Klara Urbanova's research while affiliated with Czech University of Life Sciences Prague and other places

Publications (62)

Article
Full-text available
Cassava tuber is an essential staple crop in tropical regions with versatile applications in the food, feed, and industrial sectors. However, its high moisture content and perishable nature necessitate efficient preservation methods to extend its shelf life and enhance its value. Pre-drying, drying, and post-drying processes play pivotal roles in m...
Article
Full-text available
Essential oil from Thymus vulgaris L. has valuable therapeutic potential that is highly desired in pharmaceutical, food, and cosmetic industries. Considering these advantages and the rising market demand, induced polyploids were obtained using oryzalin to enhance essential oil yield. However, their therapeutic values were unexplored. So, this study...
Article
Full-text available
This study assessed the antistaphylococcal activity of essential oil (EO) hydrodistilled from the rhizome of Curcuma mangga grown in Indonesia using the broth microdilution volatilization method and standard broth microdilution method modified for evaluation of volatile agents, as well as described its chemical composition using gas chromatography...
Article
Full-text available
Perishable commodities like cassava necessitate effective postharvest preservation for various industrial applications. Hence, optimizing pretreatment processes and modeling drying kinetics hold paramount importance. This study aimed to optimize cassava pretreatment using the central composite design of a response surface methodology while also ass...
Preprint
Full-text available
Essential oil from Thymus vulgaris L. has valuable therapeutic potential that is highly desired in pharmaceutical, food, and cosmetic industries. Considering these advantages and the rising market demand, induced polyploids were obtained using oryzalin to enhance essential oil yield. However, their therapeutic values were unexplored. So, this study...
Article
Full-text available
Essential oils (EOs) from Indian spices like Elettaria cardamomum (L.) Maton (small green cardamom), Syzygium aromaticum (L.) Merr. & L.M. Perry (clove), Cinnamomum zeylanicum Blume (cinnamon quills), and Cinnamomum tamala (Buch.-Ham.) T. Nees & C. H. Eberm (Indian bay leaves) exhibit a broad spectrum range of biological activity including antibact...
Preprint
Full-text available
Cambodian spices Amomum kravanh, Citrus hystrix and Piper nigrum 'Kampot' have long history of seasoning of food products. In this study, essential oils (EOs) and supercritical CO2 extracts from all three species have been analyzed using GC-MS with two columns of different polarity, whereas EO and CO2 extract from P. nigrum fruits and CO2 extract f...
Article
Full-text available
Essential oils (EOs) have great potential in inhalation therapy for the treatment of respiratory infections. However, innovative methods for evaluation of antimicrobial activity of their vapors are still needed. The current study reports validation of the broth macrodilution volatilization method for assessment of the antibacterial properties of EO...
Article
Full-text available
The primary goals of this study were to identify the influence of temperature and drying time on pretreated cassava flour, as well as the optimal settings for the factors and to analyze the microstructure of cassava flour. The experiment was designed using the response surface methodology with central composite design and the superimposition approa...
Preprint
Full-text available
Essential oils (EOs) have great potential in inhalation therapy for the treatment of respiratory infections, however, innovative methods for evaluation of antimicrobial activity of their vapors are still needed. The current study reports validation of the broth macrodilution volatilization method for assessment of the antibacterial properties of EO...
Poster
Acute lower respiratory infections and particularly pneumonia are still the world’s most deadly communicable diseases. While aerosolized antibiotics remain the recommended treatment in lower respiratory infections, difficulties to implement nebulization techniques have limited their widespread adoption [1]. The volatile constituents of essential oi...
Article
Full-text available
While the inhalation of Thymus vulgaris L. essential oil (EO) is commonly approved for the treatment of mild respiratory infections, there is still a lack of data regarding the antimicrobial ac- tivity and chemical composition of its vapours. The antibacterial activity of the three T. vulgaris EOs against respiratory pathogens, including Haemophilu...
Article
Hexane extracts derived from the arils and seeds of two Samoan indigenous plant species, Myristica hypargyraea A. Gray and Myristica inutilis Rich ex A. Gray, were assessed for their in vitro anti-staphylococcal effect using a broth microdilution assay. Additionally, their cytotoxic activity against human colon cancer and normal intestinal cell lin...
Article
Foodborne microbial diseases constitute major health concern and therefore it is necessary to preserve food products to prolong their shelf life and safety. Promising method of food preservation is application of volatile natural agents into modified atmosphere in food packaging. Spices and condiments containing volatile oils could potentially be u...
Article
Full-text available
Combinatory action of antimicrobial agents such as essential oils (EOs) show to be an effective strategy to overcome the problem with increasing antibiotic resistance of microorganisms, including Staphylococcus aureus. The objective of this study was to evaluate in vitro antimicrobial interactions between Origanum vulgare and Thymus vulgaris EOs ag...
Article
Full-text available
Volatile plant-derived products were observed to exhibit broad spectrum of biological effects. However, due to their volatility, results of conventional microplate-based bioassays can be significantly affected by the vapors. With aim to demonstrate this phenomenon, antimicrobial, antioxidant, and cytotoxic activities of three essential oils (Alpini...
Article
Full-text available
Aims: The objective of the study was to evaluate antimicrobial interactions between two volatile agents, Cinnamomum cassia essential oil (CCEO) and 8-hydroxyquinoline (8-HQ) against Staphylococcus aureus strains in liquid and vapour phases. Methods and results: In vitro antimicrobial effect of CCEO in combination with 8-HQ was evaluated against...
Article
Full-text available
Ranunculaceae is one of the largest families in Romania, comprising species used as medicines, spices, and ornamentals. Despite the therapeutic and industrial potential of Ranunculaceae essential oils (EOs), their presence in many plants of the family remains unexplored. In this study, the chemical composition of EOs hydrodistilled from aerial part...
Article
While bumblebees have been the focus of much research, the taxonomy of many species groups is still unclear, especially within circum-polar species. Delimiting species based on multisource datasets provides a solution to overcome current systematic issues of closely related populations. Here, we use an integrative taxonomic approach based on novel...
Article
Full-text available
A fast, inexpensive, and ecological method based on liquid-liquid extraction principle has been developed for preparation of extract with high content of Nigella sativa (N. sativa) quinones. The gas chromatography-mass spectrometry (GC-MS) analysis showed that oil extraction using 70% ethanol for 6 h yielded extract containing 50% of thymoquinone (...
Article
Full-text available
Essential oils isolated from six Philippine plant species, namely Alpinia brevilabris C. Presl, Alpinia cumingii K. Schum., Alpinia elegans (C. Presl) K. Schum., Callicarpa micrantha Vidal, Cinnamomum mercadoi S. Vidal, and Piper quinqueangulatum Miq. were assessed for their in vitro growth-inhibitory effect against pneumonia causing bacteria (Haem...
Article
Full-text available
Essential oils hydrodistilled from seven Cambodian plant species (Alpinia oxymitra, Boesenbergia rotunda, Cinnamomum cambodianum, Citrus lucida, Limnophila aromatica, Rhodamnia dumetorum, and Sindora siamensis) were tested for their in vitro growth-inhibitory effect against pneumonia causing bacteria (Haemophilus influenzae, Streptococcus pneumonia...
Article
Full-text available
Sex-specific chemical secretions have been widely used as diagnostic characters in chemotaxonomy. The taxonomically confused group of bumblebees has reaped the benefit of this approach through the analyses of cephalic labial gland secretions (CLGS). Most of currently available CLGS descriptions concern species from the West-Palearctic region but fe...
Article
Full-text available
Socially parasitic Hymenoptera have evolved morphological, chemical, and behavioral adaptations to overcome the sophisticated recognition and defense systems of their social host to invade host nests and exploit their worker force. In bumblebees, social parasitism appeared in at least three subgenera independently: in the subgenus Psithyrus consist...
Article
Full-text available
Cold-adapted species are expected to reach their largest distribution range during a part of the Ice Ages while the post-glacial warming leads to their range contracting toward high latitude and high altitude areas. This results in extant allopatric distribution of populations and possibly to trait differentiations (selected or not) or even speciat...
Poster
Full-text available
Sex-specific chemical secretions has led to the development of the chemotaxonomy in which such chemical traits are now widely used as diagnostic characters. Most of currently available CLGS descriptions concern species from the West-Palearctic region or few from the New World. Here, CLGS descriptions of East-Palaearctic Thoracobombus reveals some a...
Article
Full-text available
The evolution of signals and reproductive traits involved in the pre-mating recognition has been in focus of abundant research in several model species group such as bumblebees (genus Bombus). However, the most studied bumblebee reproductive trait, the male cephalic labial gland secretions (CLGS), remains unknown among bumblebee species from South...
Article
Full-text available
Many species display local variations in pre-mating signals and in mating preferences. This may lead to discrimination against potential foreign mates that may ultimately lead to reproductive isolation. However, the extent to which population differentiation in mating cues affects the species recognition has received little empirical support. Here...
Article
Many islands are biodiversity hotspots that host numerous endemic species. Unfortunately, insular faunas suffer from high rates of extinction and endangerment, and numerous conservation plans have been developed for their protection. These conservation plans are often assessed on the basis of occurrence and proportion of endemic taxa. However, deli...
Article
Full-text available
Labial gland secretions of 22 males of the bumblebee Bombus pomorum, collected in the Czech Republic, were analysed separately for each individual. The secretions contained 70 compounds among which saturated and unsaturated hydrocarbons strongly dominated. The proportion of hydrocarbons in the secretion was unusually high (85-100%) compared to othe...
Article
Wax esters (WEs), esters of long-chain fatty acids and long-chain alcohols, were analysed by Ag-HPLC/APCI-MS/MS. Two ChromSpher Lipids columns connected in series (a total length of 50cm) and hexane-2-propanol-acetonitrile mobile phases were used to achieve good separation of the molecular species. The chromatographic behaviour of WEs was studied u...
Article
In this study, we analyzed the chemical composition of volatile oils hydrodistilled from seeds of Consolida regalis, Delphinium elatum, Nigella hispanica, and N. nigellastrum using GC and GC/MS. In C. regalis, octadecenoic (77.79%) and hexadecanoic acid (8.34%) were the main constituents. Similarly, the oils from D. elatum and N. hispanica seeds co...
Article
Full-text available
The interpretation of the electron ionization mass spectra of straight-chain and methyl-branched saturated and unsaturated wax esters (WEs) is discussed in this study based on the spectra of 154 standards. The most important fragments indicative of the structure of the acid and alcohol chains are identified and summarized for WEs with various numbe...
Article
The aim of this study was to identify antimicrobial properties of selected essential oils in the vapour phase against different strains of Staphylococcus aureus, including MRSA and resistant clinical isolates. The resistance pattern of used S. aureus strains was checked by disc diffusion method against three antibiotics. Essential oils tested were...
Article
Full-text available
Alzheimer's disease (AD), characterized by the death of nerve cells in the cerebral cortex, is the most common subtype of dementia. Despite the exponential growth in the number of AD patients, acetylcholinesterase (AChE) inhibitors are currently used to treat AD. Plants of the Amaryllidaceae family are known to synthesize a particular type of bioac...
Article
Full-text available
Human cerumen was separated by column chromatography into the following groups of compounds: hydrocarbons, squalene, wax esters and cholesterol esters, triacylglycerols, free fatty acids, free fatty alcohols, monoacylglycerols, free cholesterol, free sterols, and free hydroxy acids. The groups of compounds obtained were examined in detail by gas ch...
Article
Full-text available
The underivatized alkaloid mixture extracted from the bulbs of Chlidanthus fragrans Herb. was investigated by capillary GC/MS for the first time. Fifteen known Amaryllidaceae alkaloids of five structure types were identified. The main alkaloids were tazzetine (9, tazettine-type), chlidanthine (2, galanthamine-type), belladine (8, belladine-type) an...
Article
Unsaturated wax esters (WEs) provided molecular adducts with C(3)H(5)N ([M + 55](+•)) in APCI sources in the presence of acetonitrile. CID MS/MS of [M + 55](+•) yielded fragments allowing the localization of double bond(s) in the hydrocarbon chains of the WEs. These fragments were formed by a cleavage on each side of the double bond. In methylene-i...
Article
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Article
Full-text available
From the bulbs of Zephyranthes robusta Baker (Amaryllidaceae), seven known compounds, belonging to four structural types of Amaryllidaceae alkaloids, were identified and quantified by GC-MS. The alkaloid extract from the bulbs showed promising acetylcholinesterase and butyrylcholinesterase inhibitory activities against HuAChE (IC50 = 35.9 +/- 3.5 m...
Article
High chromatographic resolution of wax esters (WEs) was achieved by non-aqueous reversed-phase liquid chromatography on a Nova-Pak C18 column by optimising the acetonitrile/ethyl acetate mobile phase gradient. The retention behaviour of WEs was studied in this chromatographic system. The WEs eluted according to their equivalent carbon number (ECN)...
Article
Full-text available
In termites, juvenile hormone plays a key role in soldier differentiation. To better understand the evolutionary origin of the soldiers, we studied the external and inner morphology of pseudergate-soldier intercastes and neotenic-soldier intercastes formed artificially by the application of juvenile hormone analogue in Prorhinotermes simplex. A maj...
Article
Full-text available
Extracts of three different glands (mandibular, labial, and Dufour's) of virgin Bombus terrestris queens at ten different ages (1-8, 12, and 18 days) were analyzed for chemical composition. One hundred and twenty-seven compounds were identified in the extracts. The mandibular and labial glands contained previously reported electroantennogram-active...
Article
Full-text available
Three taxa of the subgenus Sibiricobombus live in the Near-East mountain steppes: Bombus niveatus, B. sulfureus and B. vorticosus. The latter is also present in the Balkan. B. niveatus and B. vorticosus can only be distinguished based on color pattern. B. sulfureus differs in coat color and in genitalia. We identified 40 compounds in the secretions...
Article
Full-text available
According to the species recognition concept of Paterson, the analyses of the secretions of the cephalic parts of the male labial glands confirm the conspecificity of Bombus (Thoracobombus) ruderarius ruderarius and B. (T.) r. montanus populations from the Pyrenees. These secretions were compared in B. ruderarius and B. sylvarum. We identified the...
Article
Labial gland secretions of males of six cuckoo bumblebee species (Bombus vestalis, Bombus rupestris, Bombus campestris, Bombus sylvestris, Bombus bohemicus, and Bombus maxillosus) were analysed and components of their extracts were identified. The specimens of two species collected in the Czech Republic had a significantly different composition of...
Article
The absolute configurations of citronellol, 2,3-dihydrofarnesol, and 2,3-dihydrofarnesal in male marking pheromones of seven species of bumblebees and cuckoo bumblebees were determined by enantioselective gas chromatography on a capillary column coated with 60% heptakis(2,3-di-O-acetyl-6-O-TBDMS)-beta-cyclodextrin in polysiloxane PS 268. Pure (-)-S...
Conference Paper
Full-text available
The authors compare the descriptions of the sexual pheromones of male bumblebees published before and since 1996. They reveal the strong difference in described molecule quantities between those studies. Such differences can be mainly explained by the progress of the computed data acquisition and analysis. They can be also explained by the aims of...
Article
Full-text available
Résumé Les auteurs comparent les descriptions des phéromones sexuelles des mâles de bourdons publiées avant et depuis 1996. Ils mettent en évidence une importante différence dans la quantité de molécules décrites entre ces études. Cette différence s’explique notamment par l’importante évolution dans l’informatisation des données et de leur analyse....
Article
Full-text available
The authors compare the descriptions of the sexual pheromones of male bumblebees published before and since 1996. They reveal the strong difference in described molecules quantities between those studies. Such differences can be mainly explained by the progress of the computed data acquisition and analysis. They can be also explained by the aims of...
Article
Full-text available
(3 R )-(-)-Geranyllinalool and its (3 S )-(+)-isomer were synthesized in 7 steps starting from both enantiomers of citramalic acid and geranyl bromide. The synthetic sequence established the absolute configurations of naturally occurring geranyllinalools for the first time.
Article
Full-text available
Labial gland secretions of 26 males of the bumblebee Bombus lucorum (L.), collected in the Czech Republic, were analysed. The secretions consisted of 60 compounds; ethyl (Z)-9-tetradecenoate was the main component (average 53%). Although the males varied in colour, their labial gland secretions were similar in composition, which indicated they belo...
Article
Full-text available
Premating behavior in the species Bombus confusus Schenck, 1859 was studied. The marking habits of bumblebee males were revealed and the use of their labial gland secretion in scent marks was proved chemically. Identical compounds were present both in the labial gland secretion and on male-marked objects. This chemical proof is reported for the fir...
Article
Full-text available
Premating behavior in the bumblebee Bombus confusus was studied. Visual searching for females is not the only premating strategy of this species, as was believed earlier. Males of B. confusus have a normally developed labial gland and its secretion is used to mark a perch from which they visually search for females. The labial gland secretion conta...
Article
The review summarises chemical compounds found in exocrine glands of different castes of bumblebees. The sex pheromone of queens, queen pheromones, defence substances, trail pheromones, dominant signals of workers, marks of a food source, and male's marking pheromones are described. Attention is paid especially to the constituents of labial gland s...
Article
Full-text available
Ustav organické chemie a biochemie, Akademie věd České republiky, Flemingovo náměstí 2, 166 10 Praha 6 Došlo dne 21. VII. 1997 Obsah 1. Úvod 2. Zařazení čmeláků a typy produkovaných sloučenin 3. Sexuální feromon královny a mateří tlumící látka 4. Obranné látky 5. Stopovací feromony 6. Dominantní signály dělnic 7. Označení zdroje potravy 8. Značkova...

Citations

... Furthermore, it is important to disregard the potential loss of soluble nutrients, such as carbohydrates, minerals, vitamins, sugars, and proteins, which may diffuse into the blanching water [37]. In addition, the process of hot water blanching has a negative impact on the texture and microstructure of the sample [29,38]. In the end, this approach produces a substantial amount of wastewater, which gives rise to environmental problems. ...
... Through molecular docking, a large number of papers have reported that natural active molecules can be bound to PBPs [53][54][55][56]. Natural active molecules like quercetin, eugenol and kaempferol have been reported to bind effectively to PBPs [57,58]. It is worth noting that kaempferol exhibits higher specificity toward PBPs by interacting with crucial amino acids [59]. ...
... Cyperus scariosus is a perennial grass-like plant belonging to the Cyperaceae family, and is primarily found in Pakistan, India and other parts of Asia [13]. Roots, rhizomes and leaves of Cyperus scariosus have been traditionally used in Ayurvedic medicine for its various therapeutic properties, including antimicrobial, antiinflammatory, and antidiabetic activities [14]. Roots of this plant has been used as tonic, cordial, diaphoretic and vermifuge [15,16]. ...
... However, conventional hot water blanching, despite its uncomplicated equipment and straightforward operation, has certain drawbacks. The pretreatment of cassava slices with hot water blanching at a temperature of 80 ± 2 °C for 5 min yields a lower whiteness index (ranging from 80.48 to 84.05) compared to pretreatment solely through soaking [36]. On the other hand, the degradation of food quality, namely the deactivation of oxidases, can result in alterations in flavor, appearance, and the depletion of heat-sensitive components. ...
... cis-calamenene (RT = 9.52 min, VIP scores 1.14-1.16, ΔKI = 10, and total identification score of 87.9%) (Table S4 and Table S6) was found in line with previous literature on thyme phytochemical composition [32] ( Table 1). The inspection of fold change results obtained for sesquiterpenoid markers revealed the same upaccumulation trend in Polish thyme (Log2(FC) values ranging from 0.81 to 1.26) ( Table 1). ...
... Cinnamomum, Salvia, and Mentha are plant species that have been investigated for their antimicrobial properties. In vitro studies have demonstrated significant antimicrobial activity of plant extracts and EOs derived from these plants against a spectrum of foodborne pathogens, including Salmonella spp., Campylobacter spp., Listeria spp., and E. coli (Hatab et al., 2016;Huang et al., 2014;Kerekes et al., 2019;Kobus-Cisowska et al., 2019;Liang et al., 2012Liang et al., , 2019Lorenzo-Leal et al., 2019;Vihanova et al., 2021). However, factors such as extraction method, microbial strain, and chemical composition can influence their effectiveness (Burt, 2004;Gonelimali et al., 2018;Mostafa et al., 2018). ...
... For MIC, different concentrations of the sample were prepared using prepared solvent, and the minimum concentration zone of inhibition was recorded through plate assay followed by broth microdilution method through the guidelines of the CLSI (Clinical and Laboratory Standards Institute). Every extract sample was dissolved in the prepared solvent and diluted in nutrient broth in a range of (0.015-1) mg/ml [25,26]. We performed the antimicrobial activity against standard streptomycin (active pharmaceutical ingredients) for better results. ...
... Furthermore, the composition of these extracts, specifically the presence of phenolic compounds and their derivatives, fatty acids, terpenes, and other secondary metabolites, can also play a role in their antimicrobial activity (Altun & Yapici, 2022;Alves et al., 2022). Moreover, the volatility of plant derivatives, particularly EOs, can significantly influence the results of standard microplate-based assays, as reported by Houdkova et al. (2020). Vapor transition can affect the assay results, potentially leading to false positives in nonsealed microtiter plates. ...
... Another major component (9.5 %) of the CEO is linalool, which can notably influence or inhibit the synthesis of lipopolysaccharides, ribosomal assembly, and protein synthesis in E. coli [79]. Furthermore, the antimicrobial efficacy of α-Phellandrene, trans-Cinnamyl acetate, and β-Caryophyllene was reported in the literature [80][81][82]. These three elements accounted for 21.72 % of the CEO prepared in current research. ...