Analysis of fumonisin B(1) in Fusarium proliferatum-infected asparagus spears and garlic bulbs from Germany by liquid chromatography-electrospray ionization mass spectrometry

Fusarium proliferatum is one of a group of fungal species that produce fumonisins and is considered to be a pathogen of many economically important plants. The occurrence of fumonisin B(1) (FB(1)) in F. proliferatum-infected asparagus spears from Germany was investigated using a liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method with isotopically labeled fumonisin FB(1)-d(6) as internal standard. FB(1) was detected in 9 of the 10 samples in amounts ranging from 36.4 to 4513.7 ng/g (based on dry weight). Furthermore, the capability of producing FB(1) by the fungus in garlic bulbs was investigated. Therefore, garlic was cultured in F. proliferatum-contaminated soil, and the bulbs were screened for infection with F. proliferatum and for the occurrence of fumonisins by LC-MS. F. proliferatum was detectable in the garlic tissue, and all samples contained FB(1) (26.0-94.6 ng/g). This is the first report of the natural occurrence of FB(1) in German asparagus spears, and these findings suggest a potential for natural contamination of garlic bulbs with fumonisins.     

Maize (Zea mays L.) genetic factors for preventing fumonisin contamination

Fusarium moniliforme and Fusarium proliferatum are the most frequently isolated fungi from maize (Zea mays L.) in Spain. Both Fusarium species produce toxins potentially dangerous for animals and humans, the fumonisins being the most significant of those toxins. White maize is preferred for human consumption, and extra care should be taken to avoid kernel mycotoxin contamination. The objectives of this study were to identify and quantify kernel infection by Fusarium spp. and contamination by fumonisin on white maize hybrids, to search for white maize sources of resistance to infection by Fusarium spp. and mycotoxin contamination, and to preliminarily study the genetics involved in such resistances. Ten F(1) single crosses derived from a diallel mating design among five white maize inbreds were evaluated in a randomized complete block design with three replications in 2002 at two locations. Fusarium verticilloides and F. proliferatum were detected on kernels of white maize hybrids cultivated in northwestern Spain. No differences in fungal infection were found among maize genotypes, but differences in fumonisin contamination were significant and could be related, in part, to differences in husk tightness. Among the genotypes studied, general combining ability (GCA) effects were the most important for resistance to fumonisin contamination. Inbreds EP10 and EC22 showed the most favorable GCA effects for husk tightness and fumonisin content, and the cross between them, EP10 x EC22, had the most favorable specific combining ability (SCA) effect for husk tightness. Inbreds EP10 and EC22 showed favorable GCA effects for fumonisin contamination and husk tightness, and the cross EP10 x EC22 was the only one with an average fumonisin level below 1 mug/g. Although this should be confirmed with more extensive studies, white maize inbreds developed from white maize landraces could be sources of resistance to fumonisin contamination.     

Metabolites from Aspergillus fumigatus, an endophytic fungus associated with Melia azedarach, and their antifungal, antifeedant, and toxic activities

Thirty-nine fungal metabolites 1-39, including two new alkaloids, 12β-hydroxy-13α-methoxyverruculogen TR-2 (6) and 3-hydroxyfumiquinazoline A (16), were isolated from the fermentation broth of Aspergillus fumigatus LN-4, an endophytic fungus isolated from the stem bark of Melia azedarach. Their structures were elucidated on the basis of detailed spectroscopic analysis (mass spectrometry and one- and two-dimensional NMR experiments) and by comparison of their NMR data with those reported in the literature. These isolated compounds were evaluated for in vitro antifungal activities against some phytopathogenic fungi, toxicity against brine shrimps, and antifeedant activities against armyworm larvae (Mythimna separata Walker). Among them, sixteen compounds showed potent antifungal activities against phytopathogenic fungi (Botrytis cinerea, Alternaria solani, Alternaria alternata, Colletotrichum gloeosporioides, Fusarium solani, Fusarium oxysporum f. sp. niveum, Fusarium oxysporum f. sp. vasinfectum, and Gibberella saubinettii), and four of them, 12β-hydroxy-13α-methoxyverruculogen TR-2 (6), fumitremorgin B (7), verruculogen (8), and helvolic acid (39), exhibited antifungal activities with MIC values of 6.25-50 μg/mL, which were comparable to the two positive controls carbendazim and hymexazol. In addition, of eighteen that exerted moderate lethality toward brine shrimps, compounds 7 and 8 both showed significant toxicities with median lethal concentration (LC(50)) values of 13.6 and 15.8 μg/mL, respectively. Furthermore, among nine metabolites that were found to possess antifeedant activity against armyworm larvae, compounds 7 and 8 gave the best activity with antifeedant indexes (AFI) of 50.0% and 55.0%, respectively. Structure-activity relationships of the metabolites were also discussed.     

Occurrence of Fusarium spp. and fumonisin in durum wheat grains

A survey was carried out to determine Fusarium species and fumonisin contamination in 55 durum wheat (Triticum turgidum L. var. durum) samples collected during two harvest seasons (2007 and 2008) using HPLC and further LC-MS/MS confirmation. All samples showed Fusarium contamination with infection levels ranging from 8 to 66%, F. proliferatum being the species most frequently isolated during 2007 and the second most frequently isolated one during the 2008 harvest season, respectively. Natural contamination with fumonisins was found in both harvest seasons. In 2007, 97% of the samples showed total fumonisin (FB(1) + FB(2)) levels ranging from 10.5 to 1245.7 ng/g, while very low levels of fumonisins were detected in samples collected during 2008. These results could be explained by differences in the amount of rainfall during both periods evaluated. A selected number (n = 48) of F. proliferatum isolates showed fumonisin production capability on autoclaved rice. This is the first report of the presence of natural fumonisins in durum wheat grains.     

Fungistatic activity of bicyclo[4.3.0]-γ-lactones

Five optically active and sixteen racemic lactones (nine of them new) of bicyclo[4.3.0]nonane structure were synthesized. IC(50) values for the following phytopathogens were determined: Aspergillus ochraceus AM 456, Fusarium culmorum AM 282, Fusarium oxysporum AM 13, Fusarium tricinctum AM 16. Effect of compound structures, especially stereogenic centers, on fungistatic activity has been discussed. The highest fungistatic activity was observed for trans-7,8-dibromo-cis-3-oxabicyclo[4.3.0]nonan-2-one (3c), IC(50) = 30.1 μg/mL (0.10 μM/mL), and cis-7,8-epoxy-cis-3-oxabicyclo[4.3.0]nonan-2-one (3b), IC(50) = 72.2 μg/mL (0.47 μM/mL), toward F. oxysporum AM 13.     

In vitro antioxidant properties, DNA damage protective activity, and xanthine oxidase inhibitory effect of cajaninstilbene acid, a stilbene compound derived from pigeon pea [Cajanus cajan (L.) Millsp.] leaves

The antioxidant properties, DNA damage protective activities, and xanthine oxidase (XOD) inhibitory effect of cajaninstilbene acid (CSA) derived from pigeon pea leaves were studied in the present work. Compared with resveratrol, CSA showed stronger antioxidant properties, DNA damage protective activity, and XOD inhibition activity. The IC(50) values of CSA for superoxide radical scavenging, hydroxyl radical scavenging, nitric oxide scavenging, reducing power, lipid peroxidation, and XOD inhibition were 19.03, 6.36, 39.65, 20.41, 20.58, and 3.62 μM, respectively. CSA possessed good protective activity from oxidative DNA damage. Furthermore, molecular docking indicated that CSA was more potent than resveratrol or allopurinol to interact with the active site of XOD (calculated free binding energy: -229.71 kcal mol(-1)). On the basis of the results, we conclude that CSA represents a valuable natural antioxidant source and may potentially be applicable in health food industry.     

Mycoflora and fumonisin mycotoxins associated with cowpea [Vigna unguiculata (L.) Walp] seeds

Cowpea seed samples from South Africa and Benin were analyzed for seed mycoflora. Fusariumspecies detected were F. equiseti, F. chlamydosporum, F. graminearum, F. proliferatum, F. sambucinum, F. semitectum, and F. subglutinans. Cowpea seed from South Africa and Benin and F. proliferatum isolates from Benin, inoculated onto maize patty medium, were analyzed for fumonisin production. Samples were extracted with methanol/water and cleaned up on strong anion exchange solid phase extraction cartridges. HPLC with precolumn derivatization using o-phthaldialdehyde was used for the detection and quantification of fumonisins. Cowpea cultivars from South Africa showed the presence of fumonisin B(1) at concentrations ranging between 0.12 and 0.61 microg/g, whereas those from Benin showed no fumonisins. This is believed to be the first report of the natural occurrence of FB(1) on cowpea seed. Fumonisin B(1), B(2), and B(3) were produced by all F. proliferatum isolates. Total fumonisin concentrations were between 0.8 and 25.30 microg/g, and the highest level of FB(1) detected was 16.86 microg/g.     

Isolation, characterization and antifungal activity of major constituents of the Himalayan lichen Parmelia reticulata Tayl

Antifungal activity of hexane, ethyl acetate and methanol extracts of Parmelia reticulata was evaluated against soilborne pathogenic fungi, namely, Sclerotium rolfsii, Rhizoctonia solani, R. bataticola, Fusarium udum, Pythium aphanidermatum and P. debaryanum by poisoned food technique. Maximum antifungal activity was exhibited by hexane and ethyl acetate extracts against most of the test pathogens. Secondary metabolites, namely, (±)-isousnic acid, (±)-protolichesterinic acid, atranorin, evernyl, ethyl hematommate, ethyl orsellinate, methyl hematommate (3-formyl-2,4-dihydroxy-6-methylbenzoic acid methyl ester), 2-hydroxy-4-methoxy-3,6-dimethylbenzoic acid, 1-hydroxy-3,6-dimethoxy-8-methyl-xanthen-9-one, baeomycesic acid and salazinic acid, were isolated from the above extracts and identified by 1H NMR, 13C NMR and mass spectroscopic methods. When these metabolites were tested for antifungal activity against test pathogens, maximum antifungal activity was exhibited by (±)-protolichesterinic acid against R. solani (ED50=23.09 μg mL(-1)) and P. debaryanum (ED50=16.07 μg mL(-1)) and by atranorin against S. rolfsii (ED50=39.70 μg mL(-1)). The antifungal activity of protolichesterinic acid was found to be comparable to that of hexaconazole, a commercial fungicide.     

化感水稻6173内生真菌发酵产物对水稻和稗草苗期生长及生理生化特性的影响

为了考察化感水稻品系6173内生真菌的生物学功能,采用6173分离出的12株内生真菌对非化感水稻93067和稗草进行种子萌发和生长试验,以常规萌发生长的水稻及稗草幼苗为对照,研究真菌发酵产物对两者萌发率、茎长、鲜重和相关酶活性变化的影响。结果表明,12株内生真菌中,7株真菌的发酵产物对水稻萌发起促进作用,11株真菌的发酵产物可促进水稻幼苗生长,其中塔宾曲霉和粘红酵母发酵液效果极显著。然而11株真菌的发酵产物对稗草萌发具有抑制作用,燕麦镰刀菌发酵液抑制效果极显著;试验组中塔宾曲霉、粘红酵母发酵产物均显著抑制了稗草的生长。初步筛选促水稻生长和抑制稗草作用明显的燕麦镰刀菌、塔宾曲霉和粘红酵母,其发酵产物都能显著降低稗草种子的脂肪酶活性。与对照相比,萌发24 h时,粘红酵母处理稗草种子可使脂肪酶活性下降82.61%;萌发96 h时,燕麦镰刀菌和粘红酵母菌处理稗草种子可使脂肪酶活性下降30.88%和36.50%。此外,塔宾曲霉和燕麦镰刀菌发酵产物能够不同程度地提高水稻幼苗的超氧化物歧化酶(SOD)和过氧化物酶(POD)活性;燕麦镰刀菌能降低稗草幼苗的SOD、POD活性;同时塔宾曲霉能显著降低稗草幼苗POD活性。综上,化感水稻6173中分离出的内生真菌的发酵产物对普通水稻品种促生长和抑制作用并存,但对稗草主要是抑制作用,其作用可能主要通过抑制脂肪酶活性和抗氧化途径实现。本研究结果为农业生产中生物农药和微生物肥料的研发奠定了理论基础。     

Production of the mycotoxins fusaproliferin and beauvericin by South African isolates in the Fusarium section Liseola

The production of fusaproliferin (FUS), a recently described mycotoxin, and beauvericin (BEA), a mycotoxin recently reported to co-occur with FUS in Fusarium-infected corn, by South African isolates in the Fusarium section Liseola, was investigated. Five isolates each of F. verticillioides, F. proliferatum, F. subglutinans, and F. globosum were cultured on corn kernels. Four each of the five South African isolates of F. proliferatum and F. subglutinans produced FUS (10-1725 and 330-2630 mg/kg, respectively). BEA was produced by four of the F. proliferatum strains (310-1130 mg/kg) and three of the F. subglutinans strains (140-700 mg/kg). The isolates of F. verticillioides failed to produce significant levels of either of these secondary metabolites. F. globosum was a weak producer of both in that one isolate of five produced 25 mg/kg FUS and five out of five produced BEA at levels ranging between 10 and 110 mg/kg. To further characterize these strains, their production of fumonisins B(1), B(2), and B(3), as well as moniliformin, was investigated. Of the four species investigated, fumonisins were produced by all except F. subglutinans, which in turn was the only species whose isolates in this study produced moniliformin (four of five isolates, ranging from 155 to 2095 mg/kg). Analysis of visibly Fusarium-infected home-grown corn collected in the Transkei region of the Eastern Cape Province of South Africa showed that nine of the ten samples contained low levels of FUS (up to 62 microg/kg), whereas all ten samples showed BEA contamination ranging from 8 to 1734 microg/kg with a mean of 258 microg/kg.     

Occurrence of Fusarium species and mycotoxins in nepalese maize and wheat and the effect of traditional processing methods on mycotoxin levels

Maize (Zea mays) and wheat (Triticum aestivum) collected in the foothills of the Nepal Himalaya Mountains were analyzed for Fusarium species and mycotoxins: fumonisins, nivalenol (NIV), and deoxynivalenol (DON). Predominant species were Gibberella fujikuroi mating population A (F. moniliforme) in maize and F. graminearum in maize and wheat; G. fujikuroi mating population D (F. proliferatum), F. acuminatum, F. avenaceum, F. chlamydosporum, F. equiseti, F. oxysporum, F. semitectum, and F. torulosum were also present. Strains of G. fujikuroi mating population A produced fumonisins, and strains of F. graminearum produced NIV or DON. By immunoassay or high-performance liquid chromatography, fumonisins were >1000 ng/g in 22% of 74 maize samples. By immunoassay or fluorometry, NIV and DON were >1000 ng/g in 16% of maize samples but were not detected in wheat. Fumonisins and DON were not eliminated by traditional fermentation for producing maize beer, but Nepalese rural and urban women were able to detoxify contaminated maize by hand-sorting visibly diseased kernels.     

Surveillance of fumonisins in maize-based feeds and cereals from spain.

A survey has been carried out to determine the levels of fumonisins in 171 samples of maize-based feeds and cereals available in Spain. Also, the samples were examined for mold count and fungal species. Aspergillus, Penicillium, and Fusarium were the most frequent genera, and Fusarium and Aphanocladium had the highest individual percentage counts. Regarding Fusarium species, F. moniliforme (47. 4%) was the predominant species; F. proliferatum (5.3%) and F. subglutinans (7.0%) were isolated at low frequency. The high-performance liquid chromatography-o-phthaldialdehyde fluorescence method was used for the analysis of fumonisins. The highest levels of fumonisins were detected in maize. Overall, fumonisin B(1) (FB(1)) and fumonisin B(2) (FB(2)) were detected in 79.5 and 14.6%, of samples respectively, with average FB(1) levels of 3.3 microg/g and average FB(2) levels of 1.7 microg/g. Low levels of fumonisins in wheat, barley, and soybean were detected. This would appear to be the first report of concentrations of fumonisins in these commodities.     

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.     

Analysis of the Fusarium mycotoxin moniliformin in cereal samples using 13C2-moniliformin and high-resolution mass spectrometry

Moniliformin is a mycotoxin produced by fungi of the Fusarium genus and occurs as a contaminant of different cereals worldwide. This study describes the first application of isotopically labeled (13)C(2)-moniliformin for the analysis of moniliformin in cereals. Moniliformin is a small and ionic molecule that forms only a single sensitive fragment ion in the collision cell of a tandem mass spectrometer. Therefore, the methods described in the literature for this kind of instrument observe only a single mass transition and show a relatively poor sensitivity. The use of high-resolution mass spectrometry was described to be a suitable alternative technique for the detection of this compound and was therefore applied in this study. The developed method is based on the use of strong anion exchange columns for cleanup prior to HPLC analysis and has a recovery rate of 75.3%, a limit of detection (LOD) of 0.7 μg/kg, and a limit of quantitation (LOQ) of 2.5 μg/kg. Twenty-three different cereal samples were analyzed for their moniliformin content. Twenty of them showed positive results with levels up to 126 ± 12.2 μg/kg.     

Enhanced phytoremediation of multi-metal contaminated soils by interspecific fusion between the protoplasts of endophytic Mucor sp. CBRF59 and Fusarium sp. CBRF14

The aim of this study was to isolate protoplasts from different metal resistant endophytic fungi and to carry out interspecific fusion of protoplasts to enhance bioremediation of contaminated soils. Three stable fusants (F1, F2, and F3) with resistance to Cd and Zn were constructed by interspecific fusion between inactivated protoplasts from Cd-resistant endophytic Mucor sp. CBRF59 and Zn-resistant endophytic Fusarium sp. CBRF14. The fusants increased concentrations of water soluble Cd, Pb, and Zn in soils, promoted rape growth, increased metal concentrations in the rape, elevated the extractable metal amount, and increased metal translocation from roots to shoots in soils containing single metals or multi-metals. Especially, the fusants showed much higher extraction efficacy than the parents in soils contaminated by multi-metals. The results indicated that protoplast fusion should be a feasible and efficient fungal method, which could be utilized to construct stable fusants by combining the genetic traits of parents for bioremediation of contaminated soils by multi-metals.     

NODULATION,NITROGENASE ACTIVITY,AND DRY WEIGHT OF CHICKPEA AND PIGEON PEA CULTIVARS USING DIFFERENT BRADYRHIZOBIUM STRAINS

Chickpea [Cicer arietinum (L.)] and pigeon pea [Cajanus cajan (L.) Millsp.] were grown outside in large clay pots from 1992 to 1995 in Edmond, Oklahoma. Plants were studied to evaluate nodulation, nitrogenase activity, and shoot dry weight (DW) of ‘ICCV-2’ and ‘Sarah’ chickpea inoculated with multistrain, TAL 1148, and TAL 480 Bradyrhizobium, as well as ‘Georgia-1’ and ‘ICPL-87’, pigeon pea inoculated with multistrain TAL 1127, and TAL 1132 Bradyrhizobium. Following wheat [Triticum aestivum (L.) emend. Thell.] harvests in the spring, legumes were planted in the summer and harvested at three successive dates during the following months. Leaves and stems from remaining plants were incorporated into the soil after the last harvest. Across year, chickpea measurements were sensitive to temperature and precipitation whereas pigeon pea measurements were sensitive to length of growing season as well as climate. Pigeon pea consistently demonstrated higher nitrogen-fixing capacity and shoot DW compared with chickpea. Nodule and shoot DW of both species increased with plant age whereas nodule count and nitrogenase activity generally increased with plant age and leveled off or decreased at flowering. Sarah chickpea demonstrated higher nodule count and nodule DW than ICCV-2, as did the Georgia-1 pigeon pea compared with ICPL-87. Shoot DW of Georgia-1 pigeon pea was generally higher than that of ICPL-87. Multistrain inoculum improved nodulation and shoot DW of chickpea, and TAL 1127 improved nodulation of pigeon pea compared with other treatments. These results indicate that specific chickpea and pigeon pea cultivars, along with appropriate Bradyrhizobium strains, may improve nitrogen fixation and DW of these species.     

化感水稻内生真菌发酵产物的抑菌活性评价及其对水稻保护性酶活性的影响

为探究化感水稻内生真菌对植物病原真菌的抑制作用及其对水稻生理特性的影响,本研究采用来自化感水稻6173中分离得到的12株内生真菌菌株,以水稻纹枯病、稻瘟病、恶苗病菌为指示菌株,通过平板对峙法研究了内生真菌菌株的抑菌活性,再采用牛津杯扩散法对初筛获得的抗性菌株进行抑菌活性复筛,并对筛选到的抑菌菌株抗菌物质的热稳定性及其对非化感水稻93067相关保护性酶活性的影响进行了研究。结果表明,菌株REF-04抑菌活性强,其对纹枯病菌抑制率达到50.63%,发酵液乙酸乙酯提取物抑制效果显著,抑菌圈直径达到18.6 mm;菌株REF-04发酵液乙酸乙酯提取物中抗菌成分具有较强的热稳定性,其发酵液能显著提高水稻苯丙氨酸解氨酶(PAL)、超氧化物歧化酶(SOD)、过氧化物酶(POD)活性。本研究筛选获得的水稻内生真菌REF-04具有较好的抗菌活性,同时还能促进水稻幼苗保护性酶活性的提高,其作为生物农药具有一定的应用价值和开发前景。     

银杏内生真菌多样性与产黄酮类物质真菌的分离和鉴定

采用传统组织培养法从银杏根、叶片和茎中分离内生真菌,以相对频率作为指标分析其多样性,通过显色反应、薄层层析(TLC)、高效液相色谱(HPLC)等方法对内生真菌的发酵产物进行初步分析,筛选能够产黄酮类物质的内生真菌,并通过分光光度法测定总黄酮产量;同时根据菌株的形态学特征,结合真菌r DNA的居间序列(internal transcribed spacer,ITS)的系统进化分析进行菌株鉴定。结果表明:共分离得到217株内生真菌,分属于5纲、8目、10科、13属;经初步筛选,2株分离自根组织的内生真菌GF111和GF521具有产黄酮类化合物的能力,发酵液总黄酮产量分别为(14.50±1.30)mg/L和(21.10±1.30)mg/L;初步鉴定2株产黄酮内生真菌GF111和GF521分别为卷枝毛霉Mucor circinelloides和尖镰孢菌Fusarium oxysporum。可见,内生真菌在银杏不同部位在数量、种群及其组成上存在着较大差异,并且菌株GF111和GF521产黄酮能力较高,可作为生物发酵生产黄酮类物质的备选菌株。本研究为更好地开发和保护银杏资源提供了依据。     

Volatile metabolites from Salvia fruticosa as antifungal agents in soilborne pathogens

The volatile metabolites of Salvia fruticosa plants, growing wild in 15 localities scattered across Greece, were analyzed by means of GC and GC-MS. The essential oil content ranged from 0.69 to 4.68%, and the results of the analyses showed a noticeable variation in the amounts of the five main components [1,8-cineole, alpha-thujone, beta-thujone, camphor, and (E)-caryophyllene]. The antifungal activities of the essential oils from two localities, belonging in two different groups of cluster and principal component analysis, and their main components (1,8-cineole and camphor) were evaluated in vitro against five phytopathogenic fungi. Both oils were slightly effective against Fusarium oxysporum f. sp. dianthi and Fusarium proliferatum, whereas against Rhizoctonia solani, Sclerotinia sclerotiorum, and Fusarium solani f. sp. cucurbitae the oils exhibited high antifungal activities.     

Inhibitory effects of gossypol, gossypolone, and apogossypolone on a collection of economically important filamentous fungi

Racemic gossypol and its related derivatives gossypolone and apogossypolone demonstrated significant growth inhibition against a diverse collection of filamentous fungi that included Aspergillus flavus, Aspergillus parasiticus, Aspergillus alliaceus, Aspergillus fumigatus, Fusarium graminearum, Fusarium moniliforme, Penicillium chrysogenum, Penicillium corylophilum, and Stachybotrys atra. The compounds were tested in a Czapek agar medium at a concentration of 100 μg/mL. Racemic gossypol and apogossypolone inhibited growth by up to 95%, whereas gossypolone effected 100% growth inhibition in all fungal isolates tested except A. flavus. Growth inhibition was variable during the observed time period for all tested fungi capable of growth in these treatment conditions. Gossypolone demonstrated significant aflatoxin biosynthesis inhibition in A. flavus AF13 (B(1), 76% inhibition). Apogossypolone was the most potent aflatoxin inhibitor, showing greater than 90% inhibition against A. flavus and greater than 65% inhibition against A. parasiticus (B(1), 67%; G(1), 68%). Gossypol was an ineffectual inhibitor of aflatoxin biosynthesis in both A. flavus and A. parasiticus. Both gossypol and apogossypolone demonstrated significant inhibition of ochratoxin A production (47%; 91%, respectively) in cultures of A. alliaceus.