SYNTHESIS OF BISCOUMARIN DERIVATIVES AS ANTIMICROBIAL AGENTS

Objective: As a further part of our chemical and biological studies in this field, we describe the preparations of the properly substituted benzylidene-bis-(4-hydroxycoumarin) derivatives 5a-h and 3-(6-oxo-(1H)-benzopyrano[4,3-b]benzopyran-7-yl)-4-hydroxycoumarin derivatives 6a-e. Methods: The synthesized compounds were screened for their in vitro antimicrobial activity against five strains of bacteria and two fungal strains using disk diffusion assay and dilution method. The way in which the substituent group's physicochemical properties influence the antimicrobial activity is discussed in the paper. Results: The in vitro evaluation of their inhibitory properties towards five strains of Gram-positive and Gram-negative bacteria and two fungal strains indicated that the                                       4-trifluoromethylbenzylidene derivative of bis-(4-hydroxycoumarin) (compound 5c) and                    3-(6-oxo-(1H)-18-bromobenzopyrano[4,3-b]benzopyran-7-yl)-4-hydroxycoumarin derivative (compound 6b) possess the most potent antibacterial activities, with MIC of 3.9 μg/mL - 7.8 μg/mL against Gram-positive bacteria. Conclusion: The compound 6b has greater antibacterial activity than the standard chloramfenicol (inhibition zone 26 mm and MIC 1.9 μg/mL) against Staphyloccocus aureus and could be considered as leading compound in the future antimicrobial drug development.   Key words: Benzylidene-bis-(4-hydroxycoumarin), benzopyranocoumarin derivatives, antibacterial assays, antifungal activity

Antioxidant, Antimicrobial and Antiproliferative Activities of Synthesized 2,2,5,5-Tetramethyl-9-aryl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione Derivatives

Ten biologically active 2,2,5,5-tetramethyl-9-aryl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione derivatives were synthesized and their structures were confirmed by IR, 1H and 13C NMR spectroscopy and mass spectrometry. Synthesized compounds were scanned for their antioxidant, antimicrobial and antiproliferative activity. Antibacterial activity was tested by the diffusion and dilution method against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, while antifungal activity was tested against Candida albicans and Saccharomyces cerevisiae. Antiproliferative activity was tested against HeLa (cervical carcinoma), SW620 (colorectal adenocarcinoma, metastatic), hepatocellular carcinoma (HEpG2), lung carcinoma cells (A549) and mouse embryo fibroblast cell line (3T3). The best antioxidant activity showed compound 2 with two hydroxy groups substituted on phenyl ring in positions 2\u27 and 3\u27. The best antimicrobial activity of all synthesized compounds showed compound 8, while the best antiproliferative activity showed compound 6. Results signify the importance of xanthene-1,8-dione derivatives as potential antioxidant and antiproliferative agents. This work is licensed under a Creative Commons Attribution 4.0 International License

9-Aryl Substituted Hydroxylated Xanthen-3-ones: Synthesis, Structure and Antioxidant Potency Evaluation

Oxidative stress is directly related to several diseases and symptoms, where antioxidant compounds, such as xanthenes, may become important in prevention and/or treatmant. Ten biologically active 9-aryl substituted 2,6,7-trihydroxyxanthen-3-one derivatives were synthesized using reliable one-pot synthesis and their structures were confirmed by IR, 1H and 13C NMR spectroscopy and mass spectrometry. Some of the synthesized compounds were scanned for their antioxidant potency using electrochemical method cyclic voltammetry of immobilized microparticles. Substitution of hydrogen at the phenyl ring of 2,6,7-trihydroxy-9-phenylxanthen-3-one with an electron-donating group affected the reducing power of the compounds by lowering the biological oxidation potential. These results signify the importance of xanthen-3-one derivatives as antioxidant agents and their further biological evaluation

Antiproliferative and genotoxic potential of xanthen-3-one derivatives

Twelve previously synthesized, biologically active 2,6,7-trihydroxyxanthen-3-one derivatives were evaluated in vitro for antiproliferative activity. Compounds were screened against HeLa, SW620, HepG2 and A549 tumor cell lines. Compound with the trifluormethyl group on C-4\u27 position of the phenyl ring showed the best inhibitory activity towards HeLa and A549 tumor cells with IC50 of 0.7 µmol L–1 4.1 µmol L–1, resp. Compound with chlorine and fluorine substituents on aryl ring showed the best antiproliferative activity against SW620 with IC50 of 4.1 µmol L–1 and against HepG2 tumor cell line with IC50 of 4.2 µmol L–1. Analyses of cytotoxic and genotoxic potential of the trifluormethyl derivative were performed with cytokinesis-block micronucleus cytome assay in human lymphocyte culture and revealed no genotoxic and cytotoxic effects. The most potent compounds were subjected to molecular docking simulations in order to analyse bindings to molecular targets and, at the same time, further support the results of experimental cytotoxic tests. Docking studies showed sites of importance in forming hydrogen bonds of the most potent compounds with targets of interest

QTL for phytosterol and sinapate ester content in Brassica napus L. collocate with the two erucic acid genes

Improving oil and protein quality for food and feed purposes is an important goal in rapeseed (Brassica napus L.) breeding programs. Rapeseed contains phytosterols, used to enrich food products, and sinapate esters, which are limiting the utilization of rapeseed proteins in the feed industry. Increasing the phytosterol content of oil and lowering sinapate ester content of meal could increase the value of the oilseed rape crop. The objective of the present study was to identify quantitative trait loci (QTL) for phytosterol and sinapate ester content in a winter rapeseed population of 148 doubled haploid lines, previously found to have a large variation for these two traits. This population also segregated for the two erucic acid genes. A close negative correlation was found between erucic acid and phytosterol content (Spearman’s rank correlation, rs = −0.80**). For total phytosterol content, three QTL were detected, explaining 60% of the genetic variance. The two QTL with the strongest additive effects were mapped on linkage groups N8 and N13 within the confidence intervals of the two erucic acid genes. For sinapate ester content four QTL were detected, explaining 53% of the genetic variance. Again, a close negative correlation was found between erucic acid and sinapate ester content (rs = −0.66**) and the QTL with the strongest additive effects mapped on linkage groups N8 and N13 within the confidence intervals of the two erucic acid genes. The results suggests, that there is a pleiotropic effect of the two erucic acid genes on phytosterol and sinapate ester content; the effect of the alleles for low erucic acid content is to increase phytosterol and sinapate ester content. Possible reasons for this are discussed based on known biosynthetic pathways

Genetische Variation und Vererbung des Phytosterolgehaltes im Raps (<i>Brassica napus L.</i>)

Die Verbesserung der Öl- und Proteinqualität beim Raps (Brassica napus L.) ist eine wichtiges Ziel aktueller Züchtungsprogramme. Rapssamen weisen einen im Vergleich zu anderen Ölsaaten hohen Gehalt an Phytosterolen und Sinapinsäureestern auf. Phytosterole werden auf Grund ihrer cholesterolsenkenden Wirkung für die Herstellung von entsprechend angereicherten funktionellen Lebensmitteln benutzt. Sinapinsäureester führen dagegen zu einer dunklen Verfärbung des Rapsextraktionsschrots und zu einem bitteren Geschmack, welches die Verwendung des Schrots in der Tierernährung begrenzt. Eine Erhöhung des Phytosterolgehaltes im Öl und eine Verringerung des Sinapinsäureestergehaltes im Schrot könnten zu einer erhöhten Wertschöpfung des Rapsöls und Rapsschrots in der Nahrungs- und Futtermittelindustrie führen. Vorrangige Forschungsziele dieser Arbeit waren die Untersuchung der genetischen Variation des Phytosterolgehaltes und die Identifizierung von "Quantitative Trait Loci" (QTL) für Phytosterol- und Sinapinsäureestergehalt. Außerdem sollte eine Nah Infrarot Reflektions-Spektroskopische (NIRS) Kalibrierung für eine effiziente Bestimmung des Phytosterolgehaltes in Rapssamen entwickelt werden. Die varianzanalytische Verrechnung von Feldversuchsergebnissen von drei verschiedenen doppelthaploiden (DH) Populationen zeigte eine große genetische Variation mit überwiegendem Genotypeinfluss auf den Phytosterolgehalt. Eine Korrelation zwischen dem Phytosterolgehalt und anderen qualitätsbestimmenden Merkmalen konnte nicht festgestellt werden. Eine der DH-Populationen segregierte für den Gehalt an Erucasäure im Samenöl; hier war der Phytosterolgehalt und der Sinapinsäureestergehalt negativ korreliert mit dem Erucasäuregehalt. Zwei von den insgesamt drei QTL für Phytosterolgehalt kartierten in dieser Population innerhalb der Konfidenzintervalle der beiden Erucasäuregene, was auf einen pleiotropen Effekt der Erucasäuregene auf den Phytosterolgehalt hindeutet. In der gleichen Population wurden insgesamt sechs QTL für den Sinapinsäureestergehalt identifiziert. Auch hier kartierten die zwei QTL mit den größten additiven Effekten innerhalb der Konfidenzintervalle der beiden Erucasäuregene. Dies kann möglicherweise auf Konkurrenz um plastidäres Phosphoenolpyruvat zurückzuführen sein, welches eine gemeinsame Vorstufe für die de novo Synthese von Fettsäuren und Sinapinsäureester ist. Die entwickelte NIRS Kalibrierung kann in Züchtungsprogrammen, die auf einen erhöhten Phytosterolgehalt beim Raps zielen, eingesetzt werden

Antimikrobno i antiproliferativno djelovanje derivata ksanten-3-ona i njihov afinitet vezivanja za enzime

Ten biologically active derivatives of 2,6,7-trihydroxyxanthen-3-one, previously synthesized and characterised, were investigated for their in vitro antimicrobial and antiproliferative activity. Compounds were tested on three bacteria, Staphylococcus aureus, Bacillus subtilis and Escherichia coli, and two fungi strains, Candida albicans, and Saccharomyces cerevisiae. The best activity against E. coli showed non-substituted compound 1. The most potent against fungi strains was compound 7 with ortho methoxy substituent. Compound 4 exerted the most potent antiproliferative activity in the micromolar range (0.1–10 µM) on tested tumour cell lines except on SW620. Additional Western blot analyses showed increased cyclin B1 levels in HeLa cells treated with compound 4, which is a major mitotic catastrophe’s marker and decreased levels of Wee1 and Erk ½ kinases involved in regulation of the mitotic process. The most potent compounds after in vitro tests were subjected to molecular docking simulations to evaluate enzyme binding affinity, and provide further evidence for experimentally observed biological effects in vitro. This work is licensed under a Creative Commons Attribution 4.0 International License.Za deset prethodno sintetiziranih biološki aktivnih derivata 2,6,7-trihidroksiksanten-3-ona ispitivano je in vitro antimikrobno i antiproliferativno djelovanje. Mikrobiološka aktivnost spojeva ispitana je na tri bakterije: Staphylococcus aureus, Bacillus subtilis i Escherichia coli, te dva soja gljiva: Candida albicans i Saccharomyces cerevisiae. Najbolju antibakterijsku aktivnost protiv E. coli pokazao je nesupstituirani spoj 1. Najveću antifungalnu aktivnost pokazao je spoj 7 s orto metoksi supstituentom. Spoj 4 pokazao je najjače antiproliferativno djelovanje u mikromolarnom rasponu (0,1 – 10 µM) na testiranim linijama tumorskih stanica, osim na SW620. Dodatne Western blot analize pokazale su povišenu razinu ciklina B1 u HeLa stanicama tretiranim spojem 4, koji je glavni marker mitotske katastrofe, i smanjenu razinu Wee1 i Erk ½ kinaza uključenih u regulaciju mitotskog procesa. Najpotentniji spojevi podvrgnuti su molekularnim docking simulacijama da bi se procijenio afinitet vezanja za enzime i pružili daljnji dokazi o eksperimentalno opaženim biološkim učincima in vitro. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna

Antiproliferative and genotoxic potential of xanthen-3-one derivatives

Twelve previously synthesized, biologically active 2,6,7-trihydroxyxanthen-3-one derivatives were evaluated in vitro for antiproliferative activity. Compounds were screened against HeLa, SW620, HepG2 and A549 tumor cell lines. Compound with the trifluormethyl group on C-4’ position of the phenyl ring showed the best inhibitory activity towards HeLa and A549 tumor cells with IC50 of 0.7 and 4.1 µmol L−1, resp. Compound with chlorine and fluorine substituents on aryl ring showed the best antiproliferative activity against SW620 with IC50 of 4.1 µmol L–1 and against HepG2 tumor cell line with IC50 of 4.2 µmol L–1. Analyses of cytotoxic and genotoxic potential of the trifluormethyl derivative were performed with cytokinesis-block micronucleus cytome assay in human lymphocyte culture and revealed no genotoxic and cytotoxic effects. The most potent compounds were subjected to molecular docking simulations in order to analyse bindings to molecular targets and, at the same time, further support the results of experimental cytotoxic tests. Docking studies showed sites of importance in forming hydrogen bonds of the most potent compounds with targets of interest

A non-canonical function of Arabidopsis ERECTA proteins and a role of the SWI3B subunit of the SWI/SNF chromatin remodeling complex in gibberellin signaling

The Arabidopsis ERECTA family (ERf) of leucine-rich repeat receptor-like kinases (LRR-RLKs) comprising ERECTA (ER), ERECTA-LIKE 1 (ERL1), and ERECTA-LIKE 2 (ERL2) controls epidermal patterning, inflorescence architecture, and stomata development and patterning. These proteins are reported to be plasma membrane associated. Here we show that the er/erl1/erl2 mutant exhibits impaired gibberellin (GA) biosynthesis and perception alongside broad transcriptional changes. The ERf kinase domains were found to localize to the nucleus where they interact with the SWI3B subunit of the SWI/SNF chromatin remodeling complex (CRCs). The er/erl1/erl2 mutant exhibits reduced SWI3B protein level and affected nucleosomal chromatin structure. Similar to swi3c and brm plants with inactivated subunits of SWI/SNF CRCs, it also does not accumulate DELLA RGA and GAI proteins. The ER kinase phosphorylates SWI3B in vitro, and the inactiva�tion of all ERf proteins leads to the decreased phosphorylation of SWI3B protein in vivo. The identified cor�relation between DELLA overaccumulation and SWI3B proteasomal degradation, and the physical interaction of SWI3B with DELLA proteins indicate an important role of SWI3B-containing SWI/SNF CRCs in gibberellin signaling. Co-localization of ER and SWI3B on GID1 (GIBBERELLIN INSENSITIVE DWARF 1) DELLA target gene promoter regions and abolished SWI3B binding to GID1 promoters in er/erl1/erl2 plants supports the conclusion that ERf-SWI/SNF CRC interaction is important for transcriptional control of GA receptors. Thus, the involvement of ERf proteins in the transcriptional control of gene expression, and observed similar features for human HER2 (epidermal growth family receptor member), indicate an exciting target for further studies of evolutionarily conserved non-canonical functions of eukaryotic membrane receptors