Antimicrobial and antioxidant activities of silver nanoparticles synthesized by novel biogenic method using mixed reductants.

A novel method, for the synthesis of silver nanoparticles that are eco-friendly by means of mixed reductants method, has been developed. The combined extract of Mentha viridis plant and Prunus domestica gum were used as reducing agents for the synthesis of silver nanoparticles of the size less than 40 nm in diameter. The effect of time and concentration on the formation of silver nanoparticles were also monitored. The silver nanoparticles formed were verified by surface Plasmon spectra using single and double beam UV-Vis spectrophotometer. The XRD technique and scanning electron microscopy were performed to analyze the crystalline structure, crystallite size and morphology. The synthesized silver nanoparticles were tested against different bacterial and fungus strains. The silver nanoparticles showed good inhibition in antimicrobial study and low MIC for bacterial strains. The antioxidant assay was performed to check the scavenging activity. In DPPH, the silver nanoparticles showed good scavenging activity and were found close to that of ascorbic acid.

Evaluation of antioxidant, antimicrobial and anticancer activities of compounds reported Saussurea hypoleuca Spreng. roots.

Current study was intended to isolate bioactive compounds from ethyl acetate fraction of Saussurea hypoleuca root extract and evaluation of their antioxidant, antimicrobial and anti-cancerous activities which might be helpful for their chemo preventive potential against selected bacterial strains. Column chromatography was done for isolation of compounds which were characterized on the basis of extensive spectroscopic analysis; Infra-red (IR), Electron Ionization (EI-Positive), Proton Nuclear Magnetic Resonance (1H-NMR) and Carbon Nuclear Magnetic Resonance (13C-NMR). Two compounds were identified, as sesquiterpenes (40mg) and linoleic acid (33mg) from 10 grams of ethyl acetate fraction. Both compounds have shown in vitro antioxidant activity which in regard; 2, 2- diphenyl-1-picrylhydrazyl (DPPH) scavenging potential was high in sesquiterpenes (261.81) as compared to linoleic acid (90.89). The minimum inhibitory concentrations (MIC) of both compounds were evaluated in various bacterial and fungal strains against respective controls. However, in human hepatocellular carcinoma (Hep G2 cell lines) sesquiterpenes exhibited strong anticancer potential than linolenic acid which might be its potential free radical inactivator in MTT assay. This paper directs the ethano medicinal worth of plant root as it possesses bioactive compounds which in our best knowledge these compounds isolated and reported first time from this plant root specie.

Toxicity and Antimicrobial Activities of Amaranthus caudatus L. (Amaranthaceae) Harvested From Formulated Soils at Different Growth Stages.

This study examined the toxicity and antimicrobial effects of ethanol and aqueous extracts from Amaranthus caudatus grown on soils formulated from parent particles of silt, sand and clay in a glasshouse. Four different soils namely; sandy clay loam, loam, clayey loam and silty clay loam from were formulated were used for cultivation with the unfractionated soil which was the control. Crude extracts obtained from the plant shoots harvested at different growth stages were tested on some certain gram-negative and gram-positive bacteria and some fungi via agar dilution assay. The toxicity of the water and ethanol extracts was also examined via Artemia salina assay and the level of lethality was measured against Clarkson's lethality scale. All aqueous samples, as well as ethanol extracts of flowering and pre-flowering harvests of control soil tested, were non-toxic (LC50 > 1 mg/mL). At post flowering, the ethanolic extracts were highly toxic mostly in clayey loam, control, sandy-clayey loam soils (LC50 < 0.5 mg/mL). Also, antifungal effects of the plant revealed that extracts inhibited the growth of Candida albicans significantly with mild effect on Candida glabrata, Penicillium chrysogenum and Penicillium aurantiogriseum suggesting that the plant is a promising pharmacological candidate in the treatment of candidiasis. For an optimal yield of non-toxic supplement for household consumption which may also serve as pharmacological precursors, clayey loam soil is recommended for cultivation and harvesting may occur at pre-flowering or flowering stage using ethanol and water as solvents of extraction.

In vitro antifungal activity of dehydrozingerone and its fungitoxic properties.

UNLABELLED: The efficacy of Dehydrozingerone (DZ; dehydroderivative of zingerone) as an antifungal agent and its mode of action against food spoilage fungal pathogens was studied and presented. DZ is a constituent of ginger (Zingiber officinale rhizomes) and structural half analogue of curcumin. Its efficacy against Aspergillus oryzae, Aspergillus flavus, Aspergillus niger, Aspergillus ochraceus, Fusarium oxysporum and Penicillium chrysogenum was evaluated. Effect of DZ on the growth and sporulation of A. ochraceus was also studied. The fungal species were susceptible to DZ and the minimum inhibitory concentration and fungicidal concentration ranged from 755 to 911 µM and 880 to 1041 µM respectively. The mycelial and spore germination was significantly inhibited; reduction in the weight of the cell mass, carbohydrate, protein, DNA and RNA constituents in the cells isolated from cultures of A. ochraceus grown with DZ were observed. Scanning electron microscopy studies revealed morphological observations such as cell lysis, inhibition and morphological alterations in hyphae and sporulation in A. ochraceus on treatment with DZ. PRACTICAL APPLICATION: Current investigations revealed that DZ is a potential antifungal agent and can find application as an additive or adjuvant in food and pharmaceutical industries after appropriate toxicological studies.

The antifungal, cytotoxic, antitermite and insecticidal activities of Zizyphus jujube.

Plants are very useful, self-generating machines, producing a variety of useful bioactive products. Keeping in view this idea, the crude methanolic extract and various fractions of Zizyphus jujuba were screened for antifungal, cytotoxic, antitermite and insecticidal activities. Low activity was shown by the crude methanolic extract (12%), n-hexane (9%), chloroform (20%) and ethyl acetate (14%) fraction against Penicillium notatum. Low activity was shown by the n-hexane fraction against Aspergillus niger (10%) and Trichoderma harzianum (13%) and inactive against Aspergillus flavus, Fusarium oxysporum and Rhizopus stolonifer. The CHCl(3) fraction exhibited low activity of 10% against F. oxysporum while showing no activity against the rest of the test fungi. All the test samples were inactive against Rhizopus stolonifer. The crude methanolic extract was highly cytotoxic (73.33%) at the concentration of 1000 (µg/ml) while the rest of the test samples were low in toxicity at the same concentration. The crude methanolic extract of Zizyphus jujuba showed significant antitermite activity against Heterotermes indicola, among the test samples. Against Tribolium castaneum, Rhizopertha dominica and Callosbruchus analis the insecticidal activity was determined. All the test samples except n-hexane showed low activity (20%) against T. castaneum. The n-hexane fraction showed low activity (20%) against R. dominica while the rest of the fractions were inactive against it. Low activity of 40% and 20% was shown by the chloroform and n-hexane fraction respectively against C. analis. The results of the present study revealed that the plant could be as potent source of cytotoxic drugs.

Allyl isothiocyanate as a cancer chemopreventive phytochemical.

Allyl isothiocyanate (AITC), which occurs in many common cruciferous vegetables, is widely and often frequently consumed by humans. Besides antimicrobial activity against a wide spectrum of pathogens, it showed anticancer activity in both cultured cancer cells and animal models, although the underlining mechanisms remain largely undefined. Bioavailability of AITC is extremely high, as nearly 90% of orally administered AITC is absorbed. AITC absorbed in vivo is metabolized mainly through the mercapturic acid pathway and excreted in urine. Available data suggest that urinary concentrations of AITC equivalent are at least ten times higher than in the plasma, and tissue levels of AITC equivalent in the urinary bladder were 14-79 times higher than in other organs after oral AITC administration to rats. These findings suggest that AITC may be most effective in the bladder as a cancer chemopreventive compound. AITC at high-dose levels also exhibit a low degree of cytotoxicity and genotoxicity in animal studies, but such adverse effects are unlikely in humans exposed to dietary levels of AITC. Overall, AITC exhibits many desirable attributes of a cancer chemopreventive agent, and further studies are warranted in order to elucidate its mechanism of action and to assess its protective activity in humans.

Quantitative PCR study on the mode of action of oligosaccharide elicitors on penicillin G production by Penicillium chrysogenum.

AIM: To investigate the effects of single and multiple additions of the oligosaccharide elicitors, obtained from alginate and locust bean gum, on penicillin G production and the transcript level of penicillin G biosynthetic genes. METHODS AND RESULTS: The transcript copy numbers and penicillin G concentration in liquid cultures of Penicillium chrysogenum grown under control and elicited conditions were compared using quantitative PCR and HPLC assay respectively. An increase in the penicillin G production rate and transcript copy numbers of the three major penicillin G biosynthetic genes pcbAB, pcbC and penDE was observed in the elicited cultures compared to control cultures. The effects were observed to be higher in multiple elicitor added cultures compared to single elicitor supplemented and control cultures. CONCLUSIONS: The results show, for the first time in bioreactor cultures, the enhancement of penicillin G transcript copy number of the penicillin biosynthetic genes using qPCR with a corresponding increase in the penicillin G production upon multiple elicitor addition of two different types of elicitors. SIGNIFICANCE AND IMPACT OF THE STUDY: Establishment of the effect of multiple elicitor addition on penicillin G production and investigating the role of oligosaccharide elicitors as transcriptional activators has wide spread impact for antibiotic industry.

Fungistatic activity of flaxseed in potato dextrose agar and a fresh noodle system.

Although numerous researchers have studied flaxseed as a food ingredient for its health benefits, flaxseed (Linum usitatissimum) has never been considered as a food preservative. The objective of this study was to investigate the effect of flaxseed flour (FF) concentration (0, 6, 9, 12, and 15% wt/wt), cultivar ('Omega' and brown) and source (four seed companies located in Minnesota and North Dakota) on flaxseed fungistatic activity. Fungal radial growth was used to assess the fungistatic activity of FF in both potato dextrose agar (PDA) medium and a fresh noodle system. Strains of Penicillium chrysogenum, Aspergillus flavus, Fusarium graminearum, and a Penicillium sp. isolated from molded noodles were used as the test microorganisms. Results showed that growth of F. graminearum was completely inhibited at all FF concentrations in PDA, and the inhibition of the other three test microorganisms increased with increasing FF concentrations. In the model noodle system, FF concentration at 9% or higher significantly reduced the mold count of fresh noodle during storage. In the inoculated noodle system, 6% FF addition was sufficient to significantly inhibit the growth of F. graminearum and A. flavus, whereas 9% FF concentrations showed fungistatic activity against P. chrysogenum and the Penicillium sp. isolate. Differences in the degree of mold inhibition were found among FFs obtained from different sources and cultivars. Results suggested that flaxseed possesses fungistatic activity and could be used as a multifunctional food ingredient.

Fungistatic activity of heat-treated flaxseed determined by response surface methodology.

The objective of this study was to evaluate the effect of heat treatment on the fungistatic activity of flaxseed (Linum usitatissimum) in potato dextrose agar (PDA) medium and a fresh noodle system. The radial growth of Penicilliumn chrysogenum, Aspergillus flavus, and a Penicillium sp. isolated from moldy noodles, as well as the mold count of fresh noodle enriched with heat treated flaxseed, were used to assess antifungal activity. A central composite design in the response surface methodology was used to predict the effect of heating temperature and time on antifungal activity of flaxseed flour (FF). Statistical analysis determined that the linear terms of both variables (that is, heating temperature and time) and the quadratic terms of the heating temperature had significant (P<0.05) effects on the radial growth of all 3 test fungi and the mold count log-cycle reduction of fresh noodle. The interactions between the temperature and time were significant for all dependent variables (P<0.05). Significant reductions in antifungal activities were found when FF was subjected to high temperatures, regardless of heating time. In contrast, prolonging the heating time did not substantially affect the antifungal activities of FF at low temperature. However, 60% of the antifungal activity was retained after FF was heated at 100 degrees C for 15 min, which suggests a potential use of FF as an antifungal additive in food products subjected to low to mild heat treatments.

[The fermentation of 50 kinds of TCMs by Bacillus subtilis and the assay of antibacterial activities of fermented products].

50 Traditional Chinese medicines (TCMs) were fermented by Bacillus subtilis and the antimicrobial activities of the fermented products were assayed against Mycobacterium tuberculosis and Penicillium avellaneum. The results showed that some products of them had stronger antimicrobial activities, but some weaker than the corresponding raw materials, still some had no change, which indicated that microorganism and TCM can effect each other during fermentation.

Autolysis and ageing of Penicillium chrysogenum under carbon starvation: respiration and glucose oxidase production.

During the exponential growth phase of Penicillium chrysogenum NCAIM 00237 the effective conversion of glucose and O2 to gluconate and H2O2 by glucose oxidase (GOX) was the most likely source of intracellular ROS measured. In glucose-supplemented autolysing cultures, the increased of intracellular ROS concentration was attributed to respiration in the absence of any significant GOX activity. The induction of GOX and catalase by glucose and H2O2 was clearly age-dependent in P. chrysogenum. In ageing cryptic growth phase cultures, superoxide dismutase and cyanide-resistant respiration were the major elements of antioxidative defence but these activities were insufficient to prevent the progressive accumulation of ROS and the concomitant decrease in cell vitality.

Life and the outer planets I. Performance of terrestrial organisms in ammonia-rich systems.

Survival and growth of organisms has been demonstrated at 298 degrees K in NH3 atmospheres, including ammonia-methane mixtures. Included are bacteria such as Clostridium perfringens, Pseudomonas aeruginosa, fungi such as Penicillium notatum and Torula utilis. Although the biological response in onion and other species of Allium is limited to germination, standard metabolic poisons were active even in 15 M aqueous NH3, at 250 degrees K. The most extreme example of compatibility between NH3-rich environments and terrestrial life was the retention of metabolic capabilities by conidia of Penicillium after 6 months at 233 degrees K in a liquid ammonia-glycerol medium. Tritiated thymidine, uridine and amino acids were incorporated by these conidia unless subjected to intense gamma-radiation. Observations spanning the past decade suggest that the analogies between H2O and NH3 as solvent media or -OH and -NH2, as functional groups are probably valid. Chemical-biological evolution similar to early terrestrial evolution could be compatible with chemical conditions presumed to exist on the outer planets and some of their satellites.