Incidence and health risk assessment of hydrogen cyanide and multi-mycotoxins in Nigerian garri.

Garri is a granular, starchy food prepared by the fermentation of mashed cassava. Hydrogen cyanide (HCN) and mycotoxins are contaminants in certain foods at different points along the food value chain. The incidence and contamination levels of HCN and multi-mycotoxins in garri from five agroecological zones of Nigeria were determined using a spectrophotometric method and ultra-high-performance liquid chromatography-tandem mass spectroscopy (UHPLC-MS/MS), respectively. The health risk associated with the consumption of contaminated garri was assessed. The health risk assessment model was used to calculate the dietary exposure of humans to the mycotoxins in garri. This was done by estimating the daily intake (EDI), the percentage tolerable daily intake (%TDI), the annual hepatocellular carcinoma (HCC) cases attributable to exposure to aflatoxins (AFs) in garri, as well as the HCC risk. The average intake of garri was estimated at 0.303 kg/day for a Nigerian adult. The incidence of HCN was 98.3% (0.056-2.463 mg/kg), and fermentation reduced the HCN level in garri more than other processing steps. The twenty-one mycotoxins identified and quantified were all within maximum levels, as applicable to those that are regulated by the EU. The %TDI for the other mycotoxins, with the exception of AFs, showed no alarming health risk with garri consumption. Annual HCC cases resulting from AF in garri were estimated at 10-60 cases for HBsAg + ve individuals and 4-23 cases for HBsAg - ve individuals based on 8.1% hepatitis B virus (HBV) incidence. Results further revealed no interdependence between HCN levels and mycotoxin content. This work suggests an unlikely chance of acute toxicity from HCN and major mycotoxins from a garri-based diet in Nigeria. Hence, it is recommended that concerned regulatory bodies maintain the existing permissible limits for HCN in Garri.

Assessment of dietary exposure and levels of mycotoxins in sorghum from Niger State of Nigeria.

This study reports levels of mycotoxins in sorghum from Niger State, Nigeria, and provides a comprehensive assessment of their potential health risks by combining mycotoxin levels and dietary exposure assessment. A total of 240 samples of red and white sorghum were collected from both stores and markets across four microclimatic zones. Fungal species were identified using a dilution plate method. Aflatoxins (AFs), deoxynivalenol, nivalenol, and ochratoxin (OTA) were quantified using HPLC, whereas cyclopiazonic acid, fumonisins (FUMs) and zearalenone were quantified using ELISA. A. flavus and A. fumigatus were dominant fungal species followed by F. verticilloides, A. oryzae and P. verrucosum. Aflatoxins (mean: 29.97 µg/kg) were detected in all samples, whereas OTA (mean: 37.5 µg/kg) and FUMs (mean: 3269.8 µg/kg) were detected in 72% and 50% of the samples, respectively. Mycotoxins frequently co-occurred in binary mixtures of AFs + OTA and AFs + FUMs. Dietary exposure estimates were highest for FUMs at 230% of TDI and margin of exposures (MOEs) for both AFs and OTA (<10,000) indicating a potential risk associated with combined exposure to AFs and OTA. The Risk of hepatocellular carcinoma cases (HCC/year) attributable to AFs and OTA exposure from sorghum was estimated to be 5.99 × 105 and 0.24 × 105 cases for HBsAg + individuals based on 13.6% HBV incidence. Similarly, the HCC/year for AFs and OTA were assessed to be 3.59 × 105 and 0.14 × 105 at an 8.1% prevalence rate. Therefore, the results of this study demonstrate the high prevalence and dietary exposure to mycotoxins through sorghum consumption, raising public health and trade concerns.

Mycotoxin levels and characterization of natural anti-fungal phytochemicals in pearl millet (Pennisetum glaucum) from Nigeria's six agroecological zones.

This study reports levels of multiple mycotoxins across Nigeria's six agro-ecological zones and corresponding levels of natural anti-fungal phytochemicals present in pearl millet (PM). 220 representative composite samples of PM were collected for mycotoxin analysis using ultrahigh performance liquid chromatography-mass spectrometry (UHPLC-MS), and 24 were randomly selected for determination of metabolites using gas chromatography-high resolution time of flight-mass spectrometry (GC-HRTOF-MS). In total, 15 mycotoxins were detected, all with levels below the European Union (EU) permissible limits and level of aflatoxins only up to 1.34 µg/kg. This is in sharp contrast to high levels of mycotoxins reported in maize samples from the same agroecological zones. Phytochemical analysis of the same samples identified a total of 88 metabolites, 30 of which are known anti-fungal properties from other previously published studies. The most common of these include methyl ester, bis (2-ethylhexyl) phthalate, and ç-tocopherol. The number of anti-fungal metabolites recovered from each sample ranged from 3 to 17 and varied widely in both number and composition across the agroecological zones. The anti-fungal metabolites may probably make PM less susceptible to fungal proliferation compared to other grains. Hence, it is worth exploring for possible sources of biological control products from PM.

Effect of partially purified sub-fractions of Pterocarpus mildbraedii extract on carbon tetrachloride intoxicated rats.

BACKGROUND: This study was designed to determine the hepatoprotective effect of partially purified fractions from Pterocarpus mildbraedii extract on carbon tetrachloride (CCl4) intoxicated rats. METHODS: The methanol extract of P. mildbraedii was subjected to solvent partitioning using n-hexane, chloroform, ethylacetate and water. Separation of fractions with proven antioxidant activity was achieved by chromatographic techniques. Acute toxicity and hepatoprotective studies of the methanol sub-fraction 6 (Me 6), methanol sub-fraction 7 (Me 7) and methanol sub-fraction 8 (Me 8) from P. mildbraedii extract on carbon tetrachloride (CCl4) intoxicated Wister rats. RESULTS: Intoxication of rats with CCl4 resulted in significant (p < 0.05) increase in the activities of aspartate transferase (AST), alanine transferase (ALT), alkaline phosphatase (ALP), level of malondialdehyde (MDA) while glutathione (GSH) concentration, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities were decreased. Administration of Me6, Me7 and Me8 sub-fractions of P. mildbraedii caused a significant reduction (p > 0.05) in the activities of the liver enzymes, MDA level, total and direct bilirubin in dose-dependent manner. There were significant (p < 0.05) increases in GSH concentration, SOD, CAT, and Gpx activities in the treated groups. The subfractions also restored the damaged hepatic-architecture in the treated groups. CONCLUSION: Therefore, Me6, Me7 and Me8 leaf sub-fractions of P. mildbraedii extract have hepatoprotective effect. Therefore, this vegetable can further be exploited as a source of drug/supplement development in the prevention and treatment of liver damage.

Evaluation of haematological changes in Plasmodium-berghei-infected mice administered with aqueous extract of Phyllantus amarus.

This study was designed to evaluate the changes in some hematological parameters of P-berghei-infected mice treated with aqueous extract of Phyllantus amarus, a plant that is used traditionally to treat malaria patients in some Nigerian communities. The aqueous extract of the leaves at 200, 400 and 600 mg kg(-1) body weight/day dose levels were used to treat the test groups immediately after infection for the suppressive test and 72 hours post infection for the curative test while a standard antimalarial drug, Artesunate, at a dose of 50 mg kg(-1) body weight was administered on the positive control group. The negative control group was left untreated. The level of parasitemia, variation in weight, Percentage Packed Cell Volume (% PCV), erythrocytes (RBC) and leukocytes (WBC) counts in the different groups were monitored throughout the period of study. The crude extract was screened for its phytochemical composition. The crude extract at 200, 400 and 600 mg kg(-1) body weight/day suppressed parasitemia by 54.67, 61.25 and 61.24% after treating for four days in the suppressive test as against 72.32% for the standard drug while the level of parasitemia was reduced by 64.35, 66.71 and 67.13%, respectively after treating for five days in the curative test as against 71.87% for the standard drug. The variations in the values of Percentage Packed Cell Volume (% PCV), weight, leukocyte and erythrocyte counts for treated groups before and after treatment was not significant (p < 0.05). Alkaloids, flavonoids, tannins, glycosides, saponin, carbohydrate and phenols were found to be present in the crude extract. The findings of this study show that the use of Phyllantus amarus as antimalaria regimen by local medical practitioners does not adversely affect the weight and the haematological parameters determined.

Natural multi-occurrence of mycotoxins in rice from Niger State, Nigeria.

Twenty-one rice samples from field (ten), store (six) and market (five) from the traditional rice-growing areas of Niger State, Nigeria were analysed for aflatoxins (AFs), ochratoxin A (OTA), zearalenone (ZEA), deoxynivalenol (DON), fumonisin B(1) (FB(1)) and B(2) (FB(2)), and patulin (PAT) by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) respectively. T-2 toxin was determined using TLC only. AFs were detected in all samples, at total AF concentrations of 28-372 µg/kg. OTA was found in 66.7% of the samples, also at high concentrations (134-341 µg/kg) that have to be considered as critical levels in aspects of nephrotoxicity. ZEA (53.4%), DON (23.8), FB(1) (14.3%) and FB(2) (4.8%) were also found in rice, although at relatively low levels. T-2 toxin was qualitatively detected by TLC in only one sample. Co-contamination with AFs, OTA, and ZEA was very common, and up to five mycotoxins were detected in a single sample. The high AF and OTA levels as found in rice in this study are regarded as unsafe, and multi-occurrences of mycotoxins in the rice samples with possible additive or synergistic toxic effects in consumers raise concern with respect to public health.