Average MIC Values Research Articles

Bioactivity and Resistance Risk of Fluxapyroxad, a Novel SDHI Fungicide, in Didymella bryoniae.

Gummy stem blight, caused by Didymella bryoniae, is an important disease in watermelon in China. Fluxapyroxad, a new succinate dehydrogenase inhibitor fungicide, shows strong inhibition of the mycelia growth of D. bryoniae. However, its resistance risk in D. bryoniae is unclear. In this research, the sensitivities of 60 D. bryoniae strains to fluxapyroxad were investigated. The average EC50 value and MIC values of 60 D. bryoniae strains against fluxapyroxad were 0.022 ± 0.003 μg/ml and ≤0.1 μg/ml for mycelial growth, respectively. Eight fluxapyroxad-resistant mutants with medium resistance levels were acquired from three wild-type parental strains. The mycelial growth and dry weight of mycelia of most mutants were significantly lower than those of their parental strains. However, four resistant mutants showed a similar phenotype in pathogenicity compared with their parental strains. The above results demonstrated that there was a medium resistance risk for fluxapyroxad in D. bryoniae. The cross-resistance assay showed that there was positive cross-resistance between fluxapyroxad and pydiflumetofen, thifluzamide, and boscalid, but there was no cross-resistance between fluxapyroxad and tebuconazole and mepronil. These results will contribute to evaluating the resistance risk of fluxapyroxad for managing diseases caused by D. bryoniae and further increase our understanding about the mode of action of fluxapyroxad.

Development of Anti-Acne Topical Gel Formulation Containing Herbal Extract

Systemic and topical antimicrobials are effective in the treatment of inflammatory acne vulgaris; however, widespread use of these agents is becoming increasingly associated with the emergence of resistant pathogens raising concerns about microorganism resistance and highlighting the need for alternative non-antimicrobial agents for the treatment of acne. Several multinational companies like Lakme Cosmetics Ltd., Lotus Ltd., Ayur Healthcare Ltd., Patanjali Ayurveda, etc. have started developing anti-acne products which contain multiple extracts of common Indian plants. The study aims to develop herbal gel formulations containing Bougainvillea glabra extract (aqueous, methanol, ethyl acetate, and petroleum ether) for the treatment of acne. The formulations were comprehensively evaluated for Physical evaluation, Washability, Skin irritation test, Spreadability, pH, Viscosity, Extrudability, Swelling index, and Accelerated stability studies as per the standard methods. Amongst all the formulations studied, batch F2 was found optimum for all the parameters. The extraction yield was found to be 11.21%. Bougainvillea glabra aqueous extract showed low anti-bacterial activity whereas both Bougainvillea glabra methanol extract and Bougainvillea glabra ethyl acetate extract expressed moderate anti-bacterial activity with average MIC value against E. coli and B. subtilis. In contrast to them, the petroleum ether extract of Bougainvillea glabra presented highest anti-bacterial activity, however, the activity was less pronounced than the standard drug Clindamycin. The formulations (F1-F4) represented alike results with that of the extracts and expressed lesser activity as compared to the marketed herbal product.

Propolis as Natural Product in the Oral Cavity Bacterial Infections Treatment: A Systematic Review

The up-to-date records show that approximately 10% of people worldwide suffer from periodontal diseases and about 50% of adults have some sort of moderate oral cavity disease. Therefore, oral cavity diseases represent the group of the most common chronic inflammatory diseases in the world. Thus, novel, natural, safe, and effective methods of treatment need to be found. In this study, a systematic search was performed in PubMed and Google Scholar up to March 2022 to select research evaluating the activity of propolis against bacteria responsible for oral cavity diseases. Peer-reviewed journals in English containing information about the in vitro and in vivo studies were included in our research. We excluded the records without access, written in another language than English, thesis or book chapters, and review papers, and we rejected the texts when the authors did not write about the antibacterial activity. Collected results of the inhibition zone as well as average MIC and MBC values indicated that propolis exhibits antimicrobial activity against the strains of bacteria which cause, e.g., periodontitis, gingivitis, caries, subgingival plaque, supragingival plaque, recurrent aphthous ulcers (RAS), and pharyngitis. However, before propolis can be commonly used, more research is needed to fully understand its composition and antibacterial mechanism of action.

P024 Genetic determinants of antifungal drug resistance in Fusarium solani species complex

Poster session 1, September 21, 2022, 12:30 PM - 1:30 PMDue to its challenging diagnosis and treatment, fungal keratitis is one of the most serious kinds of corneal infection. The Fusarium solani species complex is responsible for nearly half of all fungal keratitis cases. Fusarium infection is difficult to treat because of the increased antifungal resistance of Fusarium species.ObjectiveTo check the antifungal susceptibility in keratitis-causing isolates of F. solani species complex.To find the genetic determinants of resistance using whole genome sequencing.MethodologyPrior to AFST and according to CLSI, clinical isolates of Fusarium species (n = 5) were cultured on potato dextrose agar for 7 days at room temperature. Fungal spores were harvested using 0.8% NaCl and antifungal drug susceptibility testing of 6 different antifungal drugs were tested using CLSI standards broth microdilution method and minimum inhibitory concentrations were obtained. After 24 and 48 h, broth microdilution plates were manually examined. The wells for growth control were also examined. The minimum inhibitory concentration of anti-fungal drugs was the lowest dose that inhibits growth completely (compared to the growth control well). Minimal effective concentration (MEC) was also determined against antifungal drugs. Whole genome sequencing was done using Illumina Hiseqx10. Bioinformatics analysis was done using different bioinformatics tools and software (FASTQC, SPAdes, OmicsBox, AUGUSTUS, etc.).ResultsIn this study the antifungal drug susceptibility from average MIC value were found as fluconazole (512 μg/ml) > itraconazole (32 μg/ml) > amphotericin B (8 μg/ml) > natamycin (8 μg/ml) > posaconazole (2 μg/ml) > voriconazole (1 μg/ml). Fluconazole had a higher MIC value (512 g/ml) in all isolates, however, voriconazole was shown to be more sensitive, with a lower MIC range (0.25-4 g/ml). Glyoxalase/Bleomycin resistance protein, mfs—multidrug resistance transporter, fusaric acid resistance protein, efflux pump antibiotic resistance protein, and copper resistance protein were found by genome-based analysis.ConclusionAs a conclusion of this study, we observed antifungal drug resistance in Fusarium spp., which is often used to treat keratitis in patients, employing fluconazole, itraconazole, and amphotericin B. Resistance to first-line azoles was as a gene variant which contributed to antifungal drug resistance. This study using the phenotypic and genotypic characterization of drug resistance patterns will help to combat antifungal drug resistance.

LC-DAD-MS Phenolic Characterisation of Six Invasive Plant Species in Croatia and Determination of Their Antimicrobial and Cytotoxic Activity.

Invasive plants’ phytochemicals are important for their invasiveness, enabling them to spread in new environments. However, these chemicals could offer many pharmaceutical compounds or active ingredients for herbal preparations. This study provides the first LC–MS phytochemical screening of six invasive alien plant species (IAPS) in the Istria region (Croatia): Ailanthus altissima, Ambrosia artemisiifolia, Conyza canadensis, Dittrichia viscosa, Erigeron annuus, and Xanthium strumarium. The study aims to identify and quantify the phenolic content of their leaf extracts and assess their antimicrobial and cytotoxic potential. A total of 32 species-specific compounds were recorded. Neochlorogenic, chlorogenic, and 5-p-coumaroylquinic acids, quercetin-3-glucoside, and kaempferol hexoside were detected in all the tested IAPS. Hydroxycinnamic acid derivatives were the main components in all the tested IAPS, except in E. annuus, where flavanones dominated with a share of 70%. X. strumarium extract had the best activity against the tested bacteria, with an average MIC value of 0.11 mg/mL, while A. altissima and X. strumarium extracts had the best activity against the tested fungi, with an average MIC value of 0.21 mg/mL in both cases. All the plant extracts studied, except X. strumarium, were less cytotoxic than the positive control. The results provided additional information on the phytochemical properties of IAPS and their potential for use as antimicrobial agents.

Bee Venom, Honey, and Royal Jelly in the Treatment of Bacterial Infections of the Oral Cavity: A Review.

Oral diseases affect a very large number of people, and the applied pharmacological methods of treatment and/or prevention have serious side effects. Therefore, it is necessary to search for new, safer methods of treatment. Natural bee products, such as honey, royal jelly, and bee venom, can be a promising alternative in the treatment of oral cavity bacterial infections. Thus, we performed an extensive literature search to find and summarize all articles about the antibacterial activity of honey, royal jelly, and bee venom. Our analysis showed that these bee products have strong activity against the bacterial strains causing caries, periodontitis, gingivitis, pharyngitis, recurrent aphthous ulcers, supragingival, and subgingival plaque. An analysis of average MIC values showed that honey and royal jelly have the highest antimicrobial activity against Porphyromonas gingivalis and Fusobacterium nucleatum. In turn, bee venom has an antibacterial effect against Streptococcus mutans. Streptococcus sobrinus and Streptoccus pyogenes were the most resistant species to different types of honey, and royal jelly, respectively. Moreover, these products are safer in comparison to the chemical compounds used in the treatment of oral cavity bacterial infections. Since the antimicrobial activity of bee products depends on their chemical composition, more research is needed to standardize the composition of these compounds before they could be used in the treatment of oral cavity bacterial infections.

Antibiofilm activity of selected plant essential oils from the Lamiaceae family against Candida albicans clinical isolates.

The virulence of Candida albicans is conditioned by several virulence factors, one of which is the formation of biofilm which reduces the sensitivity of the yeast to conventional antimycotics. This study determines the antifungal and antibiofilm activity of five essential oils (EOs) of the Lamiaceae family: Salvia officinalis, Thymus vulgaris, Rosmarinus officinalis, Origanum vulgare, and Hyssopus officinalis. In the preliminary research, the antifungal effect of eachof the EOs was tested in the concentration range of 200-0.4 mg/mL on planktonic Candida albicans (C. albicans) cells. A total of 13 C. albicans clinical isolates and one reference strain were evaluated on biofilm formation. Nine isolates (69.2%) showed weak biofilm production and four strains (30.8%) were detected as moderate biofilm producers. The EOs of Thymus vulgaris and Origanum vulgare were seen as effective antifungal agents on planktonic cells with the MIC 0.4 mg/mL. The highest average MIC values were recorded in Salvia officinalis EO (24.0 and 14.8 mg/mL). All isolates were used to determine EOs efficacy on the inhibition of adherence phase and biofilm formation. The biofilm production of C. albicans after exposition by EOs was quantitatively examined by crystal violet dye. The most effective for adherence phase and biofilm formation were EOs of Origanum vulgare (0.1 mg/mL and 0.3 mg/mL) and Thymus vulgaris (0.1 mg/mL and 0.4 mg/mL). The obtained results show that EOs of Thymus vulgaris and Origanum vulgare are potential agents for antifungal treatment or prophylaxis by reducing the resistance of pathogen.

Efficacy of Phytochemical Constituents of Castor Essential oil Towards the Mucor-Mycotic Mold Cunninghamella Bertholletiae

The aim of this experiment is to study the efficacy of phytochemical constituents of Castor essential oil towards the mucor-mycotic mold Cunninghamella bertholletiae.The standard chemical analytical methods were used for the rapid study of the phytochemical constituents responsible for the antimicrobial efficacy of the procured castor essential oil. The standard antimicrobial assay technique employed to study the comparative values of the efficacy of the procured castor essential oil with that of the standard antifungal chemical agents against the clinical isolates obtained from the immune suppressed patients samples of Cunninghamella bertholletia mold mucor-mycotic infections. The best susceptibility values recorded in the standard antifungal agents against the clinical isolates of Cunninghamella bertholletiae was with Amphotericin B showing the average zone of inhibition diameter of 20.66 mm with the average MIC value of, 1.66 (µ/ml) but the antimicrobial assay results for the Castor essential oil showed better values with an average disc diffusion of 22.44mm zone of inhibition diameter with average MIC value of 1.72 µ/ml .This study has shown that the phytochemical compounds present in the Castor essential oil proves to be more an effective alternative antifungal substance towards the clinical isolates of Cunninghamella bertholletiae.

AB0081 THE ROLE OF LOCAL BISPHOSPHONATES IN THE PRESERVATION OF THE BMD IN THE ZONE OF SURGICAL BONE DEFECT (ANIMAL STUDIES)

Background:One of the reasons for failures in Arthroplasty is the preservation in the postoperative period in the bone adjacent to the implant of the prevalence of resorption over bone formation. The possibility of inhibition of resorption by bisphosphonates, including their local use in the composition of the biocomposite material, aggravates the situation due to the simultaneous oppression of bone formation. A low level of remodeling in these cases leads to a further loss of bone mass in the intervention zone.Objectives:To evaluate in the experiment the effect of bisphosphonates in the biocomposite material on the bone mass both in the surgical intervention zone and in the segment as a whole.Methods:The study was conducted as a comparison with the control. 60 females of white non-linear rats, body weight 130-150 g. were divided into 6 groups. In 3 groups, the defect of the tibia was filled with a biocomposite material in the form of a gel (patent No. 2325170) connected to various bisphosphonates Ibandronic acid (Bonviva), zoledronic acid (Aklasta), alendronate sodium (Fosamax) was used in conjunction with a non-demineralized lyophilized bone implant. Groups, the defect was filled with a non-demineralized lyophilized bone implant with biocomposite material without bisphosphonate, in the second control group, non-demineralized lyophils th e bone implants without biocomposite matreiala in tretey- defect is not filled.Assessment of bone mineral density (BMD) in the intervention area and in the segment as a whole was performed using X-ray densitometry (Hologic, Small Animals Program Performing and Analyzing Small Animal Studies). Results Comparison (simple dispersion analysis) of the MIC of all groups using bisphosphonates on the one hand, with the MIC of all control groups on the other hand, revealed significant differences (p <0.002).Results:The analysis, using the paired t-test, the average MIC values in the combined group using bisphosphonates and the pooled control group, confirmed that the BMD in the zone of intervention in the bisphosphonate group was significantly higher than in the control: 0.320 ± 0.008 g / cm2, respectively, versus 0.285 ± 0.019 g / cm2 (p = 0.002). If the group was excluded from the analysis, where the defect was not filled, the tendency to differences remained: 0.320 ± 0.008 g / cm2 vs. 0.308 ± 0.002 g / cm2 (p = 0.11).Mean BMDs of the whole segment with the use of bisphosphonates also proved to be significantly higher than in the control, both with the inclusion in the analysis of the group without replacement of the defect, and with its exception. Thus, when all control groups were included in the analysis, the mean MIC values in the group with bisphosphonates were 0.30 ± 0.01 g / cm2 vs. 0.272 ± 0.12 g / cm2 (p <0.001). When excluding from the analysis of the group without replacement of the defect, the MIC values were respectively: 0.307 ± 0.01 g / cm2 versus 0.285 ± 0.01 g / cm2 (p = 0.01).Conclusion:Relative to the control, an increase in BMD in the group using bisphosphonates excludes the possibility of their negative impact on the process of bone formation. The marked positive bone balance confirms the ability of bisphosphonates to maintain the remodeling mechanism at the physiological level.

Antimicrobial effects of different extracts of medicinally used green leafy vegetables collected from local market of Dhaka, Bangladesh

The present study was carried out to determine the antimicrobial efficacy of green leafy vegetable samples which are traditionally used as medicinal herbs. Therefore, three samples each of Neem (Azadirachta indica, leaves), Ivy Gourd (Coccinia grandis, leaves), Water Spinach (Ipomoea aquatica, leaves) and Skunkvine (Paederia foetida, leaves) were collected and subjected to microbiological analysis, and agar well diffusion and microdilution assays to check antimicrobial activity. The samples contained total viable bacteria and fungi up to 107 and 105 CFU/g, respectively. Staphylococcus spp., Klebsiella spp. and Pseudomonas spp. were recovered in all the samples. All the samples showed potential antibacterial activity against most of the tested bacteria, especially their ethanolic and methanolic extracts. Although, crude and hot water extracts almost had no effect on the bacterial growth. The MIC value of the samples was found in a range of 3 mg/mL to 12 mg/mL and the average MIC value was recorded to be 6 mg/mL. Overall, the findings of the present study justified the therapeutic potential of the tested green leafy vegetable samples.

Exploring the Effect of the Composition of Three Different Oregano Essential Oils on the Growth of Multidrug-Resistant Cystic Fibrosis Pseudomonas aeruginosa Strains

Oregano essential oils (EOs) could represent interesting therapeutic strategies to treat multidrug-resistant (MDR) pathogens as Pseudomonas aeruginosa, responsible for respiratory infections in cystic fibrosis (CF) patients. There could be a great variability in EOs composition when extracted from different plant species. The aim of this study was to chemically characterize and to test EOs, extracted from Origanum compactum, Origanum vulgare and Origanum vulgare var. hirtum, for in vitro antimicrobial activity against a panel of twenty MDR P. aeruginosa strains isolated from CF patients. EOs main components were carvacrol (71.8-73.8-47.1%), thymol (1.6-2.3-21.5%), p-cymene (11.6-7.4-10.8%) and γ-terpinene (1.7-3.1-8.4%). In general, the EOs showed inhibitory activity even at low concentration: 0.5% (v/v) OvEO and OhEO were able to inhibit the 80% of P. aeruginosa strains. Furthermore, the three EOs killed at least 75% of the strains at concentrations lower than 1% (v/v). Average MIC and MBC values were not significantly different. Similar levels of OEOs antimicrobial activities might be related to the fact that the main chemical class (i.e. carvacrol/thymol) is represented in quite similar percentages. Hence, the results of the present study shed light on a carvacrol/thymol-rich EO with a well-represented monoterpene hydrocarbons class as promising standardized antimicrobial herbal product.

Plants used to treat skin diseases in northern Maputaland, South Africa: antimicrobial activity and in vitro permeability studies

Context: Ethnobotanical claims of medicinal plants used in northern Maputaland are limited.Objectives To establish scientific validity for a selection of the plants used in Maputaland to treat skin diseases.Materials and methods: Aqueous and dichloromethane–methanol extracts were prepared from 37 plant species which were collected from four rural communities in Maputaland. Antimicrobial screening was performed on extracts against 12 dermatological relevant pathogens using the micro-titre plate dilution assay. Their combined effect was evaluated by determining the sum of the fractional inhibitory concentrations (ΣFICs). Chemical analysis was undertaken using reverse-phase high-performance liquid chromatography (RP-HPLC) and investigated in vitro across excised intact porcine skin using the ILC07 automated system.Results: The organic extract of Garcinia livingstonei T. Anderson (Clusiaceae) was found to be the most antimicrobially active displaying an average broad-spectrum MIC value of 270 μg/mL. The combination of Sclerocarya birrea (A. Rich.) Hotsch. (Anacardaceae) with Syzygium cordatum Hochst. ex C. Krauss (Myrtaceae) displayed synergistic effects. The four antimicrobially active organic extracts were found to possess mainly anthraquinones, flavonoids, tannins and saponins. The organic extracts of Kigelia africana (Lam.) Benth. (Bignoniaceae) and S. cordatum were found to have more compounds capable of permeating intact skin after 10 min of exposure.Conclusion: More than 80% of the organic extracts tested displayed a correlation between the antimicrobial efficacy and the reported traditional uses of the plants. Furthermore, the traditional use of topically applied plant preparations is validated as some compounds from the active plants are capable of permeating the skin in vitro.

Sensitivity of clinical isolates of Candida to essential oils from Burseraceae family.

The aim of this study was to investigate the chemical composition and antifungal activity of four commercial essential oils from the Burseraceae family - two Boswellia carterii Flueck oils, Canarium luzonicum (Blume) A. Gray oil, and Commiphora myrrha (Nees) Engl oil, against most common Candida spp. recovered from the human oral cavity. The essential oil samples were analyzed by GC-FID and GC/MS. The analysis showed that major essential oils' components were α-pinene (23.04 % and 31.84 %), limonene (45.62 %) and curzerene (34.65 %), respectively. Minimum inhibitory (MIC) and minimum fungicidal (MFC) concentrations were determined using a microdilution standardized technique. All tested Candida spp. clinical isolates and ATCC strains showed susceptibility to tested essential oils in a dose dependent manner. The strongest antifungal activity was shown by essential oil of B. carterii, sample 2; the average MIC values ranged from 1.25 to 1.34 mg/ml, and MFC values ranged from 2.50 to 3.75 mg/ml, depending on the fungus. This study supports the possible use of essential oils from the Bursecaceae family in reduction and elimination of Candida spp. populations in patients with oral cavity fungal infections.

Antifungal and Antibacterial Activity of Extracts and Alkaloids of Selected Amaryllidaceae Species

Alkaloidal extracts of six selected species of Amaryllidaceae were studied with respect to their antibacterial and anti-yeast activity and their alkaloidal fingerprint. Twenty-five alkaloids were determined by GC/MS, and sixteen of them identified from their mass spectra, retention times and retention indexes. In the antimicrobial assay, Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus were used, along with isolates of the human pathogenic yeasts Candida albicans, C. glabrata, C. dubliniensis and Lodderomyces elongiosporus. The six extracts, together with 19 Amaryllidaceae alkaloids isolated in our laboratory, showed almost no inhibitory activity against the bacteria tested. However, promising anti-yeast properties were detected; the most potent activity was shown by lycorine, which inhibited C. dubliniensis with a MIC of 32 µg/mL, C. albicans and L. elongiosporus, both with MICs of 64 µg/mL, followed by caranine inhibiting C. dubliniensis with a MIC of 128 µg/mL. Among the alkaloidal extracts, Narcissus jonquilla cv. Baby Moon showed the most potent anti-yeast activity, with minimal and average MIC values of 128 and 192 µg/mL, respectively, followed by Leucojum aestivum, Narcissus poeticus var. recurvus and N. canaliculatus (average MICs 256, 267 and 299 µg/mL, respectively). The lowest MIC value among extracts was obtained for N. canaliculatus against L. elongiosporus (MIC 64 µg/mL).

PCR-RFLP detection of point mutations A2143G and A2142G in 23S rRNA gene conferring resistance to clarithromycin in Helicobacter pylori strains.

The occurrence of clarithromycin resistance among Helicobacter pylori strains is a major cause of the treatment failure. Resistance to this drug is conferred by point mutations in 23S rRNA gene and the most prevalent mutations are A2143G and A2142G. The aim of the study was to evaluate the occurrence of A2143G and A2142G mutations in a group of H. pylori strains resistant to clarithromycin. The study included 21 clarithromycin-resistant H. pylori strains collected between 2006 and 2009 in southern Poland. Resistance to clarithromycin was quantitatively tested with the E-test to determine the minimal inhibitory concentration (MIC value). The point mutations of H. pylori isolates were detected by PCR followed by RFLP analysis. The MIC values for clarithromycin for the analyzed strains ranged from 1.5 mg/L to 64 mg/L. Nine H. pylori strains exhibited A2143G mutation and A2142G mutation was found in 9 isolates as well. The results of RFLP analysis of 3 clarithromycin-resistant strains were negative for both mutations. The average MIC values for A2143G and A2142G mutants were 6 and 30 mg/L, respectively. Frequencies of A2143G and A2142G mutations were the same in all isolates tested. Strains with A2143G mutation exhibited lower MIC values than A2142G mutants. Application of PCR-RFLP method for detection of clarithromycin resistance allows for better and more efficient management of H. pylori infections.

Clerodendrumic Acid, a New Triterpenoid from Clerodendrum glabrum (Verbenaceae), and Antimicrobial Activities of Fractions and Constituents

AbstractOne new triterpenoid, (3β,11α,19β)‐3‐(butanoyloxy)‐11‐hydroxytaraxast‐20(30)‐ene‐23,28‐dioic acid (clerodendrumic acid; 1) was isolated from the hexane extract of the leaves of Clerodendrum glabrum var. glabrum along with heptadecanoic acid (2). The structure of the new compound was elucidated by interpretation of its NMR (1D and 2D), MS, and IR data. Combined fractions C and D from the column chromatography of the hexane extract exhibited significant antifungal activities (average MIC of 0.10 mg/ml) against Candida albicans and Cryptococcus neoformans. C. albicans was relatively resistant to clerodendrumic acid (1; MIC 125 μg/ml) and was resistant to heptadecanoic acid (2; MIC 188 μg/ml). Both compounds had low antibacterial activities against two Gram‐positive and two Gram‐negative bacteria with average MIC values of 157 and 172 μg/ml, respectively. Compounds 1 and 2 were relatively nontoxic against monkey kidney Vero cells in vitro with IC50 values of 202.6 and 108.4 μg/ml, respectively.

In vitro antigonococcal activity of Coscinium fenestratum stem extract

Ethnopharmacological relevance Gonorrhea is a sexually transmitted disease (STD), which originates from bacteria, Neisseria gonorrhoeae. It is still one of the major health problems worldwide in both men and women. Many medicinal plants have been recorded in Thai folk medicine for relieving STD but there is no scientific report of these plants for antigonococcal activity. Aim of the study This study was conducted to evaluate antigonococcal activity of 22 Thai medicinal plants selected from the plants popularly used in Thai folk medicine for treatment of gonorrhea. Materials and methods This study was performed by disc diffusion and agar dilution methods against Neisseria gonorrhoeae. Active compound was investigated by bioautographic assay. Results Among the selected plants, Coscinium fenestratum (Gaertn.) Colebr. extract showed the most effective activity against Neisseria gonorrhoeae ATCC 49226 with MIC value of 47.39 μg/ml. Bioautographic assay revealed that berberine was the active compound of Coscinium fenestratum against Neisseria gonorrhoeae. The average MIC values of purified berberine against Neisseria gonorrhoeae ATCC 49226 and 11 clinical isolates were 13.51 and 17.66 μg/ml, respectively while average MIC value of the crude extract of Coscinium fenestratum against all clinical isolates was about 56.39 μg/ml. There was no acute toxicity detected at the dose of 5 g of Coscinium fenestratum crude extract per kilogram. Conclusions These results provide theoretical support for ethnopharmacological relevance of antigonococcal activity of Coscinium fenestratum and its active compound.

In vitro evaluation of the antifungal activity of Sclerocarya birrea extracts against pathogenic yeasts

The antifungal activity of Sclerocarya birrea which is used in South African traditional medicine for the treatment of skin diseases was evaluated against three yeasts; Candida parapsilosis, Cryptococcus albidus and Rhodoturula mucilaginosa. Barks of S. birrea were extracted with hexane, dichloromethane (DCM), chloroform, ethyl acetate, acetone, methanol and ethanol and tested against these three yeasts. The antifungal assay was performed by the microdilution technique and bioautography. Thin layer chromatography was used to analyze the phytocompounds of the extracts as well as to assay the plant for antioxidant compounds. More compounds with antioxidant activity were observed in polar separation system, ethyl cetate:methanol:water (EMW). All test organisms were resistant against all non-polar extracts. Acetone, ethanol and methanol S. birrea extracts had average MIC values of 0.39, 0.22 and 0.27 mg/ml, respectively. C. albidus was the most sensitive organism with an average MIC value of 0.17 mg/ml. Average total activity was highest for methanol (387 ml/g) followed by ethanol (363 ml/g) and acetone (299 ml/g) bark extracts. Acetone and methanolic bark extracts were more active in EMW system at Rf values of 0.07, 0.32 and 0.70 against C. parapsilosis. The results showed that the plant could be further explored for possible antifungal agents and provides preliminary scientific validation of the traditional medicinal use of this plant.

Synthesis of Dihydropyran Subunit of (+)-Sorangicin A Using RCM Reaction

The macrolide (+)-sorangicin A (1), isolated by Hofle and co-workers from the gliding myxobacterium Sorangium cellulosum, has highly effective biological activity against a broad panel of both Gram-positive and Gram-negative bacteria, displaying average MIC values of 10 ng/mL and 10 μg/mL, respectively. The mechanism of action has been shown to be the inhibition of RNA polymerase in both Escherichia coli and Staphylococcus aureus. In addition, sorangicin A is active in vitro against several cancer cell lines. This fact motivated us to be interested in the synthesis toward sorangicin A. One of key steps in our synthetic plan is the successful preparation of dihydropyran. There have been numerous synthetic efforts reported in the literature. In general, dihydropyran units has been elegantly constructed by reactions such as Claisen rearrangement, Ferriertype reaction, radical, hetero Diels-Alder cyclizations and a few other reactions. We sought new and concise synthetic methods for this ring. Herein, we describe two new and simple preparations of the dihydropyran moiety based on olefinic ring-closing metathesis (RCM) reaction employing Grubbs catalyst. We planned two pathways according to retrosynthetic concept included formation of the C11-C12 double bond by RCM reaction (Scheme 1). First route A is employing oxazolidinone to yield the syn-aldol product. This methodology was implemented by Crimmins and She. The second route B is utilizing enantiospecific rhodium-catalyzed allylic etherification with the copper(I) alkoxide as a nucleophile. In the first reaction pathway A according to our synthetic plan (Scheme 2), the alcohol 5 was reacted with sodium salt of bromoacetic acid in refluxing THF to give glycolic acid, which was converted to its mixed pivalic anhydride and treated with (R)-3-lithio-4-benzyl-2-oxazolidinone to generate the N-glycolyloxazolidinone 7 in 81% yield over two steps. The addition reaction of 7 with acrolein furnished hydroxy compound 8 in good yield and high diastereoselectivity (73%, 93:7 dr by H NMR analysis). Protection of the resulting alcohol 8 as its TBS ether 3 and reductive removal of the chiral auxiliary group afforded primary alcohol 9 in 83% yield. The olefinic RCM reaction in the presence of Grubbs’ catalyst in CH2Cl2 transformed 9 to the desired dihydropyran compound 2. In the more convenient second synthetic approach B to dihydropyran 2 (Scheme 3), the stereospecificity in the reaction of rhodium-catalyzed allylic etherification could be maintained by suppressing the rate of isomerization. The copper(I) alkoxide as a nucleophile served to promote the etherification. Thus, this reaction allows for net retention of the absolute configuration through the alkylation of a rhodium-enyl complex. We began the second pathway with an aldol addition of chiral oxazolidinone 10 to acrolein to give syn-aldol adduct (84%, 92:8 dr by H NMR analysis). Protection of the resulting secondary hydroxy group as its TBS ether 11 and reductive removal of the chiral auxiliary group afforded an intermediate primary alcohol in 92% yield. Then, silylation of the hydroxy group as the TBS ether and removal of the MPM group yielded the alcohol 12 in 93% yield. Treatment of the allylic carbonate 13 with the trimethylphosphitemodified Wilkinson catalyst and the copper(I) alkoxide derived from the alkenyl alcohol 12, afforded the diene 4 in 67% yield with excellent diastereoselectivity (98:2 dr by H NMR analysis). The high selectivity observed can be explained using the reported proposed mechanism. Desilylation of the primary hydroxyl group with CSA gave alcohol 14 in 76% isolated yield. Finally, The RCM reaction was

Comparison of methods for antimicrobial susceptibility testing and MIC values for pleuromutilin drugs for Brachyspira hyodysenteriae isolated in Germany

In Germany treatment of swine dysentery is hampered by Brachyspira hyodysenteriae strains showing elevated MIC values to the few antibiotics licensed. Therefore, susceptibility testing of clinical isolates is an important service to the swine practitioner. This study compares the established agar dilution procedure for antimicrobial susceptibility testing of this fastidious anaerobe to the broth microdilution test newly developed [Anim. Health Res. 2 (2001) 59; Vet. Microbiol. 84 (2002) 123; J. Clin. Microbiol. 41 (2003) 2596]. A total of 221 isolates were examined twice with either test procedure using tiamulin and valnemulin as antibiotics. Both methods gave reproducible results, and the MIC values for the reference strains B. hyodysenteriae B204 and Staphylococcus aureus ATCC 29213 corresponded to previously published data. However, the results for individual strains differed significantly for both tests ( P < 0.001) with MIC values being on average one dilution step lower in the broth dilution method. The 221 strains used for comparing test procedures were isolated between 1989 and 2001. An additional 102 strains isolated in 2002 were tested only with the broth dilution procedure. A significant rise in the average MIC value for both pleuromutilins could be demonstrated when comparing earlier isolates to those from 2000 to 2001 ( P < 0.05), while in 2002 the average MIC significantly decreased when compared to the value in 2000 ( P < 0.05). However, strains with MIC values for tiamulin as high as 8 μg/ml (broth dilution) could still be isolated.