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Ivan Kosalec

Publications and source records attributed to Ivan Kosalec.

12 recordsLinked to original sources
PubMed2005

Synergistic antitumor effect of polyphenolic components of water soluble derivative of propolis against Ehrlich ascites tumour.

Effect of two preparation (Croatian and Brazilian) of water-soluble derivative of propolis (WSDP), caffeic acid, quercetin, chrysin, naringenin (components present in WSDP) on the development of Ehrlich ascites tumour (EAT) was evaluated. Test components (50 mg/kg) were given perorally or intraperitoneally 2 h prior the intraperitonel injection of EAT (2 x 10(6)) cells. It was observed that all test compounds effectively inhibited tumour growth and the proliferation of EAT. The volume of ascitic fluid induced by EAT cells and total number of cells present in the peritoneal cavity was markedly reduced in EAT-bearing mice treated with test components. In treated mice the number of polymorphonuclear (PMN) cells in the peritoneal cavity was increased while the number of macrophages was decreased. The macrophage spreading activity revealed that WSDP and all test compounds affected the functional state of macrophages increasing their tumorcidal activity; the effect of WSDP was most pronounced indicating synergistic effect of components present in WSDP. Antitumor activity of WSDP may be the result of different specific mechanism(s) of flavonoids present as compared to individual flavonoid given alone. It is likely that the part of antitumor efficacy of test components against EAT cells was the results of increased activity of macrophages.

Administration, Oral↗
PubMed2005

Influence of media and temperature on gliotoxin production in Aspergillus fumigatus strains.

Gliotoxin is a secondary metabolite of the epipolythiodioxopiperazine family with biologically active internal disulfide bridge. It is produced by many fungal species, including Aspergillus fumigatus and A. terreus. A. fumigatus, which produces gliotoxin and more than twenty other secondary metabolites, is the leading cause of invasive aspergillosis. Gliotoxin production in situ influence the development of aspergillosis. This study investigated the in vitro production of gliotoxin in nine A. fumigatus isolates from the upper respiratory tract of immunocompromised patients. The effects of media composition and incubation temperature were studied. Gliotoxin was extracted from biomass and its concentration was semi-quantitatively analysed using thin-layer chromatography. Gliotoxin production was higher in the yeast-extract liquid medium (YES) than in the synthetic Czapek-Dox liquid medium (CZA). Incubation at 37 degrees C resulted in higher gliotoxin production than at 25 degrees C, probably because higher temperatures favour expansive growth of the mycelium. Gliotoxin could be detected after three days of incubation at concentrations 4.06 mg mL(-1) (in YES at 37 degrees C) and 1.07 mg mL(-1) (in CZA at 25 degrees C). YES broth as a medium containing 4% sucrose and 2% of yeast extract is a very rich substrate for the production of gliotoxin in vitro.

Aspergillus fumigatus↗
PubMed2005

Verruculogen production in airborne and clinical isolates of Aspergillus fumigatus Fres.

Among airborne aspergilli sampled in outdoor air of the Zagreb area (2002/2003), Aspergillus niger (v. Teigh.) and A. fumigatus (Fres.) were the most abundant species (20-30%), with low mean annual concentrations (0.21-1.04 CFU m-3). Higher concentrations of A. fumigatus were observed in autumn and winter (0.5-1.05 CFU m-3) than in spring and summer (0-0.4 CFU m-3). On the other hand, A. fumigatus was found to be the most frequent isolate from upper and/or lower respiratory tracts of imunocompromised patients in many studies. This species produces several mycotoxins, including the tremorgenic mycotoxin verruculogen that can be found in spores and during myceliar growth. Verruculogen production ability was tested on 30 airborne and 33 clinical isolates of A. fumigatus. In both groups, high percentage of verruculogen-producing strains was noticed (84% of airborne and 91% of clinical isolates). Verruculogen production was not significantly different in the groups of airborne isolates (0.34+/-0.16 mg mL-1), and clinical isolates (0.26+/-0.19 mg mL-1).

Air Microbiology↗
PubMed2005

Mycotoxigenicity of clinical and environmental Aspergillus fumigatus and A. flavus isolates.

Clinical isolates of fifty strains of A. fumigatus and 30 strains of A. flavus from immmunocompromised patients from the hematological unit were analyzed for mycotoxin production and compared with the same number of environmental isolates (from soil, compost, and air). Only 9 (18%) strains of A. fumigatus produced gliotoxin in a mean concentration 2.22 mg mL-1 (range 0.5-5 mg mL-1). Aflatoxin B1 was detected in 7 (23%) isolates (range from 0.02 to 1.2 mg L-1) and aflatoxin G1 in one (3%) of clinical A. flavus isolates (0.12 mg L-1). In the group of environmental isolates, 11 (37%) were positive for aflatoxin B1 production (range from 0.02 to 1.2 mg L-1) and one for aflatoxin G1 (0.02 mg L-1). Bioautoantibiogram ("bioassay in situ") on TLC plates against Bacillus subtilis NCTC 8236 showed that only gliotoxin-producing strains have bactericidal activity of Rf values corresponding to gliotoxin. The secondary-metabolite profiles of clinical and environmental A. fumigatus and A. flavus isolates were homogeneous, except for gliotoxin production, which was detected only in the group of clinical isolates of A. fumigatus (18%).

Aflatoxin B1↗
PubMed2005

Antifungal activity of fluid extract and essential oil from anise fruits (Pimpinella anisum L., Apiaceae).

Antifungal activities of fluid extract and essential oil obtained from anise fruits Pimpinella anisum L. (Apiaceae) were tested in vitro on clinical isolates of seven species of yeasts and four species of dermatophytes. Diffusion method with cylinders and the broth dilution method were used for antifungal activity testing. Anise fluid extract showed antimycotic activity against Candida albicans, C. parapsilosis, C. tropicalis, C. pseudotropicalis and C. krusei with MIC values between 17 and 20% (v/v). No activity was noticed against C. glabrata, and anis fruits extracts showed growth promotion activity on Geotrichum spp. Anise fruits extract inhibited the growth of dermatophyte species (Trichophyton rubrum, T. mentagrophytes, Microsporum canis and M. gypseum) with MIC values between 1.5 and 9.0% (V/V). Anise essential oil showed strong antifungal activity against yeasts with MIC lower than 1.56% (V/V) and dermatophytes with MIC lower than 0.78% (V/V). Significant differences in antifungal activities were found between anise fluid extract and anise essential oil (p<0.01). Anise essential oil exhibited stronger antifungal activities against yeasts and dermatophytes with MIC values between 0.10 and 1.56% (V/V), respectively.

Antifungal Agents↗
PubMed2005

Antimicrobial activity of juniper berry essential oil (Juniperus communis L., Cupressaceae).

Juniper essential oil (Juniperi aetheroleum) was obtained from the juniper berry, and the GC/MS analysis showed that the main compounds in the oil were alpha-pinene (29.17%) and beta-pinene (17.84%), sabinene (13.55%), limonene (5.52%), and mircene (0.33%). Juniper essential oil was evaluated for the antimicrobial activity against sixteen bacterial species, seven yeast-like fungi, three yeast and four dermatophyte strains. Juniper essential oil showed similar bactericidal activities against Gram-positive and Gram-negative bacterial species, with MIC values between 8 and 70% (V/V), as well as a strong fungicidal activity against yeasts, yeast-like fungi and dermatophytes, with MIC values below 10% (V/V). The strongest fungicidal activity was recorded against Candida spp. (MIC from 0.78 to 2%, V/V) and dermatophytes (from 0.39 to 2%, V/V).

Anti-Bacterial Agents↗
PubMed2005

Flavonoid analysis and antimicrobial activity of commercially available propolis products.

Propolis ethanolic solutions are the most used propolis products on the market for the treatment of minor ulcers in the mouth, angina, thrush or skin infections. Since it is still an unofficial drug in pharmacy, we analyzed the contents of flavonoids in ten commercially available ethanolic solutions of propolis from the Croatian market using two complementary colorimetric methods. Antimicrobial activities, determined with the diffusion method, against six bacterial species (Bacillus subtilis NCTC 8236, Staphylococcus aureus ATCC 25923, Streptococcus pyogenes ATCC 12204, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 10536, Pseudomonas aeruginosa ATCC 27853, and one yeast-like fungus Candida albicans ATCC 10231 were compared. Results of flavonoids analysis suggested that the contents of flavones and flavonols in the products were uniform and ranged from 0.14 to 0.41%, but the content of flavanones varied greatly from 0.43 to 18.78%. Total flavonoid content, as the sum of two colorimetric methods, in propolis products was between 0.78 and 18.92%, and most products had the flavonoids content below 9%. All products with the total flavonoids content above 1% showed antimicrobial activity against the four Gram-positive bacterial species tested, and against P. aeruginosa and the yeast-like fungus C. albicans. Total flavonoids contents, expressed as the sum of two colorimetric methods, could be useful methods for estimating the flavonoid contents of propolis products. Our results indicate that the quality of commercially available propolis products requires verification.

Anti-Infective Agents↗
PubMed2004

Galangin expresses bactericidal activity against multiple-resistant bacteria: MRSA, Enterococcus spp. and Pseudomonas aeruginosa.

The antimicrobial activity of three propolis ethanol extracts (EEP) was examined for various Gram-negative and Gram-positive bacterial species, including multiple-resistant Staphylococcus aureus, Enterococcus spp. and Pseudomonas aeruginosa strains. EEP had a good bactericidal activity against Gram-positive species, and all multiple-resistant bacterial strains tested were sensitive to EEP. Minimal inhibitory concentrations (MICs) were lower in samples of higher flavonoid content (from 0.65 to 7.81 mg mL(-1)), indicating the influence of the concentration of some potent bactericidal compound(s) in propolis or synergism among some bactericidal compounds. Antimicrobial-guided separation of flavonoid aglycones (bioassay in situ on thin-layer chromatogram) showed that galangin (3,5,7-trihydroxyflavone) is one compound in EEP with bactericidal activity. Galangin was isolated by preparative chromatography. After determining the quantity present, the MIC against multiple-resistant bacteria was determined. The MIC of galangin against multiple-resistant bacterial strains was significantly lower (from 0.16 to 0.44 mg mL(-1), p < 0.05) than that of EEP. The bactericidal activity of galangin against P. aeruginosa strains was present at 0.17+/-0.05 mg mL(-1).

Anti-Bacterial Agents↗
PubMed2004

Quantitative analysis of the flavonoids in raw propolis from northern Croatia.

Spectrometric analyses of flavonoids in twenty propolis samples, collected from ten different geographic localities in northern Croatia using two complementary methods, are reported. Flavones and flavonols were determined using aluminum chloride and expressed as quercetine equivalent while flavanones were determined using 2,4-dinitrophenylhydrazine and expressed as naringenin. Contents of flavones and flavonols were similar for most samples and ranged from 2 to 2.3%, except for one sample with a concentration of 1.3% and one sample in which it was not possible to detect flavones and flavonols. The content of flavanones in propolis samples is very variable. 55% of samples contained flavanones between 15 and 24% and 45% of samples between 4 and 14%. Total levels of flavonoids in raw propolis samples ranged between 5 and 26%; for the majority of samples (75%), the total level of flavonoids ranged between 15 and 25.9%. The high variability of flavanone concentration will affect the biological activity of propolis preparations.

Colorimetry↗
PubMed2004

[Chemistry and biological effects of gliotoxin].

Gliotoxin is a mycotoxin from the epipolythiodioxypipeazine family with biological active internal disulfide bridge. Gliotoxin has an antibacterial and antiviral activity, but it was discarded from clinical practice due to its toxicity. The most studied effect of gliotoxin is its influence on the cell of the immune system. Today, researches are focused on treating transplantation organs ex situ and making them immunologically silent. Its toxicity has been proven on several cells (macrophages, thymocites, splenocytes, and fibroblasts) causing apoptosis and necrosis and it has acted as inhibitor of several enzymes (farnesyl-transefases, NF-kappaB, and alcohol-dehydrogenases). Its mechanism of toxicity is connected with the production of mixed disulfide and covalent bonds, and oxidative effects. An important medical mould Aspergillus fumigatus and yeast Candida albicans can secrete gliotoxin in infected tissues and, because of the proven toxic effects of gliotoxin, it is suggested that gliotoxin can exacerbate mycoses (invasive aspergillosis or candidiasis). Gliotoxin can also affect the invasiveness of fungi and their dissemination from the primary site throughout the organism.

Animals↗
PubMed2003

Analysis of propolis from the continental and Adriatic regions of Croatia.

Thin-layer chromatography of ethanolic extract of propolis (EEP) from the continental and Adriatic regions of Croatia showed that 72.2% of propolis samples contain galangin, 88.8% of samples contain kaempferol, naringenin and apigenin and 66.6% of samples contain caffeic acid. Caffeic acid, pinocembrin, galangin, chrysin and naringenin were analyzed by HPLC. In all samples, pinocembrin was the dominant flavonoid. In samples from the Adriatic region, concentration of pinocembrin ranged from 0.03 to 6.14% (x = 2.87%) and in the continental region samples from 0 to 4.74% (x = 2.84%). Chrysin was found in all propolis samples in a concentration ranging from 0.22 to 5.32% (x = 1.86%) in the continental region samples and from 0.03 to 3.64% (x = 1.96%) in samples from the Adriatic region. Chrysin was followed by naringenin, ranging from 0 to 1.14% (x = 0.42%) in samples from the Adriatic region and from 0.22 to 2.41% (x = 0.60%) in the continental region samples. Concentration of caffeic acid ranged from 0 to 10.11% (x = 2.69%) in the Adriatic region samples and from 0.27 to 2.67% (x = 1.37%) in samples from the continental region of Croatia. Results of HPLC analyses suggest that propolis samples collected from various parts of Croatia do not differ markedly in contents of chrysin, pinocembrin, naringenin and galangin but differ in the concentration of caffeic acid. All EEPs significantly inhibited the growth of Bacillus subtilis in comparison with the control (80% ethanol) (p < 0.05), showing inhibition zones of 16 +/- 2 mm for samples from the continental region, and of 18 +/- 3 mm for samples from the Adriatic region. There was no significant difference in antimicrobial activity of EEPs from the continental and Adriatic regions of Croatia, suggesting that bactericidal activity depends on synergism of all phenolic compounds.

Animals↗