Physicochemical properties of copper important for its antibacterial activity and development of a unified model

2016 ◽  
Vol 11 (1) ◽  
pp. 018902 ◽  
Author(s):  
Michael Hans ◽  
Salima Mathews ◽  
Frank Mücklich ◽  
Marc Solioz
Nova Scientia ◽  
2020 ◽  
Vol 12 (24) ◽  
Author(s):  
Rey David Vargas Sánchez ◽  
Evelin Martínez Benavidez ◽  
Javier Hernández ◽  
Gastón Ramón Torrescano Urrutia ◽  
Armida Sánchez Escalante

In this study the effect of pollen source (mesquite and catclaw) on the sensory characteristics (appearance, color, aroma, taste, consistency and visible impurities), and physicochemical properties of raw propolis, and the phenolic content and biological activities of propolis extracts (PEs) was determined. The phenolic composition of PEs was determined by the total phenolic (TPC), flavone and flavonol (FFC), and flavanone and dihydroflavonol content (FDC). The individual phenolic components were analyzed by HPLC-DAD. The antioxidant activity was determined by the ferric-reducing power (FRAP) and free-radical scavenging activity (FRS). The antibacterial activity was evaluated against Gram-positive (Staphylococcus aureus and Listeria innocua) and Gram-negative (Echerichia coli and Salmonella thyphimurium) bacteria. The results showed that sensory characteristic and physicochemical properties of mesquite and catclaw propolis complied with international quality regulations. Fifteen phenolic compounds were identified, of which pinocembrin, naringenin, galangin, chrysin and quercetin were found a high concentration (> 3 mg/g). Mesquite propolis had the highest phenolic content (TFC and FDC), as well as antioxidant activity (> 2.5 mg Fe (II) equivalent/g; > 40% of DPPH radical inhibition) and antibacterial activity against Gram-positive bacterias in the order S. aureus > L. innocua (> 50% of inhibition for both bacterias at 500 µg/mL). These results indicating that pollen source affect the sensory characteristics and physicochemical properties of propolis, as well as the biological activity of their extracts.


2010 ◽  
Vol 22 (2) ◽  
pp. 169-178 ◽  
Author(s):  
Mitchell D. Cohen ◽  
Maureen Sisco ◽  
Colette Prophete ◽  
Kotaro Yoshida ◽  
Lung-chi Chen ◽  
...  

2018 ◽  
Vol 33 (1-2) ◽  
pp. 5-9 ◽  
Author(s):  
Roushney Fatima Mukti ◽  
Md Miraj Kobad Chowdhury ◽  
Md Ausrafuggaman Nahid ◽  
Md Mizanur Rahaman ◽  
M Aftab Uddin

Seven florally diversified Bangladeshi honey samples were assessed for their physicochemical properties as well as their antibiogram profile on different human pathogenic bacterial strains. The average density, total protein content, ascorbic acid content, total phenolics content and the total antioxidant capacity of these honeys were determined as 1.50±0.09 g/ml, 5.63±1.56 mg/g, 91.87±22.16 mg/g, 571.04±289.02 mg gallic acid equivalent/gram, and 320.74±55.06 mg ascorbic acid equivalent/gram of samples, respectively. A significant correlation between the phenolics content and the total antioxidant capacity was observed in commercially available honey samples. However, the natural honey samples showed the best antibacterial activity against different pathogenic multidrug-resistant bacterial strains. Significant antibacterial activities were observed against Klebsiella pneumoniae, Salmonella typhi, Micrococcus luteus, Pseudomonas spp. and Enterobacter spp. and moderate antibacterial activities was observed on Shigella boydii, Bacillus cereus, Bacillus megaterium, and Bacillus subtilis. The antibacterial activity was correlated with the total antioxidant capacity. This study suggested that the Bangladeshi multifloral honeys have clinical potential against multidrug-resistant pathogenic bacterial strains. Bangladesh J Microbiol, Volume 33, Number 1-2, June-Dec 2016, pp 5-9


Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4241
Author(s):  
Magdalena Stepczyńska ◽  
Alona Pawłowska ◽  
Krzysztof Moraczewski ◽  
Piotr Rytlewski ◽  
Andrzej Trafarski ◽  
...  

The aim of this article is to discuss in detail the physicochemical properties of polylactide (PLA) reinforced by cortex fibers, which may cause bacterial mortality and increased biodegradation rates. PLA biocomposites containing cortex Lapacho fibers from Tabebuia (1–10 wt %) were prepared by extrusion and injection moulding processes. The effects of Lapacho on the mechanical and biocidal properties of the biocomposites were studied using tensile and impact tests, dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), thermogravimetry (TG), and the method of evaluating the antibacterial activity of antibacterial treated according to the standard ISO 22196:2011. It also presented the effects of Lapacho on the structural properties and biodegradation rates of biocomposites. This research study provides very important results complementing the current state of knowledge about the biocidal properties of Lapacho from Tabebuia plants and about cortex-reinforced biocomposites.


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