Antioxidant and antimicrobial actions of the clubmoss <Emphasis Type="Italic">Lycopodium clavatum</Emphasis> L.

Purpose of the present study was to evaluate antioxidant, antibacterial, antifungal, and antiviral activities of the petroleum ether, chloroform, ethyl acetate and methanol extracts as well as the alkaloid fraction of Lycopodium clavatum L. (LC) from Lycopodiaceae growing in Turkey. Antioxidant activity of the LC extracts was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging method at 0.2 mg/ml using microplate-reader assay. Antiviral assessment of LC extracts was evaluated towards the DNA virus Herpes simplex (HSV) and the RNA virus Parainfluenza (PI-3) using Madin-Darby Bovine Kidney (MDBK) and Vero cell lines. Antibacterial and antifungal activities of the extracts were tested against standard and isolated strains of the following bacteria; Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Acinobacter baumannii, Klebsiella pneumoniae, Staphylococcus aureus, Bacillus subtilis as well as the fungi; Candida albicans and C. parapsilosis. All of the extracts possessed noteworthy activity against ATCC strain of S. aureus (4 μg/ml), while the LC extracts showed reasonable antifungal effect. On the other hand, we found that only the chloroform extract was active against HSV (16–8 μg/ml), while petroleum ether and alkaloid extracts inhibited potently PI-3 (16–4 μg/ml and 32–4 μg/ml, respectively). However, all of the extracts had insignificant antiradical effect on DPPH. In addition, we also analyzed the content of the alkaloid fraction of the plant by capillary gas chromatography-mass spectrometry (GC-MS) and identified lycopodine as the major alkaloid.     

Inhibitory effect of extracts from Brazilian medicinal plants on the adhesion of <Emphasis Type="Italic">Candida albicans</Emphasis> to buccal epithelial cells

Plants are known to produce a plethora of secondary metabolites which are recognized as a useful source of new drugs or drug leads. Extracts and fractions of Schinus terebinthifolius Raddi (Anacardiaceae), Piper regnellii C.D.C. (Piperaceae), Rumex acetosa L. (Polygonaceae), and Punica granatum L. (Punicaceae) were assessed for their antifungal activity against eight clinical isolates of C. albicans. They were also evaluated for their effect on the adhesion of these C. albicans isolates to buccal epithelial cells (BECs). The ethyl acetate fraction from the leaves of S. terebinthifolius showed promising activity, inhibiting the growth of three C. albicans isolates at 7.8 μg ml⁻¹ and significantly inhibiting their adhesion to BEC at 15 μg ml⁻¹ . In addition, this fraction did not show cytotoxic activity against murine macrophages. The results show the potential of the plant extracts studied as a source of new antifungal compounds. Further studies are necessary for isolation and characterization of the active compounds of these plants.     

Inhibition and killing of fungi by the polyamine oxidase-polyamine system

Both components of the polyamine oxidase (PAO)-polyamine system are known to be present in phagocytes and have thus been postulated to contribute to the antimicrobial activity of these cells. Therefore, the effects of the PAO-polyamine system on three medically important opportunistic fungi were examined. Yeasts of Cryptococcus neoformans, but not Candida albicans blastoconidia or Aspergillus fumigatus conidia, were efficiently killed by the system. Two putative end products of the system, hydrogen peroxide and acrolein, both killed C. neoformans at concentrations attainable with the whole system. However, catalase failed to inhibit activity of the whole system, making hydrogen peroxide an unlikely mediator of killing. Although C. albicans blastoconidia and A. fumigatus conidia were not killed by the PAO-polyamine system, germ tube formation by the former, and hyphal growth by the latter, were markedly inhibited. These data establish that the PAO-polyamine system possesses antifungal activity.     

Fungicidal and Cytotoxic Activity of a Capsicum chinense Defensin Expressed by Endothelial Cells

Plant defensins are antimicrobial peptides that exhibit mainly antifungal activity against a broad range of plant fungal pathogens. However, their actions against Candida albicans have not been extensively studied. The mRNA for γ-thionin, a defensin from Capsicum chinense, has been expressed in bovine endothelial cells. The conditioned medium of these cells showed antifungal activity on germ tube formation (60–70% of inhibition) and on the viability of C. albicans (70–80% of inhibition). Additionally, C. albicans was not able to penetrate transfected cells. Conditioned medium from these cells also inhibited the viability (80%) of the human tumor cell line, HeLa.     

23种中草药的体外抗菌活性筛选研究

为考察中草药抗菌物质基础筛选出活性提取物,该研究通过80%乙醇冷浸和95%乙醇回流提取制备23种中草药的提取物,采用琼脂扩散法测量抑菌圈直径,用微量液体培养基倍比稀释法测定最低抑菌浓度(minimum inhibitory concentration,MIC)和最低杀菌浓度(minimum bactericidal/fungicidal concentration,MBC/MFC),并测定了提取物对临床4种常见病原菌体外抗菌活性。结果表明:紫珠草、千斤拔、黄龙尾等9种中草药对金黄色葡萄球菌有较强的抑菌活性,其MIC/MBC值除个别菌是12.5 mg·mL~(-1)外,其他都在0.09～3.12 mg·mL~(-1)之间;千斤拔、大红袍、过江龙等5种中草药对铜绿假单胞菌有较强抑菌活性,其MIC/MBC值在3.12～12.5 mg·mL~(-1)之间;紫珠草、千里光、石楠等13种中草药对大肠埃希菌有较强的抑菌活性,其MIC/MBC值在0.09～6.25 mg·mL~(-1)之间;八角对白色念珠菌有较强抑菌活性,其MIC/MFC值在0.78～12.5 mg·mL~(-1)之间。23种中草药的抗细菌活性较好,尤其是千斤拔、大红袍、过江龙、八角、黄药子对金黄色葡萄球菌、大肠埃希菌、铜绿假单胞菌都具有较好的抑菌活性,具有广谱抗菌活性;但对真菌抑菌效果不明显,仅有八角对白色念珠菌有抑菌活性。此外,提取溶剂浓度、提取温度和提取时间对中草药的提取率和活性均有影响,冷提稍优于热提。     

Synthesis and Biological Evaluation of Novel Carbazole Hybrids as Promising Antimicrobial Agents

Two series of carbazole analogs of 8‐methoxy‐N‐substituted‐9H‐carbazole‐3‐carboxamides (series 1) and carbazolyl substituted rhodanines (series 2) were synthesized through facile synthetic routes. All the final compounds from these two series were evaluated for their preliminary in vitro antifungal and antibacterial activity against four fungal (Candida albicans, Cryptococcus neoformans, Cryptococcus tropicalis and Aspergillus niger) and four bacterial (Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa) strains, respectively. Among the tested compounds, three compounds of series 1 displayed promising antifungal and antibacterial activity, especially against C. neoformans and S. aureus. In addition, one compound of series 1 displayed notable antimicrobial activity (MIC: 6.25 μg/mL) against clinical isolates of C. albicans and C. neoformans (MIC: 12.5 μg/mL). From the second series, four compounds exhibited significant antifungal and antibacterial activity, especially against C. neoformans and S. aureus. The most active compound of series 2 displayed a prominent antimicrobial activity against C. neoformans (MIC: 3.125 μg/mL) and S. aureus (MIC: 1.56 μg/mL), respectively.     

In vitro activity of eugenol against <Emphasis Type="Italic">Candida albicans</Emphasis> biofilms

Most manifestations of candidiasis are associated with biofilm formation occurring on the surfaces of host tissues and medical devices. Candida albicans is the most frequently isolated causative pathogen of candidiasis, and the biofilms display significantly increased levels of resistance to the conventional antifungal agents. Eugenol, the major phenolic component of clove essential oil, possesses potent antifungal activity. The aim of this study was to investigate the effects of eugenol on preformed biofilms, adherent cells, subsequent biofilm formation and cell morphogenesis of C. albicans. Eugenol displayed in vitro activity against C. albicans cells within biofilms, when MIC₅₀ for sessile cells was 500 mg/L. C. albicans adherent cell populations (after 0, 1, 2 and 4 h of adherence) were treated with various concentrations of eugenol (0, 20, 200 and 2,000 mg/L). The extent of subsequent biofilm formation were then assessed with the tetrazolium salt reduction assay. Effect of eugenol on morphogenesis of C. albicans cells was observed by scanning electron microscopy (SEM). The results indicated that the effect of eugenol on adherent cells and subsequent biofilm formation was dependent on the initial adherence time and the concentration of this compound, and that eugenol can inhibit filamentous growth of C. albicans cells. In addition, using human erythrocytes, eugenol showed low hemolytic activity. These results indicated that eugenol displayed potent activity against C. albicans biofilms in vitro with low cytotoxicity and therefore has potential therapeutic implication for biofilm-associated candidal infections.     

Phospholipase activity in Cryptococcus neoformans

Phospholipases have only been detected in a few fungi and yeasts, in particular in Candida albicans. Secreted phospholipases are considered by some researchers to be a potential factor of virulence and pathogenicity in C. albicans. Twenty-three Cryptococcus neoformans strains were tested in order to observe phospholipase production. Twenty-two of the 23 strains tested were able to produce phospholipases, and the ratio diameter of the colony to total diameter of the colony plus zone of precipitation (Pz) ranged between 0.271 and 0.949. C. neoformans, just like C. albicans, can be divided on the basis of the Pz into different strains according to their virulence and pathogenicity. There also appeared to be a correlation between the phospholipase production and the size of the capsule in the strains isolated from AIDS patients. For this reason, further studies on C. neoformans phospholipase activity would be useful in evaluating the virulence of different strains.     

Evaluation of antimicrobial activity of the lichens <Emphasis Type="Italic">Lasallia pustulata,Parmelia sulcata,Umbilicaria crustulosa</Emphasis>, and <Emphasis Type="Italic">Umbilicaria cylindrica</Emphasis>

The antimicrobial properties of acetone, methanol, and aqueous extracts of the lichens Lasallia pustulata, Parmelia sulcata, Umbilicaria crustulosa, and Umbilicaria cylindrica were studied comparatively in vitro. Antimicrobial activities of the extracts of different lichens were estimated by the disk diffusion test for Gram-positive bacteria, Gram-negative bacteria, and fungal organisms, as well as by determining the MIC (minimal inhibitory concentration). The obtained results showed that the acetone and methanol extracts of Lasallia pustulata, Parmelia sulcata, and Umbilicaria crustulosa manifest antibacterial activity against the majority of species of bacteria tested, in addition to selective antifungal activity. The MIC of lichen extracts was lowest (0.78 mg/ml) for the acetone extract of Lasallia pustulata against Bacillus mycoides. Aqueous extracts of all of the tested lichens were inactive. Extracts of the lichen Umbilicaria cylindrica manifested the weakest activity, inhibiting only three of the tested organisms.     

Antibacterial activity of<Emphasis Type="Italic">Ulva lactuca</Emphasis> against methicillin-resistant<Emphasis Type="Italic">Staphylococcus aureus</Emphasis> (MRSA)

Thein vitro antimicrobial activity of the marine green algaeUlva lactuca was examined against gram-positive bacteria, gram-negative bacteria, and a fungus. The ethyl-ether extract of algae exhibited a broad-spectrum of antibacterial activity. but not antifungal activity againstCandida albicans. In particular, theU. lactuca extract showed strong activity aganst the bacterium methicillin-resistantStaphylococcus aureus (MRSA). This result confirms the potential use of seaweed extracts as a source of antibacterial compounds or as a health-promoting food for aquaculture.     

In vitro antifungal activities of Bay n 7133 and Bay L 9139, two new orally absorbed antifungal imidazole derivatives,against pathogenic yeasts

Bay n 7133 and Bay L 9139 (Bayer AG, Wuppertal, Fed. Rep. Germany) are new, orally absorbable, antifungal imidazole derivatives. In vitro, Bay n 7133 was comparable to ketoconazole and miconazole when tested against isolates of Candida albicans and Cryptococcus neoformans. Bay L 9139 also was active against these organisms but to a lesser degree than the other imidazoles. LY 121019, an analog of echinocandin B, was also tested. It proved to be the most active antimycotic against C. albicans but the least active against C. neoformans. Optimal results were obtained in tests employing Kimmig's agar, a medium previously described for use in susceptibility tests with antifungal agents.     

In Vitro Antimicrobial Activity of <Emphasis Type="Italic">Acacia catechu</Emphasis> and Its Phytochemical Analysis

Acacia catechu, commonly known as catechu, cachou and black cutch is an important medicinal plant and an economically important forest tree. The methanolic extract of this plant was found to have antimicrobial activities against six species of pathogenic and non-pathogenic microorganisms: Bacillus subtilis, Staphylococcus aureus, Salmonella typhi, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. The maximum zone of inhibition (20 mm) was found to be exhibited against S. aureus. For this organism the minimum bactericidal concentration (MBC) of the crude extract was 1,000 μg/ml. The extract was found to be equally effective against gram positive and gram negative bacteria. The antimicrobial activity of the extract was found to be decreased during purification. The chemical constituents of organic plant extracts were separated by thin layer chromatography (TLC) and the plant extracts were purified by column chromatography and were further identified by Gas chromatography–mass selection (GC–MS) analysis. The composition of A. catechu extract had shown major components of terpene i.e. camphor (76.40%) and phytol (27.56%) along with other terpenes in minor amounts which are related with their high antibacterial and antifungal properties.     

Enhanced activity of antifungal drugs using natural phenolics against yeast strains of Candida and Cryptococcus

Aims: Determine whether certain, natural phenolic compounds enhance activity of commercial antifungal drugs against yeast strains of Candida and Cryptococcus neoformans. Methods and Results: Twelve natural phenolics were examined for fungicidal activity against nine reference strains of Candida and one of C. neoformans. Six compounds were selected for synergistic enhancement of antifungal drugs, amphotericin B (AMB), fluconazole (FLU) and itraconazole (ITR). Matrix assays of phenolic and drug combinations conducted against one reference strain, each, of Candida albicans and C. neoformans showed cinnamic and benzoic acids, thymol, and 2,3‐ and 2,5‐dihydroxybenzaldehydes (‐DBA) had synergistic interactions depending upon drug and yeast strain. 2,5‐DBA was synergistic with almost all drug and strain combinations. Thymol was synergistic with all drugs against Ca. albicans and with AMB in C. neoformans. Combinations of benzoic acid or thymol with ITR showed highest synergistic activity. Of 36 combinations of natural product and drug tested, none were antagonistic. Conclusions: Relatively nontoxic natural products can synergistically enhance antifungal drug activity, in vitro. Significance and Impact of the Study: This is a proof‐of‐concept, having clinical implications. Natural chemosensitizing agents could lower dosages needed for effective chemotherapy of invasive mycoses. Further studies against clinical yeast strains and use of animal models are warranted.     

和厚朴酚通过ROS的积累和破坏细胞膜杀死白色念珠菌

[目的]研究在体外情况下和厚朴酚对白色念珠菌的抑制作用及其可能机制。[方法]采用微量稀释法测定和厚朴酚对白色念珠菌的最低抑菌浓度（MIC₈₀）和最低杀菌浓度（MFC）;用透射电镜观察不同浓度和厚朴酚对白色念珠菌超微结构的影响;采用Annexin V-FITC/PI染色法分析不同浓度和厚朴酚对白色念珠菌细胞凋亡的影响;用DCFH-DA染色法测定不同浓度和厚朴酚对白色念珠菌细胞内活性氧积累的影响;用JC-1染色法分析不同浓度和厚朴酚对白色念珠菌线粒体膜电位的影响;用碘化丙啶染色、考马斯亮蓝G-250染色检测和厚朴酚对白色念珠菌细胞膜通透性的影响;通过测定加入麦角甾醇后,和厚朴酚对白色念珠菌的抑制作用的变化,检测和厚朴酚对白色念珠菌细胞膜的影响。[结果]和厚朴酚对白色念珠菌具有很强的抑制作用,MIC和MFC分别为16 μg/mL和32 μg/mL。对白色念珠菌细胞壁、细胞膜和胞浆均有明显的影响。和厚朴酚是通过增加活性氧的产生和破坏线粒体功能来诱导白念珠菌的细胞凋亡和坏死。它也影响细胞膜的通透性,这可能和细胞壁的破坏和与麦角固醇的结合有关。[结论]和厚朴酚通过产生活性氧并伴随着一系列的细胞损伤这种复杂的机制从而对白色念珠菌产生抑制作用,使和厚朴酚成为一种潜在的抗真菌药物。     

Role of cell-mediated immunity in the resistance to experimental sporotrichosis in mice

The in vitro activity of several new imidazoles, cloconazole, sulconazole, butoconazole, isoconazole and fenticonazole, were compared with those of amphothericin B, flucytosine, and three azoles: econazole, miconazole and ketoconazole against isolates of pathogenic Candida. A total of 186 clinical isolates of 10 species of the genus Candida and two culture collection strains were tested by an agar-dilution technique. Isoconazole was the most active azole, followed by butoconazole and sulconazole. Differences between some of the species in their susceptibility to the antifungal agents were noted. Sulconazole and cloconazole had the highest activity in vitro against 106 isolates of C. albicans. Butoconazole and isoconazole were also very active against isolates of C. albicans, and were the most active azole compounds against 80 isolates of Candida spp.     

Rapid screening of <Emphasis Type="Italic">Aspergillus terreus</Emphasis> mutants for overproduction of lovastatin

Summary A novel rapid screening method is demonstrated for isolating lovastatin-overproducing strains of Aspergillus terreus. The screening methodology, based on the activity of lovastatin against the yeast Candida albicans, is nearly three times as fast as the selection methods used earlier. The new 6-h assay shows a linear correlation between the quantity of lovastatin generated by A. terreus isolates and the inhibition zones obtained on plates of C. albicans. The new technique is less expensive and requires less labour.     

Bacteriocin-like inhibitory substances from <Emphasis Type="Italic">Campylobacter</Emphasis> spp.

Twenty-five Campylobacter isolates were screened for production of antimicrobial substances using a deferred antagonism assay. Sixteen isolates showed activity against either Staphylococcus aureus, Salmonella enterica serovar Enteritidis or Candida albicans. The inhibitory activity was sensitive to treatment with pronase E, trypsin and pepsin, suggesting that the antimicrobial compound(s) are proteinaceous. Activity spectra of isolates included S. aureus, Micrococcus luteus, Streptococcus sp., Bacillus subtilis, a drug-resistant clinical isolate of S. aureus and one isolate of C. albicans. Producing isolates showed cross-immunity and inhibitory activity was only observed on solid media. The findings of this study suggest that Campylobacter produces proteinaceous inhibitory substances.     

Bioactive metabolites from Alternaria brassicicola ML-P08, an endophytic fungus residing in Malus halliana

A total of 48 strains were isolated from the normal tissues of Malus halliana and the EtOAc extracts of their cultures were subjected to primary antimicrobial screening against four test bacteria and three fungi. As a result, 22 strains exhibited antimicrobial activity against at least one test microbe. Among them, Alternaria brassicicola ML-P08 showing strong activity (MICs: 0.31–2.50 mg/ml) was selected for further investigation on its secondary metabolites. Bioassay-guided fractionation of the EtOAc extract of its liquid culture afforded seven compounds, which were identified as alternariol (1), alternariol 9-methyl ether (2), altechromone A (3), herbarin A (4), cerevisterol (5), 3β,5α-dihydroxy-(22E,24R)-ergosta-7,22-dien-6-one (6) and 3β-hydroxy-(22E,24R)-ergosta-5,8,22-trien-7-one (7), respectively, by spectral means (MS, IR, ¹H- and ¹³C-NMR). In vitro antimicrobial assay showed that compound 3 was substantially active against Bacillus subtilis, Escherichia coli, Pseudomonas fluorescens and Candida albicans with the MICs of 3.9, 3.9, 1.8, and 3.9 μg/ml, respectively. Compound 4 also showed pronounced antifungal activity against Trichophyton rubrum and C. albicans with MICs of both 15.6 μg/ml. In addition, compound 1 exhibited strong xanthine oxidase inhibitory activity with the IC₅₀ of 15.5 μM, comparable to that of positive control, allopurinol (IC₅₀: 10.7 μM).     

The isolation,characterization and antifungal susceptibilities of <Emphasis Type="Italic">Cryptococcus neoformans</Emphasis> from bird excreta in Klang Valley,Malaysia

The occurrence of Cryptococcus neoformans in bird excreta in Klang valley, Malaysia was determined in this study. Of 544 samples of bird excreta collected from a local zoo, pet shops and public areas, 20 strains of C. neoformans were isolated. All C. neoformans strains were serotype A and thus identified as C. neoformans variety grubii. All did not produce color changes on canavanine–glycine–bromothymol blue agar. All were of α-mating types, as determined by a pheromone-specific PCR assay. The antifungal susceptibility testing using agar diffusion method Neo-sensitabs showed that all were susceptible to amphotericin B, fluconazole and itraconazole.     

Effect of extracts from in vitro-grown shoots of <Emphasis Type="Italic">Quillaja saponaria</Emphasis> Mol. on <Emphasis Type="Italic">Botrytis cinerea</Emphasis> Pers.

The ethanolic and aqueous extracts from in vitro shoots of Quillaja saponaria Mol. (Quillay) were studied for their antifungal activity against the phytopathogenic fungus Botrytis cinerea Pers. These extracts reduced conidial germination and mycelial growth of B. cinerea, ethanolic extracts being more active than aqueous extracts. In addition, the damage areas produced by this fungus on tomato leaves and strawberry fruits pre-treated with quillay extracts were diminished. The fungitoxic effect of in vitro-grown quillay extract was similar to those obtained with commercial fungicides of both natural (BC-1000) and synthetic (iprodione–dicarboximide) origin. On the other hand, the antifungal action of quillay extracts obtained from adult trees naturally grown was only slightly superior to the fungitoxic activity of the extract from in vitro plants. HPLC analysis of the extract showed that it contained saponins and some phenolic compounds such as chlorogenic, caffeic, vanillic, and salicylic acids, and scopoletin, which have been identified as antifungal agents on phytopathogenic fungi. The results obtained in this work, suggests that extracts of in vitro-grown quillay have an important protective effect against B. cinerea and support the use of an in vitro culture system as a biotechnological alternative to obtain environmental safe antifungal quillay extracts to control B. cinerea, contributing to the preservation of this indigenous Chilean species.