Sinapic acid is widespread in the plant kingdom (fruits, vegetables, cereal grains, oilseed crops, and some spices and medicinal plants) and as such is common in the human diet. Derivatives of sinapic acid are characteristic compounds in the Brassicaceae family. Sinapic acid shows antioxidant, antimicrobial, anti-inflammatory, anticancer, and anti-anxiety activity. 4-Vinylsyringol (a decarboxylation product of sinapic acid) is a potent antioxidative and antimutagenic agent which suppresses carcinogenesis and the induction of inflammatory cytokines. Sinapine (sinapoyl choline) is considered to be an acetylcholinesterase inhibitor which might have therapeutic applications in various disease treatments. Mainly due to their antioxidative activity, these compounds have been suggested for potential use in food processing, cosmetics, and the pharmaceutical industry, and this review aims to summarize current knowledge on the natural sources, chemistry, and biological activity of these substances.

No abstract

No abstract

Total phenolic content, concentration of flavonoids and in vitro antioxidant activity of twenty different extracts from the whole plant and plant parts (leaves, flowers and stems) of Teucrium polium were determined. The total phenolic contents ranged between 14.57 to 157.84 mg of GaA/g of extract. The concentrations of flavonoids varied from 6.48 to 139.87 mg of Ru/g of extract. Antioxidant activity was determined in vitro using DPPH reagent and expressed as concentration of each extract required to inhibit radical by 50% (IC 50 ) values that ranged from 26.30 to 2190.75 µg/ml. The methanolic leaves extract contain the greatest concentration of phenolic compounds (157.84 mg of GaA/g) and showed strong antioxidant activity (IC 50 = 26.30 µg/ml). Ginkgo and Green tea extracts were analyzed for comparison, and the results indicated that some extracts of T. polium were equal in activity with Ginkgo or Green tea and some appeared to have greater activity. The obtained results suggest strong antioxidant activity and large contribution of separate analysis for the maximum exploitation of active phenolic compounds from T. polium. Based on this information, plant parts of this plant are natural sources of antioxidant substances of high importance. Keywords: Teucrium polium subsp. polium, antioxidant activity, phenolics, flavonoids Acta Societatis Botanicorum PoloniaeJournal homepage: pbsociety.org.pl/journals/index.php/asbp ORIGINAL RESEARCH PAPER Received: 2011.06.09 Accepted: 2012.04.19 Published electronically: 2012.06.12 Acta Soc Bot Pol 81(2):117-122 DOI: 10.5586/asbp.2012 Antioxidant activity, total phenolic content and flavonoid concentrations of different plant parts of Teucrium polium L. subsp. polium

No abstract

Several novel 4-hydroxy-chromene-2-one derivatives 2b-16b were easily prepared through condensation reactions with microwave heating and characterized by elemental analysis, IR, 1H-NMR and mass spectrometry. Geometry optimization of these compounds was executed by PM3, PM5 and Minimize Energy methods to describe them via molecular descriptors. The antimicrobial activity of the synthesized compounds was evaluated against different microbial strains using two different methods: the diffusion method and the micro-dilution method. All data indicated that the products possess antimicrobial activity which depends on the nature of substituent attached to the benzopyran moiety. In general, after 24 h the MIC values of most tested coumarins was 0.13 mg/mL, but compounds 1 and 6b displayed the strongest antimicrobial activity on the tested cultures of bacteria after 48 h. Compound 13b has the strongest growth inhibitory potential on fungus C. albicans, tested by diffusion method, with an inhibition zone of 30-37 mm at a concentration of 150 µg/mL. The conclusion of this experiment is that the synthesized compounds have varied and different influence on different classes of bacteria and the fungus C. albicans.

Series of imino and amino derivatives of 4-hydroxy coumarins were synthesized via conventional and microwave promoted procedure and evaluated for antioxidant potential through different in vitro models such as (DPPH) free radical scavenging activity, linoleic acid emulsion model system, reducing power assay and phosphomolybdenum method. All prepared compounds possess good antioxidant activity and among them p-nitro-phenyl derivative 6c with IC50 at 25.9 microM possesses radical scavenging activity which is comparable to standard BHT, while the best reducing power was observed in a case of benzyl amino compound 8c (RP50 255.6 microM). Also, observed data indicated that compounds may serve as inhibitors of lipid peroxidation process.

The series of fifteen synthesized 4-hydroxycoumarin derivatives was subjected to antioxidant activity evaluation in vitro, through total antioxidant capacity, 1,1-diphenyl-2-picryl-hydrazyl (DPPH), hydroxyl radical, lipid peroxide scavenging and chelating activity. The highest activity was detected during the radicals scavenging, with 2b, 6b, 2c, and 4c noticed as the most active. The antioxidant activity was further quantified by the quantitative structure-activity relationships (QSAR) studies. For this purpose, the structures were optimized using Paramethric Method 6 (PM6) semi-empirical and Density Functional Theory (DFT) B3LYP methods. Bond dissociation enthalpies of coumarin 4-OH, Natural Bond Orbital (NBO) gained hybridization of the oxygen, acidity of the hydrogen atom and various molecular descriptors obtained, were correlated with biological activity, after which we designed 20 new antioxidant structures, using the most favorable structural motifs, with much improved predicted activity in vitro.