The mycotoxin, fumonisin B1 is produced by the mould Fusarium moniliforme, a common contaminant of maize and maize products. Small doses (mg/kg) of ingested fumonisin B1 have been shown to cause diseases and even death in animals, including non-human primates. Thus highly sensitive methods have been employed to detect fumonisin B1 presence in foods, feeds and in animals. This study comprised two parts.The initial part focused on establishing reliable extraction, purification and quantitation of fumonisin B1 using high-performance liquid chromatography (HPLC) on culture extracts. The second part was to analyse sera of Black African women with pre-eclampsia for the presence of fumonisin B1 using HPLC. Maize patty cultures and broth cultures were inoculated with Fusarium moniliforme PPRI 1059 and incubated. Fumonisin B1 was extracted and purified by centrifugation strong anion exchange chromatography (SAX). Eluents from SAX cartridges were analysed using Thin-layer chromatography (TLC) and fluorescence HPLC after o-phythadialdehyde (OPA) derivatisation. Fumonisin B1 standards on HPLC gave a retention time of 7.5 minutes using methanol/0.1 M sodium dihydrogen phosphate (68 + 32, pH 3.3) as mobile phase and a 25 cm C8 column. Patty cultures produced the highest yields of fumonisin B1. In the case of serum samples, a double-blind study was carried out using women attending the obstetric clinic at a large city teaching hospital. The population comprised normal, pre-eclamptic and eclamptic women. On HPLC analysis a significantly higher mean concentration of fumonisin B1 concentration was found in the eclamptic group (P<0,005) as compared to the other two groups.Thus fumonisin B1 may have a role to play in eclampsia for which the aetiology is still unknown. / Thesis (M.Med.Sc.)-University of Natal, 1999.

Fumonisins, mycotoxins produced by the fungus, Fusarium moniliforme, which grows on maize, are a major worldwide agricultural problem. Consumption of contaminated maize feeds causes a wide variety of toxic effects in animals depending on the species of animal. In humans, high concentrations of fumonisins have been shown to correlate with increased incidence of oesophageal cancer (OC). Most analyses for fumonisins are done using high performance liquid chromatography (HPLC) which requires time-consuming extraction and clean-up prior to preparation of a fluorescent derivative. Enzyme-linked immunosorbent assays (ELISA), which are sensitive and specific, are a viable alternative but commercially available antibodies and kits are extremely expensive. Polyclonal antibodies against fumonisin B, (FB,) were raised in chickens and rabbits; all animals produced antibodies from week 2 onwards, the highest titre was at week 8 from one of the chickens. Cross-reactivities with FB, analogues were checked. A sensitive, quantitative competitive indirect ELISA (CI-ELISA) was developed and optimised; range 0.2 to 20 ng/ml (in buffer), detection limit 0.2 nglml (in buffer), intra-assay coefficient of variation (CV) was 5.33 % and inter-assay 7.04%. This method was adapted to analyse human plasma and urine samples. After removal of proteins by boiling, the range of recoveries of FBI were 94.7% toI12.4% at 4 ng/ml; and 94.6% to 108.7% at 8 ng/ml. Blood and urine samples from patients with OC (40 plasma, 17 urine), controls (21 plasma, 12 urine) and patients with other forms of cancer (20 plasma, 10 urine) were collected from hospitals in the Durban Metropolitan area and analysed for fumonisins. Detectable levels (>0.4 nglml) were found in 86.9% of plasma samples and 94.9% of urine samples. Statistical evaluation showed a highly significant difference between plasma results for OC and controls (p<0.000 1) but no significant difference between the urine results. Comparison of other forms of cancer and controls showed no significant differences for either the plasma or the urine samples. However, there was a highly significant difference between the OC and other forms of cancer results for both plasma (p<0.005) and urine (p<0.05) samples. Some samples (9 plasma, 8 urine) were checked by HPLC. For plasma samples there was correlation between the ELISA and HPLC methods (r = 0.656, p<0.005) but not for urine samples.

Thesis (MSc)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: Please see fulltext for abstract / AFRIKAANSE OPSOMMING: Sien asb volteks vir opsomming

The use of the multi-mycotoxin screen based on dialysis to analyze foods and feeds for mycotoxins, is well documented. This study investigated the possibility of incorporating FB I into the screen. Maize meal (25g) was spiked with AFB I , CPA, FB1, ST and ZEA and extraction was done using acetonitrile/4% potassium chloride (90:10 v/v). The recoveriesof the mycotoxins were 77.4, 61.5, 97.4, 79.8 and 98% respectively on analysis by HPLC. Fumonisin B1 could not be completely incorporated into the screen due to its reaction with sodium hydrogen carbonate, which is a component in the method. Thus, FB I was determined in a separate portion of the extract. The high cost of FBI standards which are often of inferior purity necessitated that FB I standards be locally produced in the laboratory using Fusarium moniliforme MRC 826, a good producer of FB 1 . In this study, production of FB I was carried out using a stirred jar fermenter and patty cultures. The yields were 160mg/1 and 6mg/g of FB I for the two methods respectively. Methyl esterification of tricaballylic acid moieties of FB I was done for effective clean-up. This was achieved by derivatizing FBI, with diazomethane. It was found that other functional groups besides the tricaballylic acid moieties of FB I were undesirably methylated as well, which made cleanup by this method difficult as shown by electrospray mass spectrometric analysis. Attempts to de-methylate FBI methyl esters with esterase was not successful. Analysis of human faecal samples was carried out with the view of developing a short term marker for assessing human exposure to FB I . Faeces from rural (20) and urban (23) volunteers were analyzed by high performance liquid chromatography. The results showed that 35% of the rural samples and 9% of the urban volunteers had detectable amounts of FB I ranging from 0.600 to 19.56 mg/kg. There was a significant difference (p = 0.04)between the two population groups. A study was carried out to assess the occurrence of FBI in a rural area of Tugela valley in Kranskop magisterial district of KwaZulu Natal. A questionnaire was administered to gather information on the family health and nutrition. Raw (stored) and processed foods and faeces, were collected for analysis of FB1. A similar control study was carried out in the urban area of Durban Metro. Homes were mapped out using the GIS for easy follow up. Oesphageal cancer (OC) incidence from the local hospital and weather data for the study area were collected from South African Weather Bureau, Johannesburg. The questionnaire results showed that the common diseases were mainly of respiratory origin (24% and 26%) from both rural and urban groups respectively. Food analysis (by HPLC) showed that the number of maize samples with FB I were higher in the rural area (31.9%) in comparison to the urban samples (6.1%). The level ranged from 0.092-22.225 mg/kg in food and 0.513-39 mg/kg in faeces. The mean concentration of FB i in the faeces and maize samples showed a similar significant difference of 0.014 between the two groups. However, these concentrations were much lower than those of high OC area in Transkei (117 mg/kg). There was no detection of FBI in fermented food products. / Thesis (M.Med.Sci.)-University of Natal, Durban, 1998.