ChemInform Abstract: Microwave‐Assisted Synthesis and Antimicrobial Activities of Flavonoid Derivatives.

Abstract

tives. -Flavones (III) are obtained from hydroxyacetophenones (I) utilizing the Baker-Venkataraman rearrangement, followed by microwave-assisted condensation. In several cases the diketones intermediates are purified by column chromatography, but in general it is convenient to use the crude compounds in the cyclization reaction. All of the eleven synthesized compounds exhibit antifungal activity against A.niger and F.oxysporium, and two of the flavonoid analogues, (IIIb) and (IIId), inhibit the growth of methicillin-resistant S.aureus. -(GHANI, S. B. A.; WEAVER, L.; ZIDAN, Z. H.; ALI, H. M.; KEEVIL, C. W.; BROWN*, R. C. D.; Bioorg. Med. Chem. Lett. 18 (2008) 2, 518-522; Sch. Chem., Univ. Southampton, Southampton SO17 1BJ, UK; Eng.) -H. Hoennerscheid 25-138

Yield of Polyphenolic Substances Extracted From Spruce (Picea abies) Bark by Microwave-Assisted Extraction

“…Closed-system microwave-assisted extraction (MAE) is an important technique for extracting valuable compounds from lignocellulosic materials (Guo et al 2001;Hao et al 2002;Gao et al 2006;Ghaly and Adams 2007;Hemwimon et al 2007;Ghani et al 2008;Yeoh et al 2008;Gujar et al 2009;Spigno and Faveri 2009;Michel et al 2011;. MAE of extractive substances may be affected by factors such as frequency and power of the microwave, time of applying microwave radiation, moisture content, particle size, ratio of solid to liquid, type and composition of solvent, temperature, pressure, and number of extraction cycles (Wang and Weller 2006;Yang and Zhang 2011;Hadkar et al 2013).…”

Inhibition of aflatoxin B1 production of Aspergillus flavus isolated from peanut seeds using Lycium halimifolium Mill leaves fractions

“…The inhibition growth of A. flavus by secondary metabolites (flavonoids and essential oil) has already been reported. These compounds can interfere with biomembranes causing cell damage and causing leakage of cellular materials and finally the death of microorganisms (Dikbas et al, 2008;Abdel Ghani et al, 2008). Considering the large number of different groups of chemical compounds present in extracts of plants (flavonoids, phenols, saponosid, gallic tannins and catechic tannins and alkaloids), it is interesting to note that, the antimicrobial activity is not attributable to a specific mechanism alone but to several targets in the cell.…”

Recent Advances in Microwave-Assisted Extraction (Mae) of Medicinal Plants: A Review

“…The foremost advantage of MAE over ultrasonic-assisted extraction is its reduced extraction time. Yet, microwave irradiation can accelerate the chemical changes of some target secondary metabolites 21,22 , and other operational conditions (e.g., high extraction pressure) of MAE may modify the chemical structures of the target compounds, both of which might result in the reduction of extraction yield 23,15 . During the extraction of flavonoids from Acanthopanax senticosususing closed extraction vessel, rutin in the crude extract was found to degrade when the pressure was over 300 kPa.…”