7-Hydroxytropolone produced and utilized as an iron-scavenger by <Emphasis Type="Italic">Pseudomonas donghuensis</Emphasis>

Pseudomonas donghuensis can excrete large quantities of iron chelating substances in iron-restricted environments. At least two kinds of iron-chelator can be found in the culture supernatant: fluorescent siderophores pyoverdins, and an ethyl acetate-extractable non-fluorescent substance. The non-fluorescent substance was the dominant contributor to the iron chelating activity of the culture supernatant of P. donghuensis. Electron ionization mass spectrometry, NMR spectroscopy, and IR spectroscopy identified the non-fluorescent iron-chelator as 7-hydroxytropolone. The stoichiometry of 7-hydroxytropolone ferric complex was determined to be 2:1 by the continuous variation method. The production of 7-hydroxytropolone was repressible by iron in the medium. Moreover, the inhibited growth of doubly siderophore-deficient strain of P. donghuensis under iron-limiting conditions could be partly restored by 7-hydroxytropolone. Thus, 7-hydroxytropolone was considered to play a previously undiscovered role as an iron-scavenger for P. donghuensis.     

Protective effects of luteolin-7-O-β-D-glucuronide methyl ester from the ethyl acetate fraction of Lycopi Herba against pro-oxidant reactive species and low-density lipoprotein peroxidation

In this study the potent scavenging activity of “Lycopi Herba” (LH) extract was studied using the following: evaluation of the total phenolics, measuring the antioxidant activity by Trolox equivalent antioxidant concentration, measuring the scavenging effects on reactive oxygen species, on reactive nitrogen species, and measuring the inhibitory effect on Cu²⁺ induced human low-density lipoprotein oxidation in vitro. The ethyl acetate fraction from the LH extracts were found to have a potent scavenging activity against all of the reactive species tested, as well as an inhibitory effect on LDL oxidation. Therefore, we isolated and identified luteolin-7-O-β-D-glucuronide methyl ester as the major compound from the ethyl acetate fraction of LH and their antioxidant activities were evaluated.     

Herbal remedies for the management of seed-borne fungal pathogens by an edible plant Decalepis hamiltonii (Wight & Arn)

Abstract

Antifungal activity-guided assay of solvent extracts of Decalepis hamiltonii (Wight & Arn) (Asclepiadaceae) against important phytopathogenic fungi, known to cause diseases in sorghum, maize and paddy proved to be highly significant. Among the five solvent extracts tested, Petroleum ether extract showed highly significant antifungal activity. Phytochemical analysis revealed that the antifungal active principle is a phenolic compound. TLC separation of the phenolic fraction using chloroform as an eluting solvent revealed the presence of seven bands but the antifungal activity was observed only in band five with R_f value 0.77. The antifungal active compound is identified as 2-hydroxy-4-methoxybenzaldehyde based on Nuclear Magnetic Resonance (NMR) and mass spectral analysis. The Minimal inhibitory concentration (MIC) varied between 200 μg ml^?1 and 700 μg ml^?1 depending on the fungal species. Seed treatment of the active principle significantly increased seed germination and seed vigour with a corresponding decrease in seed mycoflora. The antifungal active compound was effective against all the 24 fungal species tested suggesting broad-spectrum antifungal activity. Comparative evaluation of the active principle with the synthetic fungicides revealed that the antifungal activity of the active principle obtained from the plant is better than that of synthetic fungicide. This plant being an edible one can be exploited in the management of seed-borne pathogenic fungi and the prevention of biodeterioration of grains and mycotoxin elaboration during storage.     

Comparative activity against pathogenic bacteria of the root,stem, and leaf of <Emphasis Type="Italic">Raphanus sativus</Emphasis> grown in India

Aqueous, methanol, ethyl acetate, and chloroform extracts of the root, stem, and leaf of Raphanus sativus were studied for antibacterial activity against food-borne and resistant pathogens. All extracts except the aqueous extracts had significant broad-spectrum inhibitory activity. The ethyl acetate extract of the root had the potent antibacterial activity, with a minimum inhibitory concentration (MIC) of 0.016–0.064 mg/ml and a minimum bactericidal concentration (MBC) of 0.016–0.512 mg/ml against health-damaging bacteria. This was followed by the ethyl acetate extracts of the leaf and stem with MICs of 0.064–0.256 and 0.128–0.256 mg/ml, respectively and MBCs of 0.128–2.05 and 0.256–2.05 mg/ml, respectively. The ethyl acetate extracts of the different parts of R. sativus retained their antibacterial activity after heat treatment at 100°C for 30 min, and their antibacterial activity was enhanced when pH was maintained in the acidic range. Hence this study, for the first time, demonstrated that the root, stem, and leaf of R. sativus had significant bactericidal effects against human pathogenic bacteria, justifying their traditional use as anti-infective agents in herbal medicines.     

Antifungal and other Biological Activities from Oudemansiella Canarii(Basidiomycota)

Summary The ethyl acetate extract from the fungus Oudemansiella canarii grown in malt extract medium was evaluated against (a) the recombinant enzyme trypanothione reductase from Trypanosoma cruzi, (b) lymphocyte proliferation in human peripheral blood mononuclear cells (PBMCs) stimulated with phytohaemaglutinin, (c) the human tumour cell lineages MCF-7, TK-10 and UACC-62, and (d) the phytopathogenic fungus Cladosporium sphaerospermum. At 10 μg/ml, the crude extract was inactive against PBMC but inhibited the growth of UACC-62 cells by 47% and the enzyme trypanothione reductase (TryR). It also presented strong inhibition in the bioautographic assay with C. sphaerospermum. Chromatographic fractionation guided by this assay allowed the isolation of oudemansin A (1), a known fungitoxic compound that showed a minimum inhibitory concentration (MIC) of 1.25 μg/spot in the bioautographic assay. As oudemansin A was not active in the other assays, other components in the extract may be responsible for the observed activities by the crude extract against the UACC-62 cells or the TryR enzyme.     

Characterization of the Biocidal Spectrum of Extracellular Filtrates of <Emphasis Type="Italic">Microcystis aeruginosa</Emphasis>

The effect of dichloromethane (DCM) and ethyl acetate (EA) extract of a cyanobacterium, Microcystis aeruginosa was evaluated against unicellular cyanobacteria and the phytopathogenic fungus Rhizoctonia solani. Fractionation of the filtrate showed the presence of five spots of different Rf values on silica gel coated plates indicating the presence of a number of compounds in the extract. A marked reduction in growth (52%) of the fungus was recorded on the plates supplemented with cyanobacterial extract, indicating the involvement of anti-fungal metabolite(s). The extract did not show any negative influence on seed germination and growth of seedlings of wheat, rice and mung, emphasizing the suitability of the compound for use in agriculture.     

Bionectria ochroleuca NOTL33—an endophytic fungus from Nothapodytes foetida producing antimicrobial and free radical scavenging metabolites

Endophytic fungi are reported to produce diverse classes of secondary metabolites. This study investigated the antimicrobial and free radical scavenging activity of a foliar endophytic fungus from Nothapodytes foetida, a medium sized tree known to produce the antineoplastic compound camptothecin. The fungal isolate was identified as Bionectria ochroleuca based on the ITS rDNA analysis. The differences among endophytic, pathogenic and free living Bionectria ochroleuca were established by RNA secondary structure analysis. The metabolites showed a broad spectrum of antibacterial, antifungal and anti-dermatophytic activity. Minimum inhibitory concentration values of ethyl acetate extracts were in the range of 78–625 μg/mL against all test organisms, except for Pseudomonas aeruginosa (5 mg/mL). Antimicrobial components in the ethyl acetate extract were identified by GC-MS analysis. The isolate was also produced volatile antifungal compounds. A dose-dependent free radical quenching was observed in the ethyl acetate extract. This is the first report on Bionectria sp. as an endophyte of N. foetida. The results indicate that the B. ochroleuca NOTL33 isolate is a potential source of antimicrobial agents and could be used as an effective biofumigant.     

Partial Characterization of the Antimicrobial Activity of Streptomyces antimycoticus FZB53

The paper describes experiments aimed at evaluating the sensitivity of different fungi, most of them plant pathogens and bacteria towards Streptomyces antimycoticus FZB53, a biocontrol agent that, when applied as a seed treatment, in previous studies has shown good activity against different seed‐borne fungal diseases. When incorporated into agar media, the filtrate from shake cultures of S. antimycoticus FZB53 inhibited the mycelial growth or spore germination, respectively, of a broad spectrum of fungi. The most sensitive of the fungi tested was Fusarium culmorum. The inhibitory activity could be removed from the culture filtrate by extraction with ethyl acetate. When ethyl acetate extracts of the pellet and supernatant obtained by centrifugation of the shake culture were added to the agar medium, inhibition of mycelial growth of F. culmorum was restored, especially with the extracts of the pelleted biomass. Autoclaving of the culture filtrate reduced the inhibition of F. culmorum but completely eliminated the inhibitory activity against Fusarium graminearum. Among the bunt fungi tested, spore germination of Tilletia tritici was more sensitive to the culture filtrate of S. antimycoticus FZB53 than spore germination of Ustilago avenae and U. tritici. Separation by thin layer chromatography (tlc) and spraying with different reagents showed that ethyl acetate extracts from shake cultures or biomass scraped from agar media contained several hydrophobic metabolites. When eluted from the tlc‐plates, the material from one of the spots had strong antifungal activity against spore germination of T. tritici and mycelial growth of F. culmorum, respectively. Ethyl acetate extracts from biomass of S. antimycoticus FZB53 prevented the growth of the tested Gram‐positive bacteria, namely Clavibacter michiganensis and different species of Bacillus. The results indicated that these bacteria were at least as sensitive towards the metabolites of S. antimycoticus FZB53 as F. culmorum. The tested Gram‐negative bacteria were not affected.     

Acremonium hansfordii,一中国新记录种及其抗植物病原真菌活性的研究

Acremonium hansfordii是中国一新记录种,在PDA平板上对多种植物病原真菌有很强的抑制作用。通过95%乙醇提取、YPR-Ⅱ型大孔吸附树脂吸附、乙酸乙酯萃取、沸点30-60℃石油醚沉淀等方法从Acremonium hansfordii菌丝体分离纯化出具有抗植物病原真菌活性的化合物枝顶孢素(acremonin),并得到结晶。acremonin对多种植物病原真菌都有抑制作用,其中对苹果腐烂病菌Valsa mali的IC50为0.095μg/mL,热稳定,121℃灭菌30min抑菌活性保留91.9%,pH4-9稳定。     

Biological Insights and NMR Metabolic Profiling of Different Extracts of Spermacoce verticillata (L.) G. Mey.

Spermacoce verticillata (L.) G. Mey. is commonly used in the folk medicine by various cultures to manage common diseases. Herein, the chemical and biological profiles of S. verticillata were studied in order to provide a comprehensive characterization of bioactive compounds and also to highlight the therapeutic properties. The in vitro antioxidant activity using free-radical scavenging, phosphomolybdenum, ferrous-ion chelating and reducing power assays, and the inhibitory activity against key enzymes such as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), tyrosinase, α-amylase and α-glucosidase of S. verticillata extracts (dichloromethane, ethyl acetate, methanol and water) were investigated. The highest total phenolic and flavonoid content were observed in the methanolic and aqueous extracts. Exhaustive 2DNMR investigation has revealed the presence of rutin, ursolic and oleanoic acids. The methanolic extract, followed by aqueous extract have showed remarkable free radical quenching and reducing ability, while the dichloromethane extract was the best source of metal chelators. The tested extracts showed notable inhibitory activity against cholinesterases (AChE: 1.63–4.99 mg GALAE/g extract and BChE: 12.40–15.48 mg GALAE/g extract) and tyrosinase (60.85–159.64 mg KAE/g extract). No inhibitory activity was displayed by ethyl acetate and aqueous extracts against BChE and tyrosinase, respectively. All the tested extracts showed modest α-amylase inhibitory activity, while only the ethyl acetate and aqueous extracts were potent against α-glycosidase. This study further validates the use of S. verticillata in the traditional medicine, while advocating for further investigation for phytomedicine development.     

中国金孢属一新记录种

Fermentation broth of endophytic fungus Trichoderma taxi ZJUF0986 has high antifungal activity to the common 15 species of phytopathogenic fungi. Three bioactive metabolites I, II and III were obtained by extracted with petroleum ether, ethyl acetate and n-butanol and subsequent silica gel column chromatography and preparative HPLC. Among them, compound I, the main metabolite, has strong broad-spectrum antifungal activity, especially to Botrytis cinerea, Rhizoctonia solani and Sclerotinia sclerotiorum with IC50 1.06, 1.08 and 1.13 mg/L, respectively.     

Siderophore containing 2,3-dihydroxybenzoic acid and threonine formed by Rhizobium trifolli

An iron-binding compound was isolated from ethyl acetate extract of culture supernatant fluid of Rhizobium trifolii AR6 and was purified by iron-exchange chromatography. The compound was characterized by UV and IR. It contained 2,3-dihydroxy-benzoic acid and threonine and was accumulated during stationary phase of growth in iron-deficient media. Synthesis of the siderophore was repressed by FeCl3. In iron limited medium the compound promoted growth of R. trifolii strains.     

Susceptibility of some clinical isolates of <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> to fractions from the aerial parts of <Emphasis Type="Italic">Leuzea carthamoides</Emphasis>

The antimicrobial activity of the dichloromethane extract from aerial parts of Leuzea carthamoides DC. was tested in vitro against 19 Staphylococcus aureus strains (ATCC 25923, CNCTC Mau 43/60, clinical isolates). The extract was fractionated by column chromatography on silica gel into six fractions (petroleum ether, toluene, dichloromethane, ethyl acetate, methanol and water). The minimum inhibitory concentrations (MICs) of the fractions ranged from 64 to 1024 μg/mL. An ethyl acetate fraction (EA 1) with the widest range of activity inhibited all of the strains with MIC in the range 128–512 μg/mL. This fraction exhibited potent activity against strains which showed associated resistance to oxacillin, ciprofloxacin and erythromycin.     

Enzyme inhibition and radical scavenging activities of aerial parts of Paeonia emodi Wall. (Paeoniaceae)

The ethanolic extract derived from aerial parts of an indigenous medicinal plant Paeonia emodi was screened for enzyme inhibition activities against Urease (jack bean and Bacillus pasteurii) and α-Chymotrypsin. The extract was also investigated for its radical scavenging activity using DPPH assay. The crude extract was found to possess significant enzyme inhibition activities against jack bean (74%) and Bacillus pasteurii (80%) urease and a moderate activity (54%) against α-Chymotrypsin. The extract also displayed excellent (83%) radical scavenging activity. On the basis of these results, the crude extract was subsequently fractionated into n-hexane, chloroform, ethyl acetate, n-butanol and water fractions and tested independently for the aforesaid activities. Significant inhibitory activity against urease enzyme was observed for the ethyl acetate, n-butanol and water fractions while the n-hexane and chloroform fractions were devoid of any such activity. In the α-Chymotrypsin enzyme inhibition studies the activity was concentrated into the ethyl acetate fraction. All the fractions displayed potent radical scavenging activity. The crude extract and fractions thereof were also subjected to total phenolic content determination. A correlation between radical scavenging capacities of extracts and total phenolic content was observed in the majority of cases.     

紫杉木霉ZJUF0986抗真菌活性代谢产物分离提取及其活性研究

南方红豆杉Taxus chinensis var.maimi内生真菌紫杉木霉Trichoderma taxi菌株ZJUF0986发酵液对15种常见植物病原真菌具有很强的抑菌活性;用石油醚、乙酸乙酯和正丁醇对发酵液进行活性物质的提取分离,并通过硅胶柱层析和制备HPLC纯化,得到3个活性代谢产物Ⅰ、Ⅱ和Ⅲ,其中主要活性代谢产物Ⅰ具有广谱高效抑制植物病原真菌的特点,特别是对灰葡萄孢Botrytis cinema、立桔丝核菌Rhizoctonia solani、核盘菌Sclerotinia sclerotiorum具有很强的抑菌活性,其IC50为1.1mg/L.     

中国金孢属一新记录种

金孢属Chrysosporium是Corda于1833年以革质金孢C. corii Corda为模式种建立的一类有丝分裂产孢真菌.它的有性型主要隶属爪甲团囊菌目Onygenales中的爪甲团囊菌科Onygenaceae和裸囊菌科Arthrodermataceae(Kirk et al.2001;Oorschot 1980).此属真菌大多能分解角蛋白,极有应用价值.     

Isolation and Identification of a Novel Antioxidant with Antitumour Activity from <Emphasis Type="Italic">Serratia ureilytica</Emphasis> Using Squid Pen as Fermentation Substrate

The antioxidant activity of the culture supernatant of Serratia ureilytica TKU013 with squid pen as the sole carbon/nitrogen source was assessed by three methods, and the phenolic contents were assayed. The supernatant with the highest antioxidant activity was further purified by liquid–liquid partition, revealing the ethyl acetate extract exhibited the strongest antioxidant activity and the highest total phenolic content. Eight fractions were retrieved from silica gel column chromatography of this extract, designated F1–F8. F4 was found to possess the strong antioxidative activity and the highest total phenolic content and also exhibited strong cytotoxic activities against two different tumoural cell lines. A new compound (Serranticin) with antioxidant and antitumor activity was obtained from F4. The structure of Serranticin is analogous to that of siderophores (hexacoordinated catecholamine), which are iron chelators. As such, Serranticin has the potential for use as a deferration agent in various iron overload diseases.     

Endomelanconiopsis microspora发酵产物乙酸乙酯提取物对人参核盘菌的抑制机理

【背景】人参菌核病是人参的主要病害之一,严重影响人参的产量。【目的】探索白花蒲公英内生菌(Endomelanconiopsis microspora)发酵产物乙酸乙酯提取物对人参核盘菌的抑制机理。【方法】采用人参核盘菌菌丝生长和孢子萌发试验测定抑制效果;采用显微镜观察菌丝形态变化,通过电导率和核酸含量的变化测定细胞膜通透性,通过丙二醛(malondialdehyde,MDA)含量和超氧化物歧化酶(superoxide dismutase,SOD)、过氧化物酶(peroxidase,POD)和过氧化氢酶(catalase,CAT)活力的变化测定膜脂过氧化程度。【结果】内生菌E. microspora发酵产物乙酸乙酯提取物能显著抑制人参核盘菌菌丝生长,最小抑菌浓度为3.75 mg/mL,培养6 d后抑制率为76.22%。该提取物能显著抑制人参核盘菌孢子萌发,15.00 mg/mL时抑制效果最好,抑制率达90.69%。提取物影响菌丝形态,增加人参核盘菌细胞膜通透性,造成菌丝内含物外渗,7.50 mg/mL处理10 h后电导率和核酸含量分别比对照组增加30.11%和62.85%。同时提取物显著增加人参核盘菌MDA含量和SOD、POD、CAT活力,7.50 mg/mL处理组呈现先上升后下降的变化趋势,并在12 h时达到最高值。【结论】内生菌E. microspora发酵产物乙酸乙酯提取物通过改变人参核盘菌细胞膜通透性,加剧膜脂过氧化,破坏细胞膜完整性,导致细胞内含物流失,显著抑制孢子萌发和菌丝生长。     

Broad-spectrum In vitro antimicrobial activities of Streptomyces sp. strain BCNU 1001

Streptomyces sp. strain BCNU 1001 was isolated from forest soil samples. Cultural, morphological, and physiological characteristics as well as 16S rDNA analysis revealed that the isolate, BCNU 1001, belonged to the genus Streptomyces. The antimicrobial activity of the ethyl acetate extract was confirmed using the broth microdilution technique. The minimum inhibitory concentration (MIC) of the BCNU 1001 ethyl acetate extract was 0.25 mg/mL for Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa, and 0.125 mg/mL for Micrococcus luteus, Staphylococcus aureus, and Pseudomonas fluorescens. The MIC of the BCNU 1001 ethyl acetate extract for Aspergillus niger, Candida albicans, and Saccharomyces cerevisiae was 0.5, 0.125, and 0.25 mg/mL, respectively. BCNU 1001 was also active against dermatophytic fungi such as Trichophyton mentagrophytes and T. rubrum. Furthermore, BCNU 1001 was also found to be effective against Methicillin-resistant Staphylococcus aureus (MRSA), and its ethyl acetate extract showed MIC = 0.5 mg/mL against MRSA. The most abundant antimicrobial compound was identified as a 2-hydroxybenzyl alcohol through analysis utilizing a nuclear magnetic resonance spectroscopy. This compound was seen to be very effective against some kinds of bacteria and fungi.     

Cancer Chemopreventive Effect of Bergenin from Peltophorum pterocarpum Wood

The aqueous extract of Peltophorum pterocarpum (Fabaceae) wood exhibited potent inhibitory effects against Epstein? Barr virus early antigen (EBV‐EA) activation induced with 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) in Raji cells and against melanogenesis in α‐melanocyte‐stimulating hormone (α‐MSH)‐stimulated B16 melanoma cells, as well as potent 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) free radical‐scavenging activity. Two phenolic acid derivatives, bergenin ( 1 ) and gallic acid ( 2 ), were isolated from the ethyl acetate (AcOEt)‐soluble fraction obtained from the extract. Compound 1 exhibited potent inhibitory effect against EBV‐EA activation and against skin tumor promotion in an in vivo two‐stage mouse skin carcinogenesis test based on 7,12‐dimethylbenz[a]anthracene (DMBA) as initiator, and with TPA as promoter. Both compounds 1 and 2 exhibited melanogenesis‐inhibitory activities in α‐MSH‐stimulated B16 melanoma cells, and, in addition, compound 2 showed strong DPPH radical‐scavenging activity.