Evaluation of antimicrobial efficacy of flavonoids of withania somnifera L

In the present study antimicrobial activity of Withania somnifera L. Dunal (Solanaceae) has been evaluated against selected pathogens. Free and bound flavonoids of different parts (root, stem, leaf and fruit) of W. somnifera have been studied for their antimicrobial activity using disc diffusion assay against three Gram negative bacteria (Escherichia coli MTCC 46, Proteus mirabilis MTCC 3310 and Pseudomonas aeruginosa MTCC 1934), one Gram positive bacteria (Staphylococcus aureus MTCC 3160) and three fungi (Candida albicans MTCC 183, Aspergillus flavus MTCC 277 and Aspergillus niger MTCC 282). Minimum inhibitory concentration (MIC) of the extracts was evaluated through micro broth dilution method, while minimum bactericidal/fungicidal concentration was determined by sub culturing the relevant samples. C. albicans was found to be the most susceptible organism followed by S. aureus, P. mirabilis, E. coli and P. aeruginosa. Out of the tested organisms, A flavus and A. niger were observed to be resistant as none of the tested extracts showed activity against them. Total activity (TA) of extracts (ml/g) against each sensitive pathogens was also evaluated. Bound flavonoid extract of root showed best activity against C. albicans (IZ 30, MIC 0.039, MFC 0.039, respectively). However all the microorganisms were found to be sensitive against the extracts tested. Total activity of bound flavonoid extract of root was found to be same for E.coli, P. mirabilis, S. aureus and C. albicans (153.84 ml/g). Results of the present study reveal that extracts of W. somnifera showing great antimicrobial potential against test microorganisms may be exploited for future antimicrobial drugs.     

黄酮类成分在蜂蜜抗菌性中的效能研究

目的 为了解蜂蜜的抗菌性与其黄酮类成分含量的相关性。方法 采用UV测定蜂蜜中的总黄酮含量;采用UPLC-MS/MS,以12种黄酮类成分为对照品对蜂蜜中的黄酮类成分及其含量进行测定;以平皿法检测蜂蜜和81%糖溶液在不同质量分数下的抗菌性能。结果 7个市售蜂蜜均含有黄酮类物质,但因蜜源植物不同,总黄酮含量差异显著,其中以枣花蜜（千红）含量最高（87.138 μg·g^-1）,玫瑰花蜜（青海）含量最低（28.649 μg·g^-1）,12种黄酮类成分在各蜂蜜中的含量各不相同,其中以白杨素在总黄酮中含量占比最高,最高占比达85.1%,其次为生松素、山奈酚和芹菜素;供试蜂蜜和81%糖溶液均表现出一定的抗菌性,但抗菌效果因蜂蜜品种而异,其中总黄酮含量越高的蜂蜜,其抗菌性表现也较好,81%糖溶液的高渗性对黑曲霉和白色念珠菌不起作用。结论 黄酮类组分含量与蜂蜜的抗菌性呈一定程度的正相关,蜂蜜的抗菌性能可用于进一步鉴别蜂蜜的真假。     

Antibacterial Activity of Barringtonia acutangula against Selected Urinary Tract Pathogens

Barringtonia acutangula (L.) Gaertn belonging to family Barringtoniaceae was investigated to evaluate In vitro antibacterial activity of aqueous, ethanolic, petroleum ether and chloroform extracts against Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Enterococcus faecalis and Escherichia coli the major urinary tract infection causing pathogens were tested by disc diffusion assay method and the minimum inhibitory concentration was evaluated. Ethanol (95%) extract exhibited broader spectrum of inhibition followed by chloroform, petroleum ether and aqueous extracts against the urinary tract pathogens under test. An attempt has been made to compare the activity of extracts with standard antibiotics against selected urinary tract infection causing pathogens.     

Antimicrobial activity of essential oil and various extracts of fruits of greater cardamom

Greater cardamom (Amomum subulatum Roxb. Zingiberaceae) commonly known as "Bari ilaichi" is a well known plant used in Ayurvedic and Unani medicine. It has been used for the treatment of various diseases and disorders like gastric ulcer. Therefore antimicrobial activity of petroleum ether, methanol and aqueous extracts from leaves and roots, essential oil and isolated vasicine from A. vasica were tested against various microorganisms. Antimicrobial activity was done by disc diffusion method. The zone of inhibition observed was compared with that of standard drugs, ciprofloxacin and fluconazole. Minimum inhibitory concentration was determined against microorganisms used in the study. The results of this study reveal that methanol extract of fruits of A. subulatum shows remarkable antimicrobial activity against Escherichia coli whereas in case of other microorganisms used it was found inferior to the standard drug used. Methanol extract of rind showed good antimicrobial activity against Staphylococcus aureus. It was found that the essential oil isolated was effective against majority of microorganisms used viz. Bacillus pumilus, Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Saccharomyces cerevisiae.     

Triterpenoids from Psidium guajava with Biocidal Activity

In continuation of our studies on the phytochemical investigation of medicinal plants available in the foothills of Darjeeling and Teri, we report herein the isolation of two triterpenoids betulinic acid and lupeol from the leaf extract of Psidium guajava and their potential antimicrobial and phytotoxic activities. All the structures of the isolated compounds were confirmed by spectral (IR, NMR) analysis and by comparison with the literature reports.     

藏药二十五味鬼臼丸对金黄色葡萄球菌的抑菌作用及机制研究

目的 研究藏药二十五味鬼臼丸对金黄色葡萄球菌的抑菌作用,初步探讨相关抑菌机制。方法 采用琼脂平板打孔法,测定二十五味鬼臼丸（50、100、200mg·mL^-1）对金黄色葡萄球菌的抑菌圈大小。通过微量肉汤稀释法,测定最小抑菌浓度（MIC）。调整肉汤培养基中的二十五味鬼臼丸浓度为0.5MIC、1.0MIC和2.0MIC,分别加入1.0×10⁸CFU·mL^-1菌悬液,以不含药液而含菌量相同的培养基作为对照组,在37℃、120r·min^-1恒温培养箱中振荡培养,每小时取样,用紫外可见分光光度计在600nm处测定吸光度（A₆₀₀）值,绘制细菌的生长曲线;每2小时取样,离心取上清液,试剂盒法测定碱性磷酸酶（AKP）活性;每小时取样,离心取上清液,用紫外可见分光光度计在260nm处测定A₂₆₀值,以A₂₆₀值表示DNA/RNA大分子相对量;每小时取样,离心取上清液,加入考马斯亮蓝G250溶液,于595nm处测定A₅₉₅值,检测胞外可溶性蛋白含量;培养8h后,离心留沉淀,进行SDS-PAGE电泳,检测菌体蛋白含量。结果 二十五味鬼臼丸50、100、200mg·mL^-1对金黄色葡萄球菌的抑菌圈直径分别为（12.33±0.75）、（16.33±0.41）、（19.17±0.68）mm;对金黄色葡萄球菌的MIC为100mg·mL^-1;与对照组相比,二十五味鬼臼丸组的金黄色葡萄球菌生长显著减缓（P＜0.05）,胞外的AKP活性显著升高（P＜0.05）,胞外DNA/RNA大分子相对量显著升高（P＜0.01）,胞外可溶性蛋白含量显著升高（P＜0.01）,菌体总蛋白表达量明显减少。结论 二十五味鬼臼丸对金黄色葡萄球菌具有抑菌作用,其抗菌作用可能与致细菌细胞壁、细胞膜结构破损,且对菌体蛋白具有一定抑制作用有关。     

Determination of anthelmintic activity of the leaf and bark extract of tamarindus indica linn

The aim of the present study was to evaluate the anthelmintic activity of ethanolic and aqueous extract of leaves and bark of Tamarindus indica Linn using Pheretima posthuma and Tubifex tubifex as test worms. The time of paralysis and time of death were studied and the activity was compared with piperazine citrate as reference standard. The alcohol and aqueous extract of bark of Tamarindus indica exhibited significant anthelmintic activity as evidenced by decreased paralyzing time and death time. The results thus support the use of Tamarindus indica as an anthelmintic agent.     

Antioxidant and antilipid peroxidation potential of supercritical fluid extract and ethanol extract of leaves of vitex negundo linn

Supercritical fluid extract and ethanol extract of Vitex negundo Linn. were subjected to the chromatographic evaluation for identification of their constituents. Free radical scavenging activity of both extracts was studied by subjecting them to DPPH assay. IC(50) values of ethanol and supercritical fluid extract of Vitex negundo indicate that ethanol extract has stronger reducing potential and ability to scavenge free radicals as compared to the supercritical fluid extract. The in vivo effect of extracts on lipid peroxidation was studied using ethanol induced oxidative stress model in rat. Ingestion of extracts for 14 days exhibited significant reduction in plasma MDA level of stressed animals. Ethanol extract exhibited higher in vivo antilipid peroxidation potential as compared to supercritical fluid extract which correlated well with radical scavenging potential of extract.     

Thiazolidione derivatives targeting the histidine kinase YycG are effective against both planktonic and biofilm-associated Staphylococcus epidermidis

Aim:

To evaluate the efficacies of six derivatives of Compound 2, a novel YycG histidine kinase inhibitor with the thiazolidione core structure in the treatment of medical device-related biofilm infections.

Methods:

The minimal inhibitory concentration (MIC) of the derivatives was determined using the macrodilution broth method, and the minimal bactericidal concentration (MBC) was obtained via sub-culturing 100 μL from each negative tube from the MIC assay onto drug-free Mueller-Hinton agar plates. Biofilm-killing effect for immature (6 h-old) biofilms was examined using a semiquantitative plate assay, and the effect on mature (24 h-old) biofilms was observed under a confocal laser scanning microscope (CLSM).

Results:

The derivatives potently suppressed the growth of Staphylococcus epidermidis. The MIC values of the derivatives H2-10, H2-12, H2-20, H2-29, H2-27, and H2-28 on S epidermidis ATCC 35984 were 24.3, 6.5, 6.2, 3.3, 3.1, and 1.5 μg/mL, respectively. The MBC values of these derivatives were 48.6, 52.2, 12.4, 52.6, 12.4, and 6.2 μg/mL, respectively. The derivatives killed all bacteria in immature (6 h-old) biofilms and eliminated the biofilm proliferation. The derivatives also displayed strong bactericidal activities toward cells in mature (24 h-old) biofilms, whereas they showed low cytotoxicity and hemolytic activity toward Vero cells and human erythrocytes.

Conclusion:

The bactericidal and biofilm-killing activities of the new anti-YycG compounds were significantly better than the parent Compound 2.     

Quantitative Determination of L-DOPA in Seeds of Mucuna Pruriens Germplasm by High Performance Thin Layer Chromatography

Mucuna pruriens Linn. is an important medicinal plant used for treatment of Parkinson's disease and many others in ancient Indian medical system. L-DOPA extracted from seeds of Mucuna is a constituent of more than 200 indigenous drug formulations and is more effective as drug than the synthetic counterpart. A densitometric high performance thin-layer chromatographic (HPTLC) method was developed for quantification of L-DOPA content present in the seeds extract. The method involves separation of L-DOPA on precoated silica gel 60 GF(254) HPTLC plates using a solvent system of n-butanol-acetic-acid-water (4:1:1, v/v) as the mobile phase. Quantification was done at 280 nm using absorbance reflectance mode. Linearity was found in the concentration range of 100 to 1000 ng/spot with the correlation coefficient value of 0.9980. The method was validated for accuracy, precision and repeatability. Mean recovery was 100.89%. The LOD and LOQ for L-DOPA determination were found to be 3.41 ng/spot and 10.35 ng/spot respectively. The proposed HPTLC method was found to be precise, specific and accurate for quantitative determination of L-DOPA. It can be used for rapid screening of large germplasm collections of Mucuna pruriens for L-DOPA content. The method was used to study variation in fifteen accessions of Mucuna germplasm collected from different geographical regions.     

巴洛沙星的体外抗菌作用研究

目的评价巴洛沙星的体外抗菌作用。方法以琼脂稀释法测定巴洛沙星对临床分离菌的最低抑菌浓度，并与有关抗菌药进行比较；测定巴洛沙星的杀菌作用，观察巴洛沙星的抗菌活性影。结果巴洛沙星对革兰氏阳性菌及革兰氏阴性菌具广谱抗菌活性，尤其对葡萄球菌、肺炎球菌、肠球菌等革兰氏阳性菌活性优于诺氟沙星、氧氟沙星和环丙沙星。巴洛沙星有较强的杀菌作用，其MBC与MIC相一致，在体外具有较长的抗菌后效应。结论巴洛沙星是一种广谱抗菌药，抗菌作用强，临床应用前景好。     

Simultaneous Analysis and Quantification of Markers of Manjisthadi Churna Using High Performance Thin Layer Chromatography

Manjisthadi churna has been traditionally used in the Ayurvedic system of medicine and by traditional medical practices of India to treat hyperlipidemia. A rapid, simple and accurate method with high performance thin layer chromatography has been developed to standardised Manjisthadi churna using rubiadin, sennoside and ellagic acid as markers. Methanol extract of Manjisthadi churna were used for high performance thin layer chromatography on silica gel plates. The Rf of rubiadin, sennoside-A and ellagic acid were found to 0.48, 0.23 and 0.72, respectively with densitometric scanning at 280 nm and the calibration plot were linear in the range of 100-600 ng of markers. The correlation coefficients were higher than 0.99 were indicative of good linear dependence of peaks area on concentration. The rubiadin, sennoside-A and ellagic acid contents in Manjisthadi churna were found to be 0.014, 0.038 and 0.534% w/w, respectively. This method permits reliable quantification of rubiadin, sennoside-A and ellagic acid with good resolution and separation of the same from other constitutes of the extract of Manjisthadi churna. Recovery value from 95.66-102.33% showed the reliability and reproducibility of the method. The proposed high performance thin layer chromatography method for simultaneous quantification of markers in Manjisthadi churna can be used for routine quality testing.     

酸克糖颗粒的质量标准研究

目的：建立酸克糖颗粒的质量控制方法。方法：采用薄层色谱法鉴别其所含山茱萸、白芍，薄层扫描法测定其熊果酸的含量。结果：薄层色谱法鉴别专属性强、重现性好。熊果酸的含量测定线性范围为0．24～1．20μg，回归方程Y=7186．3 X-1356.4，相关系数r=0.9972；加样回收率为100．5％，RSD=2．4％(n=5)。结论：方法操作简便、可行，可用于酸克糖颗粒的质量控制。     

Antioxidant and immunomodulatory activity of the alkaloidal fraction of Cissampelos pareira linn

The alkaloidal fraction (AFCP) of roots of Cissampelos pareira Linn. was screened for in-vitro antioxidant activity and immunomodulatory activity in mice. The HPTLC finger print profile was also established for the identification of AFCP which was found to contain 0.176 % of berberine. AFCP possess strong antioxidant activity which was revealed by its ability to scavenge the stable free radical DPPH, superoxide ion and to inhibit lipid peroxidation in rat liver homogenate induced by iron/ADP/Ascorbate complex. AFCP was found to have significant immunosuppressive activity at lower doses (25 and 50 mg/kg) while no activity was observed at higher doses (75 and 100 mg/kg). Humoral antibody titre was significantly (p<0.01) lowered by AFCP at the doses of 25 and 50 mg/kg. Delayed type hypersensitivity response was also significantly (p<0.01) suppressed by the AFCP at the dose of 75 mg/kg. Thus the present study revealed the immunosuppressive and antioxidant activities of the alkaloidal fraction of C. pareira roots.     

Synthesis and in vitro antibacterial activity of some N-(5-aryl-1,3,4-thiadiazole-2-yl)piperazinyl quinolone derivatives

A series of N-[5-(1-methyl-5-nitro-2-imidazolyl)-1,3,4-thiadiazole-2-yl] and N-[5-(nitrophenyl)-1,3,4-thiadiazole-2-yl] piperazinyl quinolone derivatives (5a-c and 5d-l) were synthesized and evaluated for in vitro antibacterial activity against some Gram-positive and Gram-negative bacteria. The antibacterial data revealed that all nitroimidazole derivatives (5a-c) showed interesting activity against tested Gram-positive bacteria (minimum inhibitory concentration, MIC=0.008-0.03 microg/ml) while they did not show good activity against Gram-negative organisms. Despite the significant activity of nitroimidazole series, all nitrophenyl analogues (5d-l) were inactive against both Gram-positive and Gram-negative bacteria. Among all of the tested compounds, 5a (ciprofloxacin derivative in nitroimidazole series) exhibited excellent activity against Staphylococcus aureus and Staphylococcus epidermidis (MIC=0.008 microg/ml).     

Synthesis,Characterization and In Vitro Antimicrobial Evaluation of Novel Pyrazolothiazol-4(5H)-one Derivatives

Antimicrobial screening of several novel pyrazolothiazol-4(5H)-one derivatives (3a-3j) has been performed. Reaction of aromatic aldehydes with aromatic ketones yielded starting chalcones (1a-1j) which have been subsequently reacted with thiosemicarbazide for obtaining N-thiocarbamoylpyrazole derivatives (2a-2j). These were further cyclized to pyrazolothiazol-4(5H)-one derivatives (3a-3j) in the presence of ethylbromoacetate. The structures of newly synthesized compounds were confirmed by FTIR and ¹H NMR and/or MS. The in vitro antimicrobial activity of these compounds was evaluated against Gram positive bacteria, Gram negative bacteria and fungi. Their minimum inhibitory concentration was determined by tube dilution method. The results showed that most of the compounds have promising antimicrobial activity as compared to standard drugs. Among the test compounds, 2-[5(4-chlorophenyl)-3-phenyl-4,5-dihydropyrazol-1-yl]-thiazol-4(5H)-one (3e) was found to show the most potent antimicrobial activity.     

Inhibitory activity of 6-O-angeloylprenolin fromCentipeda minima on farnesyl protein transferase

The methanolic extract of the aerial parts of Centipeda minima was found to show inhibitory activity on farnesyl protein transferase (FPTase). Bioassay-guided fractionation of the methanolic extract resulted in the isolation of 6-O-angeloylprenolin, as an inhibitor on FPTase. This compound inhibited FPTase activity in a dose-dependent manner, and the IC50 value of 6-O-angeloylprenolin was 18.8 microM.     

Investigation of the antibacterial and antifungal activity of thiolated naphthoquinones

The WHO has stated that antibiotic resistance is escalating to perilously high levels globally and that traditional therapies of antimicrobial drugs are futile against infections caused by resistant microorganisms. Novel antimicrobial drugs are therefore required. We report in this study on the inhibitory activity of the 1,4-naphthoquinone-2,3-bis-sulfides and 1,4-naphthoquinone sulfides against two bacteria and a fungus to determine their antimicrobial properties. The 1,4-naphthoquinone sulfides have potent activity with a minimum inhibitory concentration (MIC) of 7.8 μg/mL against Staphylococcus aureus (Gram +ve), an MIC of 23.4 μg/mL against the fungus, Candida albicans, which was better than that of Amphotericin B (MIC = 31.3 μg/mL), and against Escherichia coli (Gram −ve) an MIC of 31.3 μg/mL was obtained. The 1,4-naphthoquinone had an MIC of 11.7 μg/mL against S. aureus and the 1,4-naphthohydroquinone also had the same activity against E. coli.

Effects of Methanol Extract of Wedelia chinensis Osbeck (Asteraceae) Leaves against Pathogenic Bacteria with Emphasise on Bacillus cereus

The antibacterial activity of the methanol extract of Wedelia chinensis leave was studied and tested against three pathogenic Gram positive bacteria (Bacillus cereus, B. subtilis and Stapylococcus aureus) and three pathogenic Gram negative bacteria (Escherichia coli, Proteus rettgeri and Pseudomonas aeruginosa) by the disk diffusion assay and broth dilution methods. The extract exhibited favourable antibacterial activity against the bacterial cells but was more potent against Gram positive bacteria with the minimum inhibition concentration of 3.12 to 6.25 mg/ml compared to the Gram negative bacteria which had minimum inhibition concentration values of 25 mg/ml. The time-kill study suggested that the extract possessed bactericidal properties at higher concentrations and eradicated the growth of bacterial cells. The major abnormalities occurred to the bacterial cells after exposed to the extract were complete alterations in their morphology and collapsed of the cells beyond repair. The methanol extract of W. chinensis may be an effective antibacterial agent to treat bacterial infections.     

Development and Validation of an HPLC Method for Karanjin in Pongamia pinnata linn. Leaves

A rapid, simple and specific reversed-phase HPLC method has been developed for analysis of karanjin in Pongamia pinnata Linn. leaves. HPLC analysis was performed on a C₁₈ column using an 85:13.5:1.5 (v/v) mixtures of methanol, water and acetic acid as isocratic mobile phase at a flow rate of 1 ml/min. UV detection was at 300 nm. The method was validated for accuracy, precision, linearity, specificity. Validation revealed the method is specific, accurate, precise, reliable and reproducible. Good linear correlation coefficients (r²>0.997) were obtained for calibration plots in the ranges tested. Limit of detection was 4.35 μg and limit of quantification was 16.56 μg. Intra and inter-day RSD of retention times and peak areas was less than 1.24% and recovery was between 95.05 and 101.05%. The established HPLC method is appropriate enabling efficient quantitative analysis of karanjin in Pongamia pinnata leaves.