Bioactive compounds in Diospyros mafiensis roots inhibit growth, sporulation and aflatoxin production by Aspergillus flavus and Aspergillus parasiticus

2017 ◽  
Vol 10 (3) ◽  
pp. 237-248
Author(s):  
J.A. Mmongoyo ◽  
M.G. Nair ◽  
J.E. Linz ◽  
F. Wu ◽  
J.K. Mugula ◽  
...  
Keyword(s):  
Aspergillus Flavus ◽  
Bioactive Compounds ◽  
Vegetative Growth ◽  
Aspergillus Parasiticus ◽  
Fungal Infections ◽  
Aflatoxin Production ◽  
Enzyme Linked Immunosorbent Assay ◽  
Root Bark ◽  
Total Aflatoxin ◽  
Food And Feed

Diospyros mafiensis F. White is a medicinal shrub or small tree (6 m tall) widely distributed in the Zanzibar-Inhambane regional mosaic and traditionally used to treat leprosy, diarrhoea, and skin fungal infections in Tanzania and Mozambique. Our objective was to determine the anti-aflatoxigenic properties of compounds from D. mafiensis root bark against vegetative growth, sporulation and aflatoxin production by Aspergillus flavus and Aspergillus parasiticus. Bioassay-guided extraction, fractionation, and isolation of bioactive compounds using A. parasiticus B62 were employed. The bioactive compounds were elucidated using 1H and 13CNMR and LC-MS. Growth inhibition was determined by measuring the colony diameter of A. flavus AF3357 and A. parasiticus SU-1 ATCC56775. Inhibitory effects on sporulation were estimated using a haemocytometer. Total aflatoxin was quantified by direct competitive enzyme-linked immunosorbent assay (ELISA). Bioactive compounds diosquinone (DQ) and 3-hydroxydiosquinone (3HDQ) were identified. DQ weakly inhibited A. flavus and A. parasiticus vegetative growth (MIC50 > 100 µg/ml) and 3HDQ strongly inhibited A. flavus (MIC50 = 14.9 µg/ml) and A. parasiticus (MIC50 = 39.1 µg/ml). DQ strongly reduced total aflatoxin production by A. flavus from 157 to 36 ng/plate, and by A. parasiticus from 1,145 ng/plate to 45 ng/plate at 100 µg/ml. 3HDQ reduced total aflatoxin production by A. parasiticus from 1,145 to 32 ng/plate; stimulated production by A. flavus from 157 to 872 ng/plate at 12.5 µg/ml but reduced to 45 ng/plate at 100 µg/ml. In summary, DQ and 3HDQ could be used as natural antifungal compounds to prevent mould growth and aflatoxin accumulation in food and feed.

scholarly journals The Potential of Baobab (Adansonia digitata L.) Extracts as Biocontrol on the Growth and Aflatoxin Production by Aspergillus flavus and A. parasiticus

2013 ◽  
Vol 2 (3) ◽  
pp. 93 ◽  
Author(s):  
Saifeldin A. F. El-Nagerabi ◽  
Abdulkadir E. Elshafie ◽  
Suleiman S. AlKhanjari ◽  
Saif N. Al-Bahry ◽  
Mohamed R. Elamin
Keyword(s):  
Essential Oil ◽  
Vegetative Growth ◽  
Aflatoxin Production ◽  
Inhibitory Effect ◽  
Adansonia Digitata ◽  
Fruit Extract ◽  
Total Aflatoxin ◽  
Food And Feed ◽  
Toxigenic Strains ◽  
Aflatoxin B

Moulds and associated mycotoxins, especially aflatoxins, are important factors that advesely affect food and feed produced from contaminated plant and animal prodcuts. They are lethal to humans and animals, which emphasizes the great concern in food and feed production. In this study, the effects of baobab (<em>Adansonia digitata</em>) extracts on the vegetative growth and aflatoxin secretion by <em>A. flavus </em>(SQU21) and <em>A. parasiticus</em> (CBS921.7) strains were exzmined. Different concentrations of baobab fruit extract (1.5, 3, 5, and 7% w/v) and essential oil (0.5, 1, 3 and 5% v/v) was used. Fruit extract of baobab apparently inhibited the total aflatoxin secretion up to 20.4-68.5% for <em>A. flavus</em> and 11.9-69.1% for <em>A. parasiticus, </em>whereas the inhibition of aflatoxin B<sub>1 </sub>production ranged between 29.9-79.2% and 13-68% for the two strains, respectively. The highest inhibition levels of total aflatoxin and aflatoxin B<sub>1</sub> secretion by <em>A. flavus</em> (47.2-95.7%; 28.1-89.7%) and <em>A. parasiticus </em>(42.7-93.3%; 25.9-80.2%) were obtained with essential oil extracted from baobab seeds. The two extracts significantly reduced the vegetative growth and the mycelial dry weights of selected fungi. This indicates the antifungal activity and inhibitory effect of baobab on the growth and aflatoxin production by the two toxigenic strains. Thus, fruit extract and essential oil of <em>A. digitata</em> can be suggested as potentially effective biocontrol and biopreservative substrates against food and feed contamination by aflatoxigenic moulds.

Production of Aflatoxin in Cocoa Beans

1979 ◽  
Vol 62 (5) ◽  
pp. 1076-1079 ◽  
Author(s):  
Lawrence M Lenovich ◽  
W Jeffrey Hurst
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
Ivory Coast ◽  
Aspergillus Parasiticus ◽  
Aflatoxin Production ◽  
Growth Conditions ◽  
Aflatoxin Contamination ◽  
Cocoa Beans ◽  
Total Aflatoxin ◽  
Substrate Variation

Abstract Aflatoxin was produced in both non-autoclaved and autoclaved Ivory Coast cocoa beans inoculated with Aspergillus parasiticus NRRL 2999 under optimum laboratory growth conditions. Total aflatoxin levels ranged from 213 to 5597 ng/g substrate. Aflatoxin was quantitated by using high pressure liquid chromatography (HPLC). Raw, non-autoclaved cocoa beans, also inoculated with aspergilli, produced 6359 ng aflatoxin/g substrate. Variation in aflatoxin production between bean varieties was observed. Total aflatoxin levels of 10,446 and 23,076 ng/g substrate were obtained on Ivory Coast beans inoculated with A. parasiticus NRRL 2999 and NRRL 3240, respectively. Aflatoxin production on Trinidad and Malaysian beans was 28 and 65 ng aflatoxin/g substrate. These data support previously reported low level natural aflatoxin contamination in cocoa.

Extracts of Agave americana inhibit aflatoxin production in Aspergillus parasiticus

2011 ◽  
Vol 4 (1) ◽  
pp. 37-42 ◽  
Author(s):  
A. Rosas-Taraco ◽  
E. Sanchez ◽  
S. García ◽  
N. Heredia ◽  
D. Bhatnagar
Keyword(s):  
Aspergillus Parasiticus ◽  
Public Awareness ◽  
Aflatoxin Production ◽  
Aflatoxin Contamination ◽  
Aqueous Extracts ◽  
Total Aflatoxin ◽  
Toxigenic Fungi ◽  
Agave Americana ◽  
Acid Accumulation ◽  
Norsolorinic Acid

Toxigenic fungi invade crops prior to harvest as well as during storage and produce harmful, even carcinogenic toxins such as aflatoxins. Since consumers demand safe commodities, and due to enhanced public awareness of the dangers of many synthetic fungicides, the importance of investigating alternative, natural products to control these toxigenic fungi is clear. This study investigated the effect of aqueous extracts of Agave americana on growth, conidia and aflatoxin production. Aspergillus parasiticus strains SRRC 148, SRRC 143 (Su-1), and A. parasiticus SRRC 162, a mutant (nor-) that accumulates norsolorinic acid (NOR, an orange-coloured intermediate of the aflatoxin pathway), were first inoculated into Adye and Mateles liquid medium, then plant extracts were added, and incubated at 28 °C for 7 days. Aflatoxin and norsolorinic acid were assayed by HPLC and spectrophotometry, respectively. While the extract of A. americana stimulated growth of the studied fungi, conidiogenesis, norsolorinic acid accumulation (in the nor- mutant), and aflatoxin production were significantly affected. The reduction was produced by the extracts at concentrations higher than 5-10 mg/ml, where all types of total aflatoxin analysed (aflatoxins B1, B2, G1 and G2) were reduced from 64% to >99% in the whole culture, and a reduction of 75% of norsolorinic acid. The results of the present work indicate that extracts of A. americana may be promising safe alternatives to harmful fungicides for controlling aflatoxin contamination.

Effects of Potassium Sorbate on Growth and Aflatoxin Production by Aspergillus parasiticus and Aspergillus flavus1

1983 ◽  
Vol 46 (11) ◽  
pp. 940-942 ◽  
Author(s):  
LLOYD B. BULLERMAN
Keyword(s):  
Aspergillus Flavus ◽  
Yeast Extract ◽  
Aflatoxin B1 ◽  
Spore Germination ◽  
Mycelial Growth ◽  
Aspergillus Parasiticus ◽  
Aflatoxin Production ◽  
Potassium Sorbate ◽  
Mycelial Mass ◽  
Yeast Extract Sucrose

Growth and aflatoxin production by selected strains of Aspergillus parasiticus and Aspergillus flavus in the presence of potassium sorbate at 12°C were studied. Potassium sorbate at 0.05, 0.10 and 0.15% delayed or prevented spore germination and initiation of growth, and slowed growth of these organisms in yeast-extract sucrose broth at 12°C. Increasing concentrations of sorbate caused more variation in the amount of total mycelial growth and generally resulted in a decrease in total mycelial mass. Potassium sorbate also greatly reduced or prevented production of aflatoxin B1 by A. parasiticus and A. flavus for up to 70 d at 12°C. At 0.10 and 0.15% of sorbate, aflatoxin production was essentially eliminated. A 0.05% sorbate, aflatoxin production was greatly decreased in A. flavus over the control, but only slightly decreased in A. parasiticus.

Enhanced Aflatoxin Production by Aspergillus flavus and Aspergillus parasiticus after Gamma Irradiation of the Spore Inoculum

1980 ◽  
Vol 43 (1) ◽  
pp. 7-9 ◽  
Author(s):  
A. F. SCHINDLER ◽  
A. N. ABADIE ◽  
R. E. SIMPSON
Keyword(s):  
Radiation Dose ◽  
Aspergillus Flavus ◽  
Gamma Rays ◽  
Aspergillus Parasiticus ◽  
Aflatoxin Production ◽  
Distilled Water ◽  
Mycotoxin Production ◽  
High Production ◽  
Dose Levels ◽  
Medium Dose

Distilled water plus 0.1% surfactant suspensions of spores of Aspergillus flavus and Aspergillus parasiticus were exposed to several radiation levels of cobalt-60 gamma rays. Spores of A. flavus isolate M-141 were exposed to radiation levels of approximately 16, 90 and 475 Krads and inoculated onto a sterile rice substrate which was then monitored for aflatoxin production. In this initial trial with A. flavus M-141, aflatoxins B1 and M production on rice increased as radiation dose increased. At the highest dose, this increase was more than 50 times higher than the non-irradiated controls. Spores of an aflatoxin G1-producing A. parasiticus isolate, M-1094, were exposed to 90, 215 and 430 Krads and resulted in increased production of aflatoxins G1, B1, and M. Aflatoxin production by M-1094 was highest at the low and medium dose levels. Irradiation of spores of this isolate with 430 Krads produced no observable spore germination or growth on rice and no detectable aflatoxin after 1 week of incubation at 27 C. A typical colonies from irradiated spores were selected and their mycotoxin production was determined. Increase in aflatoxin production by these strains, as compared to non-irradiated controls, was 67:1 for aflatoxin B1, 136:1 for B2, and 138:1 for M. This potential for greatly increased mycotoxin production must be considered when food is irradiated or when a high production of aflatoxins is desired.

Temperature Limits for Production of Aflatoxin by Twenty-five Isolates of Aspergillus flavus and Aspergillus parasiticus

1977 ◽  
Vol 40 (1) ◽  
pp. 39-40 ◽  
Author(s):  
A. F. SCHINDLER
Keyword(s):  
Aspergillus Flavus ◽  
Aspergillus Parasiticus ◽  
Agar Medium ◽  
Aflatoxin Production ◽  
Wort Agar

Aflatoxicogenic isolates of Aspergillus were tested for their aflatoxin production after 8 weeks of growth on wort agar medium at high (41, 46 ± 1 C) and low (2, 7 ± 0.5 C) temperatures. Controls were grown at approximately 22 C, a temperature known to be favorable for aflatoxin production. There were two replications of each treatment. All replicate cultures of the 25 isolates grown at 22 C were positive for aflatoxin. Aflatoxins were not detected in wort agar when cultures were incubated at other test temperatures. It appears that both Aspergillus flavus and Aspergillus parasiticus will not produce aflatoxins when grown at ⩽ 7.5 C or at ⩾ 40 C.

An Enzyme-Linked Immunosorbent Assay for the Detection of Aspergillus parasiticus and Aspergillus flavus

1997 ◽  
Vol 60 (8) ◽  
pp. 978-984 ◽  
Author(s):  
GUO-JANE TSAI ◽  
SHOU-CHIN YU
Keyword(s):  
Aspergillus Flavus ◽  
Immunosorbent Assay ◽  
False Positive ◽  
Aspergillus Parasiticus ◽  
False Negative ◽  
Zealand White Rabbit ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Molecular Weights ◽  
Sds Page

An enzyme-linked immunosorbent assay (ELISA) was established for the specific detection of Aspergillus parasiticus and Aspergillus flavus. A New Zealand white rabbit was immunized intravenously with 100 μg of A. parasiticus CCRC 30117 mycelial protein extracts. The antibodies were separated and purified. The optimal concentration of the antibody and antibody-peroxidase conjugate used in the established ELISA was 10 μg/ml with a detection limit of 1 μg/ml. Among the 126 strains tested (including 21 strains of A. parasiticus, 11 strains of A. flavus, 34 isolates of A. parasiticus/A. flavus from cereals, and 60 strains of non-A. parasiticus/A. flavus fungi), the false-negative and false-positive rates were 1.5 and 3.3%, respectively. Strains of Aspergillus flavofrucatis and Aspergillus sojae produced false-positive reactions. However, their antigens had much lower cross-reactivity with the antibodies raised against A. parasiticus, as shown from I50 values. The molecular weights of the main antigens of A. parasiticus were 94, 82, and 40 kDa. The two heavier antigens had higher sugar contents, as demonstrated by SDS-PAGE and immunoblotting. A good correlation (r = 0.97) was found between mycelium measurement by weighing and by ELISA for A. parasiticus grown in yeast extract sucrose broth (YESB) at 25°C.

Sign in / Sign up

Export Citation Format

Share Document