our study of natural polyphenols, the fruits of Paulownia tomentosa were extracted by EtOH and than subjected to liquid/liquid extraction. Fractions were analysed by TLC and HPLC to determine presence of phenolic substantaces. We identified and quantified acteoside (1) and isoacteoside (2) in the EtOAc and n-BuOH extracts; mimulone (3) and diplacone (4) in the MeOH extract. To determine the antiradical activity of extracts we used the anti DPPH and peroxynitrite assays. The activity was expressed as Trolox C equivalents, IC₅₀ for DPPH scavenging and a time dependency course was established. The polyphenols content was determined; results were expressed as gallic acid equivalents. Using these methods we found the fractions of the n-BuOH, EtOAc and MeOH extracts that display antiradical activity, which could be exploited as potential pharmaceuticals. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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Molecules, Volume 12, Issue 6 (June 2007) – 5 articles , Pages 1202-1258

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