In vitro selective growth-inhibitory effect of 8-hydroxyquinoline on Clostridium perfringens versus Bifidobacteria in a medium containing chicken ileal digesta

Clostridium perfringens-induced necrotic enteritis is generally controlled by antibiotics. However, because of increasing antibiotic resistance, other antibacterial agents are required, preferably ones that do not affect the beneficial intestinal microbiota of the host. This study evaluated the in vitro selective growth-inhibitory effect of 8-hydroxyquinoline (8HQ) on C. perfringens vs. bifidobacteria in a medium containing chicken ileal digesta. Prior to the experiments, the minimum inhibitory concentrations of 8HQ and penicillin G were determined by broth microdilution assay. The minimum inhibitory concentration values of 8HQ for C. perfringens were 16-32 times lower than the values for bifidobacteria. Treatment of autoclaved and non-autoclaved chicken ileal digesta with 8HQ showed a selective anticlostridial effect. After incubation of C. perfringens with autoclaved ileal digesta for 3 h, all 8HQ concentrations tested (32-2048 mu g/mL) significantly reduced C. perfringens bacterial count. In contrast, the same treatment had no or only a slight effect on bifidobacteria counts. Unlike 8HQ, penicillin G did not exhibit any selectivity. Similar results were obtained after incubation for 24 h. In non-autoclaved ileal digesta, all 8HQ concentrations tested significantly reduced C. perfringens bacterial counts after incubation for 30 min and 3 h, while no effect was observed on bifidobacteria. These results suggest that 8HQ may serve as a prospective veterinary compound for use against necrotic enteritis in poultry

In vitro growth-inhibitory activity of Calophyllum inophyllum ethanol leaf extract against diarrhoea-causing bacteria

Purpose: To investigate the in vitro growth-inhibitory effect of Calophyllum inophyllum, a medicinal plant traditionally used to cure gastrointestinal disorders caused by diarrhoea-causing bacteria.Methods: The minimum inhibitory concentration (MIC) of C. inophyllum ethanol leaf extract was determined against six diarrhoea-causing bacteria, namely, Clostridium difficile infant, Clostridium perfringens, Enterococcus faecalis, Escherichia coli, Listeria monocytogenes, and Salmonella enterica. The effect of the plant extract on bacterial growth kinetics was further evaluated by slightly modified broth microdilution method.Results: The plant extract showed significant inhibitory activity against C. perfringens and L. monocytogenes (MIC = 128 μg/mL) followed by C. difficile (MIC = 512 μg/mL). Monitored growth curves also showed that the plant extract at ½ MIC inhibits bacterial growth by distinct extension of the lag phase or suppression of the whole growth rate in C. difficile and L. monocytogenes, respectively.Conclusion: These results demonstrate the significant anti-clostridial and anti-listerial activities of C. inophyllum ethanol leaf extract. Thus, the extract seems to be a promising material for the development of new antibacterial agents.Keywords: Calophyllum inophyllum, Alexandrian laurel, Intestinal infections, Antibacterial activity, Anticlostridial, Anti-listeria

The relationship between structure and in vitro antistaphylococcal effect of plant-derived stilbenes

Staphylococcus aureus is a major human pathogen that is responsible for both hospital- and community-acquired infections. Stilbenes are polyphenol compounds of plant origin known to possess a variety of pharmacological properties, such as antibacterial, antiviral, and antifungal effects. This study reports the in vitro growth-inhibitory potential of eight naturally occurring stilbenes against six standard strains and two clinical isolates of S. aureus, using a broth microdilution method, and expressing the results as minimum inhibitory concentrations (MICs). Pterostilbene (MICs = 32–128 μg/ml), piceatannol (MICs = 64–256 μg/ml), and pinostilbene (MICs = 128 μg/ml) are among the active compounds that possess the strongest activity against all microorganisms tested, followed by 3′-hydroxypterostilbene, isorhapontigenin, oxyresveratrol, and rhapontigenin with MICs 128–256 μg/ml. Resveratrol (MIC = 256 μg/ml) exhibited only weak inhibitory effect. Furthermore, structure–activity relationships were studied. Hydroxyl groups at ortho-position (B-3′ and -4′) played crucial roles for the inhibitory effect of hydroxystilbene piceatannol. Compounds with methoxy groups at ring A (3′-hydroxypterostilbene, pinostilbene, and pterostilbene) produced stronger effect against S. aureus than their analogues (isorhapontigenin and rhapontigenin) with methoxy groups at ring B. These findings provide arguments for further investigation of stilbenes as prospective leading structures for development of novel antistaphylococcal agents for topical treatment of skin infections

In vitro antimicrobial activity of plants used in traditional medicine in Gurage and Silti Zones, south central Ethiopia

Background: To overcome the escalating problems associated with infectious diseases and drug resistance, discovery of new antimicrobials is crucial. The present study aimed to carry out in vitro antimicrobial analysis of 15 medicinal plant species selected according to their traditional medicinal uses in Gurage and Silti Zones, south central Ethiopia. Methods: Ethanol extracts of various plant parts were investigated for their antimicrobial activity against 20 bacterial and one yeast strains. The minimum inhibitory concentration (MIC) was determined by broth microdilution method. Results: Asparagus africanus, Guizotia schimperi, Lippia adoensis var. adoensis and Premna schimperi were active against Candida albicans, Enterococcus faecalis and Staphylococcus aureus at a concentration of 512 mu g/ml or lower. Strong antibacterial activity (MIC >= 128 mu g/ml) was observed for G. schimperi extract against 17 resistant and sensitive Staphylococcus strains, at a concentration comparable to standard antibiotics. Moreover, this extract showed higher antibacterial activity for the test against S. aureus ATCC 33591, ATCC 33592, SA3 and SA5 strains (128-256 mu g/ml) than oxacillin (512 mu g/ml). Conclusions: The study revealed in vitro antibacterial activity of plants used in folk medicine in south central Ethiopia. The usefulness of these plants, in particular of G. schimperi, should be confirmed through further phytochemical and toxicity analyses

Toxicological Studies of Czech Beers and Their Constituents

Background: Czech beers are unique because they are brewed using specific technology at a particular latitude and for being entirely produced in the area of the Czech Republic. The purpose of this work is the evaluation of toxicological e ects of a variety of freeze-dried Czech beers, their raw materials (malts, hops and yeast) and processed-beer (wort, hopped wort and young beer). Methods: In vivo assays to evaluate the safety and protective e ects in the Drosophila melanogaster eukaryotic system, and the in vitro evaluations of chemopreventive and DNA damage activity using the HL-60 tumour human cell line were carried out. Results: The safe e ects for all the analysed substances and general protective e ects against H2O2 were shown both at the individual and genomic level in the Drosophila animal model, with some exceptions. Moreover, all the substances were able to inhibit the tumour cell growth and to induce DNA damage in the HL-60 cells at di erent levels (proapoptotic, single/double strands breaks and methylation status). Conclusions: The promising e ects shown by freeze-dried Czech beers due to their safety, protection against a toxin, chemopreventive potential and the induction of DNA damage in tumour cells, allow the proposition of Czech beer as a beverage with nutraceutic potentia

Genetic Diversity and Relatedness Among Six Ranunculus Species Unraveled by SRAP Markers

The main aim of this study was to investigate the genetic diversity and phylogenetic relationships of six Ranunculus species using SRAP markers. The genotyping of 73 Ranunculus accessions showed that 12 primer pairs generated a total number of 212 polymorphic fragments with a 99.53 % level of polymorphism. Nei’s gene diversity ranged between 0.2237 and 0.3436 with an average of 0.3001. The UPGMA method with Nei72’s similarity coefficient ranging from 0.23 to 1.11 separated 73 accessions into two distinct groups (A and B). Cluster-A included R. acris members, while cluster-B included the rest of the tested species. Cluster-B was subsequently divided into two sub-groups (I and II). Subgroup-I consisted of R. carpaticus and R. serpens subsp. nemorosus accessions, while subgroup-II included the members of R. platanifolius, R. polyanthemos, and R. repens. R. polyanthemos and R. repens were founded the most closely related species. These findings provide a brand-new understanding of the evolutionary relationships of above mentioned Ranunculus species and may be useful tools for plant breeding and conservation purposes

Fatty acids, minerals, phenolics and vitamins in the seeds of <i>Inocarpus fagifer</i>, a Pacific Island underutilized legume

Recently, Pacific nations have faced to alarming increase in prevalence of noncommunicable diseases connected with consumption of non-traditional processed food. It is believed that re-introduction of native diet may mitigate these negative trends. One of the traditional staple food of Pacific region are seeds of underutilized leguminous tree Inocarpus fagifer. Nevertheless, information on their chemical composition and nutritional properties are missing. Therefore we decided to analyze this crop for the presence of fatty acids, minerals, phenolics and vitamins. Performed analyses revealed a slightly predominating portion of unsaturated (e.g. 18:2 n-6; 18:1 n-9 and 18:3α n-3) over saturated (e.g. C18 and C16) fatty acids. Considering minerals, the substantial concentrations of copper, magnesium, manganese, potassium and zinc (19.32; 1823.21; 8.44; 23308.41 and 77.99 mg kg-1 of dry matter respectively) were recorded. Ferulic and coumaric acids were the most abundant phenolics (3.23 and 1.48 mg kg-1 of dry matter respectively), whereas flavonoids, isoflavonoids and coumestrol were also present. Regarding vitamins, niacin and riboflavin were found in respective concentrations 131.80 and 4.47 mg kg-1 of dry matter. Our findings suggest I. fagifer seeds as a prospective food source of several health-beneficial constituents which might contribute to the well-being of Pacific islanders.   The online version of this article (doi: 10.5073/JABFQ.2016.089.034) contains a supplementary file

Antibacterial Activity of Thymus vulgaris L. Essential Oil Vapours and Their GC/MS Analysis Using Solid-Phase Microextraction and Syringe Headspace Sampling Techniques

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 activity and chemical composition of its vapours. The antibacterial activity of the three T. vulgaris EOs against respiratory pathogens, including Haemophilus influenzae, Staphylococcus aureus, and Streptococcus pyogenes, was assessed in both liquid and vapour phases using the broth microdilution volatilisation (BMV) method. With the aim of optimising a protocol for the characterisation of EO vapours, their chemical profiles were determined using two headspace sampling techniques coupled with GC/MS: solid-phase microextraction (HS-SPME) and syringe headspace sampling technique (HS-GTS). All EO sample vapours exhibited antibacterial activity with minimum inhibitory concentrations (MIC) ranging from 512 to 1024 μg/mL. According to the sampling technique used, results showed a different distribution of volatile compounds. Notably, thymol was found in lower amounts in the headspace—peak percentage areas below 5.27% (HS-SPME) and 0.60% (HS-GTS)—than in EOs (max. 48.65%), suggesting that its antimicrobial effect is higher in vapour. Furthermore, both headspace sampling techniques were proved to be complementary for the analysis of EO vapours, whereas HS-SPME yielded more accurate qualitative results and HS-GTS proved a better technique for quantitative analysis

Chemical Composition of Essential Oils and Supercritical Carbon Dioxide Extracts from <i>Amomum kravanh</i>, <i>Citrus hystrix</i> and <i>Piper nigrum</i> ‘Kampot’

The fruits of Amomum kravanh, Citrus hystrix and Piper nigrum ‘Kampot’ are traditionally used as spices in Cambodian cuisine. In this study, the chemical composition of essential oils (EOs) and supercritical CO2 extracts from all three species was determined using GC-MS, with two columns of different polarity (HP-5/DB-HeavyWAX). Differences between the chemical profile of the EOs and CO2 extracts were observed for all species. The greatest difference was detected in A. kravanh EO containing mainly eucalyptol (78.8/72.6%), while the CO2 extract was rich in fatty acids (13/55.92%) and long-chain alkanes (25.55/9.54%). Furthermore, the results for the CO2 extract of this species differed, where tricosane (14.74%) and oleic acid (29.26%) were the main compounds identified when utilizing the HP-5 or DB-HeavyWAX columns, respectively. Moreover, the EO and CO2 extract from P. nigrum ‘Kampot’ fruits and the CO2 extract from C. hystrix fruit peel, containing respective amounts 34.84/39.55% (for EO) and 54.21/55.86% (for CO2 extract) of β-caryophyllene and 30.2/28.9% of β-pinene, were isolated and analyzed for the first time. Generally, these findings suggest that supercritical CO2 could potentially be used for the extraction of all three spices. Nevertheless, further research determining the most efficient extraction parameters is required before its commercial application