Phytochemical, antimicrobial, antioxidant and antigenotoxic potentials of Cyperus rotundus extracts

AbstractThe aqueous, ethyl acetate, methanolic and Total Oligomer Flavonoids (TOF) enriched extracts, obtained from the aerial parts of Cyperus rotundus, were investigated for their contents in phenolic compounds. Antioxidative activity using the NBT/riboflavin assay system, antimicrobial activity against Gram positive and Gram negative bacterial reference strains as well as antigenotoxic activity tested with the SOS chromotest assay were also studied. Significant antibacterial activity against reference strains; Staphylococcus aureus, Enterococcus faecalis, Salmonella enteritidis and Salmonella typhimurium, was detected in the presence of ethyl acetate and TOF enriched extracts. In addition to their antimicrobial activity, the same extracts showed a significant ability to inhibit nitroblue tetrazolium reduction by the superoxide radical in a non enzymatic O2.− generating system, and were also able to reduce significantly the genotoxicity induced by nifuroxazide and Aflatoxin B1. The antioxidant, antimicrobial and antigenotoxic activities exhibited by C. rotundus depend on the chemical composition of the tested extracts

Supramolecular approach to new inkjet printing inks

Electronically complementary, low molecular weight polymers that self-assemble through tunable π−π stacking interactions to form extended supramolecular polymer networks have been developed for inkjet printing applications and successfully deposited using three different printing techniques. Sequential overprinting of the complementary components results in supramolecular network formation through complexation of π-electron rich pyrenyl or perylenyl chain-ends in one component with π-electron deficient naphthalene diimide residues in a chain-folding polyimide. The complementary π−π stacked polymer blends generate strongly colored materials as a result of charge-transfer absorption bands in the visible spectrum, potentially negating the need for pigments or dyes in the ink formulation. Indeed, the final color of the deposited material can be tailored by varying the end-groups of the π-electron rich polymer component. Piezoelectric printing techniques were employed in a proof of concept study to allow characterization of the materials deposited, and a thermal inkjet printer adapted with imaging software enabled in situ analysis of the ink drops as they formed and of their physical properties. Finally, continuous inkjet printing allowed greater volumes of material to be deposited, on a variety of different substrate surfaces, and demonstrated the utility and versatility of this novel type of ink for industrial applications

Detection and characterization of the novel bacteriocin entomocin 9, and safety evaluation of its producer, Bacillus thuringiensis ssp. entomocidus HD9

Aims: To identify and characterize new bacteriocins from a collection of 41 strains belonging to 27 subspecies of Bacillus thuringiensis, and to evaluate the safety of the producers. Methods and Results: Bacillus thuringiensis ssp. entomocidus HD9 produced in the culture supernatant an antimicrobial activity against Gram-positive bacteria including Listeria monocytogenes, one of four pathogenic Pseudomonas aeruginosa and several fungi. Production of the antibacterial activity, named entomocin 9, started during mid-logarithmic growth reaching its maximum at the early stationary phase. Entomocin 9 retained more than 72% of activity after incubation for 20 min at 121 C. Activity was lost after proteinase K treatment, it was stable in a pH range between 3 and 9, and resistant to lyophilization. After partial purification with ammonium sulphate precipitation followed by gel-filtration and anion-exchange chromatography, an active protein of ca 12.4 kDa was isolated. The mode of action of entomocin 9 was bactericidal and caused cell lysis of growing cells. Despite the presence of a range of virulence related genes, including haemolysin BL, nonhaemolytic enterotoxin, cytotoxin K and several hydrolytic activities, B. thuringiensis HD9 was not toxic against Vero cells. Conclusions: Entomocin 9 is a novel heat-stable, bacteriocin produced by B. thuringiensis HD9. The absence of toxicity against Vero cells suggests the suitability of strain HD9 for a safe application in antimicrobial treatments. Significance and Impact of the Study: New finding on entomocin 9 would make B. thuringiensis attractive in biotechnological applications as an antimicrobial agent in agriculture and food industry

Relationship correlation of antioxidant and antiproliferative capacity of Cyperus rotundus products towards K562 erythroleukemia cells

A Total Oligomers Flavonoids (TOFs) and ethyl acetate extracts of Cyperus rotundus were analyzed, in vitro, for their antioxidant activity using several biochemical assays: the xanthine (X)/xanthine oxidase (XO), the lipid peroxidation induced by H2O2 in K562 human chronic myelogenous leukemia cells and the DNA damage in pKS plasmid DNA assay induced by H2O2/UV-photolysis and for their apoptotic effect. TOF and ethyl acetate extracts were found to be efficient in inhibiting xanthine oxidase with IC50 values of 240 and 185 μg/ml and superoxide anion with IC50 values of 150 and 215 μg/ml, respectively. Also, all the extracts tested were effective in reducing the production of thiobarbituric acid reactive substances (TBARS) and were able to protect against H2O2/UV-photolysis induced DNA damage. The highest activity, measured as equivalents of MDA concentration, was observed in the ethyl acetate extract (MDA = 2.04 nM). In addition, the data suggest that only TOF enriched extract exerts growth inhibition on K562 cells through apoptosis induction. Therefore, these extracts were subjected to further separation by chromatographic methods. Thus, three major compounds (catechin, afzelechin and galloyl quinic acid) were isolated from the TOF enriched extract and five major compounds (luteolin, ferulic acid, quercetin, 3-hydroxy, 4-methoxy-benzoic acid and 6,7-dimethoxycoumarin) from ethyl acetate extract. Their structures were determined by spectroscopic data analysis and comparison with the literature. In addition, we evaluate the biological activities of the catechin, ferulic acid and luteolin. This investigation has revealed that the luteolin was the most active in reducing the production of TBARS (MDA = 1.5 nM), inhibiting significantly the proliferation of K562 cells (IC50 = 25 μg/ml) and protecting against H2O2/UV-photolysis induced DNA damage. In conclusion, the study reveals that the ability of C. rotundus to inhibit the enzyme xanthine oxidase (XO), the lipid peroxidation and to exert apoptotic effect, may explain possible mechanisms by which C. rotundus exhibits its health benefits