Chemical constituents, antifungal and antioxidative effects of ajwain essential oil and its acetone extract

GC and GC-MS analysis of ajwain essential oil showed the presence of 26 identified components which account for 96.3% of the total amount. Thymol (39.1%) was found as a major component along with p-cymene (30.8%), gamma-terpinene (23.2%), beta-pinene (1.7%), terpinene-4-ol (0.8%) whereas acetone extract of ajwain showed the presence of 18 identified components which account for 68.8% of the total amount. The major component was thymol (39.1%) followed by oleic acid (10.4%), linoleic acid (9.6%), gamma-terpinene (2.6%), p-cymene (1.6%), palmitic acid (1.6%), and xylene (0.1%). Moreover, the oil exhibited a broad spectrum of fungitoxic behavior against all tested fungi such as Aspergillus niger, Aspergillus flavus, Aspergillus oryzae, Aspergillus ochraceus, Fusarium monoliforme, Fusarium graminearum, Pencillium citrium, Penicillium viridicatum, Pencillium madriti, and Curvularia lunata as absolute mycelial zone inhibition was obtained at a 6-microL dose of the oil. However, the acetone extract showed better antioxidative activity for linseed oil as compared with synthetic antioxidants such as butylated hydroxyl toluene and butylated hydroxyl anisole.     

Antifungal properties of wheat histones (H1-H4) and purified wheat histone H1

Wheat ( Triticum spp.) histones H1, H2, H3, and H4 were extracted, and H1 was further purified. The effect of these histones on specific fungi that may or may not be pathogenic to wheat was determined. These fungi included Aspergillus flavus , Aspergillus fumigatus , Aspergillus niger , Fusarium oxysporum , Fusarium verticillioides , Fusarium solani , Fusarium graminearum , Penicillium digitatum , Penicillium italicum , and Greeneria uvicola . Non-germinated and germinating conidia of these fungi were bioassayed separately. The non-germinated and germinating conidia of all Fusarium species were highly susceptible to the mixture (H1-H4) as well as pure H1, with viability losses of 99-100% found to be significant (p < 0.001) at ≤10 μM or less for the histone mixture and pure H1. F. graminearum was the most sensitive to histone activity. The histones were inactive against all of the non-germinated Penicillium spp. conidia. However, they significantly reduced the viability of the germinating conidia of the Penicillium spp. conidia, with 95% loss at 2.5 μM. Non-germinated and germinating conidia viability of the Aspergillus spp. and G. uvicola were unaffected when exposed to histones up to 10 μM. Results indicate that Fusarium spp. pathogenic to wheat are susceptible to wheat histones, indicating that these proteins may be a resistance mechanism in wheat against fungal infection.     

Inhibition of aflatoxin biosynthesis in Aspergillus flavus by diferuloylputrescine and p-coumaroylferuloylputrescine

A mixture of diferuloylputrescine/p-coumaroylferuloylputrescine (85:15, w/w) demonstrated inhibitory activity against aflatoxin B1 biosynthesis in Aspergillus flavus isolate AF13. Inhibition was concentration dependent, with a 50% effective dose of 30 microg of diferuloylputrescine/p-coumaroylferuloylputrescine per milliliter of medium. Aflatoxin inhibition levels of up to 93% were achieved using this conjugated polyamine material. This diconjugated polyamine mixture did not display inhibitory effects on A. flavus growth (mycelial weight) at any of the concentrations tested. A survey of hand-dissected corn (Zea mays) kernel tissues, including endosperm, germ, pericarp, and wax, revealed that the highest concentrations of these conjugated polyamines were localized in the pericarp of the seed. Analysis of a number of corn accessions did not reveal a correlation between diferuloylputrescine/ p-coumaroylferuloylputrescine concentration and resistance/susceptibility to A. flavus infection. The localization of these diconjugated polyamine components in the pericarp, which functions as a physical barrier and surrounds the internal food storage reserves, suggests a defensive role for these materials.     

Inhibition of aflatoxin B(1) biosynthesis in Aspergillus flavus by anthocyanidins and related flavonoids.

Anthocyanidins and precursors or related flavonoids were tested at concentrations from 0.3 to 9.7 mM ( approximately 0.1-3.0 mg/mL) for activity against growth and aflatoxin B(1) biosynthesis by Aspergillus flavus Link:Fr. NRRL 3357. Aflatoxin B(1) production was inhibited by all anthocyanidins tested, and 3-hydroxy compounds were more active than 3-deoxy forms. Monoglycosides of cyanidin were 40% less inhibitory than the aglycon, whereas a monoglucoside and a diglucoside of pelargonidin were 80 and 5%, respectively, as active as the aglycon. Of eight flavonoids tested, only kaempferol was moderately active, whereas luteolin and catechin were weakly inhibitory. Binary combinations of delphinidin and three other aflatoxin inhibitors acted independently of each other. Results with an aflatoxin pathway mutant indicated that anthocyanidin inhibition occurred before norsolorinic acid synthesis.     

Mycoflora and occurrence of aflatoxin B(1) and fumonisin B(1) during storage of Brazilian sorghum

The present study is a 1-year follow up of the mycoflora of 140 samples of Brazilian freshly harvested (10) and stored (130) sorghum, the levels of aflatoxin and fumonisin contamination detected in the grains, and the prevailing abiotic factors (grain moisture content, water activity, temperature, relative humidity, and mean rainfall) at the time of sampling. The results show a predominance of the genera Phoma (57.1%), Aspergillus (42.7%), Fusarium (25.0%), and Rhizopus (21.4%) and the presence of nine other filamentous fungi. Fusarium, Aspergillus, and Penicillium, the three most important genera in terms of toxicity, presented numbers of colony forming units per gram of sorghum (CFU/g) that varied from 1 x 10(3) to 36 x 10(3), from 1 x 10(3) to 295 x 10(3), and from 1 x 10(3) to 20 x 10(3) CFU/g, respectively. The species most frequently found were Aspergillus flavus and Fusarium moniliforme. Of the total samples analyzed, 12.8% were contaminated with aflatoxin B(1) (concentration mean = 7-33 microg/kg) and 74.2% with fumonisin B(1) (concentration mean = 0.11-0.15 microg/g). This paper is the first report of the natural occurrence of aflatoxins and fumonisins in sorghum grain from Brazil.     

Mold occurrence and aflatoxin B(1) and fumonisin B(1) determination in corn samples in Venezuela

Fumonisins are mycotoxins produced mainly by Fusarium moniliforme and Fusarium proliferatum, which have been associated with several animal and human diseases. Aflatoxins are hepatotoxic, mutagenic, and teratogenic metabolites produced by Aspergillus flavus and Aspergillus parasiticus. Both have been reported at high levels in corn. This study was pursued to determine mold, aflatoxin B(1) (AFTB(1)), and fumonisin B(1) (FB(1)) levels in white and yellow corn. Mold levels were determined using potato dextrose agar and identification of the main genus of molds present in corn, AFTB(1) levels by immunoaffinity chromatography, and FB(1) levels by a Bond-Elut SAX cartridge and HPLC. AFTB(1) an     

Characterization of the volatile constituents in the essential oil of Pistacia lentiscus L. from different origins and its antifungal and antioxidant activity

Essential oil (EO) from aerial parts (leaves, juvenile branches, and flowers when present) of Pistacia lentiscus L. growing wild in five localities of Sardinia (Italy) was extracted by steam-distillation (SD) and analyzed by gas chromatography (GC), FID, and GC-ion trap mass spectrometry (ITMS). Samples of P. lentiscus L. were harvested between April and October to study the seasonal chemical variability of the EO. A total of 45 compounds accounting for 97.5-98.4% of the total EO were identified, and the major compounds were alpha-pinene (14.8-22.6%), beta-myrcene (1-19.4%), p-cymene (1.6-16.2%), and terpinen-4-ol (14.2-28.3%). The yields of EO (v/dry w) ranged between 0.09 and 0.32%. Similar content of the major compounds was found in samples from different origins and seasonal variability was also observed. The EOs were tested for their antifungal activity against Aspergillus flavus, Rhizoctonia solani, Penicillium commune, Fusarium oxysporum. Two samples were weakly effective against Aspergillus flavus. Furthermore, terpinenol and alpha-terpineol, two of the major components of EO of Pistacia lentiscus L., totally inhibited the mycelian growth of A. flavus. Quite good antioxidant activity of the EO was also found.     

Changes in free amino acid and sugar levels of dried figs during aflatoxin B1 production by Aspergillus flavus and Aspergillus parasiticus

An aqueous slurry of gamma-irradiated sterilized dried figs was inoculated with toxigenic strains of Aspergillus flavus and Aspergillus parasiticus. During incubation at 28 degrees C, pH, fructose, glucose, and free amino acids were determined by high-performance liquid chromatography and liquid chromatography (LC)/mass spectrometry, respectively, over 13 time points (1-20 days). At the same 13 time points using a LC/time-of-flight mass spectrometry screening method, aflatoxin B 1 and other secondary metabolites were simultaneously monitored. During the course of incubation, the pH significantly decreased and aflatoxin B 1 formation correlated with a reduction in proline content for both fungi. Of the 22 free amino acids that were monitored, only proline and cystine were found to be critical in supporting aflatoxin production. Levels of fructose and glucose steadily declined during incubation, until glucose was almost exhausted after 21 days. These time-course experiments confirmed the need for carbon and nitrogen sources for aflatoxin production in dried figs, and the favorable composition of figs as a fungal growth medium.     

Cyclopiazonic acid production by cultures of Aspergillus and Penicillium species isolated from dried beans, corn meal, macaroni, and pecans

Ninety-five isolates of Aspergillus and Penicillium species from selected dried foods were examined for their ability to produce cyclopiazonic acid (CPA). The isolates were grown in sterile synthetic liquid medium at 28 degrees C for 8 days in the dark. The medium and mold mycelia were then extracted with chloroform. CPA was semiquantitatively determined by thin layer chromatography through visual comparison with standards. The cultures of A. flavus were also examined for their ability to produce aflatoxin. One A. tamarii and all 13 P. urticae isolates produced CPA, whereas only 19 of the 31 (61%) A. flavus isolates produced CPA, and 6 (19%) A. flavus produced aflatoxin. All 13 P. urticae isolates also produced patulin and griseofulvin. CPA-producing A. flavus was found in all food types but not in all samples. CPA-producing P. urticae was found only in dried beans and macaroni.     

Occurrence of mycotoxins in cereals and animal feedstuffs in Natal, South Africa

During the period 1982-1983, just under 800 samples of agricultural commodities, comprising cereals, compound feeds, hay, and silage, were examined for molds and mycotoxins. Aflatoxin B1 showed the highest incidence rate; it occurred in over 27% of all samples analyzed, the highest levels being found in peanut meal at 1500 ppb. Other mycotoxins detected were patulin and a number of trichothecene toxins at incidence rates in all commodities of 5.6 and 3.1%, respectively. The commodities at highest risk were oil seeds, excluding soya bean; the latter was found to be fairly free from contamination with mycotoxins. The most prevalent fungi were Aspergillus flavus and parasiticus, which were found in over 22% of all samples, whereas Penicillium spp. showed the lowest incidence of genera, specifically identified in 8.3% of all samples examined. This latter finding explains in part the low incidence of Penicillium mycotoxins.     

Antifungal effects of different organic extracts from Melia azedarach L. on phytopathogenic fungi and their isolated active components

Extracts from different parts of Melia azedarach L. were studied as potential antifungal agents for selected phytopathogenic fungi. In a serial agar dilution method, hexanic and ethanolic extracts from fruit, seed kernels, and senescent leaves exhibited fungistatic activity against Aspergillus flavus,Diaporthe phaseolorum var. meridionales, Fusarium oxysporum, Fusarium solani, Fusarium verticillioides, and Sclerotinia sclerotiorum. Both hexanic extract from senescent leaves and ethanolic extract from seed kernel were highly effective on all tested fungi, with minimum inhibitory concentration (MIC) values ranging from 0.5 to 25 mg/mL and 0.5 to 5 mg/mL, respectively. In addition, all of the above-mentioned extracts showed fungicidal activity on these fungi, with ethanolic seed kernel extract being the most active. Three compounds displaying activity against F. verticillioides were isolated from the ethanolic seed kernel extract and were characterized as vanillin (1), 4-hydroxy-3-methoxycinnamaldehyde (2), and (+/-)-pinoresinol (3), with MICs of 0.6, 0.4, and 1.0 mg/mL, respectively. These compounds also showed a synergistic effect when combined in different concentrations, needing four times less concentration to reach complete inhibition in the growth of F. verticillioides.     

Antimycotic activities of selected plant flora,growing wild in Lebanon,against phytopathogenic fungi

Petroleum ether (PE) and methanolic extracts of nine wild plant species were tested in vitro for their antimycotic activity against eight phytopathogenic fungi. The efficacy of PE extracts against all pathogens tested was higher than that of methanolic extracts. Wild marjoram (Origanum syriacum) PE extract showed the highest and widest range of activity. It resulted in complete inhibition of mycelial growth of six of eight fungi tested and also gave nearly complete inhibition of spore germination of the six fungi included in the assay, namely, Botrytis cinerea, Alternaria solani, Penicillium sp., Cladosporium sp., Fusarium oxysporum f. sp. melonis, and Verticillium dahlia. The other plant extracts showed differential activities in the spore germination test, but none was highly active against mycelial growth. Inula viscosa and Mentha longifolia were highly effective (>88%) in spore germination tests against five of six fungi tested, whereas Centaurea pallescens, Cichorium intybus, Eryngium creticum, Salvia fruticosa, and Melia azedarach showed >95% inhibition of spore germination in at least two fungi. Foeniculum vulgare showed the least antimycotic activity. Fractionation followed by autobiography on TLC plates using Cladosporium sp. as a test organism showed that O. syriacum PE extracts contained three inhibition zones, and those of Inula viscosa and Cichorium intybus, two, whereas the PE extracts of the remaining plants showed each one inhibition zone. Some of the major compounds present in these inhibition zones were identified by GC-MS. The possibility for using these extracts, or their mixtures, to control plant diseases is discussed.     

Mycoflora and multimycotoxin detection in corn silage: experimental study

Agricultural activities involve the use of crop preservation such as "trench-type" silo, which can sometimes be contaminated by fungi. To investigate the exposure of livestock and farm workers to fungal spores and mycotoxins, a multimycotoxin analysis method has been developed. Six mycotoxins (aflatoxin B1, citrinin, deoxynivalenol, gliotoxin, ochratoxin A, and zearalenone) were quantified by high-performance liquid chromatography coupled to mass spectrometry after solid-phase extraction. An experimental study of fungal species and mycotoxins was conducted in corn silage (Normandy, France) during 9 months of monitoring. The results indicated the recurrence of around 20 different species, with some of them being potentially toxigenic fungi such as Aspergillus fumigatus, Aspergillus parasiticus, Fusarium verticillioides, and Monascus ruber, and the detection of aflatoxin B1 (4-34 ppb), citrinin (4-25 ppb), zearalenone (23-41 ppb), and deoxynivalenol (100-213 ppb). This suggested a possible chronic exposure to low levels of mycotoxins.     

Antioxidant and biocidal activities of Carum nigrum (seed) essential oil, oleoresin, and their selected components

In the present study, chemical constituents of the essential oil and oleoresin of the seed from Carum nigrum obtained by hydrodistillation and Soxhlet extraction using acetone, respectively, have been studied by GC and GC-MS techniques. The major component was dillapiole (29.9%) followed by germacrene B (21.4%), beta-caryophyllene (7.8%), beta-selinene (7.1%), and nothoapiole (5.8%) along with many other components in minor amounts. Seventeen components were identified in the oleoresin (Table 2) with dillapiole as a major component (30.7%). It also contains thymol (19.1%), nothoapiole (15.2.3%), and gamma-elemene (8.0%). The antioxidant activity of both the essential oil and oleoresin was evaluated in mustard oil by monitoring peroxide, thiobarbituric acid, and total carbonyl and p-anisidine values of the oil substrate. The results showed that both the essential oil and oleoresin were able to reduce the oxidation rate of the mustard oil in the accelerated condition at 60 degrees C in comparison with synthetic antioxidants such as butylated hydroxyanisole and butylated hydroxytoluene at 0.02%. In addition, individual antioxidant assays such as linoleic acid assay, DPPH scavenging activity, reducing power, hydroxyl radical scavenging, and chelating effects have been used. The C. nigrum seed essential oil exhibited complete inhibition against Bacillus cereus and Pseudomonas aeruginosa at 2000 and 3000 ppm, respectively, by agar well diffusion method. Antifungal activity was determined against a panel of foodborne fungi such as Aspergillus niger, Penicillium purpurogenum, Penicillium madriti, Acrophialophora fusispora, Penicillium viridicatum, and Aspergillus flavus. The fruit essential oil showed 100% mycelial zone inhibition against P. purpurogenum and A. fusispora at 3000 ppm in the poison food method. Hence, both oil and oleoresin could be used as an additive in food and pharmaceutical preparations after screening.     

种植至储藏期花生黄曲霉毒素B_1污染研究

为解析种植至储藏期花生受黄曲霉侵染及黄曲霉毒素B1(AFB_1)污染的规律,揭示花生AFB_1污染的源头及主要影响因素,选取种植湛红2号和湛油75的花生田,采集种植期花生果和土壤及储藏1~4个月的花生果,分析花生和土壤真菌菌相,并采用高效液相色谱法测定花生AFB_1含量。结果表明,种植期黄曲霉侵染花生果主要发生在成熟期,但黄曲霉污染率均在8%以下;湛油75花生田土壤黄曲霉菌落数显著低于湛红2号,但花生果黄曲霉污染率显著高于湛红2号,表明湛红2号具有一定的黄曲霉抗性;湛油75和湛红2号分别在110 d和120 d检测到AFB_1,含量分别为3.37μg·kg~(-1)和2.08μg·kg~(-1),表明花生黄曲霉毒素含量与污染率呈正相关。储藏期花生果中未检测到黄曲霉和AFB_1,这主要是由于花生晾晒后水活度(aw)降低至0.70以下,不适合黄曲霉生长繁殖和毒素生物合成。综上,黄曲霉在荚果成熟期开始侵染花生果导致产生AFB_1,而储藏期保持较低的aw可有效预防黄曲霉及AFB_1污染。本研究结果为制定种植至储藏期花生黄曲霉毒素全程防控措施提供了理论依据。     

Occurrence of ochratoxin A- and aflatoxin B1-producing fungi in Lebanese grapes and ochratoxin a content in musts and finished wines during 2004

This paper reports the results of an extensive survey on the occurrence of filamentous fungi isolated from wine-grapes in Lebanon and to test their ability to produce ochratoxin A (OTA) and aflatoxin B1 (AFB1) on CYA culture medium, in order to assess their potential for producing these mycotoxins on grapes. From the 470 grapes samples taken during season 2004, 550 fungi strains were isolated with 490 belonging to Aspergillus spp. and 60 belonging to Penicillium spp. All these isolated fungi starins were tested for their ability to produce OTA and AFB1. Aspergillus carbonarius shows that it is the only species able to produce OTA with a production percentage reaching 100% and a maximum concentration of 52.8 microg/g of Czapek yeast extract agar (CYA). In its turn, Aspergillus flavus was considered as the only AFB1-producing species with production percentage of 45.3% and a maximum concentration reaching 40 microg/g CYA. A total of 47 handmade musts produced from the collected grapes were also analyzed in order to correlate the presence of OTA in must and the occurrence of filamentous fungi on grapes; 57.4% were contaminated with OTA at low level with concentrations ranging between 0.011 and 0.221 microg OTA L(-1). The analysis of these must samples was not performed with regard to AFB1. Seventy samples of finish red wine were also assayed for OTA content. The results showed that 42 of the tested samples (60%) were found to be positive for OTA with low levels (0.012-0.126 microg OTA L(-1)).     

Effect of microbial culture filtrates on the growth of sal (Shorea robusta gaertn.) leaf litter fungi

Experiments were made on the nature of fungal competition on sal leaf-litter with emphasis on the antibiotic action of culture filtrates. The culture filtrates of Mortierella subtilissima, Aspergillus candidus, A. flavus, A. niger, Penicillium rubrum, Papulaspora sp., Staphylococcus aureus and Bacillus subtilis were found most effective in suppressing the growth of various leaf-litter fungi. Dominant fungi which displayed best competitive tolerance to the staling products of culture filtrates were Aspergillus flavus, A. niger, A. sclerotiorum, A. terreus and Trichoderma harzianum.     

异硫氰酸苄酯对于黄曲霉生长速率和产毒情况的影响

为明确异硫氰酸苄酯(BITC)在不同条件下对黄曲霉的抑制效果,本研究以熏蒸法,在28℃培养条件下,分别以花生和玉米为培养基质,研究不同浓度(0、5、10、15、20 mg·L-1)异硫氰酸苄酯在不同水分活度(aw)(0.930、0.960、0.980、0.995)下对黄曲霉(Aspergillus flavus)生长和...     

Chemical composition, seasonal variability, and antifungal activity of Lavandula stoechas L. ssp. stoechas essential oils from stem/leaves and flowers

Essential oils from the stems/leaves (L) and flowers (F) of Lavandula stoechas L. ssp. stoechas growing wild in southern Sardinia (Italy) were extracted by hydrodistillation and analyzed by gas chromatography coupled with flame ionization detector and ion trap mass spectrometry. The major compound was fenchone, accounting for, on average, 52.60% in L and 66.20% in F, followed by camphor (13.13% versus 27.08%, in L and F, respectively). F essential oil yields (volume per dry weight) decreased from the beginning to the end of the flowering stage, whereas L yields remained constant during the year. The nine main compounds derived from two different subpathways, A and B. The compounds that belong to the same subpathway showed a similar behavior during the year. The essential oils were tested for their antifungal activity using the paper disk diffusion method. The essential oils tested were effective on the inactivation of Rhizoctonia solani and Fusarium oxysporum and less effective against Aspergillus flavus. Among the single compounds tested, fenchone, limonene, and myrtenal appeared to be the more effective on the inhibition of R. solani growth.