More herbal antibiotic studies

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[Determination of the antibacterial and antiviral activity of the essential oil from Minthostachys verticillata (Griseb.) Epling]

"The in vitro antiviral activity of the essential oil from Minthostachys verticillata was investigated against herpes simplex virus type 1 (HSV-1) and pseudorabies virus (PrV). The viral inhibition was assayed employing viral plaque reduction assay. The antiviral activity of the essential oil specifically affects PrV and HSV-1 multiplication, since it was found that non toxic effects on cells were observed at the concentrations assayed. The therapeutic index values were 10.0 and 9.5 for HSV-1 and PrV, respectively. The antibacterial activity was studied using a diffusion assay and the broth tube dilution method. Gram-positive bacteria were more sensitive to inhibition by plant essential oil than the gram-negative bacteria. The essential oil of M. verticillata was analyzed by gas chromatography (GC) technique. Of the six components identified in the volatile oil, pulegone (44.56%) and menthone (39.51%) were the major constituents. The antimicrobial activity can be explained to some extent by the presence of pulegone. Results suggest that further investigations concerning the isolation of the substance responsible for the antimicrobial activity and an effort to define the mechanisms of action are warranted."




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Percutaneous treatment of chronic MRSA osteomyelitis with a novel plant-derived antiseptic.

"BACKGROUND: Antibiotic-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococcus (VRE, are an increasing problem world-wide, causing intractable wound infections. Complex phytochemical extracts such as tea tree oil and eucalypt-derived formulations have been shown to have strong bactericidal activity against MRSA in vitro. Polytoxinol (PT) antimicrobial, is the trade name of a range of antimicrobial preparations in solution, ointment and cream form. METHODS: We report the first use of this drug, administered percutaneously, via calcium sulphate pellets (Osteoset,TM), into bone, to treat an intractable MRSA infection of the lower tibia in an adult male. RESULTS AND DISCUSSION: Over a three month period his symptoms resolved with a healing response on x-ray and with a reduced CRP."




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Biological activity of feijoa peel extracts.

"Fractionated extracts of Feijoa peels were studied for cytotoxic activity, anti-human immunodeficiency virus (HIV) activity and antibacterial activity. Two most cytotoxic fractions A3 of acetone extract and M2 of methanol extract had potent inhibitory activity against Gram-positive and Gram-negative bacteria as well as fungi tested. Fraction A4 of acetone extract showed multidrug resistance (MDR)-reversal activity comparable with that of verapamil (positive control). These results indicate the therapeutic value of Feijoa peel extracts as potential antimicrobial and MDR-modulating agents."




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Activity of plant flavonoids against antibiotic-resistant bacteria.

"Thirty eight plant-derived flavonoids representing seven different structural groups were tested for activities against antibiotic-resistant bacteria using the disc-diffusion assay and broth dilution assay. Among the flavonoids examined, four flavonols (myricetin, datiscetin, kaempferol and quercetin) and two -flavones (flavone and luteolin) exhibited inhibitory activity against methicillin-resistant Staphylococcus aureus (MRSA). Myricetin was also found to inhibit the growth of multidrug-resistant Burkholderia -cepacia, vancomycin-resistant enterococci (VRE) and other medically important organisms such as -Klebsiella pneumoniae and Staphylococcus epidermidis. Myricetin was bactericidal to B. cepacia. The results of the radiolabel incorporation assay showed that myricetin inhibited protein synthesis by -B. cepacia."





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Antimicrobial and phytochemical studies on 45 Indian medicinal plants against multi-drug resistant human pathogens.

"Ethanolic extracts of 45 Indian medicinal plants traditionally used in medicine were studied for their antimicrobial activity against certain drug-resistant bacteria and a yeast Candida albicans of clinical origin. Of these, 40 plant extracts showed varied levels of antimicrobial activity against one or more test bacteria. Anticandidal activity was detected in 24 plant extracts. Overall, broad-spectrum antimicrobial activity was observed in 12 plants (L. inermis, Eucalyptus sp., H. antidysentrica, H. indicus, C. equistifolia. T. belerica, T. chebula, E. officinalis, C. sinensis, S. aromaticum and P. granatum). "





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The antibacterial activity of tea in vitro and in vivo (in patients with impetigo contagiosa).

"Tea ointment was very effective with a cure rate of 81.3%. Forty patients were taken as controls and divided into two groups. The first one was given an ointment containing Framycetin and gramicidin (soframycin) with a cure rate of 72.2%; the other group was given oral cephalexin with a cure rate of 78.6%."





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Characterization and cDNA Cloning of two glycine- and histidine-rich antimicrobial peptides from the roots of shepherd's purse, Capsella bursa-pastoris.

"Both shepherins have a Gly-Gly-His motif. These antimicrobial peptides exhibit antimicrobial activity against Gram-negative bacteria and fungi."





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Isolation of a potent anti-MRSA sesquiterpenoid quinone from Ulmus davidiana var. japonica.

"A highly potent anti-MRSA sesquiterpenoid has been isolated from Ulmus davidiana var. japonica, which has been traditionally used to treat infectious diseases in Korea. This naturally occurring Antibiotic was identified as mansonone F (1). This compound has been found to be highly active specifically against MRSA and showed an MIC range of 0.39-3.13 microg/ml which is comparable to that of vancomycin."





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Antimicrobial activity of flavonoids in medicinal plants from Tafi del Valle (Tucuman, Argentina).

"Preliminary studies of flavonoids have been realised in five native species from Tafi del Valle (Tucuman, Argentina) used in popular medicine. Most of compounds detected were flavonoids mono and dihydroxylated in B ring. Screening for antimicrobial activity against Gram positive and Gram negative microorganisms has been realised with Lippia turbinata, Satureja parvifolia, Sambucus peruviana, Verbena officinalis and Chenopodium graveolens. The total extracts of flavonoids of each plant were tested and four species studied showed antimicrobial activity."





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Phenolic constituents of licorice. VIII. Structures of glicophenone and glicoisoflavanone, and effects of licorice phenolics on methicillin-resistant Staphylococcus aureus.

"Two new phenolic compounds, glicophenone (1) and glicoisoflavanone (2), were isolated from commercial licorice, and their structures were elucidated on the basis of spectroscopic data. Antibacterial assays of licorice phenolics for Staphylococcus aureus, including four strains of methicillin-resistant S. aureus (MRSA), and also for Escherichia coli K12 and Pseudomonas aeruginosa PAO1, were then examined. Two compounds among them, 8-(gamma,gamma-dimethylallyl)-wighteone (21) and 3'-(gamma,gamma-dimethylallyl)-kievitone (28), showed remarkable antibacterial effects [minimum inhibitory concentrations (MICs), 8 microg/ml on the MRSA strains and methicillin-sensitive S. aureus. Licochalcone A (14), gancaonin G (20), isoangustone A (24), glyasperins C (30) and D (31), glabridin, (32), licoricidin (33), glycycoumarin (34) and licocoumarone (40) showed antibacterial effects on the MRSA strains with MIC values of 16 microg/ml. Effects on the beta-lactam resistance of the MRSA strains were also examined, and licoricidin (33) noticeably decreased the resistance of the MRSA strains against oxacillin, as shown by the reduction in the MICs of oxacillin (lower than 1/128-1/1000 in the presence of 8 microg/ml of 33, and 1/8-1/32 in the presence of 4 microg/ml of 33). Mechanistic study suggested that 33 does not inhibit the formation of penicillin-binding protein 2' (PBP2'), but affects the enzymatic function of PBP2'."





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New antimicrobial flavanones from Physena madagascariensis.

"Two new flavanones (1 and 2) with antibacterial activity were isolated from the methanolic extract of the dried leaves of Physena madagascariensis using activity against Staphylococcus aureus to guide the isolation. A third flavonoid, a flavanone dimer linked by a methylene group (3) was also isolated and proved to be inactive. The structures of 1 and 2 were established primarily from NMR studies, while that of 3 required more extensive mass spectrometric analysis. All three flavanones had lavandulyl units in the limonene form. Flavanones 1 and 2 were active against several bacteria at concentrations as low as 4 microM."





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Screening of antibacterial and antiparasitic activities of six Moroccan medicinal plants.

"The extracts of six plants selected on the basis of folk-medicine reports were examined for their antibacterial effects against eight pathogenic bacteria. The results showed that n-butanol extract of Calotropis procera proved to be the most effective against the bacteria tested using the paper disc diffusion method. The antiprotozoal activity was also examined and showed that ethyl ether extract of Sium nodiflorum exhibits a parasiticidal effect against Trichomonas intestinalis and vaginalis."





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Antibacterial and antifungal activities of Cistus incanus and C. monspeliensis leaf extracts.

"In this study, the antimicrobial activity of leaf extracts obtained from two species of genus Cistus L. was examined in vitro against five strains of bacteria and five strains of fungi. The species studied are Cistus villosus L. = incanus and Cistus monspeliensis L. All extracts showed inhibitory activity against microorganisms. These results encourage us towards further biological investigation."





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Antibacterial and antiandrogen flavonoids from Sophora flavescens.

"Sixteen flavanones, three flavanonols, and four pterocarpans were isolated from the MeOH extract of the roots of Sophora flavescens. Twelve of these were new compounds, including eight prenylflavanones (1-8), one prenylflavanonol (9) and three novel pterocarpane derivatives (10-12). Their structures were elucidated using NMR and mass spectral methods. Some of these compounds have irregular C10 prenyl moieties at C-8 of the flavanone skeleton. These compounds exhibited significant antibacterial activities against the Gram-positive bacteria Staphylococcus aureus, Bacillus subtilis, S. epidermidis, and Propionibacterium acnes."





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Screening of antibacterial activity of Amaicha del Valle (Tucuman, Argentina) propolis.

"Propolis is extensively used in Argentine folk medicine. Alcoholic extracts of propolis from four localities of Amaicha del Valle (El Paraiso, La Banda Este, La Banda Oeste and El Molino), Province of Tucuman and from Cerrillos, Province of Santiago del Estero, Argentina were prepared. All showed antibacterial activity against Gram positive bacteria"





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Antimicrobial activity of xanthones from Calophyllum species, against methicillin-resistant Staphylococcus aureus (MRSA).

"During the past 5 years, a considerable number of known and new xanthones from the Calophyllum species of Sri Lanka have been isolated and characterized. We have investigated the antimicrobial activity of Calophyllum xanthones, with a special reference to methicillin-resistant Staphylococcus aureus (MRSA). These activity studies were carried out using the agar plate method. Calozeloxanthone, a xanthone which has been isolated from C. moonii and C. lankensis, showed the highest activity against methicillin-resistant S. aureus (MRSA) strains at a concentration of 8.3 microg/ml. Hence, calozeyloxanthone appears to hold promise as an antimicrobial agent in the treatment of infections with S. aureus, including methicillin-sensitive S. aureus (MRSA), and should be investigated further."





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Dihydrofolate reductase and cell growth activity inhibition by the beta-carboline-benzoquinolizidine plant alkaloid deoxytubulosine from Alangium lamarckii: its potential as an antimicrobial and anticancer agent.

"Abstract

Carboline-benzoquinolizidine plant alkaloid deoxytubulosine (DTB) was evaluated and assessed for the first time for its biochemical and biological activity employing the biomarker dihydrofolate reductase (DHFR) (5,6,7,8-tetrahydrofolate: NADP+ oxidoreductase, EC 1.5.1.3) as the probe enzyme, a key target in cancer chemotherapy. DHFR, employed in the present investigations was purified from Lactobacillus leichmannii. DTB, isolated from the Indian medicinal plant Alangium lamarckii was demonstrated to exhibit potent cytotoxicity. The alkaloid potently inhibited the cell growth of L. leichmannii and the cellular enzyme activity of DHFR (IC50=40 and 30M for the cell growth and enzyme inhibitions, respectively). DTB concentrations >75M resulted in a total loss of the DHFR activity, thus suggesting that the carboline-benzoquinolizidine plant alkaloid is a promising potential antitumor agent. Our results are also suggestive of its potential antimicrobial activity. DTB binding to DHFR appears to be slow and reversible. Inhibition kinetics revealed that DHFR has a KI value of 5×10-6 M for DTB and that the enzyme inhibition is a simple linear `non-competitive' type. "





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Comparative study on the in vitro antibacterial activity of Australian tea tree oil, cajuput oil, niaouli oil, manuka oil, kanuka oil, and eucalyptus oil.

"To compare the antibacterial activity of the Australian tea tree oil (TTO) with various other medicinally and commercially important essential myrtaceous oils (cajuput oil, niaouli oil, kanuka oil, manuka oil, and eucalyptus oil) the essential oils were first analysed by GC-MS and then tested against various bacteria using a broth microdilution method. The highest activity was obtained by TTO, with MIC values of 0.25% for Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Salmonella choleraesuis, Shigella flexneri, Bacillus subtilis, Listeria monocytogenes, Staphylococcus aureus, S. saprophyticus, and S. xylosus. It is noteworthy that manuka oil exhibited a higher activity than TTO against gram-positive bacteria, with MIC values of 0.12%. Both TTO and manuka oil also demonstrated a very good antimicrobial efficacy against various antibiotic-resistant Staphylococcus species."





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Anti-Helicobacter pylori flavonoids from licorice extract.

"Licorice is the most used crude drug in Kampo medicines (traditional Chinese medicines modified in Japan). The extract of the medicinal plant is also used as the basis of anti-ulcer medicines for treatment of peptic ulcer. Among the chemical constituents of the plant, glabridin and glabrene (components of Glycyrrhiza glabra), licochalcone A (G. inflata), licoricidin and licoisoflavone B (G. uralensis) exhibited inhibitory activity against the growth of Helicobacter pylori in vitro. These flavonoids also showed anti-H. pylori activity against a clarithromycin (CLAR) and amoxicillin (AMOX)-resistant strain. We also investigated the methanol extract of G. uralensis. From the extract, three new isoflavonoids (3-arylcoumarin, pterocarpan, and isoflavan) with a pyran ring, gancaonols A[bond]C, were isolated together with 15 known flavonoids. Among these compounds, vestitol, licoricone, 1-methoxyphaseollidin and gancaonol C exhibited anti-H. pylori activity against the CLAR and AMOX-resistant strain as well as four CLAR (AMOX)-sensitive strains. Glycyrin, formononetin, isolicoflavonol, glyasperin D, 6,8-diprenylorobol, gancaonin I, dihydrolicoisoflavone A, and gancaonol B possessed weaker anti-H. pylori activity. These compounds may be useful chemopreventive agents for peptic ulcer or gastric cancer in H. pylori-infected individuals."




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Bactericidal activity of Pistacia lentiscus mastic gum against Helicobacter pylori.

"In this study we evaluated the antibacterial activity of mastic gum, a resin obtained from the Pistacia lentiscus tree, against clinical isolates of Helicobacter pylori. The minimal bactericidal concentrations (MBCs) were obtained by a microdilution assay. Mastic gum killed 50% of the strains tested at a concentration of 125 microg/ml and 90% at a concentration of 500 microg/ml."



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