Siniša L. Markov

Radical Scavenging, Antibacterial, and Antiproliferative Activities of Melissa officinalis L. Extracts

The aromatic herb Melissa officinalis L. can be used as an easily accessible source of natural antioxidants and as a possible food supplement and as a phytochemical. Radical scavenging, antibacterial, and antiproliferative activities of petroleum ether, chloroform, ethyl acetate, n-butanol, and water extracts of M. officinalis L. extracts were investigated. The results of antioxidative activity, obtained by electron spin resonance spectroscopy, confirmed that investigated extracts suppressed the formation of 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, and lipid peroxyl radicals in all investigated systems in a dose-dependent manner. The maximum DPPH and hydroxyl radical scavenging activities (SA(DPPH) = SA(OH) = 100%) were achieved in the presence of n-butanol extract at concentrations of 0.4 mg/mL and 0.5 mg/mL, respectively. The highest lipid peroxyl scavenging activity (93.20%) was observed at a higher concentration (5 mg/mL) of n-butanol extract in the lipid peroxidation system. The most effective antibacterial activities were expressed by petroleum ether and ethyl acetate extracts on Sarcina lutea. Chloroform extract showed the strongest antiproliferative effect with 50% inhibitory concentration values of 0.09 mg/mL and 0.10 mg/mL for HeLa and MCF-7 cell lines, respectively. The present study demonstrated the high phenolic content and radical scavenging, antibacterial, and antiproliferative activities of extracts of M. officinalis L. originating from Serbia.

PROGRESS IN THE PRODUCTION OF BIOETHANOL ON STARCH-BASED FEEDSTOCKS*

Bioethanol produced from renewable biomass, such as sugar, starch, or lignocellulosic materials, is one of the alternative energy resources, which is both renewable and environmentally friendly. Although, the priority in global future ethanol production is put on lignocellulosic processing, which is considered as one of the most promising second-generation biofuel technologies, the utilization of lignocellulosic material for fuel ethanol is still under improvement. Sugar-based (molasses, sugar cane, sugar beet) and starch-based (corn, wheat, triticale, potato, rice, etc.) feedstock are still currently predominant at the industrial level and they are, so far, economically favorable compared to lingocelluloses. Currently, approx. 80 % of total world ethanol production is obtained from the fermentation of simple sugars by yeast. In Serbia, one of the most suitable and available agricultural raw material for the industrial ethanol production are cereals such as corn, wheat and triticale. In addition, surpluses of this feedstock are being produced in our country constantly. In this paper, a brief review of the state of the art in bioethanol production and biomass availability is given, pointing out the progress possibilities on starch-based production. The progress possibilities are discussed in the domain of feedstock choice and pretreatment, optimization of fermentation, process integration and utilization of the process byproducts.

Bioactivity of Lemon Balm Kombucha

There is inadequate published data referring to bioactivity of lemon balm tea and its Kombucha. The aim of this study, therefore, was to investigate antimicrobial, antiproliferative, genotoxic, and antigenotoxic potential of lemon balm tea and its Kombucha with consuming acidity. Antimicrobial activity was determined by agar-well diffusion method. Cell growth effects were determined in HeLa, MCF7, and HT-29 human tumor cell lines. Genotoxic and antigenotoxic effects were determined using chromosome aberration assay in Chinese hamster cell line CHO-K1. Differences between control and treated groups were evaluated using analysis of variance, at significance level of p < 0.05. Kombucha from lemon balm tea (Melissa officinalis L.) exibited antimicrobial activity against prokaryotic microorganisms independently of their cell wall structure (both Gram-positive and Gram-negative bacteria), while there was no observed activity against eukaryots (yeasts and moulds). There was absence of genotoxic effects while antigenotoxic effects of lemon balm Kombucha and tea were confirmed on MMC-damaged CHO-K1 cells. For the explanation of cell growth effects that were not concentration dependent, concept of hormesis was used. Antiproliferative activity was lower compared with traditional Kombucha and Satureja montana L. Kombucha, with lemon balm tea showing higher activity than its Kombucha.

Membrane fouling during cross-flow microfiltration of Polyporus squamosus fermentation broth

The application of microfiltration to biological systems is hindered by membrane fouling that results in a decrease in the filtrate flux and solute transmission with time. In this work, the effects of transmembrane pressure, cross-flow feed velocity, biomass structure and feed composition, on membrane fouling during cross-flow microfiltration of Polyporus squamosus fermentation broth, were investigated. The results of cross-flow trials with 0.2 μm aluminum oxide membrane showed the existence of the optimal operation transmembrane pressure and cross-flow velocity, in respect of membrane fouling, for examined range of operation conditions. It was noticed that the process of membrane fouling was moved from a predominantly surface layer phenomenon to internal membrane fouling as the cross-flow velocity was increased. Comminution of the fungal biomass prior to microfiltration to reduce particle size showed a beneficial effect on the transient flux. The steady-state flux and the transmission of solutes were not significantly affected by the biomass comminution. The observations of the filtrate flux and the transmission of solutes indicated a decrease in the rate of fouling with decreasing content of soluble components with large molecular weights in the feed.

Decrease of aflatoxin B1 in yoghurt and acidified milks

Fermentation of yoghurt and acidified milks containing aflatoxin B1 (AB1) were studied. AB1 added to milk before fermentation at concentrations of 600, 1000 and 1400 μg/kg was reduced in yoghurts (pH 4.0) by 97, 91 and 90%, respectively. Coagulation time was approximately the same as in the controls. Streptococci had longer chains than those in the controls. The main decrease of AB1 occurred during the milk fermentation. A decrease of AB1 (conc. 1000 μg/kg) in milks acidified with citric, lactic and acetic acids (pH 4.0) was 90, 84 and 73%, respectively.

Design of self-cleaning TiO2 coating on clay roofing tiles

The phenomenon of heterogeneous photocatalysis takes place in the degradation process of many organic contaminants on solid surfaces. Photocatalysis is based on the excitation of the semiconductor by irradiation with supraband gap photons and the migration of electron-hole pairs to the surface of the photocatalysts, leading to the reaction of the holes with adsorbed H2O and OH− to form hydroxyl radicals. Due to the stability and photosensitivity of TiO2 semiconductors, this system is well studied and is of great interest from an ecological and industrial point of view for use in the field of building materials. Clay roofing tiles, due to their long-term exploitation, are subject to physical, chemical and biological degradation that leads to deterioration. Ceramic systems have a high percentage of total porosity and considering their non-tolerance of organic coating, the use of surface active materials (SAM) that induce porosity in TiO2 coatings is of vital significance. Photocatalytic coatings applied on clay roofing tiles under industrial conditions were designed by varying the quantity of TiO2 (mass/cm2) on the tile surface (thin and thick TiO2 layer). The positive changes in specific surface area and mesopore structure of the designed coatings were made by the addition of PEG 600 as a surface active material. It was shown that a thin photocatalytic layer (0.399 mg suspension/cm2 tile surface), applied onto ceramic tiles under industrial conditions, had better photocatalytic activity in methylene blue decomposition, hydrophilicity and antimicrobial activity than a thick photocatalytic coating (0.885 mg suspension/cm2).

Bioactivity of Meeker and Willamette raspberry (Rubus idaeus L.) pomace extracts

Taking into account the substantial potential of raspberry processing by-products, pomace extracts from two raspberry cultivars, Meeker and Willamette, were investigated. Total phenolic, flavonoid and anthocyanin contents were determined. Willamette pomace extract (EC₅₀=0.042 mg/ml) demonstrated stronger 2,2-diphenyl-1-picrylhydrazyl DPPH radical-scavenging activity than did Meeker pomace extract (EC₅₀=0.072 mg/ml). The most pronounced cell growth inhibition effect was obtained in the breast adenocarcinoma cell line, reaching EC50 values of 34.8 and 60.3 μg/ml for Willamette and Meeker extracts, respectively. Both extracts demonstrated favourable non-tumor/tumor cell growth ratios and potently increased the apoptosis/necrosis ratio in breast adenocarcinoma and cervix carcinoma cells. In reference and wild bacterial strains, minimal inhibitory concentrations (MIC) were achieved in a concentration range from 0.29 to 0.59 mg/ml, and minimal bactericidal concentrations (MBC) in a range from 0.39 to 0.78 mg/ml. The results indicate significant antioxidant, antiproliferative, proapoptotic and antibacterial activities of raspberry pomace and favour its use as a functional food ingredient.

Characterization of Starch Edible Films with Different Essential Oils Addition

Abstract This study investigated properties of starch-based edible films with oregano and black cumin essential oil addition. Essential oils addition positively affected film swelling (decreased due to essential oil addition), mechanical properties (tensile strength decreased while elongation at break increased), and water vapor barrier properties (decreased along with essential oils addition). Control film did not have any biological activity, which proves the need for essential oils addition in order to obtain active packaging. Oregano oil was more effective in terms of biological activity. Endothermal peak, above 200°C, represents total thermal degradation of edible films. Diffraction pattern of control film showed significant destruction of A-type crystal structure. Addition of essential oils resulted in peak shape change: diffraction peaks became narrower. Principal Component Analysis has been used to assess the effect of essential oils addition on final starch-based edible films characteristics with the aim to reveal directions for the film characteristics improvement, since the next phase will be optimal film application for food packaging.

Chemometrics approach based on chromatographic behavior, in silico characterization and molecular docking study of steroid analogs with biomedical importance

ABSTRACT Physicochemical characterization of steroid analogs (triazole, tetrazole, toluenesulfonylhydrazide, nitrile, dinitrile and dione) is considered to be a very important step in further drug selection. This study applies to the determination of lipophilicity of previously synthesized steroid derivatives using reversed‐phase high‐performance liquid chromatography (RP HPLC). Chemometric aspect of chromatographic lipophilicity is given throughout multiple linear regression (MLR) quantitative structure‐retention relationships (QSRR) approach. Minimal inhibitory concentration (MIC) is determined for two steroid derivatives possessing antimicrobial activity against Staphylococcus aureus. Molecular docking study was performed in order to identify the compound with the most promising potential as human cytochrome P450 CYP17A1inhibitor. Identified 3&bgr;‐hydroxyandrost‐5‐eno[16,17‐d]‐1,2,3‐triazole (I.2.) could be recommended for further trials for anticancer drugs and subjected to the absorption, distribution, metabolism, excretion and toxicity (ADMET) evaluation. Graphical Abstract Figure. No Caption available.

Antimicrobial activity of composite chitosan biofilms with beeswax and caraway essential oil

In this paper, influence of increasing concentrations of beeswax on the antimicrobial activity of chitosan-caraway essential oil biofilm was investigated. Selected microorganisms for the test were Salmonella Typhimurium and Listeria monocytogenes. Reduction of S. Typhimurium and L. monocythogenes viable counts in bacterial suspension in the presence of chitosan films with or without added beeswax amounted over 80 % after 24 h contact time, and over 95 % after 3 h of contact time, respectively and influence of added beeswax on growth reduction was not detected. However, when number of S.Typhimurium viable cells was analyzed (log CFU/ml), it was shown that addition of beeswax led to increased activity of films, especially for the films with 36 kg/m and 54 kg/mof beeswax. When films were transferred, after 24 h in bacterial suspension, onto Petri dishes with nutrient agar and incubated for 24 h on 37 °C, results also showed beeswax contribution to growth inhibition of S.Typhimurium.