Screening of antibacterial effects of anise essential oil alone and in combination with conventional antibiotics against Streptococcus pneumoniae clinical isolates

AIM

This study aimed to investigate the effects of anise essential oil alone and in combination with conventional antibiotics (amoxicillin, ciprofloxacin) against Streptococcus pneumoniae clinical isolates. MATERIAL AND METHODs: Anise essential oil (AEO) was isolated by hydrodistillation from dried powdered fruits. Its chemical composition was investigated by GC-MS and GC-FID. Broth dilution assay was used to evaluate the antibacterial effects of anise essential oil. The interactions with antibiotics were studied by the checkerboard assay.

RESULTS

Trans-anethole (90.18%) was identified as major constituent in anise essential oil. Almost all combinations AEO-amoxicillin and AEO-ciprofloxacin showed indifferent interactions (1 < FIC index < or = 2). Positive interactions (addition and weak synergism) were found only for four combinations AEO-amoxicillin (FIC index = 1,0.62, 0.75 and 0.5) and one combination AEO-ciprofloxacin (FIC index = 0.62).

CONCLUSIONS

Herbal products containing anise essential oil may be used as expectorants in combination with amoxicillin or ciprofloxacin in Streptococcus pneumoniae infections without diminishing antibiotic efficacy.

Evaluation of free radical scavenging activity of some antioxidants

Measurement of free radical scavenging capacity of antioxidants is influenced by a number of parameters that depend on reaction rate.

AIM

A new method for assessing the free radical scavenging activity in which the influence of antioxidant concentration and reaction rate on chlorpromazine radical cation absorbance are simultaneously monitored.

MATERIALS AND METHODS

The change in radical solution absorbance at 525 nm within a fixed time at different concentrations of the standard antioxidant--ascorbic acid (AA) are determined and percent inhibition is calculated.

RESULTS

The percent inhibition of color was plotted versus time, and the area under the curve was calculated for each concentration of the standard antioxidant. The calibration curve was obtained by plotting the area under the curve versus ascorbic acid concentration. The antioxidant activity of the samples was calculated using the regression line equation (r2 = 0.9991) and expressed as ascorbic acid molar equivalents (AAE) depending on the unit of measurement chosen for the tested product.

CONCLUSIONS

The proposed method takes into account the two parameters influencing the kinetics of the reaction between antioxidant and radicals, namely the antioxidant concentration and fixed time for measuring absorbance.

Spectrometric determination of total antioxidant activity in chlorpromazine radical cation - ascorbic acid system

Through univalent oxidation chlorpromazine forms a colored and relatively stable radical cation with maximum absorbance at 525 nm, considered a redox mediator in a number of b iochemical reactions.

AIM

To develop a spectrometric method for the determination of total antioxidant activity based on the reaction of chlorpromazine radical capture by ascorbic acid (standard antioxidant).

MATERIAL AND METHODS

The calibration curve was drawn by monitoring the decrease in the absorbance of the preformed radical solution (obtained by oxidation of chlorpromazine by potassium persulfate in an acidic environment) depending on ascorbic acid concentration.

RESULTS

The method was validated. In the ascorbic acid concentration range 10-100 microM/L linearity was good (r2 = 0.9991). Limit of detection (LOD) was 3.13 microM/L and limit of quantification (LOQ) was 9.49 microM/L. System precision (RSD = 0.75%), method precision (RSD = 4.50%) and intermediate precision (RSD = 4.63%) were determined. The average recovery of 101.7% for the concentration range 91.1 -105.9% confirmed the accuracy of the method.

CONCLUSIONS

The method has a good linearity, precision, accuracy, and is easy to use for evaluation of antioxidant action of different products. Total antioxidant activity is expressed as ascorbic acid molar equivalents (AAE). The method has the advantage of using a radical involved in redox processes in the body.

[Studies regarding chemical composition of lavender volatile oils]

AIM

In this paper, we studied comparatively volatile fractions obtained by hydrodistillation from 5 samples of lavender flowers (L. angustifolia ssp. angustifolia, L. hybrida, L. angustifolia spp. pyrenaica, L. angustifolia spp. angustifolia cv. Munstead and cv. Hidcote blue) cultivated during 2009 in the Botanical Garden from Galati.

MATERIAL AND METHODS

The essential oils have been characterized using gas-chromatography and mass spectroscopy analysis (GC-MS).

RESULTS

The main compounds in all lavender volatile oils were: linalool (20.60%-35.99%), linalyl acetate (12.58%-19.65%), lavandulyl acetate (3.74%-10.48%), t-p3-ocimene (1.26%-9.23%), a-terpineol (3.67%-6.73%), nerol (0.81%-3.32%), neryl acetate (0.95%-3.64%) and beta-caryophyllene (0.93%-2.43%).

CONCLUSIONS

None of the separated volatile fractions met the minimal quality parameters for the standard volatile oil of fine lavender used in aromatherapy. Low concentration in monoterpene esthers could be explained by the fact that, on one hand, the average daily temperature during the blooming period is below the one from Mediterranean Sea area, and, on the other hand, the city of Galati is only 42 meters above the sea level (the volatile oil from fine lavender used in aromatherapy is obtained from plants cultivated at 800-1200 meters altitude).

[Chemical composition of essential oil obtained from Romanian fennel fruits]

For therapeutical purposes, fennel (Foeniculum vulgare Mill.), an important aromatic plant, is used for its expectorant, antispasmodic, carminative and diuretic properties. The chemical composition, especially of the volatile fraction, depends on the origin of the plant, and the ecological and environmental conditions in which it grows.

AIM

To determine the chemical composition of the volatile fractions obtained from fennel fruits (Foeniculum vulgare Mill.) available on the Romanian market.

MATERIAL AND METHODS

The essential oils obtained from dried fruits by hydrodistillation have been characterized by using gas chromatography and mass spectroscopy (GC-MS).

RESULTS

In all oils, the main components were: trans-anethole (9.72-56.57%), fenchone (7.72-34.66%) and estragole (4.69-49.04%).

CONCLUSIONS

The essential oil from fennel samples showed an inadequate chemical profile for aromatherapy purposes.

[Contribution to the phytochemical study of polyphenols in ten hydroalcoholic extracts of Chamomile floss]

Continuing a series of studies that intend to evaluate the pharmaceutical quality of 10 commercial samples of chamomile, we tried to investigate the chemical composition of the hydroalcoholic extracts obtained in our laboratory, starting from this raw material.

MATERIAL AND METHOD

The qualitative and semiquantitative analysis of the extracts was done by HPLC means.

RESULTS

All extractive solutions have a high content in ferulic acid, whereas the caffeic acid level is the lowest. Regarding the flavonoids, there are many quantitative differences between the samples: one extract lacking the rutoside and two of them having low apigenin-7-glucoside contents.

[High blood and urine concentration of hepatotoxic mycotoxins (aflatoxin B1, sterigmatocystin) in patients with liver cirrhosis]

Aflatoxins and sterigmatocystin are potent carcinogens, certainly involved in pathogenesis of liver cancer.

AIM

To evaluate the risk of mycotoxin intake and to determine the presence of aflatoxin B1 (AFB1) and sterigmatocystin (STC) in patients with liver cirrhosis.

MATERIAL AND METHOD

The study included 92 patients (33 controls, 59 liver cirrhosis) that completed a food frequency questionnaire (FFQ). Blood and urine samples were collected and mycotoxins determined by high performance liquid chromatography.

RESULTS

18.18% samples in controls and 72.88% in cirrhosis group presented detectable levels of mycotoxins. The mean values of AFB1 in blood were 0.7 ng/mL in controls and 1.67 ng/mL in test group (p = 0.11); STC presented 60 times higher levels in second group (p < 0.01). AFB1 presented a mean level of 1.2 ng/mL in urine of test group (not detected in controls); STC presented 256 time higher concentration in urine of cirrhotic patients, with a perfect correlation between blood and urine levels in control (r=1) and no correlation in test group (r = 0.05). There were no correlations between mycotoxin, liver enzymes, alpha-fetoprotein and mycotoxin intake risk estimated by FFQ.

CONCLUSION

Most of the patients presented detectable levels of mycotoxins, significantly increased in cases with liver cirrhosis, probable due to a specific metabolic pattern.

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

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

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.

[Pharmacognostic research of some species of Achillea. Note 1. Volatile oils analysis]

We established the hydrodistilled essential oil yields from the dried flower heads of A. collina J. Becker ex Reichenb. (collected in Austria and Romanina), A. millefolium L. (s.l.) (Romania) and of three mixtures of some species belonging to the Achillea millefolium L. group. Constitutents of the essential oils were studied by GC method. The main components of the monoterpene fraction of the oils were 1.8 cineol, camphor, and borneol. The main active principle of the volatile oil, chamazulene, was in highest concentration (53%) in the essential oil hydrodistilled from A. collina collected in Austria. The results obtained for a mixture of some species (Plafar Botoşani) differ from literature data in the presence of bisabolol, which have not been found so far in Achillea species.

Possible involvement of L-arginine-nitric oxide pathway in the modulation of stress-induced analgesia

The possible participation of NO in the pain modulation and stress analgesia was studied in Wistar adult rats. Cerebral citruline as a stoichiometric coproduct of NO from L-arginine increased from the mean value 5.6 +/- 0.4 nM/mg.Pt. to 8.9 +/- 0.5 nM/mg.Pt. in acute immobilization stress. Intraperitoneal administration of L-arginine caused only in high doses (50 mg/kg body weight) a small transient decrease of tail-flick latencies to the thermoalgesic stimulus, without significant changes of the stress analgesia induced by the restraint stress. In the pretreated animals with L-NAME a progressive increase of latency time was obtained and the increased latencies induced by acute immobilization appeared significantly potentiated. These results offer new indirect evidence in favour of the modulatory role of NO in the thermoalgesic sensitivity and stress induced analgesia.

Possible involvement of the L-arginine-nitric oxide pathway in the modulation of stress-induced analgesia

The possible participation of nitric oxide (NO) in pain modulation and stress analgesia was studied in adult Wistar rats. Cerebral citruline as a coproduct of NO from L-arginine increased from the mean value 5.6 +/- 0.4 nM/mg.Pt. to 8.9 +/- 0.5 nM/mg.Pt. in acute restraint stress. In high doses (50 mg/kg body weight), intraperitoneal administration of L-arginine caused a small and transient decrease of the tail-flick latencies to the thermal stimulus, without significant changes of the stress analgesia induced by restraint stress. In animals pretreated with N-nitro-L-arginine methyl ester (NAME) a progressive increase of the latency time was obtained and the increased latencies induced by acute immobilization appeared significantly potentiated. These results offer new indirect evidence in favour of the modulatory role of NO in thermoalgesic sensitivity and stress-induced analgesia.