Antimicrobial activity of Polygonum tinctorium Lour: extract against oral pathogenic bacteria

Extract of the leaves of the indigo plant (Polygonum tinctorium Lour.) was examined for antimicrobial activity against oral pathogenic bacteria. The indigo plant extract at concentrations of 1.74–3.48 mg/ml inhibited the growth of oral cariogenic and periodontopathic bacteria. Tryptanthrin, one of the components of indigo plant extract, showed the strongest antimicrobial effect at doses ranging from 3.13–25 g/ml, indicating that this compound is one of the active ingredients. Furthermore, treatment of periodontopathic bacteria Porphyromonas gingivalis and Prevotella intermedia with the indigo plant extract for 3–8 h resulted in death of the bacteria in a dose-dependent manner, whereas Streptococcus mutans was not affected by the extract. Thus, for its antimicrobial and bactericidal effects on oral pathogens, indigo plant extract would provide useful material for preventing and treating periodontal diseases and dental caries.     

In vitro and in vivo antibacterial activities of garenoxacin against group G Streptococcus dysgalactiae subsp. equisimilis

In this study, garenoxacin showed potent in vitro activity against clinical isolates of group G Streptococcus dysgalactiae subsp. equisimilis [minimum inhibitory concentration for 90% of the organisms (MIC₉₀) = 0.125 μg/mL] and was superior to levofloxacin (MIC₉₀ = 1 μg/mL) and moxifloxacin (MIC₉₀ = 0.25 μg/mL). In experimental pneumonia caused by group G S. dysgalactiae subsp. equisimilis in mice, the effective dose for 50% survival (ED₅₀) of garenoxacin following single oral administration was 1.87 mg/kg, >10.7-fold and 4.6-fold less than the ED₅₀ values of levofloxacin (>20 mg/kg) and moxifloxacin (8.54 mg/kg), respectively. The area under the free serum concentration-time curve from 0-24 h (fAUC_0-24)/MIC ratio of garenoxacin in serum following oral administration of 20 mg/kg was 73.2, which was 8.7-11.4-fold and 1.4-fold greater than that of levofloxacin (6.44-8.46) and moxifloxacin (51.4), respectively. These results suggest that garenoxacin has potential for the treatment of infectious diseases caused by S. dysgalactiae subsp. equisimilis.     

Bioactive Terpenoids and Flavonoids from Daucus littoralis Smith subsp. hyrcanicus Rech.f,an Endemic Species of Iran

Background

Daucus littoralis Smith subsp. hyrcanicus Rech.f. (Apiaceae) is an endemic species in northern parts of Iran where it is commonly named Caspian carrot. The fruits have been used as condiment.

Methods

In a series of in vitro assays, antioxidant (DPPH and FRAP assays), cytotoxic and antimicrobial activities of different extracts of roots and fruits were evaluated for the first time. The separation and purification of the compounds were carried out on the most potent extracts using various chromatographic methods and identified by spectroscopic data (¹H and ¹³C NMR).

Results

The results showed that among the extracts only fruit methanol extract (FME) has significant antioxidant activity (IC₅₀ = 145.93 μg.ml^-1 in DPPH assay and 358 ± 0.02 mmol FeII/g dry extract in FRAP assay). The radical scavenging activity of FME at 400 μg.ml^-1 was comparable with α-tocopherol (40 μg.ml^-1) and with BHA (100 μg.ml^-1) (p > 0.05). FME did not show any toxicity against cancerous and normal cell lines. Fruit ethyl acetate extract (FEE) had cytotoxic activity against breast carcinoma and hepatocellular carcinoma cells (IC₅₀ 168.4 and 185 μg.ml^-1, respectively), while it did not possess antioxidant activity in comparison with α-tocopherol and BHA as standard compounds. Ethyl acetate and methanol extract of fruits showed antimicrobial activity against Staphylococcus aureus (MIC: 3.75 mg.ml^-1) and Candida albicans (MIC: 15.6 and 7.8 mg.ml^-1, respectively). Four terpenoids were isolated form FEE including: β-sitosterol (1), stigmasterol (2), caryophyllene oxide (3), β-amyrin (4). Also, three flavonoids namely quercetin 3-O-β-glucoside (5), quercetin 3-O-β-galactoside (6) and luteolin (7) were isolated from FME.

Conclusion

This study showed that FEE and FME of D. littoralis Smith subsp. hyrcanicus Rech.f. had the highest biological activities which may be correlated with in vitro cytotoxic, antimicrobial and antioxidant activities of terpenoids and flavonoids components of the extracts.     

Composition, enantiomeric distribution, and antimicrobial activity of Tanacetum argenteum subsp. flabellifolium essential oil

Tanacetum argenteum (Lam.) Willd. subsp. flabellifolium (Boiss. & Heldr.) Grierson of Asteraceae is an endemic species in Turkey. Hydrodistillation of aerial parts using a Clevenger apparatus yielded an essential oil, which was subsequently analyzed by gas chromatography–mass spectroscopy (GC–MS). -Pinene (29%), (E)-sesquilavandulol (16%), and camphor (14%) were found as main constituents. Enantiomeric distribution of the monoterpenes -pinene and camphor was determined on a fused silica Lipodex E capillary column using a multidimensional gas chromatography–mass spectroscopy (MDGC–MS) system, (−)--pinene (86%), (+)--pinene (14%), and (−)-camphor (100%) enantiomeric distributions were found in the oil. Furthermore, antimicrobial activity of the oil was carried out using a micro-dilution assay against human pathogenic bacteria and the yeast Candida albicans resulting in moderate inhibitory concentrations (MIC = 125 μg/mL).     

Antibacterial and antitumor macrolides fromstreptomyces sp. Is9131

Four compounds, including two novel macrolides, were isolated from an endophyte Streptomyces sp. Is9131 of Maytenus hookeri. Spectral data indicated that these compounds were dimeric dinactin (1), dimeric nonactin (2), cyclo-homononactic acid (3), and cyclo-nonactic acid (4). Bioassay results showed that dimeric dinactin had strong antineoplastic activity and antibacterial activity.     

Antimicrobial Activities of Fruits of Crataegus. and Pyrus. Species

Abstract

The antimicrobial activity of the ethyl acetate extracts from fruits of Crataegus tanacetifolia., Crataegus x bornmülleri., Pyrus communis. subsp. communis., and Pyrus serikensis. (Rosaceae) were investigated by the agar-well diffusion assay, and the extracts exhibited antimicrobial effect against most of the bacteria and all of the yeasts tested. Although the plants differed in their activities against the microorganisms tested, the extracts of C. x bornmülleri. and P. communis. subsp. communis. displayed no antifungal activity against the fungi tested. P. serikensis. extract inhibited the growth of all bacteria tested but not Aspergillus niger., Aspergillus parasiticus., Aspergillus citri., and Aspergillus fumigatus.. In conclusion, P. serikensis. was the most active antimicrobial plant. Particularly, P. serikensis. extract showed significant antifungal activities and could be used as an antimicrobial agent in new drug therapy.     

Antimicrobial constituents of Foeniculum vulgare

A phenyl propanoid derivative, dillapional(1) was found to be a antimicrobial principle of the stems of Foeniculum vulgare (Umbelliferae) with MIC values of 125, 250 and 125/ against Bacillus subtilis, Aspergillus niger and Cladosporium cladosporioides, respectively. A coumarin derivative, scopoletin(2) was also isolated as marginally antimicrobial agent along with inactive compounds, dillapiol(3), bergapten(4), imperatorin(5) and psolaren(6) from this plant. The isolates 1-6 were not active against the Escherichia coli.     

Secoiridoid glycosides from the leaves of <Emphasis Type="Italic">Hydrangea macrophylla</Emphasis> subsp. <Emphasis Type="Italic">serrata</Emphasis>

Seven secoiridoid glycosides, secologanin dimethyl acetal (1), n-butyl vogeloside (2), n-butyl epi-vogeloside (3), (7R)-n-butyl morroniside (4), hydrangenoside A (5), hydrangenoside C (6), and hydrangenoside A dimethyl acetal (7), have been isolated from the leaves of Hydrangea macrophylla subsp. serrata (Thunb.) Makino (Saxifragaceae). The structures were elucidated on the basis of spectral data.     

Antimicrobial and antibiofilm activity of LL-37 and its truncated variants against Burkholderia pseudomallei

The Gram-negative bacterium Burkholderia pseudomallei is the aetiological agent of melioidosis, which is an endemic disease in tropical areas of Southeast Asia and Northern Australia. Burkholderia pseudomallei has intrinsic resistance to a number of commonly used antibiotics and has also been reported to develop a biofilm. Resistance to killing by antimicrobial agents is one of the hallmarks of bacteria grown in biofilm. The aim of this study was to determine the antimicrobial activity and mechanisms of action of LL-37 and its truncated variants against B. pseudomallei both in planktonic and biofilm form, as LL-37 is an antimicrobial peptide that possessed strong killing activity against several pathogens. Antimicrobial assays revealed that LL-31, a truncated variant of LL-37 lacking the six C-terminus residues, exhibited the strongest killing effect. Time-kill experiments showed that 20 μM LL-31 can reach the bactericidal endpoint within 2 h. Freeze-fracture electron microscopy of bacterial cells demonstrated that these peptides disrupt the membrane and cause leakage of intracellular molecules leading to cell death. Moreover, LL-31 also possessed stronger bactericidal activity than ceftazidime against B. pseudomallei grown in biofilm. Thus, LL-31 should be considered as a potent antimicrobial agent against B. pseudomallei both in planktonic and biofilm form.     

The effect of L-cysteine on the portion-selective uptake of cadmium in the renal proximal tubule

Cadmium (Cd), co-administered with an excess of L-cysteine, accumulates rapidly in the kidneys of the rat. After subcutaneous (s. c.) injection of 3 mol CdCl₂/kg body wt the concentrations of Cd in the blood and kidneys increase with the dose of cysteine over the range 0.06–5.0 mmol/kg body wt. At cysteine doses of less than 1.5 mmol/kg body wt the ratio of the concentrations of Cd in the outer medulla and cortex of the kidney remains the same as that after the injection of Cd alone. This ratio, however, is more than doubled at dose levels of 5–10 mmol cysteine/kg body wt. Hepatic uptake of Cd is unaffected by doses of cysteine below 1.5 mmol/kg body wt but decreases markedly at higher doses. In animals that are dosed simultaneously with 5 mmol cysteine/kg body wt, renal uptake of ¹⁰⁹Cd is known to occur in the straight segments of the proximal tubules. At a dose level of less than 1.5 mmol cysteine/kg body wt the present autoradiographical studies show that ¹⁰⁹Cd is taken up predominantly by the proximal convoluted tubules of the kidney cortex. At the critical dose level (1.5 mmol/kg body wt), cysteine decreases the retention of Cd at the s. c. injection site, but probably has little effect on the distribution of Cd between protein and other carrier molecules in the blood. This distribution, however, is altered at higher cysteine dose levels. It is suggested that, under the latter conditions, stable Cd-cysteine complexes are formed in the blood and are filtered readily through the glomeruli. These complexes are taken up in the kidney at the sites of cysteine reabsorption which, by studies with L-[³⁵S]-cysteine, are identified as the straight segments of the proximal tubules.     

Antimicrobial and antioxidant activities of Russula delica Fr.

Russula delica Fr. is a well known macrofungi which is used as a food in Turkey. The ethanolic extract of R. delica exhibited antimicrobial activity against some of the tested foodborne and spoilage bacteria. The phenolic composition of R. delica ethanolic extract was analyzed by high performance liquid chromatography (HPLC). The major component in R. delica ethanolic extract was catechin (5.33 mg/L). Antioxidant activities of the ethanolic extract of R. delica was evaluated by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals scavenging and chelating ability on ferrous ions assays. Scavenging effect on DPPH radicals was 26% at 10 mg/ml and chelating effects on ferrous ions was 58% at 5 mg/ml. In addition, the amounts of total phenol content (6.23 mg/g), ascorbic acid (2.93 mg/g), β-carotene (0.11 mg/g) and lycopene (0.03 mg/g) in the macrofungi ethanolic extract were determined.     

In vitro activity of dermaseptin S4 derivatives against genital infections pathogens

OBJECTIVES: Sexually transmitted infections present a great risk to the reproductive health of women. Therefore, female-controlled vaginal products directed toward disease prevention are needed urgently. In the present study, efforts were made to evaluate the antimicrobial potency of dermaseptin DS4, an antimicrobial peptide derived from frog skin. To assess the structure-activity relationship between the native DS4 and their derivatives, a set of chemically modified peptides was synthesized and evaluated. METHODS: Different strains of bacteria and fungi were used to detect the antimicrobial activity of the new compounds. HeLa cultures were used to determine the safety of compounds towards their toxicity. RESULTS: All DS4 derivatives elicited concentration-dependent antimicrobial activity at micrograms concentrations (MIC values: 4 microg/mL-l mg/mL). K4S4(1-28) and K4S4(1-16)a were the most active peptides whereas S4(6-28) was the less one. The order was K4S4(1-28)>K4S4(1-16)a>S4a>S4>S4(6-28). In cytotoxicity assay, some compounds were found to be significantly safer than current antibiotics. Our data also show that increasing the number of positive charges of the peptide resulted in a reduced cytotoxicity without affecting the antimicrobial effect. CONCLUSIONS: This study indicates that dermaseptins are antimicrobial molecules that deserve to be tested as topical microbicide with useful associated activities that can add to their prophylaxis, safety and effectiveness.     

Antimicrobial activity,phenolic profile and role in the inflammation of propolis

Nowadays a great amount of information regarding chemical and biological aspects of bee products is available in the literature, but few data on its therapeutic uses are found. The aim of this study was to evaluate the phenolic profile, the in vitro antimicrobial activity and effect in the hyaluronidase enzyme (widely related with the inflammation process) of propolis harvested in Portugal. The efficacy of three extracts (hydro-alcoholic, methanolic and aqueous) was also compared. It was chosen the hydro-alcoholic extract, because this was the most effective for extracting phenolic compounds. The antimicrobial activity was accessed in Gram-positive and Gram-negative bacteria and yeasts, isolated from different biological fluids and the results were then compared with the obtained for reference microorganisms. The propolis from Bragança was the one that possessed the highest polyphenols’ content. The sample from Beja showed the less significant inhibition of the hyaluronidase enzyme. Concerning the antimicrobial activity, Candida albicans was the most resistant and Staphylococcus aureus the most sensitive. The reference microorganisms were more sensitive than the ones isolated from biological fluids.     

Synthesis of praziquantel derivatives and theirin vitro activity against adultClonorchis sinensis

Several praziquantel derivatives have been prepared by the acylation of compound5, and examined on their biological activityin vitro against adultClonorchis sinensis collected from rabbits infected with metacercariae which was isolated fromPseudorasbora parva, a second intermediate host, captured in Nakdong river in Korea.     

Evaluation of the effects of Olea europaea L. subsp. africana (Mill.) P.S. Green (Oleaceae) leaf methanol extract against castor oil‐induced diarrhoea in mice

Objectives Olea europaea L. subsp. africana (Mill.) P.S. Green is widely used in South Africa by traditional medicine practitioners to treat diarrhoea. However, little is known scientifically about this South African species in the treatment of diarrhoea. The main aim of the study therefore was to investigate the antidiarrhoeal effect of the leaf methanol extract of the plant species in mice. Methods The antidiarrhoeal activity of the leaf methanol extract of O. europaea subsp. africana was studied using a castor oil‐induced diarrhoeal test. The antipropulsive activity of the plant extract was also investigated using the charcoal meal transit test. Standard methods were used to investigate the acute toxicity and effect of O. europaea subsp. africana on castor oil‐induced intraluminal fluid accumulation. Results Leaf methanol extract of O. europaea subsp. africana and loperamide, a standard antidiarrhoeal drug, significantly reduced the number of diarrhoeal episodes induced by castor oil, significantly decreased the stool mass, significantly delayed the onset of the diarrhoea and protected the animals against castor oil‐induced diarrhoea. Both O. europaea subsp. africana and loperamide significantly decreased the gastrointestinal transit of charcoal meal and castor oil‐induced intraluminal fluid accumulation in mice. The LD50 value was found to be 3475 mg/kg (p.o.). Conclusions The results obtained suggest that the leaf methanol extract of O. europaea subsp. africana has an antidiarrhoeal property and that, given orally, it may be non‐toxic and/or safe in mice.     

Antipseudomonal activity and nephrotoxicity of cephradine-netilmicin combination

The effects of intraperitoneal injections of cephradine in a dose of 75 mg/kg and netilmicin in dose of 50 mg/kg and their combination on creatinine and urea serum levels of rabbits were studied as well as the antipseudomonal activity against three multiresistant clinicial isolates. The antibacterial activity was investigated by two methods: Checkerboard titration method and time-kill studies. Finally, the antibacterial activity of the sera obtained from the rabbits receiving the used drugs in the previous regimen was studied using time-kill study method againstPseudomonas aeruginosa isolates. Results obtained from this study indicated that both creatinine and urea serum levels of the rabbits receiving both drugs were not significantly different from those of the rabbits receiving either cephradine or netilmicin alone. At the same time thein vitro antibactrial activity (either of the prepared solutions of the used drugs and their combination or of the sera obtained from the rabbits receiving these drugs as mentioned before) showed a synergistic effect against the tested strains ofPseudomonas aeruginosa     

Protection of renal tubular cells against the cytotoxicity of cadmium by glycine

Glycine treatment is reported to protect against the nephrotoxicity of cadmium (Cd) in rats. The purpose of the present study was to explore the mechanism of this protection using a renal epithelial cell line, LLC-PK(1). The cells were incubated with 10-30 microM Cd in serum-free DMEM and cytotoxicity was evaluated by LDH leakage into the incubation medium. Under these conditions, 20 and 30 microM Cd concentrations were cytotoxic. As compared to the non-Cd-exposed cells, the LDH release was elevated more than six-fold in cells exposed to 30 microM Cd for 24h. Co-treatment with 5-50mM glycine was cytoprotective in a concentration-dependent manner. Prior treatment with 50 mM glycine for 16 h, or co-treatment for 24h, reduced LDH leakage due to 30 microM Cd exposure by 60 and 66%, respectively. Co-incubation with 50 mM alanine was also protective but only about half as effective as with glycine. During the first 4h, prior to the onset of any significant cell membrane damage, the Cd-exposed cells accumulated 0.55 microg Cd/mg protein. Glycine pre-treatment or co-treatment reduced Cd accumulation by about one-quarter or one-half, respectively. To delineate the mechanism of glycine's effect on Cd accumulation, the efflux of Cd was studied after a 30 min pulse exposure. The results suggested that pre-treatment reduced Cd accumulation by increasing its efflux from the cells. In contrast, co-treatment reduced Cd efflux, suggesting that the co-treatment lowered Cd accumulation by suppressing its uptake. When co-incubated, Cd and glycine formed a complex that was apparently responsible for the marked reduction in Cd uptake. It is concluded that, regardless of the mode of treatment, glycine is cytoprotective against Cd and that it may do so by lowering the intracellular Cd burden.     

Molluscicidal activity of cardiac glycosides from Nerium indicum against Pomacea canaliculata and its implications for the mechanisms of toxicity

Cardiac glycosides from fresh leaves of Nerium indicum were evaluated for its molluscicidal activity against Pomacea canaliculata (golden apple snail: GAS) under laboratory conditions. The results showed that LC₅₀ value of cardiac glycosides against GAS was time dependent and the LC₅₀ value at 96 h was as low as 3.71 mg/L, which was comparable with that of metaldehyde at 72 h (3.88 mg/L). These results indicate that cardiac glycosides could be an effective molluscicide against GAS. The toxicological mechanism of cardiac glucosides on GAS was also evaluated through changes of selected biochemical parameters, including cholinesterase (ChE) and esterase (EST) activities, glycogen and protein contents in hepatopancreas tissues of GAS. Exposure to sublethal concentrations of cardiac glycosides, GAS showed lower activities of EST isozyme in the later stages of the exposure period as well as drastically decreased glycogen content, although total protein content was not affected at the end of 24 and 48 h followed by a significant depletion at the end of 72 and 96 h. The initial increase followed by a decline of ChE activity was also observed during the experiment. These results suggest that cardiac glycosides seriously impair normal physiological metabolism, resulting in fatal alterations in major biochemical constituents of hepatopancreas tissues of P. canaliculata.     

Design and synthesis of cationic antimicrobial peptides with improved activity and selectivity against Vibrio spp

Extensive use of classical antibiotics has led to the growing emergence of many resistant strains of pathogenic bacteria. Evidence has suggested that cationic antimicrobial peptides (AMPs) are of greatest potential to represent a new class of antibiotics. The largest group of AMPs comprises peptides that fold into an amphipathic alpha-helical conformation when interacting with the target microorganism. In the current study, a series of cationic AMPs of 20 amino acids was designed and synthesised based on four structural parameters, including charge, polar angle, hydrophobicity and hydrophobic moment. The effect of these parameters on antimicrobial activity and selectivity was assessed by structural and biological analyses. Our results indicated that high hydrophobicity and amphipathicity (hydrophobic moment) were correlated with increased haemolytic activity, whilst antimicrobial activity was found to be less dependent on these factors. Three of the synthetic AMPs (GW-Q4, GW-Q6 and GW-H1) showed higher antimicrobial activity and selectivity against a broad spectrum of Gram-positive and Gram-negative bacteria compared with the naturally occurring AMPs magainin 2a and pleurocidin. This study also demonstrates that these rationally designed cationic and amphipathic helical AMPs exhibited high selectivity against several Vibrio spp. and are potential agents for future use in the treatment of these marine pathogens.     

Antimicrobial activity of some N-alkyl substituted of (E)-4-azachalconium and (E)-3'-hydroxy-4-azachalconium bromides

Twelve new N-substituted (E)-azachalconium bromides were synthesized and tested for antimicrobial and antifungal activities. Compounds 5c, 5d and 5h-5l showed very good antimicrobial activity against Staphylococcus aureus, Enterococcusfaecalis as well as Bacillus subtilis and 5h-5j showed moderate activity against Escherichia coli. In particular, (E)-N-dodecyl-4-azachalconium bromide (5i) and (E)-N-tetradecyl-4-azachalconium bromide (5j) showed the most intensive activity against all tested microorganisms.