Antimicrobial activity of extracts of the lichen Xanthoparmelia pokornyi and its gyrophoric and stenosporic acid constituents

The antimicrobial activity of the diethyl ether, acetone, chloroform, petroleum ether, and ethanol extracts of the lichen Xanthoparmelia pokornyi and its gyrophoric acid and stenosporic acid constituents has been screened against some foodborne bacteria and fungi. Both the extracts and the acids showed antimicrobial activity against Aeromonas hydrophila, Bacillus cereus, Bacillus subtilis, Listeria monocytogenes, Proteus vulgaris, Staphylococcus aureus, Streptococcus faecalis, Yersinia enterocolitica, Candida albicans and Candida glabrata. The extracts were inactive against the tested filamentous fungi. The MIC values of the extracts and the acids for the bacteria have also been determined.     

Antimicrobial activity of extracts of the lichen Parmelia sulcata and its salazinic acid constituent

The antimicrobial activity of the acetone, chloroform, diethyl ether, methanol, and petroleum ether extracts of the lichen Parmelia sulcata and its salazinic acid constituent have been screened against twenty eight food-borne bacteria and fungi. All of the extracts with the exception of the petroleum ether extract showed antimicrobial activity against Aeromonas hydrophila, Bacillus cereus, Bacillus subtilis, Listeria monocytogenes, Proteus vulgaris, Yersinia enterocolitica, Staphylococcus aureus, Streptococcus faecalis, Candida albicans, Candida glabrata, Aspergillus niger, Aspergillus fumigatus, and Penicillium notatum. Salazinic acid did not show antimicrobial activity against L. monocytogenes, P. vulgaris, Y. enterocolitica, and S. faecalis but showed activity against Pseudomonas aeruginosa and Salmonella typhimurium as well. The MIC values of the extracts and the acid for the bacteria and fungi have also been determined.     

The antimicrobial activity of extracts of the lichen Cladonia foliacea and its (-)-usnic acid, atranorin, and fumarprotocetraric acid constituents

The antimicrobial activity of the chloroform, diethyl ether, acetone, petroleum ether, and ethanol extracts of the lichen Cladonia foliacea and its (-)-usnic acid, atranorin, and fumarprotocetraric acid constituents against 9 bacteria and fungi has been investigated. The extracts and pure compounds alone were found active against the same bacteria and the same yeasts. Bacillus cereus, Bacillus subtilis, Staphylococcus aureus, Streptococcus faecalis, Proteus vulgaris, Listeria monocytogenes, Aeromonas hydrophila, Candida albicans, and Candida glabrata growth were inhibited. In addition, the MICs of the extracts, (-)-usnic acid, atranorin and fumarprotocetraric acid were determined.     

The antimicrobial activity of extracts of the lichen Hypogymnia tubulosa and its 3-hydroxyphysodic acid constituent

The antimicrobial activity and the MIC values of the diethyl ether, acetone, chloroform, petroleum ether, and ethanol extracts of the lichen Hypogymnia tubulosa and its 3-hydroxyphysodic acid constituent have been investigated against some microorganisms. At least one of the extracts or 3-hydroxyphysodic acid showed antimicrobial activity against Aeromonas hydrophila, Bacillus cereus, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Listeria monocytogenes, Proteus vulgaris, Salmonella typhimurium, Staphylococcus aureus, Streptococcus faecalis, and Candida albicans. No antifungal activity of the extracts has been observed against ten filamentous fungi.     

Antimicrobial activity of extracts of chemical races of the lichen Pseudevernia furfuracea and their physodic acid, chloroatranorin, atranorin, and olivetoric acid constituents

The antimicrobial activity and the MIC values of the ethanol, chloroform, diethyl ether, and acetone extracts of the chemical races of Pseudevernia furfuracea (var. furfuracea and var. ceratea) and their physodic acid, chloroatranorin, atranorin, and olivetoric acid constituents have been investigated against some microorganisms. Nearly all extracts of both chemical races showed antimicrobial activity against Aeromonas hydrophila, Bacillus cereus, Bacillus subtilis, Listeria monocytogenes, Proteus vulgaris, Staphylococcus aureus, Streptococcus faecalis, Yersinia enterocolitica, Candida albicans, Candida glabrata, Alternaria alternata, Ascochyta rabiei, Aspergillus niger, Fusarium culmorum, Fusarium moniliforme, Fusarium oxysporum, Fusarium solani, and Penicillium notatum. There was no antimicrobial activity of the extracts against Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Pseudomonas syringae, Salmonella typhimurium, Alternaria citri, Alternaria tenuissima, and Gaeumannomyces graminis. Chloroatranorin and olivetoric acid were active against the same microorganisms with few exceptions. Physodic acid was active against about the same bacteria and yeasts and inactive against all of the filamentous fungi tested. Also no activity of atranorin against the filamentous fungi was observed.     

Evaluation of the antimicrobial activity of the acetone extract of the lichen Ramalina farinacea and its (+)-usnic acid, norstictic acid, and protocetraric acid constituents

The acetone extract of the lichen Ramalina farinacea and its (+)-usnic acid constituent showed antimicrobial activity against Bacillus subtilis, Listeria monocytogenes, Proteus vulgaris, Staphylococcus aureus, Streptococcus faecalis, Yersinia enterocolitica, Candida albicans, and Candida glabrata. Norstictic acid was active against Aeromonas hydrophila as well as the above microorganisms except Yersinia enterocolitica. Protocetraric acid showed activity only against the tested yeasts Candida albicans and Candida glabrata. The MIC values of the extract as well as of the three substances were determined. No antifungal activity of the acetone extract has been observed against ten filamentous fungi.     

Identification and quantitation of usnic acid from the lichen Usnea species of Anatolia and antimicrobial activity

Six species of lichens, such as Usnea florida, Usnea barbata, Usnea longissima, Usnea rigida, Usnea hirta and Usnea subflorida, were collected from different areas of Anatolia (district of Antalya, Karabük, Qankiri, Giresun and Trabzon) in Turkey. Their usnic acid amounts in acetone extracts were determined by HPLC. In addition, antimicrobial activities of these extracts were determined against Escherichia coli (ATCC 35218), Enterococcus faecalis (RSKK 508), Proteus mirabilis (Pasteur Ens. 235), Staphylococcus aureus, Bacillus subtilis and Bacillus megaterium. It was shown that with increasing amount of usnic acid, the antimicrobial activity increased. Usnic acid contents of Usnea species varied between 0.22-6.49% of dry weight.     

Evaluation of antimicrobial activity of certain Chinese plants used in folkloric medicine

Six selected plants, belonging to 3 families from Nanjing of China, were extracted with the solvent 95% (v/v) ethanol to yield 11 extracts. The extracts were evaluated for their effects on the growth of eight clinical bacteria, two fungi and one yeast using a modified agar diffusion method. The results showed that the majority of the extracts investigated showed greater activities against the Gram-positive bacteria than against the Gram-negative bacteria, the fungi and the yeast. The strongest antimicrobial activity was exhibited by the stem extracts of Mahonia fortunei against multiresistant Staphylococcus aureus strains, followed by the stem extracts of Mahonia bealei, while Bacillus thuringiensis was the most sensitive to all extracts.     

Antimicrobial activity of some Hypericum species

The crude methanolic extracts of six species of Hypericum [H. caprifoliatum Cham. & Schlecht., H. carinatum Griseb., H. connatum Lam., H. ternum A. St. Hil., H. myrianthum Cham. & Schlecht. and H. polyanthemum Klotzsch ex Reichardt] growing in southern Brazil were analyzed for antimicrobial activity against several microorganisms (bacteria and fungi). The most active plant was H. caprifoliatum, which showed activity against Staphylococcus aureus. Only H. polyanthemum and H. ternum extracts were active against Bacillus subtilis. None of the crude methanolic extracts showed activity against S. epidermidis, Escherichia coli or Saccharomyces cerevisiae. Extracts from these species were evaluated chemically and tannin, flavonoid and phenolic acids were the prominent compounds. The plants contained quercitrin, hyperoside (except H. connatum) and, less frequently, isoquercitrin and chlorogenic acid. In contrast to H. perforatum, which has high concentrations of rutin, these species do not produce this flavonoid or it appears as traces. The tannin concentration varied between 5.1 and 16.7% in H. myrianthum and H. ternum, respectively.     

Bioactivity studies of extracts from Tridax procumbens.

An updated review on the biological activity of Tridax procumbens is presented. A detailed biological screening comprised of gram-positive and gram-negative bacteria, yeasts and fungi using crude extracts of this plant was undertaken. The n-hexane extract of the flowers showed activity against Escherichia coli. The same extract of the whole aerial parts was active against Mycobacterium smegmatis, Escherichia coli, Salmonella group C and Salmonella paratyphi. The ethyl-acetate extract of the flowers was active against Bacillus cereus and Klebsiella sp. The aerial parts extract also showed activity only against Mycobacterium smegmatis and Staphylococcus aureus, while the aqueous extract showed no antimicrobial activity. None of the tested extracts was active against the yeasts, Candida albicans, Candida tropicalis and Rhodotorula rubra; or the fungi: Aspergillus flavus, Aspergillus niger, Mucor sp. and Trichophyton rubrum.     

Determination of usnic acid in some Rhizoplaca species from Middle Anatolia and their antimicrobial activities

Three species of lichens, Rhizoplaca chrysoleuca (Sm.) Zopf, Rhizoplaca melanopthalma (DC.) Leuckert & Poelt and Rhizoplaca peltata Ramonds Leuckert, were collected from middle Anatolia, Erciyes Mountain (Kayseri) in Turkey. Their usnic acid amounts were determined by HPLC in acetone extracts. In addition, antimicrobial activities of these extracts were determined against Escherichia coli (ATCC 35218), Enterococcus faecalis (RSKK 508), Proteus mirabilis (Pasteur Ens. 235), Staphylococcus aureus, Bacillus subtilis, Bacillus megaterium and Pseudomonas aeruginosa. It was shown that, as the usnic acid amount increased, the antimicrobial activities increased too. The usnic acid contents of Rhizoplaca species varied between 0.19-4.0% dry weight.     

Antimicrobial activity and phytochemical analyses of Polygonum aviculare L. (Polygonaceae), naturally growing in Egypt

Polygonum aviculare (Polygonaceae) is an herb commonly distributed in Mediterranean coastal regions in Egypt and used in folkloric medicine. Organic and aqueous solvent extracts and fractions of P. aviculare were investigated for antimicrobial activities on several microorganisms including bacteria and fungi. Phytochemical constituents of air-dried powered plant parts were extracted using aqueous and organic solvents (acetone, ethanol, chloroform and water). Antimicrobial activity of the concentrated extracts was evaluated by determination of the diameter of inhibition zone against both Gram-negative and Gram-positive bacteria and fungi using paper disc diffusion method.Results of the phytochemical studies revealed the presence of tannins, saponins, flavonoids, alkaloids and sesquiterpenes and the extracts were active against both Gram-negative and Gram-positive bacteria. Chloroform extract gave very good and excellent antimicrobial activity against all tested bacteria and good activity against all tested fungi except Candida albicans. Structural spectroscopic analysis that was carried out on the active substances in the chloroform extract led to the identification of panicudine (6-hydroxy-11-deoxy-13 dehydrohetisane).Evaluation of the antimicrobial activity of panicudine indicated significant activity against all tested Gram-negative and Gram-positive organisms. Panicudine displayed considerable activity against the tested fungi with the exception of C. albicans. Antimicrobial activity of the extracts was unaffected after exposure to different heat treatments, but was reduced at alkaline pH. Studies of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of panicudine on the tested organisms showed that the lowest MIC and the MBC were demonstrated against Salmonella paratyphi, Bacillus subtilis and Salmonella typhi and the highest MIC and MBC were against Staphylococcus aureus.     

麻叶荨麻籽抑菌成分和抑菌特性的研究

目的：为了确定麻叶荨麻籽的抑菌成分和其抑菌特性。方法：以麻叶荨麻籽的不同提取物为抑菌剂进行抑菌。结果：麻叶荨麻籽的抑菌活性部位是石油醚和乙酸乙脂提取物,其中石油醚提取物的抑菌作用最强,对大肠杆菌和枯草芽孢杆菌的最低抑菌浓度是1．25mg/mL,金黄色葡萄球菌是2．5mg/mL。麻叶荨麻籽抗菌活性成分是：酚类、鞣质、有机酸等化合物。石油醚提取物对三种细菌脲酶活性均有不同程度的抑制作用。结论：麻叶荨麻籽提取物是较为有效的抑菌物。     

Antimicrobial activity of broccoli (Brassica oleracea var. italica) cultivar Avenger against pathogenic bacteria,phytopathogenic filamentous fungi and yeast

Aims

The objective of this study was to show whether the edible part of broccoli has antibacterial and antifungal activity against micro‐organism of importance in human health and vegetable spoilage, and to test if this effect was partially due to antimicrobial peptides (AMPs).

Methods and Results

Crude extracts were obtained from florets and stems of broccoli cultivar Avenger and the inhibitory effect was demonstrated against pathogenic bacteria (Bacillus cereus, Staphylococcus xylosus, Staphylococcus aureus, Shigella flexneri, Shigella sonnei, Proteus vulgaris), phytopathogenic fungi (Colletotrichum gloeosporioides, Asperigillus niger) and yeasts (Candida albicans and Rhodotorula sp.). It was shown that samples treated with proteolytic enzymes had a reduction of approximately 60% in antibacterial activity against Staph. xylosus, suggesting that proteinaceous compounds might play a role in the inhibitory effect. Antimicrobial components in crude extracts were thermoresistant and the highest activity was observed under acidic conditions. It was shown that antifungal activity of broccoli's crude extracts might not be attributed to chitinases.

Conclusions

Organic broccoli cultivar Avenger has antimicrobial activity against pathogenic bacteria, yeast and phytophatogenic fungi. Data suggest that this effect is partially due to AMPs.

Significance and Impact of the Study

Broccoli's crude extracts have activity not only against pathogenic bacteria but also against phytophatogenic fungi of importance in agriculture. We suggest for first time that the inhibitory effect is probably due to AMPs.     

Heat stable antimicrobial activity of Allium ascalonicum against bacteria and fungi

To study antimicrobial activity of shallot in comparison with that of garlic and onion against 23 strains of fungi and bacteria, water extracts of garlic, shallot and onion bulbs were prepared. Each extract was studied in different forms for their antimicrobial activity viz., fresh extract, dry extract and autoclaved extract. Minimal inhibitory concentration and minimal lethal concentrations of these extracts were determined against all organisms by broth dilution susceptibility test. Fresh extract of garlic showed greater antimicrobial activity as compared to similar extracts of onion and shallot. However, dried and autoclaved extracts of shallot showed more activity than similar extracts of onion and garlic. Fungi were more sensitive to shallot extract than bacteria. Amongst bacteria, B. cereus was most sensitive (MIC=5 mg ml(-1)). The lowest minimum bactericidal concentration of shallot extract amongst bacteria tested was 5 mg ml(-1) for B. cereus. Amongst fungi, Aureobasidium pullulans and Microsporum gypseum were most sensitive (MIC= 0.15 mg ml(-1)). The lowest minimum lethal concentration was 2.5 mg ml(-1) for Microsporum gypseum and Trichophyton mentagrophytes. It was therefore, expected that the antimicrobial principle of shallot was different than the antimicrobial compounds of onion and garlic. In addition, the antimicrobial component of the shallot extract was stable at 121 degrees C.     

玉米须提取物对食品腐败菌及致病菌抑制作用的研究

首次以玉米须提取物对7种常见的食品腐败菌及致病菌进行抑菌试验,发现玉米须的乙醇提取物的效果最好,其最低抑菌浓度（MIC）为3．0g/100g,此外,对食品加工条件（如杀菌方式等）及食品介质（如PH）对玉米须提取物抑菌活性的也作了研究,结果表明,玉米须提取物在常规食品杀菌条件（UHT）及中酸到酸性环境下抑菌活性稳定,因而可作为潜在的食品防腐剂。     

Isolation and characterization of a transposon mutant of Pseudomonas fluorescens AU63 deficient in antifungal activity against Pythium ultimum

Tn5 transposon mutagenesis via electroporation of Pseudomonas fluorescens AU63 was used to generate mutants deficient in antifungal activity against the phytopathogenic fungi Pythium ultimum and Thielaviopsis basicola. Mutant C-45 was obtained by an initial screen for the loss of antibacterial activity against Bacillus subtilis and a subsequent screen of mutants obtained for the loss of antifungal activity against pathogenic fungi. A single chromosomal insertion of Tn5 in the chromosome of Ps. fluorescens C-45 was confirmed by Southern blot hybridization. A metabolite responsible for the observed antibacterial and antifungal activities was identified using thin layer chromatography. The antimicrobial activities of the partially purified substance present in the parental strain and missing in the C-45 mutant were not affected by protease, high temperature, acid or alkali treatment. These results provide the basis for a structural analysis of this new antimicrobial substance and the genetic elucidation of its biosynthesis.     

Biological activities from extracts of endophytic fungi isolated from Viguiera arenaria and Tithonia diversifolia

A total of 39 endophytic fungi have been isolated from Viguiera arenaria and Tithonia diversifolia, both collected in S?o Paulo State, Brazil. The isolates were identified based on their ribosomal DNA sequences. The ethyl acetate (EtOAc) extracts of all endophytic fungi were evaluated for their antimicrobial, antiparasitic and antitumoral activity. Antimicrobial screening was conducted using an agar diffusion assay against three pathogenic microorganisms: Staphylococcus aureus, Escherichia coli and Candida albicans. Antiparasitic activity was determined by enzymatic inhibition of gGAPDH of Trypanosoma cruzi and adenine phosphorybosiltransferase (APRT) of Leishmania tarentolae. Antitumoral activity was tested against human T leukemia cells by the Mosmann colorimetric method. All extracts showed activity in at least one assay: 79.5% of the extracts were cytotoxic against leukemia cells, 5.1% of the extracts were active against S. aureus, 25.6% against E. coli and 64.1% against Candida albicans. Only one extract showed promising results in the inhibition of parasitic enzymes gGAPDH (95.0%) and three were found to inhibit APRT activity. The cytotoxic extract produced by the strain VA1 (Glomerella cingulata) was fractionated and yielded nectriapyrone and tyrosol. Nectriapyrone showed relevant cytotoxic activity against both human T leukemia and melanoma tumor cell lines.     

Antimicrobial activity of isocytisoside and extracts of Aquilegia vulgaris L

AIMS: The aim of this study was to analyse the antimicrobial properties extracts of Aquilegia vulgaris, and their principial flavonoid component and to compare the obtained results with the activity of gentamicin and nystatin. METHODS AND RESULTS: The ethanol, acetone and isopropanol extracts as well as the subextracts isolated from the methanol extract together with the main flavonoid: 4'-methoxy-5,7-dihydroxyflavone 6-C-glucoside (isocytisoside) were obtained from the leaves with stems of Aquilegia vulgaris L. All the extracts were analysed by TLC to confirm flavonoids and phenolic acids occurrence. The antimicrobial activity was tested by the method of series dilutions against different Gram-positive, Gram-negative bacteria and also fungi. The results have shown that the extracts, subextracts and isocytisoside inhibit growth of all studied micro-organisms, revealing the greatest activity against Gram-positive Staphylococcus aureus, Staph. epidermidis and the mould Aspergillus niger. CONCLUSIONS: The antimicrobial activity of the tested materials it is possibly related to the content of isocytisoside. SIGNIFICANCE AND IMPACT OF THE STUDY: This study has determined new activity of A. vulgaris and suggested the necessity of further studies.     

Cross-Species Induction of Antimicrobial Compounds, Biosurfactants and Quorum-Sensing Inhibitors in Tropical Marine Epibiotic Bacteria by Pathogens and Biofouling Microorganisms

Enhancement or induction of antimicrobial, biosurfactant, and quorum-sensing inhibition property in marine bacteria due to cross-species and cross-genera interactions was investigated. Four marine epibiotic bacteria (Bacillus sp. S3, B. pumilus S8, B. licheniformis D1, and Serratia marcescens V1) displaying antimicrobial activity against pathogenic or biofouling fungi (Candida albicans CA and Yarrowia lipolytica YL), and bacteria (Pseudomonas aeruginosa PA and Bacillus pumilus BP) were chosen for this study. The marine epibiotic bacteria when co-cultivated with the aforementioned fungi or bacteria showed induction or enhancement in antimicrobial activity, biosurfactant production, and quorum-sensing inhibition. Antifungal activity against Y. lipolytica YL was induced by co-cultivation of the pathogens or biofouling strains with the marine Bacillus sp. S3, B. pumilus S8, or B. licheniformis D1. Antibacterial activity against Ps. aeruginosa PA or B. pumilus BP was enhanced in most of the marine isolates after co-cultivation. Biosurfactant activity was significantly increased when cells of B. pumilus BP were co-cultivated with S. marcescens V1, B. pumilus S8, or B. licheniformis D1. Pigment reduction in the quorum-sensing inhibition indicator strain Chromobacterium violaceum 12472 was evident when the marine strain of Bacillus sp. S3 was grown in the presence of the inducer strain Ps. aeruginosa PA, suggesting quorum-sensing inhibition. The study has important ecological and biotechnological implications in terms of microbial competition in natural environments and enhancement of secondary metabolite production.