Assessment of the microbial load of some medicinal plants commonly used in Romania.

AIM: This study aims to assess the microbial load of some medicinal plants (Matricaria chamomilla, Achillea millefolium, Ocimum basilicum, Calendula officinalis, Tilia cordata, Hypericum perforatum) commonly used as medicinal teas. MATERIAL AND METHODS: A total of 24 samples collected from the local market, as well as from the spontaneous flora of Galati County, were analyzed in terms of the total number of germs, the content of coliform bacteria, yeasts and molds, and the presence of specific pathogenic bacteria (Escherichia coli, Bacillus cereus, Coagulase-positive Staphylococcus, Salmonella spp.). RESULTS: The values obtained for total number of germs, yeasts and molds were in accordance with the limits set by the European Pharmacopoeia for plant products to which hot water is added before use. In the case of specific pathogenic bacteria, the presence of E. coli was confirmed in 41.66% of the samples, the presence of Coagulase-positive Staphylococcus in 16.66% of the samples, and the presence of Bacillus cereus in 33.33% of the samples. Salmonella spp. was absent in all samples. CONCLUSIONS: The study highlights a certain microbial load of medicinal plants analyzed, emphasizing the importance of quality control in all stages of production.

Chemical, antioxidant and antimicrobial investigations of Pinus cembra L. bark and needles.

The chemical constituents and biological activity of Pinus cembra L. (Pinaceae), native to the Central European Alps and the Carpathian Mountains, are not well known. The aim of the present work was to examine the phenolic content, antioxidant and antimicrobial effects of hydromethanolic extracts of Pinus cembra L. bark and needles. Bark extract had higher concentrations of total phenolics (299.3 vs. 78.22 mg gallic acid equivalents/g extract), flavonoids (125.3 vs. 19.84 mg catechin equivalents/g extract) and proanthocyanidins (74.3 vs. 12.7 mg cyanidin equivalents/g extract) than needle extract and was more active as a free radical scavenger, reducing agent and antimicrobial agent. The EC50 values in the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS) and reducing power assays were 71.1, 6.3 and 26 mg/mL for bark extract and 186.1, 24 and 104 mg/mL for needle extract, respectively. In addition, needle extract showed ferrous ions chelating effects (EC50 = 1,755 µg/mL). The antimicrobial effects against Staphylococcus aureus, Sarcina lutea, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans were assessed by the agar diffusion method. Both extracts (4 mg/well) were active against all the microorganisms tested; bark extract showed higher inhibition on all strains. These results indicate that Pinus cembra L. bark and needles are good sources of phytochemicals with antioxidant and antimicrobial activities.

[Antimicrobial activity of some cinnamic acid derivatives]. / Evaluarea actiunii antimicrobiene a unor derivati de acid cinamic.

Due to drug-resistance phenomenon, there is a constant need for discovering new antiinfectious agents. A series of cinnamic acid derivatives was synthesized and then brominated with bromine in the presence of chloroform or acetic acid. The structure of the new compounds was confirmed by elemental and spectral data. Their antimicrobial activity was tested by disc-diffusion method. The tested compounds had mainly antifungal activity and were moderately active against Gram-positive bacteria. Bromination of the double bond determined the enhancement of the antimicrobial activity for all the tested compounds.

Antibacterial activity of some Artemisia species extract.

The antimicrobial activities of ethanol, methanol and hexane extracts from Artemisia absinthium, Artemisia annua and Artemisia vulgaris were studied. Plant extracts were tested against five Gram-positive bacteria, two Gram-negative bacteria and one fungal strain. The results indicated that Artemisia annua alcoholic extracts are more effective against tested microorganisms. However, all plants extracts have moderate or no activity against Gram-negative bacteria. The obtained results confirm the justification of extracts of Artemisia species use in traditional medicine as treatment for microbial infections.

[Microbiological evaluation of some commercial brands of Chamomillae floss]. / Controlul microbiologic al unor sorturi comerciale de Chamomillae flos.

UNLABELLED: Different strains of microorganisms contaminate medicinal herb, and theirs, enzymes could modify the normal composition of herbal products. MATERIAL AND METHODS: We evaluated the microbiological quality of 12 samples of Chamomillae floss commercialized in, markets and specific stores. Microbiological quality has been evaluated according European Pharmacopoeia rules. In all samples we determined the total number of germs, total number of fungi and we evaluated the presence of coliform bacilli, respectively Staphylococcus species. RESULTS: For all samples, the total number of germs was under the limits with variation between 320 CFU/g (P 4) and 14000 CFU/g (P 11). The total number of fungi was under the limits; in most of samples, we detected Penicillium sp. and Aspergillus sp. In 4 samples the total number of Escherichia coli strains was over the limits (100 CFU/g). CONCLUSIONS: An important decrease of total number of coliform bacilli was observed after boiling water has been added but the total number of germs was decreased insignificantly, so these extracts are not very safe for patient especially when vegetal products contain a great number of germs.

In vitro antimicrobial activity and chemical composition of the essential oil of Foeniculum vulgare Mill.

UNLABELLED: In our study, four samples of volatile oil from Foeniculum vulgare, cultivated in different pedoclimatic conditions, were investigated for their antimicrobial activity and chemical composition. MATERIAL AND METHODS: Organisms. Staphylococcus aureus ATCC 25923, Bacillus cereus, Pseudomonas aeruginosa, Escherichia coli ATCC 25922, Candida albicans were included in the report. Antimicrobial susceptibility tests. The comparative inhibitory activity of volatile oil samples with other antimicrobial agents was quantitative determined by minimum inhibitory concentration (MIC). Oil samples are the volatile oils extracted by steam distillation, from two ecological vegetative populations of Foeniculum vulgare. Gas chromatography coupled to mass spectrometry (GC-MS) was used to determine the chemical composition of the essential oils. RESULTS: All oil samples have a good activity against E. coli and S. aureus at low concentrations. Against B. cereus and P. aeruginosa these oil samples are less active. The oil samples were generally bactericidal at a concentration up to twofold or fourfold higher than the MIC value. Significantly synergic activity with amoxicillin or tetracycline showed all fennel samples against E. coli, Sarcina lutea and B. subtilis strains. Fennel oil samples have shown high activity against Candida albicans. CONCLUSION: No significant antimicrobial activity variations were observed for Foeniculum vulgare volatile oil samples obtained after two or three years cultivation period. The most important identified compounds in all samples of fennel volatile oils were trans-anethole, estragole, fenchone, limonene, alpha-pinene and gamma-terpinene.

Chemical composition and in vitro antimicrobial activity of essential oil of Melissa officinalis L. from Romania.

UNLABELLED: Melissa officinalis L. (lemon balm) is used in traditional medicine to treat insomnia, anxiety, gastric conditions, psychiatric conditions, migraines, hypertension and bronchial conditions. Natural essential oils (mixtures of fragrant chemical) obtained from various parts of plants are efficient active antimicrobial agents. The widespread use of antimicrobial agents selects resistant bacterial strains, which seriously compromise the effectiveness of antibiotic treatment. The use of herbal medicines might be a precautionary measure to prevent the development of lack of susceptibility to synthetic antibiotics that is associated with therapeutic failures. MATERIAL AND METHODS: In this work, the chemical composition and the antimicrobial properties of essential oil from romanian Melissa officinalis were determined. Therefore, the purpose of this study was to evaluate in vitro antimicrobial activity of lemon balm oil by comparison with lavender essential oil, which is also utilised for its antimicrobial properties in folk medicine. RESULTS: The most important identified compounds, well known for their antimicrobial effects were citral (neral and geranial) (16.10%), citronellal (3.76%) and trans-caryophyllene (3.57%).The lemon balm oil sample exhibited a higher degree antibacterial activity than did Lavandula oil against Gram-positive strains. The both oil samples tested has shown a high activity against Candida albicans. The gram-negative bacteria were not affected by the lemon balm oil.

Correlation between linezolid zone diameter and minimum inhibitory concentration values determined by regression analysis.

Linezolid is a new synthetic antibiotic belonging to the oxazolidinone class, available for the therapy of gram-positive infections, caused by methicillin-resistant staphylococci, vancomycin-resistant enterococci and penicillin-resistant pneumococci. The aim of the study was to determine the in vitro activity of linezolid against staphylococci strains and also to determine the relationship between the minimum inhibitory concentration (MIC) and inhibition zone diameter by calculating the regression analysis. We tested one hundred S. aureus isolates, obtained from healthy persons (naso-pharyngeal swabs) during 2005 year. The antibiotic susceptibility of strains was determined by disk diffusion standardized method and by agar dilution method using a multipoint inoculator. The relationship between the diameter of the inhibition zone produced by a linezolid disc impregnated with a fixed amount (30 eg) was determined by regression performed with the least squares method, considering the log2 of the minimum inhibitory concentrations (MICs) as the independent variable and the zone diameter as the dependent variable. The MIC values expressed in logarithmic form are plotted against inhibition zone diameter (arithmetic scale) of the same strain. The activity of linezolid against staphylococci was very good, with MIC 90 of 1 mg/l. All strains were fully sensitive. The regression line for linezolid passes through a continuous series of points that all are approximately located on the a straight line. For each of the MIC values the differences result no greater than 23 mm in diameter sizes were registered. Regression equation was y= -0.188x + 8.048. In conclusion, the regression line analysis calculated for linezolid, demonstrates a significant correlation between MIC values and the inhibition zone diameters obtained by a 30 mg disc.