Tube Dilution Research Articles

Effects of a Novel Hydration Accelerant on the Biological and Mechanical Properties of White Mineral Trioxide Aggregate

Introduction The objective of this study was to investigate the antibacterial, biocompatibility, and mechanical properties of mineral trioxide aggregate (MTA) set using a calcium lactate gluconate (CLG) solution. Methods ProRoot white MTA (WMTA) (Dentsply Tulsa Dental, Tulsa, OK) was used as the control group; MTA-like cement was prepared by mixing Portland cement/bismuth oxide/calcium sulfate (75/20/5) as the experiment group. A solution of 23.1 wt% CLG was used as a hydration accelerant and was compared with deionized water (DDW). Changes in pH values, antibacterial properties, in vitro cell viability, and diametral tensile strength (DTS) of the hydrated cements were assessed. Results Like WMTA, pH values for the MTA-like cement set using DDW and the CLG solution showed minor but statistically significant differences ( P < .05). The antibacterial effects of hydrated specimens set by DDW and CLG against Streptococcus mutans assessed with an in vitro tube dilution test showed a significant difference in the early hydration time but no significant difference after 60 minutes ( P > .05). A mouse osteoblastic cell (MC3T3-E1)-based MTT assay revealed that WMTA set using CLG had significantly higher cell viability than that set using DDW ( P < .05). The DTS test for hydrated MTA-like cement with different liquids showed a significant difference on day 1 but no statistical difference on day 21. Conclusions The results suggest that using a CLG solution as the hydration accelerant may enhance the biocompatibility but not compromise WMTA’s antibacterial and mechanical properties.

Antioxidant, antimicrobial and cytotoxic bioassay of Mollugo oppositifolius L

The present study was conducted according to the traditional uses of Mollugo oppositifolius L. by the kabiraj (traditional practioner) for the treatment of infectious diseases of the ill fated and poor people of Bangladesh. For this antioxidant, antimicrobial and biolethality potentials were conducted by methanol (MOME), ethanol (MOEE) and petroleum ether (MOPE) extractives of the suspected species. To determine the antioxidant activity the DPPH inhibition method was used. For antimicrobial test, antibacterial and antifungal sensitivities were performed by disc diffusion method and serial tube dilution method was carried out to determine the minimum inhibitory concentrations on some human pathogenic bacteria and fungi. For cytotoxicity test, brine shrimp lethality bioassay was conducted. Among the three crude extracts, MOEE produced more significant inhibition of DPPH (IC50; 27 μg/ml); MOPE produced highest zone of inhibition against Bacillus subtilis (16.67 mm) and Microsporum spp. (16.0 mm). On the other hand, MOME produced mild cytotoxicity as 50% and 90% mortality (LC50 and LC90) 8.0 μg/ml and 85.12 μg/ml. Key words: Antioxidant, antimicrobial, cytotoxicity, Mollugo oppositifolius

Study of antimicrobial activity and root symbionts of Hemionitis arifolia

Antibacterial and antifungal activity of crude extract, alcoholic extract and extracted phenol from various parts of tropical pteridophyta, Hemionitis arifolia were tested by agar diffusion and tube dilution assay. Both the crude and alcoholic extracts of vegetative and reproductive leaves of H. arifolia showed considerable antibacterial activity against Gram negative test strain of Escherichia coli (MTCC-739). Extract from reproductive leaves also showed moderate antibacterial activity against Bacillus subtilis (MTCC-441) (Gram positive test strain) but didn't show any antifungal activity against Candida albicans (MTCC-7353). Mycorrhizal and other symbiotic association with the root system of H. arifolia was studied and it is revealed that a number of mycorrhizal strains were present in both vegetative and reproductive form. Presence of Dark Septate Endophytic Fungi (DSF) was also detected.

Evaluation of Antimicrobial Activity of 3-(4-1H-Indol-3-yl)-(2,3- dihydro-1H-benzo[b]diazepin-2-yl)- 2H-chromen-2-one

1,5- Benzodiazepines and its derivatives constitute an important class of heterocyclic compounds which possess wide range of therapeutic and pharmacological properties as anticonvulsant, analgesic, sedative, antidepressive, and hypnotic agents. In the last decade, the area of biological interest of 1,5-Benzodiazepines has been extended to several diseases such as cancer, viral infection and cardiovascular disorders. With this background, we had synthesized RVB-01 (3- (4-1H-Indol-3-yl)-2,3-dihydro-1H-benzo[b][1,5]diazepin-2-yl)-2H-Chromen-2-one) . Structure of this compound have been elucidated by using physical and extensive spectral data. The antimicrobial activity of RVB-01 against B subtilis , P aeruginosa, E coli, M luteus, S aureus was determined by agar diffusion method at 10, 50, 500 and 1000 mcg/ml using ciprofloxacin as a reference. MIC value of RVB-01 against B subtilis was determined by tube dilution method. RVB-01 showed remarkable activity against all microorganisms except E coli and having an MIC value of 250-300 mcg/ml against B subtilis. The results indicated that 2,3-Dihydro-1H-1,5-Benzodiazepines could be the potential candidate eliciting antibacterial activity, and further studies can be conducted using molecular modeling tools for designing 1,5-benzodiazepines having better activity. © 2011 IGJPS. All rights reserved

Synthesis and evaluation of n-substituted imidazole derivatives for antimicrobial activity

A series of N-substituted imidazole derivatives was synthesized. Imidazole nucleus was reacted with ethylchloroacetate to form imidazole ester. Reaction of the imidazole ester (I) with different amines yields the desired products (1a- 1e). The compounds were characterized by FT-IR, 1H-NMR and mass spectra. The synthesized compounds were evaluated for the antimicrobial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger by determination of MIC (minimum inhibitory concentration) using tube dilution method. Compound (1b) was found to be the most active antimicrobial compound amongst others in the series.

Evaluation of inhibitory effect of chamomile alcoholic extract on the growth and production of certain factors of Staphylococcus aureus

Investigation of the alcoholic extract of chamomile against growth and production of catalase, Dnase and haemolysin of Staphylococcus aureus (ATCC29213) were the aims of this study In this study, German chamomile was prepared from Tehran agricultural researches center. Extraction was performed by ethanol 85 (Maceration method) then solvent is removed by vacuum distillation system (concentrated extract). For initial screening of antibacterial property of the concentrated extract and determination of the mean diameter of growth inhibition zone of the MIC concentration, agar well diffusion assay were used. One ml of the concentrated extract was dried at 50°C within 24 hours. Its dried weight per ml was then measured. Dried extract powder is used for determination of Minimal Inhibitory Concentration (MIC) & Minimal Bactericidal Concentration (MBC) by using of the tube dilution method in broth media. In order to investigate the enzymatic activities, bacteria were treated by MIC (sub-inhibitory Concentrations, SIC) of extract for 24 hours as well as control tube (without extract). Catalase activity on 3% H2O2 by Iodometric & KMnO4 titration method, Dnase activity by culture of the treated bacteria and control tube on Dnase agar plate and comparison of nucleic acid precipitated zones and haemolysin activity in supernatant of the bacterial suspensions against sheep RBC for tests and control tube were performed and compared. All results were repeated three times and were analyzed by SPSS software. Our results were as follows: -Mean dry weight: 83.8±0.002 mg/ml -MIC: 2.615 mg/ml -MBC: 5.23 mg/ml -SIC: 1.35 mg/ml -SIC: 0.653 mg/ml -Inhibitory zone of MIC: 15±1.2 mm In concentration 1.35 mg/ml of extract 28-34% was decreased. Haemolysin activity: In concentration 0.653 mg/ml of extract 12-14% was decreased In concentration 1.35 mg/ml of extract 79-84% was decreased Catalase activity: In concentration 0.653 mg/ml of extract 34-38% was decreased In concentration 1.35 mg/ml of extract 71-74% was decreased Dnase activity: In concentration 0.653 mg/ml of extract 46-50% was decreased Although some of the concentrations of the chamomile alcoholic extract showed pronounced antibacterial activity on the Staphylococcus aureus; but its introduction as an antibacterial compound requires more information.

The concentration of antibiotic in fresh-frozen bone graft

We investigated the antibiotic concentration in fresh-frozen femoral head allografts harvested from two groups of living donors. Ten samples were collected from patients with osteoarthritis of the hip and ten from those with a fracture of the neck of the femur scheduled for primary arthroplasty. Cefazolin (1 g) was administered as a pre-operative prophylactic antibiotic. After storage at -80 degrees C for two weeks the pattern of release of cefazolin from morsellised femoral heads was evaluated by an in vitro broth elution assay using high-performance liquid chromatography. The bioactivity of the bone was further determined with an agar disc diffusion and standardised tube dilution bioassay. The results indicated that the fresh-frozen femoral heads contained cefazolin. The morsellised bone released cefazolin for up to four days. The concentration of cefazolin was significantly higher in the heads from patients with osteoarthritis of the hip than in those with a fracture.Also, in bioassays the bone showed inhibitory effects against bacteria.We concluded that allografts of morsellised bone from the femoral head harvested from patients undergoing arthroplasty of the hip contained cefazolin, which had been administered pre-operatively and they exhibited inhibitory effects against bacteria in vitro.

Antibacterial activity of chloroform and ethanol extracts of black cumin seeds (Nigella sativa) against multi-drug resistant human pathogens under laboratory conditions.

Chloroform and ethanol extracts of black cumin seeds (Nigella sativa) were analyzed for antibacterial activity against five food and water borne pathogens, namely, Staphylococcus aureus, Bacillus cereus, Vibrio cholerae, Klebsiella pneumoniae, Escherichia coli, and one food spoilage bacteria Bacillus subtilis, all of which were previously found to be resistant to different antibiotics. The antibacterial activities of the extracts were determined by disc diffusion and tube dilution methods. All the bacterial strains except E. coli and K. pneumoniae, showed sensitivity to the chloroform extract as well as the bacterial strains except the K. pneumoniae showed sensitivities to ethanol extract. The minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC) of both extracts were also evaluated. Ethanol extract of black cumin was as found to be highly effective for B. subtilis (MIC value 375 µg/ml), followed by S. aureus (MIC value 1125 µg/ml). The highest concentration of extract was required for E. coli for complete inhibition of their growth. MIC value for E. coli was 3000 µg/ml. These results suggest that black cumin seeds may have potential antibacterial activity against multiple antibiotic-resistant bacteria. Key words: Black cumin, multi-drug resistant bacteria, ethanol extract, chloroform extract.

Antimicrobial and miticide activities of Eucalyptus globulus essential oils obtained from different Argentine regions

The biological activity of Eucalyptus globulus essential oils derived from plant material obtained from different geographic areas was analyzed in in vitro experiments on Paenibacillus larvae, Varroa destructor, and Apis mellifera. The physicochemical properties, composition, antimicrobial, and bioactivity of these essential oils were studied. The bioactivity against P. larvae was analyzed by means of two in vitro techniques (tube dilution and bioautography). Mite and bee lethality were estimated using a complete exposure method test with oils at different concentrations. Essential oils differed in their composition, albeit their similar physicochemical properties. The minimal inhibitory concentrations range for E. globulus essential oil lay between 600-700 µg mL–1 for Mar del Plata and 900-1,200 µg mL–1 for Valle de Conlara essential oils against all P. larvae strains. The bioautography method determined that limonene accounted for the greatest antimicrobial activity with respect to the other compounds. The complete exposure method at 24, 48, and 72 h yielded lower LC50 values for mites exposed to E. globulus essential oils from Conlara. LC50 values for acari after 72 h of treatment with E. globulus from Mar del Plata and Conlara were 47.1 and 11.7 µL capsule–1, respectively; whilst those for bees was &gt; 20 µL capsule–1 for both oils. The E. globulus essential oils tested in this study featured high efficiency against V. destructor, yet their antimicrobial activity against P. larvae proved to be lower, and innocuous to bees. The present experience promotes the use of active compounds for American fouldbrood and Varroosis management.

Screening for drug-resistantCandidayeasts with chromogenic agar

We examined the utility of agar dilution to screen yeasts for reduced susceptibility to several newer antifungal drugs including echinocandins and azoles. We compared agar dilution susceptibility screening with the Clinical and Laboratory Standards Institute (CLSI) method for Candida isolates. We added echinocandins and azoles to CHROMagar Candida medium prior to its solidification. Assessment of resistance was based on growth characteristics, wherein decreased colony size in the presence of antifungal drugs was used as an indicator of susceptibility. Clinical Candida isolates of C. albicans, C. glabrata, C. parapsilosis, C. tropicalis, C. guilliermondii, C. lusitaniae, C. rugosa and C. dubliniensis were screened for drug susceptibility. Overall, antifungal susceptibility of the yeasts to anidulafungin, caspofungin, micafungin, posaconazole and voriconazole, determined using CHROMagar agar dilution, were shown to be 96, 80, 94, 90 and 97% as accurate, respectively, as those determined by the CLSI method, i.e., within one tube dilution of CLSI MICs. Categorical errors by percentage had a broader range. Major errors noted with anidulafungin, caspofungin and micafungin were 3, 6 and 0%, respectively, while very major errors were 15, 55 and 38%, respectively. Major errors with posaconazole and voriconazole were 12 and 0%, respectively, while very major errors were 0 and 22%, respectively, compared to CLSI standards. Most of the assessment errors were found with C. glabrata and C. parapsilosis. Agar dilution screening for drug susceptibility with the current panel of antifungal drugs is rapid, accurate and effective. However, the determination of resistance or non-susceptibility in yeasts may be more problematic, and may be species dependent.

ChemInform Abstract: Synthesis and Antifungal Activities of Some New Tetrahydro-2H-1,3,5- thiadiazine-2-thiones.

A number of new 3-benzyl-5-[alpha-(substituted)carboxymethyl]- tetrahydro-2H-1,3,5-thiadiazine-2-thiones has been synthesized as prodrugs by incorporating the amine group of some amino acids into tetrahydro-2-H-1,3,5-thiadiazine-2-thione ring. The compounds have been prepared by the reactions of benzylamine with potassium hydroxide, carbon disulphide formaldehyde and various amino acids. The structures of the compounds have been elucidated by UV, IR, 1H-NMR, mass spectra and elementary analysis. The in vitro activity of these compounds against yeast-like fungi (Candida albicans, C. parapsilosis, C. pseudotropicalis, C. stellatoidea) was investigated by tube dilution method. Their minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) values were determined. All the compounds were found to be active between 3.12-12.5 micrograms/ml against the four fungi tested.

ChemInform Abstract: Syntheses and Antifungal Activities of Some 3-(2-Phenylethyl)-5- Substituted-tetrahydro-2H-1,3,5-thiadiazine-2-thiones.

Ten new 3-(2-phenethyl)-5-substituted-tetrahydro-2H-1,3,5-thiadiazine-2- thiones were synthesized by the reaction of phenylethylamine with carbon disulfide and potassium hydroxide, followed by formaldehyde and appropriate amino acids. The structures of these compounds have been confirmed by UV, IR, 1H-NMR and elementary analysis. The antifungal activities of the compounds were tested by tube dilution method against yeast-like fungi (Candida albicans, C. parapsilosis, C. stellatoidea and C. pseudotropicalis) and minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) values were determined. All compounds proved to be highly effective against yeast-like fungi (MFC range: 1.56-12.5 micrograms/ml).

Preparation and antimicrobial activity of scleraldehyde from Schizophyllum commune

The present study investigates the antimicrobial activity of oxidized schizophyllan (scleraldehyde) against Gram-positive and Gram-negative bacteria by diffusion and tube dilution analysis. Schizophyllan is a natural polysaccharide produced by fungi of the genus Schizophyllum. Periodate oxidation specifically cleaves the vicinal glycols in scleraldehyde to form their dialdehyde derivatives. The antibacterial activity exhibited by scleraldehyde was defined using various tests such as the disc diffusion assay, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). MIC and MBC values were found to be in the range of 3.0–8.0 mg/mL. Hence, the present studies establish that the scleraldehyde possesses effective antibacterial properties and can be used as a biopreservative for preservation of raw hides and skins.

Microcalorimetric investigation of the toxic action of berberine on Tetrahymena thermophila BF5

Tetrahymena thermophila (T. thermophila) BF(5) produces heat through growth and metabolism. By microcalorimetry, the power-time curves of the metabolism of T. thermophila BF(5) at 28 °C were measured and some quantitative parameters were obtained from these curves. Then the action of berberine on this microbe was investigated. Furthermore, the minimum inhibitory concentration (MIC) of berberine against T. thermophila BF(5) growth was obtained by tube dilution method. Berberine of different concentrations had various actions on T. thermophila BF(5) growth: a low concentration (25 μg/ml) of berberine began to inhibit the growth of T. thermophila BF(5) and a high concentration (450 μg/ml) of berberine completely inhibited T. thermophila BF(5) growth. The toxic action of berberine could also be expressed as half-inhibitory concentration IC(50), i.e., 50% effective in this inhibition. The value of IC(50) was 175.60 μg/ml, while the MIC of this compound against T. thermophila BF(5) was 20.76 mg/ml. Berberine has strong toxic action on T. thermophila BF(5) growth. The microcalorimetric method for the assay of toxic action is quantitative, inexpensive and versatile.

In vitro antimicrobial and antioxidant activities of the essential oil of Craniotome furcata

The aim of present study was, to investigate the essential oil of Craniotome furcata for its antimicrobial and antioxidant activities. The essential oil was obtained by steam distillation of the flowering aerial parts of C. furcata. The oil was tested for its antimicrobial activity in vitro against four Gram-positive, four Gram-negative bacteria and three fungi, by using disk diffusion and tube dilution methods. The antioxidant potential of the essential oil was investigated by two different models DPPH free radical and ABTS free radical cation scavenging. The essential oil was effective against all the tested microorganisms, with minimum inhibitory concentrations (MICs) ranged from 4.11±1.44 to 0.30±0.10 mg/ml. The oil showed antioxidant activity in DPPH free radical and ABTS free radical cation scavenging model. The results of this study revealed that the essential oil of C. furcata possesses antimicrobial and antioxidant activities.

English

&nbsp; Antimicrobial activity of aqueous, methanol and chloroform leaf extracts of&nbsp;Cissusmultistriata&nbsp;were investigated against 8 bacterial and 2 fungal test organisms, using the tube dilution and agar ditch diffusion methods. Aqueous leaf extract had no activity against both the bacterial and fungal test organisms. Both the methanol and chloroform leaf extracts inhibited all the test organisms with chloroform leaf extract showing the highest zone of inhibition against&nbsp;Escherichia coli&nbsp;(diameter 25 mm) and least against&nbsp;Staphylococcus&nbsp;aureus&nbsp; (diameter 13 mm). The methanol leaf extract was least inhibitory against&nbsp;Salmonella typhi&nbsp;(diameter 8 mm) and most inhibitory against&nbsp;S.&nbsp;aureus&nbsp;(diameter 15 mm). The methanol leaf extract of&nbsp;C. multistriata&nbsp;show more antifungal activity compared with chloroform leaf extract, with&nbsp;Candida&nbsp;albicans&nbsp;being more susceptible than&nbsp;Aspergillus&nbsp;niger&nbsp;to both methanol and chloroform leaf extracts. The minimum inhibitory concentration (MIC) of methanol leaf extract show least activity against&nbsp;Yersinia&nbsp;enterocolitica&nbsp;andPseudomonas&nbsp;aeruginosa&nbsp;(MIC = 100 mg/ml) and higher activity of MIC at 50 mg/ml against the other bacterial test organisms. The chloroform leaf extract MIC of 100 mg/ml had least activity against&nbsp;Proteus&nbsp;mirabilis&nbsp;and&nbsp;P.&nbsp;aeruginosa&nbsp;and MIC of 20 mg/ml most inhibitory against&nbsp;E. coli,&nbsp;Klebsiella&nbsp;pneumonia&nbsp;and&nbsp;S.&nbsp;typhi. The antimicrobial activity of the heated extracts persisted after exposure to various temperatures between 30oC to 121oC for 15 to 30 min. However, the extract activity decreased as the temperature increased. The killing rate of the MBC of chloroform extract on&nbsp;E. coli&nbsp;was 1 cfu/3 min while on&nbsp;S. &nbsp;typhi&nbsp;was 1 cfu/3.8 min. &nbsp; Key words:&nbsp;&nbsp;Cissus&nbsp;multistriata, antimicrobial, extract, inhibition, susceptible.

Antibacterial Activity of Cacao (Theobroma Cacao Linn.) Pulp Crude Extract Against Selected Bacterial Isolates

Cacao (Theobroma cacao Linn.), a plant with great perennial leaves and yellow or reddish flowers is reported to be antiseptic, diuretic, ecbolic (promotes labor by stimulating uterine contractions), emmenagogue (promotes or stimulates menstrual flow), and parasiticide, Cacao is a folk remedy for alopecia, burns, cough, dry lips, eyes, fever, listlessness, malaria, nephrosis, parturition, pregnancy, rheumatism, snakebite, and wounds. With its wide range of medicinal values, its activity against selected bacterial isolates will be determined in order to find alternative substances that will prevent the widespread of bacterial infection. This study used the experimental research method to determine the antibacterial activity of cacao (Theobroma cacao Linn.) pulp crude extract against selected bacterial isolates including Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853 using the paper disc diffusion method. The Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC) and the biological stability of cacao against the test microorganisms were also determined using the tube dilution method. Stability tests were also performed such as the determination of the effects of pH and temperature on the activity of cacao against bacterial isolates. Â Keywords - Cacao, Theobroma cacao, Bacterial Isolates

Measurement System for Characterization of Gas and Particle Phase of High Temperature Combustion Aerosols

A measurement system was developed to sample and analyze the particle and gas phase of high temperature combustion aerosols up to a particle aerodynamic diameter of approximately 3 mm. The rapid changes of aerosol composition and concentration caused by the inhomogeneous fuel and changing burning conditions were accommodated by a combined measurement of both gas and particle phase and a synchronous measurement of two identical systems at two different positions at the boiler. Based on works reported earlier, an air-cooled dilution probe was designed and adapted to the corrosive composition of the combustion aerosol by use of a silica glass inlet and a ceramic porous tube diluter (PTD). Directly behind the probe, the raw gas is passing a cyclone which precipitates the coarse particles > 25 μm, and is then split into a gas analysis and a particle analysis branch. The particle branch, after further dilution and cooling to ambient temperature, is split for a simultaneous analysis by an APS and a low pressure impactor (ELPI or BLPI). The whole sampling line is conditioned to 300°C until final dilution and cooling to ambient temperature. The measurement system was employed at different incineration plants between 220°C and 950°C for various experiments, e.g., time resolved concentration analysis during soot blowing cleaning routine. The mass concentration balance, including the content of the inlet, achieved a 92% match of the total slag mass balance of the investigated plant.

In Vitro Bactericidal Activities of Extracts From Ripe and Unripe Fruit of 'Noni'

AbstractIn an era of nutraceuticular research, ‘Noni’ fruit is considered as a panacea because of the profound claim on its medicinal uses in treating many diseases inclusive of infections of microbial origin. Hence, the present study was done to know the antibacterial activity of aqueous extracts from ripe and unripe fruits of ‘Noni’ Morinda citrifolia L on gastroenteritic and pyogenic bacteria. The study was done for eight gastroenteritic bacteria and six pyogenic bacteria. The estimation of antibacterial activity of the ripe fruit &amp; unripe fruit extract were carried out by serial two fold tube dilution techniques. Minimum Bactericidal Concentration of the ripe as well as unripe fruit extracts for the susceptible bacteria were estimated by Recovery plate method. Both the Unripe and ripe fruit extracts exhibited nearly equal and effective activity. As the unripe fruit is devoid of unpleasant odour, the unripe fruit is preferable over the ripe fruit extract

Inhibitory effect of Torilis anthriscus on growth of microorganisms

Abstract Antibacterial and antifungal activities of aqueous, ethanol and ethyl acetate extract of Torilis anthriscus (L.) Gmel. (Apiaceae) were tested in vitro against ten species of bacteria and five of fungi. Antimicrobial properties were determined by disk diffusion and broth tube dilution method. In the minimum inhibitory concentrations (MICs), the ethanol extract showed the highest activity, followed by the ethyl acetate extract and the aqueous extract against bacterial species, while the extracts were inactive against the tested fungi species. The most active extract was chosen to examine the effects of its combinations with commercial antibiotics by checkerboard method. The obtained results showed that the interactions between ethanol extract/streptomycin and ethanol extract/chloramphenicol were additive and indifferent against the tested human-pathogenic bacteria. Synergism and antagonism were not observed.