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In the present study, the effect of different in vitro cultures (callus, in vitro shoots) and commercially available peppercorn extract was investigated for its activity against toxic metabolite-producing strains (Escherichia coli, Pseudomonas aeroginosa, Salmonella typhi, Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, and Candida albicans). These in vitro cultures were extracted with ethanol, hexane, and chloroform, and the antipathogenic activity was determined by well-diffusion method. Hexane extract of callus showed 22 mm zone of inhibition against B. cereus, 23 mm against S. aureus, while regenerated shoots and seeds have shown 24.3 and 26 mm zones of inhibition. The ethanolic extracts of regenerated Piper shoots have shown 25 mm activity against S. aureus, 21 mm against B. cereus, and 16 mm in the case of C. albicans in comparison with standard antibiotics. Peppercorn extracts in chloroform and ethanol had shown activities against B. cereus (23.6 mm) and B. subtilis (23.5 mm). During in vitro organogenesis and morphogenesis, cells and tissues produced a comparable phytochemicals profile like mother plant. Morphogenesis is critically controlled by the application of exogenous plant-growth regulators. Such addition alters the hormonal transduction pathways, and cells under in vitro conditions regenerate tissues, which are dependant on the physiological state of cells, and finally enhance the production of secondary metabolites. To the best of our knowledge, this is the first report to compare the antimicrobial potential of in vitro regenerated tissues and peppercorn with standard antibiotics. In conclusion, most of the extracts showed pronounced activities against all the pathogenic microbes. This is a preliminary work, and the minimum inhibitory concentration values needs to be further explored. Regenerated tissues of P. nigrum are a good source of biologically active metabolites for antimicrobial activities, and callus culture presented itself as a good candidate for such activities., (© The Author(s) 2013.)

Sulfated polysaccharides were extracted from gray triggerfish (GTSP) and smooth hound (SHSP) skins. Their chemical and physical characteristics were determined using X-ray diffraction and Infrared spectroscopic analysis. The antibacterial activities of GTSP and SHSP against Listeria monocytogenes (ATCC 43251), Staphylococcus aureus (ATCC 25923), Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 25922), Salmonella enterica (ATCC 43972) and Enterobacter sp were evaluated by determining clear growth inhibition zone diameters and the minimum inhibitory concentration (MIC) values and by essays in liquid media. GTSP and SHSP were fractionated by a Diethylaminoethyl-cellulose chromatography. Fraction FGII, from GTSP, and fraction FSII, from SHSP, showed the most important inhibitory effects against the tested bacterial species. The sulfated polysaccharides from fish skins did not show hemolytic activity towards bovine erythrocytes. Overall, the results suggested that those polysaccharides could offer promising sources of polysaccharides for future application as dietary ingredients in the nutraceutical industry., (Copyright © 2015 Elsevier B.V. All rights reserved.)

The objective of the present study is to the total phenolic compound determination, as well as the in vitro evaluation of methanolic and ethanolic extracts antimicrobial activity of the medicinal plant Mentha rotundifolia L. against pathogenic strains. The Follin-Cioacalteu method was used to determine the total polyphenols, while the flavonoids were estimated according to the colorimetric method with aluminum chloride. In addition, the determination of condensed tannins is performed by the vanillin method. The antimicrobial activity is tested on five pathogenic bacterial strains, two of which are Gram-negative (Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 27853), three Gram-positive (Bacillus cereus ATCC 11778, Staphylococcus aureus ATCC 25923 and Micrococcus leutus ATCC 4698), and one yeast (Candida albicans ATCC 26790), by the diffusion on solid medium and microdilution methods. The ethanolic extract of round leaf mint from the Bechar region is very rich in polyphenols and flavonoids (401.75 ± 0.32 mg GAE/g, 549.75 ± 1.23 mg QE/g) compared to the methanolic and hydroalcoholic extracts of this plant from the Sidi-Bel-Abbes region. The results of the obtained well method showed that all bacterial strains exhibited sensitivity to the ethanolic extract of Mentha rotundifolia L. from the Bechar region, with inhibition zones up to 21,67 ± 0,57 mm and minimum inhibitory concentrations (MIC) varying between 06.25 mg/ml and 100 mg/ml, The effect of the other extracts on the tested strains was less significant, the methanolic extract was the least effective. These results demonstrate that the Mentha rotundifolia L. ethanolic extract has a great potential of secondary metabolites with antimicrobial activity. [ABSTRACT FROM AUTHOR]

Abstract: Locally prevalent pathogenic bacteria 189 Gram (−) and 135 Gram (+) strains, all isolated from pediatric patients severely infected, were tested in vitro against 11 essential oils from commercial origin. All the strains showed resistance to selected antibiotics. Cinnamomum verum, Origanum vulgare and Thymus vulgaris exhibited the highest and broadest antibacterial activity. Emphasis is made in the potential implications of these resources, uncommon at the clinical setting of the study, employed against non-commercial, locally pathogenic strains, being a step to submit in the ensuing period essential oils from plants used in Mexican traditional medicine. [Copyright &y& Elsevier]