In vitro activities of LB20304, a new fluoroquinolone

Thein vitro activity of LB20304 was evaluated against clinical isolates and compared with those of Q-35, ciprofloxacin, sparfloxacin, lomefloxacin and ofloxacin. LB20304 demonstrated 16- to 64-fold more potent activity than ciprofloxacin against gram-positive bacteria. LB20304 inhibited 90% of the isolates of methicillin-susceptibleStaphylococcus aureus (MSSA) at a concentration of 0.016 μg/ml (MIC₉₀). MIC₉₀ values of LB20304 against methicillin-resistantStaphylococcus aureus (MRSA), methicillin-susceptibleStaphylococcus epidermidis (MSSE), methicillin-resistantS. epidermidis (MRSE) andStreptococcus pneumoniae were 2 μg/ml, 0.016 μg/ml, 0.5 μg/ml and 0.031 μg/ml, respectively. LB20304 was also very active against gram-negative bacteria. AgainstEscherichia coli, Klebsiella pneumoniae, Serratia marcescens, Pseudomonas aeruginosa andAcinetobacter calcoaceticus, MIC₉₀S of LB20304 were 0.031 μg/ml, 0.25 μg/ml, 2 μg/ml, 8 μg/ml and 0.5 μg/ml, respectively. Its activity was comparable to that of ciprofloxacin but much better than those of Q-35, sparfloxacin, ofloxacin and lomefloxacin. LB20304 also exhibited the most potent activity among quinolones tested against laboratory standard strains, ofloxacin-resistant strains, β-lactamase-producing strains and anaerobic strains. The inhibitory effect (IC₅₀) of LB20304 on DNA gyrase fromMicrococcus luteus, determined by the supercoiling assay, was 8-fold more potent than that of ciprofloxacin. LB20304 did not induce topoisomerase-associated DNA cleavage even at a concentration of 10 mg/ml, although ciprofloxacin induced DNA cleavage at a concentration of 1 mg/ml.     

Synthesis and antifungal evaluation of 6-(N-arylamino)-7-methylthio-5,8-quinolinediones

A series of 6-(N-arylamino)-7-methylthio-5,8-quinolinedione derivatives4a-4l was newly synthesized for the evaluation of antifungal activity. 6-(N-Arylamino)-7-methylthio-5,8-quinolinediones were prepared by regioselective nucleophilic substitution of 6,7-dichloro-5,8-quinolinediones with arylamines in the presence of Ce³⁺, and Na₂S/dimethylsulfate. The MIC values of4a-4l were determined for antifungal susceptibilityin vitro againstCandida species by agar streak method. The derivatives4a-4l had generally potent antifungal activities against all human pathogenic fungi. Especially they had the most potent activity againstC. krusei at 12.5≈0.8 μg/ml. Compounds4d, 4g, 4h, 4j and4k had more potent antifungal activities than fluconazole. Compounds4g and4h completely inhibited the fungal growth at 0.8≈6.3 μg/ml against allCandida species, while fluconazole inhibited the growth at 25 μg/ml. The compounds such as4g and4h containing an N-(4-bromo-2-methylphenyl)- or N-(4-bromo-3-methylphenyl)amino substituent exhibited the most potent antifungal activities.     

O-Acetyljervine: A new β-adrenoceptor agonist fromVeratrum album

Intravenous administration ofO-acetyljervine (an alkaloid from Vertrum album) produced a dose-dependent (10–100 μg/kg) fall in blood pressure and tachycardia in anaesthetized normotensive rats. Pretreatment of animals with propranolol (1 mg/kg) abolished these cardiovascular responses ofO-acetyljervine similar to that of isoprenaline (1 μ/kg). In isolated tissue experiments,O-acetyljervine (10–100 μ/ml) produced a dose-dependent relaxation of phenylephrine-induced contraction of the rabbit aorta. In guinea-pig spontaneously beating atria, it caused positive inotropic and chronotropic responses in a dose-dependent fashion (10–100 μ/ml). These responses were abolished in the presence of propranolol (1 μg/ml) similar to that of isoprenaline. These results indicate thatO-acetyljervine is a adrenoceptor stimulant (β₁ and β₂) like isoprenaline.     

Anti-staphylococcal potential of Callistemon rigidus

The last decade witnessed the emergence of Staphylococcus aureus- a versatile human pathogen, as a deadly superbug. The enormous genetic plasticity of the organism assists it to endlessly evolve resistance mechanisms against existing anti-infectives thus necessitating the need to control the spread of resistant staphylococcal isolates in hospitals and health care settings. This in turn demands the incessant exploration of newer biological matrices in search of diverse chemical entities with novel drug targets. Since time immemorial higher plants continue to be the best source of newer compounds with high therapeutic potential. Lead fractions from same or different plants can be developed into effective antibacterial polyherbal formulations. A lead fraction from methanolic extract of leaves of Callistemon rigidus exhibited a dose dependent antistaphylococcal activity during in vitro agar well assay against a panel of twenty seven clinical multidrug resistant S. aureus isolates. Further, minimal inhibitory concentration (MIC) evaluation by in vitro 96-well microplate based assay established a MIC range of 1.25–80 μg/ml as compared to 5–320 μg/ml of positive control, Cefuroxime sodium. The MIC₅₀ and MIC₉₀ of the methanolic lead fraction were 5 μg/ml and 40 μg/ml respectively. The present study thus signifies the vast potential of the lead fraction from Callistemon rigidus for future development into a herbal drug/ formulation and to impede global health crisis due to multidrug resistant Staphylococcus aureus.     

Screening and isolation of antibiotic resistance inhibitors from herb materials IV-resistance inhibitors fromAnetheum graveolens andAcorus gramineus

The hexane fractions from methanolic extracts ofAnetheum graveolens L. (Umbelliferae) andAcorus gramineus Soland. (Araceae) revealed potent inhibitory activities against the resistance of multi-drug resistantStaphylococcus aureus SA2 when combined with ampicillin (Am) or chloramphenicol (Cm). As active principles, carvone and the liquid mixture containing carvone fromAnetheum graveolens L. and a liquid mixture mainly consisting of benzoic acid phenylmethyl ester (benzyl benzoate) fromAcorus gramineus Soland. were identified. They showed resistance inhibition at the level of 20–50 μg/ml when combined with 100 or 50 μg/ml of Am or Cm, respectively.     

Ceftolozane/tazobactam activity against drug-resistant Enterobacteriaceae and Pseudomonas aeruginosa causing healthcare-associated infections in the Asia-Pacific region (minus China,Australia and New Zealand): report from an Antimicrobial Surveillance Programme (2013–2015)

The aim of this study was to evaluate the in vitro activity of ceftolozane/tazobactam and comparator agents tested against Enterobacteriaceae and Pseudomonas aeruginosa isolates from patients in the Asia-Pacific (APAC) region with healthcare-associated infections. Ceftolozane/tazobactam is an antipseudomonal cephalosporin combined with a well-established β-lactamase inhibitor. A total of 1963 Gram-negative organisms (489 P. aeruginosa and 1474 Enterobacteriaceae) were consecutively collected using a prevalence-based approach from 14 medical centres in the APAC region. Antimicrobial susceptibility testing was performed by broth microdilution method as described by the CLSI and the results were interpreted according to EUCAST and CLSI breakpoint criteria. Ceftolozane/tazobactam [MIC_50/90, 0.25/4?µg/mL; 89.2/85.8% susceptible (CLSI/EUCAST)] and meropenem [MIC_50/90, ≤0.06/≤0.06?µg/mL; 96.3/96.5% susceptible (CLSI/EUCAST)] were the most active compounds tested against Enterobacteriaceae. Isolates displayed susceptibility rates to other β-lactam agents ranging from 85.8/81.0% for piperacillin/tazobactam to 74.4/72.7% for cefepime and 72.8/68.1% for ceftazidime using CLSI/EUCAST breakpoints. Among the Enterobacteriaceae isolates, 3.6% were carbapenem-resistant Enterobacteriaceae (CRE) and 25.6% exhibited an extended-spectrum β-lactamase (ESBL) non-CRE phenotype. Ceftolozane/tazobactam showed good activity against ESBL non-CRE phenotype strains of Enterobacteriaceae (MIC_50/90, 0.5/16?µg/mL), but not against isolates with a CRE phenotype (MIC_50/90, >32/>32?µg/mL). Ceftolozane/tazobactam was the most potent (MIC_50/90, 0.5/4?µg/mL) β-lactam agent tested against P. aeruginosa isolates, inhibiting 90.8% at an MIC of ≤4?µg/mL. Pseudomonas aeruginosa exhibited high rates of susceptibility to amikacin [91.2/89.4% (CLSI/EUCAST)] and colistin [98.4/100.0% (CLSI/EUCAST)]. Ceftolozane/tazobactam was the most active β-lactam agent tested against P. aeruginosa and demonstrated higher in vitro activity than available cephalosporins when tested against Enterobacteriaceae.     

A cytotoxic constituent fromSophora flavescens

A cytotoxic constituent was isolated by bioassay-guided procedure from the roots ofSophora flavescens Aiton (Leguminosae). The constituent was identified as sophoraflavanone G (I) by means of chemical methods and in comparsion with spectral data of standard compound. The ED₅₀ values of constituent I were 0.78, 1.57, 2.14 and 8.59 μg/ml against A549, HeLa, K562 and L1210 cell lines respectively. ConstituentI exhibited highly cytotoxic activities against A 549, K562 and HeLa cells, but showed a mild activity (ED₅₀ value, 5 μg/ml) against L1210 cells. Among the tested cell lines, A549 cells were the most sensitive to constituentI.     

Ceftolozane/tazobactam activity tested against Gram-negative bacterial isolates from hospitalised patients with pneumonia in US and European medical centres (2012)

During 2012, a total of 2968 isolates were consecutively collected from 59 medical centres in the USA and 15 European countries from hospitalised patients with pneumonia. Ceftolozane/tazobactam (tazobactam at a fixed concentration of 4 mg/L) and comparator agents were tested by reference methods, and MIC endpoints were interpreted by CLSI (2013) and EUCAST (2013) breakpoint criteria. Pseudomonas aeruginosa was the most common isolated pathogen (1019 strains; 34.3%), and ceftolozane/tazobactam was the most active β-lactam tested against P. aeruginosa (MIC_50/90, 0.5/4 mg/L; 94.1% inhibited at ≤8 mg/L). P. aeruginosa exhibited moderate susceptibility to meropenem (MIC_50/90, 0.5/>8 mg/L; 73.7% susceptible), ceftazidime (MIC_50/90, 2/>32 mg/L; 73.6% susceptible), cefepime (MIC_50/90, 4/>16 mg/L; 76.5% susceptible), piperacillin/tazobactam (MIC_50/90, 8/>64 mg/L; 69.5% susceptible), levofloxacin [MIC_50/90, 0.5/>4 mg/L; 69.9/61.0% susceptible (CLSI/EUCAST criteria)] and gentamicin (MIC_50/90, 2/>8 mg/L; 80.7% susceptible). Ceftolozane/tazobactam exhibited activity against many ceftazidime-non-susceptible, meropenem-non-susceptible and piperacillin/tazobactam-non-susceptible, multidrug-resistant (MDR) and extensively drug-resistant (XDR) P. aeruginosa isolates. Ceftolozane/tazobactam was active (MIC_50/90, 0.25/4 mg/L; 94.6% inhibited at ≤8 mg/L) against 1530 Enterobacteriaceae, including activity against many MDR and XDR strains. MDR and XDR prevalence varied widely between countries both for P. aeruginosa (24.1% MDR and 17.1% XDR overall) and Enterobacteriaceae (15.4% MDR and 2.7% XDR overall). All β-lactams had limited activity against Acinetobacter spp. and Stenotrophomonas maltophilia. Ceftolozane/tazobactam demonstrated greater in vitro activity than currently available cephalosporins, carbapenems and piperacillin/tazobactam when tested against P. aeruginosa. In addition, ceftolozane/tazobactam demonstrated greater activity than contemporary cephalosporins and piperacillin/tazobactam when tested against most Enterobacteriaceae.     

In vitro anti-plasmodial and in vivo anti-malarial activity of some plants traditionally used for the treatment of malaria by the Meru community in Kenya

Extracts of seven medicinal plant species used for treatment of malaria in traditional/cultural health systems of the Ameru people in Kenya were tested in vitro and in vivo against Plasmodium falciparum (D6 and W2 strains) and P. berghei, respectively. Of the plants tested, 28.57% were highly active (IC₅₀ <10 μg/ml) and 42.86% moderately active (IC₅₀ 10–50 μg/ml), while 28.57% had weak activity of 50–125 μg/ml in vitro. The water and methanol extracts of Boscia salicifolia Oliv. and Artemisia afra Jacq. (ex-Willd.) were the most active against both the chloroquine (CQ)-sensitive (D6) and the CQ-resistant (W2) P. falciparum strains. Artemisia afra and Rhus natalensis Bernh. (ex-Krauss) exhibited the highest parasite clearance and chemo-suppression (>70%) in vivo (in mice). The plants with high in vitro anti-plasmodial (low IC₅₀ values) and high anti-malarial activity (high chemo-suppression) in vivo are potential sources of novel anti-malarial drugs.     

Isolation of a multidrug resistance inhibitor fromAconitum pseudo-laeve var.erectum

To overcome multidrug resistance (MDR) in cancer chemotherapy, we prepared various plant extracts and searched for a component which is effective for inhibition of MDR. MDR inhibition activity was determined by measuring cytotoxicity to MDR cells using multidrug resistant human fibrocarcinoma KB V20C, which is resistant to 20 nM vincristine and expresses high level ofmdr1 gene. Of various plant extracts, the MeOH extract of the root ofAconitum pseudo-laeve var.erectum was found to have potent inhibitory activity on MDR. The bioassay-guided fractionation of the MeOH extract of the plant led to the isolation of an alkaloid, lycaconitine, as an active principle. And the IC₅₀ of lycaconitne for KB V20C cells was 74 μg/ml.     

In-vitro activity of ceftolozane/tazobactam against Pseudomonas aeruginosa and Enterobacteriaceae isolates recovered from hospitalized patients in Germany

To evaluate the activity of ceftolozane/tazobactam compared with other broad-spectrum antimicrobials against Pseudomonas aeruginosa and Enterobacteriaceae, 497 non-duplicate P. aeruginosa and 802 Enterobacteriaceae clinical isolates were consecutively collected during the period from September 2014 to April 2015 from patients in Germany with bloodstream, lower respiratory tract, intra–abdominal or urinary tract infections. Antimicrobial susceptibility testing was performed by broth microdilution. Results were interpreted according to EUCAST criteria. Ceftolozane/tazobactam showed good activity against Escherichia coli and Klebsiella pneumoniae isolates with MIC_50/90 values of 0.25/0.5?mg/L and 0.25/1?mg/L, respectively. Comparatively, piperacillin/tazobactam, ceftazidime and meropenem MIC_50/90 values were 2/8?mg/L, 0.25/8?mg/L and ≤0.03/?≤?0.03?mg/L, respectively, for E. coli, and 2/16?mg/L, 0.12/8?mg/L, and ≤0.03/?≤?0.03?mg/L, respectively, for K. pneumoniae isolates. The activity of ceftolozane/tazobactam against P. aeruginosa was superior to that of other antipseudomonal antimicrobials. Based on MIC_50/90 values, ceftolozane/tazobactam (0.5/2?mg/L) was more active than piperacillin/tazobactam (8/64?mg/L), ceftazidime (2/16?mg/L), cefepime (2/16?mg/L) or meropenem (0.5/8?mg/L). In conclusion, ceftolozane/tazobactam exhibited the best in vitro potency of the antibiotics tested against P. aeruginosa, including isolates that were resistant to piperacillin/tazobactam, cefepime, ceftazidime, doripenem, meropenem, ciprofloxacin, levofloxacin, amikacin, and tobramycin. Ceftolozane/tazobactam has the potential to become a useful addition to the limited armamentarium of drugs that can be used to treat this problem pathogen.     

Anti-oxidative and anti-inflammatory activities of some isolated constituents from the stem bark of Allanblackia monticola Staner L.C (Guttiferae)

Stem bark of Allanblackia monticola has been used in association with others plant in the Cameroonian folk medicine for the treatment of various diseases such amoebic dysentery, diarrhoea, lung infections, and skin diseases. The methylene chloride fraction, its isolated compounds like α-mangostin, lupeol and acid betulinic were screened for antioxidant activity using free radical scavenging method. These isolated compounds were further tested for anti-inflammatory properties using carrageenan-induced model. Methylene chloride fraction, showed concentration-dependent radical scavenging activity, by inhibiting 1,1-diphenyl-1-picryl-hydrazyl radical (DPPH) with an IC₅₀ value of 14.60 μg/ml. α-Mangostin and betulinic acid (500 μg/ml), showed weak radical scavenging activity with a maximum inhibition reaching 38.07 μg/ml and 26.38 μg/ml, respectively. Betulinic acid, lupeol and α-mangostin (5 mg/kg and 9.37 mg/kg) showed anti-inflammatory activity with a maximum inhibition of 57.89%, 57.14% and 38.70%, respectively. Methylene chloride fraction of Allanblackia monticola and some derivatives, have antioxidant and anti-inflammatory activities. Received 7 July 2008; accepted 7 October 2008     

Antiviral triterpenes fromPrunella vulgaris

Two triterpenes 1 and 2 with antiviral activity againstHerpes simplex virus type 1in vitro were isolated fromPrunella vulgaris. Each compound caused a significant reduction in viral cytopathic effect whenvero cells were exposed to them for 72 hours after viral challenge. They were identified asbetulinic acid(1) and 2α, 3α-dihydroxyurs-12-en-28-oic acid(2) on the basis of their spectroscopic properties. The antiviral activity of them was estimated as EC₅₀=30 μg/ml(1) and 8 μg/ml(2), respectively by plaque reduction assay.     

Inhibitory effects of compounds from Anemarrhenae Rhizoma on α-glucosidase and aldose reductase and its contents by drying conditions

An aqueous extract of Anemarrhena asphodeloides Bunge (Anemarrhenae Rhizoma) showed inhibitory effects on α-glucosidase and aldose reductase (AR). We obtained two active compounds, mangiferin (α-glucosidase: IC₅₀ = 96.1 μg/ml, AR:IC₅₀ = 0.13 μg/ml) and mangiferin 7-O-β-D-glucopyranoside (α-glucosidase: IC₅₀ = 158 μg/ml, AR:IC₅₀ = 65.7 μg/ml ), from Anemarrhenae Rhizoma. In addition, the amount of mangiferin in Anemarrhenae Rhizoma changed with the method of preparation (drying conditions), namely, low-temperature, long-term drying conditions and harvesting in August were most effective.     

Antiplasmodial and antitrypanosomal activity of plants from the Kingdom of Saudi Arabia

The antiplasmodial and antitrypanosomal activity of the methanol extracts of 42 plants collected from the Kingdom of Saudi Arabia and some fractions obtained thereof were evaluated. The antiplasmodial activity was tested in vitro against chloroquine-resistant strain (K1) and sensitive strain (FCR3), and the antitrypanosomal activity was tested in vitro against Trypanosoma brucei brucei GUTat 3.1 strain. For host cells, the cytotoxicity of the active extracts was also evaluated against the MRC5 human cell line. Only extracts of three samples demonstrated good antiplasmodial activity (IC₅₀ < 12.5 and > 1.56 μg/ml, score 2), the methanol extracts of Lycium shawii, Heliotropium zeylanicum and the petroleum ether-soluble fraction of the methanol extract of Caralluma tuberculata, while extracts of the remaining 42 plants were inactive (IC₅₀ > 12.5 μg/ml, score 1). As for the antitrypanosomal activity, the methanol extract of Solanum schimperianum demonstrated the highest activity (IC₅₀ 0.061 μg/ml), followed by the petroleum ether-soluble fraction of the methanol extract of C. tuberculata (IC₅₀ 0.5 μg/ml). The chloroform-soluble fraction of the methanol extract of C. tuberculata was moderately active (IC₅₀ 3.5 μg/ml), with low cytotoxicity (IC₅₀ 62.6 μg/ml) and moderate selectivity index (SI 17.9). The methanolic extracts of 34 plants showed good activity with score 2 (IC₅₀ < 12.5 and > 1.56 μg/ml), while the extracts of seven plants were inactive (IC₅₀ > 12.5 μg/ml, score 1).     

Growth inhibitory activities of kalopanaxsaponins A and I against human pathogenic fungi

Antifungal activities of the compounds isolated fromKalopanax pictus against representative fungi of dermatomycosis were investigated using paper disc diffusion method. It was found that kalopanaxsaponins A and I were effective in inhibiting the growth ofCandida albicans KCTC 1940 andCryptococcus neoformans KCTC 7224 with minimum inhibitory concentration (MIC) of 25 μg/ml. It showed that antifungal activity of both compounds have strong selectivity against the fungi of dermatomycosis.     

Antitumor activity of the aqueous-alcoholic extracts from unripe cotton ball ofGossypium indicum

The present study investigated the antitumor activity of the aqueous-alcoholic extracts from unripe cotton balls ofGossypium indicum. An Exposure of murine B16 melanoma and L1210 lymphoma cells to the extracts resulted in their severe deaths in time- and concentration-dependent manners. Of the extracts, hydrophilic fractions were most efficacious for the antitumor activity and found to contain certain amounts of catechin and its derivatives. The hydrophilic extract fraction C36B2-8 had approximately 10 times more cytotoxic effects on B12 and L1210 cells than on isolated murine thymocytes. High concentrations (>150 μg/ml) of C 36B3-8 mainly induced necrotic cell death. At low concentrations (<100 μg/ml), however, C 36B3-8 induced not only necrosis but also apoptosis of the two tumor cell lines, which was proved by the TUNEL staining and DNA fragmentation techniques. The data indicate that certain ingredients of the cotton ball extract ofG. indicum have an antitumor activity.     

Dose dependency of earthworm powder on antithrombotic and fibrinolytic effects

The freeze-dried powder ofLumbricus rubellus earthworm was administered orally to rats and its fibrinolytic and antithrombotic effects were investigated. The fibrinolytic activity of plasma was determined by measuring the plasmin activity of the euglobulin fraction and was increased to two-folds of the control at a dose of 0.5g/kg/day and five times with 1 g/kg/day after 4-day administration. The antithrombotic effect was studied in an arterio-venous shunt model of rats. The thrombus weight decreased significantly from 43.2 mg to 32.4 mg at a dose of 0.5g/kg/day after 8-day treatment. The level of fibrinogen/fibrin degradation product (FDP) in serum was elevated in a dose-dependent manner during the treatment period. On the 8th day after administration, the FDP value was increased to 7.7 μg/ml compared with the control value of 3.3 μg/ml. These results support that earthworm powder is valuable for the prevention and/or treatment of thrombotic conditions.     

Potent antimalarial activity of newly synthesized substituted chalcone analogs in vitro

Abstract   Several new chalcone analogues were synthesized and evaluated as inhibitors of malaria parasite. Inhibitory activity was determined in vitro against a chloroquine-sensitive Plasmodium falciparum strain of parasites. The compound 3-(4-methoxyphenyl)-1-(4-pyrrol-1-yl-phenyl)prop-2-en-1-one was found to be the most active with 50% inhibition concentration (IC₅₀) of 1.61 μg/ml. This inhibitory concentration is comparable to a prototype phytochemical chalcone, licochalcone A, with an IC₅₀ of 1.43 μg/ml. The present study suggests that small, lipophilic nitrogen heterocyclic ring A together with small hydrophobic functionality at ring B can enhance antimalarial activity. These results suggest that chalcones are a class of compounds that provides an option of developing inexpensive, synthetic therapeutic antimalarial agents in the future. Graphical Abstract  Claisen-Schmidt condensation method was employed to synthesize various substituted chalcones. Among all, 3-(4-Methoxyphenyl)-1-(4-pyrrol-1-yl-phenyl)prop-2-en-1-one was found to be most effective with IC₅₀ value of 1.6 μg/ml in vitro against chloroquine sensitive strain (3D7) of Plasmodium falciparum.