Sphingosine N-acyltransferase/ceramide synthase

Fumonisin B1 (FB1) and fumonisin B2 (FB2) are the most abundant fumonisins (FBs) occurring worldwide in maize, infected mainly by Fusarium verticillioides and F. proliferatum. A total of 307 corn kernel samples were collected from 45 districts of Gansu, Shandong, Ningxia and the Inner Mongolia provinces of the north and northwest China. The samples were analysed for FB1 and FB2 by high-performance liquid chromatography. The FBs (FB1+ FB2) incidence rate in samples from Gansu, Shandong, Ningxia and Inner Mongolia were 31.5%, 81.1%, 46.2% and 53.6%, respectively. Average FBs concentration was 703 μg/kg and the concentrations ranged from ≤11 to 13,110 μg kg(-1). Results were compared with the European Commission (EC) regulation for FB1+ FB2 in unprocessed maize for human consumption of 4 mg kg(-1). Contamination in 17 samples was higher than these levels. More than 80% of the samples from Liaocheng county, which is located in the Shandong province, were contaminated with FBs, with a mean total FB concentration of 2496 μg/kg. The result was significantly different from that of the Inner Mongolia (1399 μg/kg), Ningxia (373 μg/kg) and Gansu (175 μg/kg). Average exposure to FBs (0.12 μg/kg body weight/day) is within the provisional maximum tolerable daily intake of 2.0 mg/kg of body weight set by the Joint Food and Agriculture Organization and World Health Organization Expert Committee on Food Additives [1].

Three recently described and toxicologically important mycotoxins, fumonisin B1 (FB1), fumonisin B2 (FB2), and fumonisin B3 (FB3), produced by Fusarium moniliforme in various grains, have been associated with a number of diseases in both humans and animals. The toxicity of purified FB1, FB2, and FB3, individually and in combination (3:1:1 ratio), were evaluated with regard to their embryo toxicity by injection of the toxins into the air cell of chicken eggs at 72 h of incubation. Under these conditions, FB1 at doses of 0, 2, 4, 8, 16, 32, and 64 microg per egg resulted in embryonic mortality of 5, 12.5, 17.5, 20.0, 52.5, 77.5, and 100%, respectively. The 50% lethal dose for FB1, when injected into the air cell of embryonating chicken eggs, was determined to be 18.73 microg per egg. A comparison of the toxicity of FB1, FB2, and FB3, individually and in combination (3:1:1 ratio), at doses of 16 microg of total fumonisin per egg, indicated that the toxicity of the fumonisins differed, FB1 being the most toxic. Microscopic examination of chicken embryos exposed to fumonisin did not reveal any gross developmental abnormalities; however, severe hemorrhages of the head, neck, and thoracic area of the dead embryos were evident.[1]

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The fumonisin mycotoxins are produced by Fusarium moniliforme Sheldon, a contaminant of corn worldwide. The two most abundant analogues (fumonisins B1 and B2) are known to be potent inhibitors of sphingosine N-acyltransferase (ceramide synthase) and hence to disrupt de novo sphingolipid biosynthesis. The sphingoid bases, sphingosine and sphinganine (and hence their ratio), were measured at varying intervals over a period of 60 weeks in the serum of non-human primates (vervet monkeys; Cercopithecus aethiops) which were consuming diets containing 'low' and 'high' amounts of F. moniliforme culture material, such that their total daily fumonisin intake was approximately 0.3 and 0.8 mg/kg body weight/day, respectively. Although no significant differences were found in the serum levels of sphingosine compared to controls, serum sphinganine levels in the experimental groups (mean of 219 nM and 325 nM, respectively) were significantly (P = 0.02) elevated above the levels in controls (mean 46 nM). As a consequence, the ratio sphinganine:sphingosine was significantly (P = 0.003) elevated from a mean of 0.43 in the control group to 1.72 and 2.57 in the experimental groups, respectively. Similar changes in sphingolipid profiles were also measured in urine with an increase of the ratio from 0.87 in controls to 1.58 and 2.17 in the experimental groups, although the differences were not statistically significant. Hence, the disruption of sphingolipid biosynthesis in vervet monkeys by fumonisins in culture material added to their diet can effectively be monitored in the serum as an elevation of the sphinganine:sphingosine ratio[2].

The Committee reviewed the studies that have become available since the previous evaluation in 2011, and concluded that they would not change the overall toxicological assessment performed previously by the Committee. Thus, the previously established group PMTDI of 2 µg/kg bw for FB1, FB2 and FB3, alone or in combination, was retained by the current Committee. The Committee noted that the international exposure estimates for FB1 and total fumonisins were lower than those estimated by the Committee at its seventy-fourth meeting in 2011. In the current assessment, a larger part of the occurrence data was from countries belonging to the WHO European Region compared with 2011, resulting in lower overall fumonisin levels in maize. In the current assessment, no information on fumonisin levels in maize was available from countries belonging to the African, Eastern Mediterranean or South-East Asia regions, where higher fumonisin concentrations are typically detected. Given these limitations of the occurrence data used in the exposure assessment and high exposures reported in the literature in some countries, it is likely that the exposures to fumonisins in areas where maize is a staple food and high contamination with fumonisins can occur are higher than those estimated by the Committee at this meeting, as can be seen in the previous evaluation, which was based on a larger and more representative data set. At the eighty-third meeting the Committee also evaluated co-exposure to aflatoxins and fumonisins. Fumonisins and aflatoxins are both frequent contaminants in cereals and cerealbased foods. Aflatoxins are common contaminants in groundnuts and tree nuts. Co-exposure to both mycotoxins is likely in areas where these foods are regularly consumed. Although evidence in laboratory animals from the previous and the present evaluations has suggested an additive or synergistic effect of fumonisin and aflatoxin co-exposure in the development of preneoplastic lesions or hepatocellular carcinoma, currently no data are available on such effects in humans. The Committee concluded that there are few data available to support co-exposure as a contributing factor in human disease. However, the interaction between AFB1, a compound with known genotoxic properties, and fumonisins, which have the potential to induce regenerative cell proliferation (particularly at exposures above the PMTDI), remains a concern. This is due to the fact that the incidences of chronic liver disease and stunting are high in the areas of the world where the exposures to both mycotoxins are high and the co-exposure has been confirmed with biomarkers.

[1]. The toxicity of fumonisin B1, B2, and B3, individually and in combination, in chicken embryos. Poult Sci. 2001 Apr;80(4):401-7.

[2]. Disruption of sphingolipid metabolism in non-human primates consuming diets of fumonisin-containing Fusarium moniliforme culture material. Toxicon. 1996 May;34(5):527-34.

[3]. Natural occurrence of fumonisins B1 and B2 in corn in four provinces of China. Food Addit Contam Part B Surveill. 2013;6(4):270-4.

Fumonisin B2 is a fumonisin that is (2S,3S,12S,14S,15R,16R)-2-amino-12,16-dimethylicosane-3,14,15-triol in which the hydroxy groups at positions 14 and 15 have each been esterified by condensation with the 1-carboxy group of 3-carboxyglutaric acid (giving a 3-carboxyglutarate ester group with R configuration in each case). It has a role as an Aspergillus metabolite and a carcinogenic agent. It is a fumonisin, a primary amino compound, a diol and a diester.
Fumonisin b2 has been reported in Fusarium fujikuroi, Streptomyces, and Aspergillus niger with data available.

C34H59NO14

705.83056

705.393

C, 57.86; H, 8.43; N, 1.98; O, 31.73

116355-84-1

Fumonisin B2-13C34;1217481-36-1

2733489

White to yellow solid powder

1.2±0.1 g/cm3

864.4±65.0 °C at 760 mmHg

<3200(dec)

476.6±34.3 °C

0.0±0.6 mmHg at 25°C

1.520

4.39

7

15

31

49

1040

9

CCCC[C@@H](C)[C@H]([C@H](C[C@@H](C)CCCCCC[C@H](C[C@@H]([C@H](C)N)O)O)OC(=O)C[C@@H](CC(=O)O)C(=O)O)OC(=O)C[C@@H](CC(=O)O)C(=O)O

UXDPXZQHTDAXOZ-STOIETHLSA-N

InChI=1S/C34H59NO14/c1-5-6-12-21(3)32(49-31(43)18-24(34(46)47)16-29(40)41)27(48-30(42)17-23(33(44)45)15-28(38)39)14-20(2)11-9-7-8-10-13-25(36)19-26(37)22(4)35/h20-27,32,36-37H,5-19,35H2,1-4H3,(H,38,39)(H,40,41)(H,44,45)(H,46,47)/t20-,21+,22-,23+,24+,25+,26-,27-,32+/m0/s1

(2R)-2-[2-[(5R,6R,7S,9S,16R,18S,19S)-19-amino-6-[(3R)-3,4-dicarboxybutanoyl]oxy-16,18-dihydroxy-5,9-dimethylicosan-7-yl]oxy-2-oxoethyl]butanedioic acid

fumonisin b2; 116355-84-1; fumonisin-B2; Fumonisin B2, Fusarium moniliforme; CCRIS 4434; CHEBI:38225; UX4WHT4MKB; (2R)-2-[2-[(5R,6R,7S,9S,16R,18S,19S)-19-amino-6-[(3R)-3,4-dicarboxybutanoyl]oxy-16,18-dihydroxy-5,9-dimethylicosan-7-yl]oxy-2-oxoethyl]butanedioic acid;

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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 (Please use freshly prepared in vivo formulations for optimal results.)