Antifungal and antibacterial activities of Taxus wallichiana Zucc

Current study was undertaken to evaluate the in vitro antifungal and antibacterial potential of methanol extract and subsequent fractions obtained after partitioning in organic solvents with variable polarity of the aerial parts of the tree Taxus wallichiana Zucc. Traditionally, this plant is often used in folk medicines in Pakistan for treating microbial infections. In order to rationalize the traditional use, methanol extracts of leaf, bark, and heartwood of Taxus wallichiana Zucc. were tested against six bacteria and six fungal strains using the Hole diffusion and macro-dilution methods. All extracts and fractions displayed significant antimicrobial effect. Only three fungal strains, Trichophyton longifusus, Microspoum canis, and Fusarium solani were susceptible to the extracts and fractions with MICs ranging from 0.08 to 200 mg/mL. In case of bacterial strains, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi were susceptible to the extracts and fractions with MICs ranging from 0.08 to 200 mg/mL. Comparison results were carried out using imipinem, miconazole and amphotericin B as standard antibiotics.     

In vitro antifungal and antibacterial activities of extracts of Galium tricornutum subsp. longipedunculatum

The aim of this study was to evaluate the antimicrobial activity of crude ethanolic extracts and fractions of the ariel parts and the fruits of Galium tricornutum subsp. longipedunculatum, traditionally used in northern areas of Pakistan for treating microbial infections of skin. Extracts and their fractions were tested against six bacteria and six fungal strains using the hole diffusion method and macrodilution method. All extracts and fractions possessed significant antimicrobial effect. Four fungal strains, Candida albicans, Trichophyton longifusus, Fusarium.solani and Candida glabrata, showed interesting susceptibility profiles when evaluated using the extracts and fractions with MICs ranging from 0.18 to 200 mg/mL. In case of bacterial strains, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi were significantly susceptible to the extracts and fractions with MICs ranging from 0.12 to 200 mg/mL. Comparative results were carried out using imepenem, miconazole and amphotericin B as standard antibiotics.     

In vitro antifungal and antibacterial activities of extracts of Galium tricornutum subsp. longipedunculatum

The aim of this study was to evaluate the antimicrobial activity of crude ethanolic extracts and fractions of the ariel parts and the fruits of Galium tricornutum subsp. longipedunculatum, traditionally used in northern areas of Pakistan for treating microbial infections of skin. Extracts and their fractions were tested against six bacteria and six fungal strains using the hole diffusion method and macrodilution method. All extracts and fractions possessed significant antimicrobial effect. Four fungal strains, Candida albicans, Trichophyton longifusus, Fusarium.solani and Candida glabrata, showed interesting susceptibility profiles when evaluated using the extracts and fractions with MICs ranging from 0.18 to 200 mg/mL. In case of bacterial strains, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi were significantly susceptible to the extracts and fractions with MICs ranging from 0.12 to 200 mg/mL. Comparative results were carried out using imepenem, miconazole and amphotericin B as standard antibiotics.     

Antimicrobial activity of extracts and fractions of Euphorbia lateriflora (Schum. and Thonn) on microbial isolates of the urinary tract

Euphorbia lateriflora is used in ethnomedicine for treating several conditions, including genital and urinary tract infections (UTI). Although ethnobotanical claims support its use in therapy, there is limited evidence on its effect on UTI, even though UTI remains a public health problem in Nigeria especially due to increasing antimicrobial resistance. We investigated the activity of E. lateriflora extracts and fractions on bacterial and fungal isolates from symptomatic urinary tract infections and vaginosis respectively. Qualitative phytochemical screening was conducted on dried pulverised leaves. Successive gradient extraction was carried out with the aid of a soxhlet extractor with n-Hexane, ethyl acetate and methanol respectively. Bioactivity guided fractionation was conducted on the ethyl acetate extract using Vacuum Liquid Chromatography. Antimicrobial susceptibility testing by disc diffusion was conducted on test isolates. Antimicrobial susceptibility of isolates to extracts and fractions was done using the agar well diffusion technique. Minimum Inhibitory Concentrations (MIC) and Minimum Biocidal Concentrations (MBC) were determined by agar and broth dilutions respectively. Time-kill assay of the ethyl acetate extract was conducted using the viable count technique. Phytochemicals present include saponins, tannins and flavonoids. The majority of isolates used in this study were multidrug resistant. Extracts and fractions of E. lateriflora produced appreciable zones of inhibition on both antibiotic susceptible and resistant bacteria with MICs of 6.25 mg/mL and MBC ranging from 6.25–50 mg/mL. Bactericidal activity of the ethyl acetate extract was concentration and time dependent with 100% kill at 25 mg/mL after 6 h for E. coli and 2 h for C. albicans. Euphorbia lateriflora contains phytochemicals which possess antimicrobial activity on antibiotic resistant bacteria and has potential in the development of chemotherapeutics for bacterial and fungal infections.     

Antibacterial, antifungal, insecticidal, cytotoxicity and phytotoxicity studies on Indigofera gerardiana

The antibacterial, antifungal, acute cytotoxicity, phytotoxicity and insecticidal profile of the crude extract and various fractions of Indigofera gerardiana have been studied. Six bacterial and fungal strains were used, of which Samonella typhi and Microsporum canis were the most susceptible strains with MICs 0.37 mg/mL and 0.09 mg/mL, respectively. The crude extract and the fractions showed low insecticidal activity against Sitophilus oryzae, Rhyzopertha dominica and Callosbruchus analis but no activity against Tribolium castaneum. The brine shrimp lethality assay showed absence of any measurable cytotoxicity of the crude extract and fractions, showing a good safety profile at a preliminary level. All the fractions except crude extract revealed profound and highly significant herbicidal activity against Lemna minor at the concentration of 1000 microg/mL. Indigofera gerardiana was shown by in-vitro assays to be a potential source for natural antifungal, antibacterial and herbicidal agents.     

Antibacterial,antifungal, insecticidal,cytotoxicity and phytotoxicity studies on Indigofera gerardiana

The antibacterial, antifungal, acute cytotoxicity, phytotoxicity and insecticidal profile of the crude extract and various fractions of Indigofera gerardiana have been studied. Six bacterial and fungal strains were used, of which Samonella typhi and Microsporum canis were the most susceptible strains with MICs 0.37 mg/mL and 0.09 mg/mL, respectively. The crude extract and the fractions showed low insecticidal activity against Sitophilus oryzae, Rhyzopertha dominica and Callosbruchus analis but no activity against Tribolium castaneum. The brine shrimp lethality assay showed absence of any measurable cytotoxicity of the crude extract and fractions, showing a good safety profile at a preliminary level. All the fractions except crude extract revealed profound and highly significant herbicidal activity against Lemna minor at the concentration of 1000 μg/mL. Indigofera gerardiana was shown by in-vitro assays to be a potential source for natural antifungal, antibacterial and herbicidal agents.     

Biflavones of Taxus wallichiana Zucc

Three biflavones have been isolated from the leaves of Taxus wallichiana Zucc. distributed in Himalaya Mountains in Xizang. Based on IR, UV, MS, and chemical method, they were identified as sciadopitysin (Ⅰ), ginkgetin (Ⅱ) and sequoiaflavone (Ⅲ), respectively.     

一株产紫杉醇菌的分离及其代谢产物对HeLa细胞抑制作用的研究

从东北红豆杉Taxus cuspidata的主干和侧枝树皮及皮下分离筛选得到181株纯化的内生菌株。经过摇瓶发酵培养,再用甲醇、乙酸乙酯萃取抽提,抽提产物经以标准紫杉醇为对照的薄层层析(TLC)、高效液相色谱(HPLC)、质谱(MS)分析,发现有1株菌株HD181-23能够产生紫杉醇,其紫杉醇产量为206.34μg/L。对菌株HD181-23菌落、菌丝体和孢子形态和产孢特征进行了研究,表明菌株HD181-23为葡萄孢属的种,暂定为Botrytissp.。该菌株的发酵提取纯化产物经HeLa细胞毒实验,结果显示对HeLa细胞具有较强的抑制作用。     

Evaluation of several tree species for activity against the animal fungal pathogen Aspergillus fumigatus

Aspergillus fumigatus causes severe problems in poultry production systems. Seven South African tree species were selected from the database of the Phytomedicine Programme based on its antifungal activity against the fungus Cryptococcus neoformans. The acetone leaf extracts of the selected species had minimum inhibitory concentrations (MICs) of 0.16 mg/ml and lower in the preliminary screening. The antibacterial and antifungal activities of hexane, dichloromethane, acetone and methanol extracts of the leaves were determined using a two-fold serial microdilution method against a range of commonly encountered animal pathogenic fungi (A. fumigatus, Candida albicans, C. neoformans, Microsporum canis and Sporothrix schenckii) and four nosocomial bacteria (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Pseudomonas aeruginosa). The plant species investigated were Combretum vendae (A.E. van Wyk) (Combretaceae), Commiphora harveyi (Engl.) Engl. (Burseraceae), Khaya anthotheca (Welm.) C.DC (Meliaceae), Kirkia wilmsii Engl. (Kirkiaceae), Loxostylis alata A. Spreng. ex Rchb. (Anacardiaceae), Ochna natalitia (Meisn.) Walp. (Ochnaceae) and Protorhus longifolia (Bernh.) Engl. (Anacardiaceae). All the extracts had activity against at least one of the test organisms over an incubation period of 24 or 48 h. The MIC values of the non-polar and intermediate polarity extracts of O. natalitia, K. anthotheca, C. vendae, C. harveyi, and P. longifolia had MICs as low as 0.08 mg/ml against at least one of the tested bacteria. Furthermore, the acetone extracts of L. alata, K. wilmsii, O. natalitia and C. vendae had antifungal activities with MIC values ranging from 0.04 to 0.08 mg/ml against at least one of the tested fungi. The average MIC values of the plant extracts against the different bacteria ranged from 0.17 to 2.11 mg/ml, while the range was 0.23–1.98 mg/ml for fungi. The Gram-positive bacteria (S. aureus and E. faecalis) were more susceptible to the plant extracts than the Gram-negative bacteria (E. coli and P. aeruginosa). E. faecalis was the most susceptible microbe and C. vendae extracts were the most active against nearly all the bacteria tested. The acetone extract of L. alata was the most active against fungal pathogens, with activity against at least 3 fungal organisms. L. alata was selected for further work to isolate compounds active against A. fumigatus and other fungal pathogens.     

Susceptibility of some clinical isolates of <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> to fractions from the aerial parts of <Emphasis Type="Italic">Leuzea carthamoides</Emphasis>

The antimicrobial activity of the dichloromethane extract from aerial parts of Leuzea carthamoides DC. was tested in vitro against 19 Staphylococcus aureus strains (ATCC 25923, CNCTC Mau 43/60, clinical isolates). The extract was fractionated by column chromatography on silica gel into six fractions (petroleum ether, toluene, dichloromethane, ethyl acetate, methanol and water). The minimum inhibitory concentrations (MICs) of the fractions ranged from 64 to 1024 μg/mL. An ethyl acetate fraction (EA 1) with the widest range of activity inhibited all of the strains with MIC in the range 128–512 μg/mL. This fraction exhibited potent activity against strains which showed associated resistance to oxacillin, ciprofloxacin and erythromycin.     

Taxines from the needles of Taxus wallichiana.

A taxine, 5 alpha O-(3'-dimethylamino-3'-phenylpropionyl) taxinine M (1) together with two known compounds 7-O-acetyltaxine A (2) and 2 alpha-acetoxy-2' beta-deacetylaustrospicatine (3) were isolated from the needles of the Himalayan yew, Taxus wallichiana Zucc. Their structures were elucidated on the basis of the NMR spectral data, ESI-MS/MS analysis and chemical methods. Compounds 1 and 3 showed moderate cytotoxic activity against the lung cancer cell line A549 in vitro.     

中药提取物对酵母菌抗真菌活性研究

目的探讨6味中药2种方法提取成分对酵母菌的抑菌和杀菌作用。方法采用药基琼脂稀释法,测定6味中药水提和醇提成分对白念珠菌和糠秕马拉色菌的MIC和MFC。结果对白念珠菌：水提黄连、醇提黄柏、醇提土槿皮MIC范围分别为0．625—1．25mg／mL、0．625～1．25mg/mL、0．313—0．625mg／mL;均值均为0．625mg／mL;对糠秕马拉色菌：水提和醇提黄连MIC范围分别为0．625～1．25mg／mL和1．25mg／mL,均值均为1．25mg／mL。对白念珠菌：醇提土槿皮MFC范围0．625～2．5mg/mL,均值0．625rag／mL。结论水提黄连、醇提黄柏和土槿皮对白念珠菌有较强抑菌作用,其中醇提土槿皮有较强杀菌作用。水提和醇提黄连对糠秕马拉色菌有较强抑菌作用。     

维吾尔药材红豆杉植物基原研究

从分子学角度探明维吾尔药材红豆杉的植物基原,为维吾尔药材标准化与维吾尔药产业化提供科学依据。采用试剂盒法提取红豆杉属植物及药材基因组DNA,PCR扩增ITS2片段,双向测序,应用Mega 6.0软件分析序列,计算种内及种间遗传距离,构建NJ鉴别树。红豆杉属植物ITS2序列长度为229~231bp,GC含量为59.13%~60.26%;西藏红豆杉与红豆杉及南方红豆杉种内种间K2P距离为0,与东北红豆杉、命叶红豆杉及曼地亚红豆杉种间K2P距离分别为0.012、0.013、0.015。NJ树结果表明,西藏红豆杉与红豆杉及南方红豆杉无法区分,与东北红豆杉、命叶红豆杉可区分;曼地亚红豆杉与其母本东北红豆杉聚在一起,无法区分。根据ITS2序列鉴定结果,西藏红豆杉与红豆杉、南方红豆杉可作为药材的同一基原,东北红豆杉可与曼地亚红豆杉作为同一基原,为维吾尔药材的真伪鉴别及质量标准提升提供基原鉴定依据。     

RAPID PROCEDURE FOR DETECTING CIGUATOXINS IN FISH

Flesh and viscera/gill tissues of six amberjacks (Seriola dumerilii), suspected positive for ciguatoxins, were each extracted and the toxins partially purified. Both flesh and viscera/gill of only five fish were toxic to mice exhibiting ciguatoxins (CTX) symptoms. The methanol extracts of the five fish were pooled and concentrated, the volume of flesh extract was 50.0 mL (129.4 mg toxins/mL) and viscera/gill had 25.0 mL (25.5 mg toxins/mL). Pooled extracts exhibited CTX symptoms in mice but only flesh killed mice in 6 h and the LD₅₀ was 1.72 mg toxins. The lethal potencies of the pooled flesh killed mice in 6 h and the LD₅₀ was 1.72 mg toxins. The lethal potencies of the pooled flesh was 198.17 g fish, equivalent to 58.3 mouse unit. An efficient fractionation and purification procedure was developed for the extracts using an HPTLC and silica gel 60 plate with a chromatographic solvent mixture of chloroform:methanol:water (60:35:8, v/v). The system yielded 10 fractions for flesh and 9 for viscera/gill. Scanned plates were subdivided into three equal zones, each scraped, methanol extracted and tested in mice. The 2nd zone (R_f fractions between 0.40 and 0.66) was very toxic to mice compared to 1st or 3rd zones and the mice had CTX symptoms. The scanner for this 2nd zone had a cluster of minor peaks on both sides of the major one with a sum total area of 62.47% indicating multiplicity of CTX in amber-jack fish. The major peak, at retention time of 1.48 s and a single area of 43.28%, is believed to be the main ciguatoxins present. The HPTLC is a rapid and sensitive procedure for ciguatoxins in fish flesh extracts with a detection limit of 40.0 ± 1.9 picogram toxins.     

Antibacterial activity of some salt marsh halophytes and mangrove plants against methicillin resistant Staphylococcus aureus

The antibacterial activity of aqueous and methanol extracts of leaves/shoots of five salt marsh halophytes and six mangroves was studied against methicillin resistant, clinical isolates of Staphylococcus aureus. There was a clear comparability between the salt marsh halophytes and mangroves in their antibacterial action. The mangrove plants possessed higher antibacterial potency than the salt marsh halophytes. The highest activity was recorded with the methanol extract of Excoecaria agallocha followed by the methanol extracts of Aegiceras corniculatum, Lumnitzera racemosa and Ceriops decandra. The minimum inhibitory concentration (MIC) values ranged from 0.125 to 4 mg/mL and 1 to 16 mg/mL for methanol and aqueous extracts, respectively. Further separation of active principle from the potent mangrove plant will be useful for the control of drug resistant strains of S. aureus.     

20种中药提取物对牙龈卟啉单胞菌抑制作用的体外研究

目的筛选评价20种中药提取物对牙龈卟啉单胞菌抑制作用。方法选择20种有较强抑菌作用及清热解毒作用的中药提取物,采用杯碟法进行体外抑菌试验,比较各中药对牙龈卟啉单胞菌的抑菌环直径和最低抑菌浓度(MIC)。结果水煎剂中黄连、乌梅、五味子、五倍子和黄芩的MIC为0.0488~1.5625mg/mL。油剂中丁香油、香薷油的MIC为0.3906~1.5625mg/mL。结论本实验选择的20种中药提取物中香薷油、黄连、乌梅、五味子、五倍子和黄芩的抑菌敏感度最高。     

Phytochemical characterization,antioxidant activity,and in vitro investigation of antimicrobial potential of Dittrichia viscosa L. leaf extracts against nosocomial infections

Dittrichia viscosa L., is a perennial plant belonging to the Asteraceae family, and this study was performed to investigate the chemical composition of its extract, using gas chromatography–mass spectrometry (GC–MS). Total phenol (TPC), flavonoid (TFC), and tannins contents (TTC), were quantified using colorimetric methods in two extracts (EtOH and ACE). The antioxidant activity was evaluated using DPPH scavenging, phosphomolebdenum test (TAC) and ferric reducing power assay (FRAP). The antimicrobial activity was determined against six nosocomial pathogens: Bacillus subtilis, Staphylococcus aureus, Salmonella enterica, Escherichia coli, Candida albicans, Aspergillus niger, using disc diffusion method and microdilution assay. The ACE and EtOH extracts had similar TPC: 151.18 ± 1.57 and 127.09 ± 15,81 mg GAE/ g DW. TFC & TTC recorded were also closely matched. The chemical composition revealed the presence of 18 phytochemical compounds with a total of 99.91%, where trimethylsilyl-meso-inositol (20.54%) was the major compound, followed by 5(4H)-Thebenidinone (16.80%). Both extracts showed high radical scavenging activity with an IC₅₀ equal to 12.54 ± 0.2 μg/mL for EtOH, and 7.84 ± 0.1 μg/mL for ACE in DPPH test. In the FRAP test, we recorded an EC₅₀ of 6.37 ± 0,012 mg/mL for EtOH, and 6 ± 0.022 mg/mL for ACE. The ACE presented higher antioxidant capacity (253.52 ± 2.98 mg AAE/g) compared to EtOH (189.14 ± 4,86 mg AAE/g) in the TAC assay. The higher inhibition zone was observed on B. subtilus (13 ± 0.1 mm) for EtOH, and the ACE was more effective on S. enterica (13.3 ± 0.08 mm). All the microbial strains were sensitive for both extracts, with MICs ranging from 0.93 mg/mL to 15 mg/mL.     

Fluorescence spectroscopy: a rapid tool for assessing tetracycline resistance in Bifidobacterium longum

The tetracycline uptake kinetics of 35 Bifidobacterium longum strains isolated from the human gastrointestinal tract were examined by fluorescence spectroscopy, and the suitability of the technique as a screening tool of tetracycline resistance or susceptibility was determined. The strains were first grouped into three classes based on their corresponding minimum inhibitory concentrations (MICs) of tetracycline, as established by the microdilution method: susceptible (MICs or=32 microg mL(-1)). The kinetics of tetracycline uptake for the strains in each resistance group were then analyzed over a 20 min period by fluorescence spectroscopy (absorbance wavelength 524 nm, excitation wavelength 400 nm) in a buffer system containing 100 microg mL(-1) tetracycline. Principal component analysis and factorial discriminant analysis of the results showed excellent distinction among susceptible, semi-resistant, and resistant strains. The proposed method provides a powerful and convenient means of rapidly screening tetracycline resistance in B. longum.     

<Emphasis Type="Italic">In vitro</Emphasis> susceptibility of viridans streptococci to leaf extracts of <Emphasis Type="Italic">Mangifera Indica</Emphasis>

The susceptibility of Viridans streptococci to leaf extracts of Mangifera indica was studied on 53 clinical isolates from 39 patients. All the isolates were found to be susceptible to both water and methanol extract of M. indica leaves. Minimum inhibitory concentration (MIC) of methanol extract for all isolates were <50 mg/mL and MIC of water extract for all isolates were <200 mg/mL. Methanol extract was found to have better action against Viridans streptococci than water extract.     

Lignin is linked to ethyl-carbamate formation in ume (Prunus mume) liqueur

Ethyl carbamate concentrations in oak barrel-aged ume (Prunus mume) liqueurs were measured, and possible explanations for elevated levels were examined. The average concentration was 0.30 mg/L, significantly higher than in ume liqueurs not aged in oak (0.08 mg/L). Oak powder extracts were prepared from both untoasted and toasted oak powder by extraction with aqueous ethanol, and these were used to make ume liqueurs. Relative to a no-oak control, the ethyl carbamate concentrations were 3.8 and 11 times higher in the ume liqueur made with the untoasted and toasted oak powder extracts respectively. The extracts were loaded onto a C18 column, washed with water, and eluted with methanol. The (13)C-NMR spectra for the main constituents of the methanol elution fractions were consistent with those for lignin or fragments thereof. The methanol fractions were added to ume liqueur which was stored for 3 months. Relative to a control, the ethyl carbamate concentrations in the 3-month old liqueurs were found to be 1.2 and 4.6 higher for the untoasted oak-powder and the toasted oak-powder respectively. Ethyl carbamate was formed when lignin was added to a 40% aqueous ethanol solution that contained potassium cyanide. These observations suggest that lignin or fragments thereof promote the formation of ethyl carbamate.