Risks for human and animal health related to the presence of phorbol esters in Jatropha kernel meal

Abstract

Following a request from the European Commission, the risks for human and animal health related to the presence of phorbol esters (PEs) in Jatropha kernel meal were assessed by the EFSA Panel of Contaminants in the Food Chain (CONTAM). Jatropha curcas (Jatropha) seeds contain substantial amounts of extractable oil utilised for biodiesel production. The remaining protein‐rich products (seed meal or kernel meal) may be used as a protein source in animal feed after removal of anti‐nutritive factors and toxic PEs. The available data on absorption of Jatropha PEs after oral ingestion, biotransformation, elimination, and dose‐dependent toxic effects are very limited, and only for pigs a no observed adverse effect level (NOAEL) of 0.4 mg PEs/kg bw per day (12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) equivalent), based on decreases in body weight gain and feed intake, could be identified from short‐term feeding studies. No health based guidance value for humans could be established. Processes that almost completely remove or degrade toxic PEs in Jatropha products are available, resulting in levels below the limit of detection of 3 mg Jatropha PEs/kg (TPA equivalent). Replacement of 50% of the protein in compound feeds with treated Jatropha materials would result in animal exposures that are still 10 to 200‐fold lower than the NOAEL for pigs. The CONTAM Panel concluded that such use of Jatropha material would not pose a health risk to pigs and that the risk to other species is likely to be low. The transfer of Jatropha PEs to animal derived products is unknown. In a human exposure scenario using a 50% transfer rate from feed to milk, a daily intake of 1 μg Jatropa PEs/kg bw per day was calculated. The CONTAM Panel concluded that more data are needed to draw firm conclusions on human risks.

Safety of hydrothermally treated kernels from edible Jatropha curcas L. (Chuta) as a novel food pursuant to Regulation (EU) 2015/2283

“…The Panel made a theoretical exposure calculation to PEs possibly present in the NF (Section 3.8.4) and took into account uncertainties in the analytical method, by considering an LOD corrected with a factor of two (1.5 instead of the 0.75 lg PEs/g de-shelled kernel (as TPA equivalent) as reported in the specifications). Margins of exposure to the NOAEL (no observed adverse effect level) of 0.4 mg PEs/kg bw per day as identified by EFSA CONTAM Panel (2015) are reported in Table 13.…”

“…If a non-edible kernel is ingested, clinical symptoms include burning and pain in the mouth or throat and vomiting and this intoxication is generally self-limiting. However, it is reported that sometimes dizziness, nausea, abdominal pain and severe diarrhoea may occur and a few cases of more severe symptoms are also reported, mainly in children due to ingestion of a number of kernels (Devappa et al, 2010a;Shah and Sanmukhani, 2010;Chomchai at al., 2011;EFSA CONTAM Panel, 2015;Langrand et al, 2015;Gupta et al, 2016).…”

“…The phorbol esters, like TPA, are reported to mimic the action of diacyl glycerol, activator of protein kinase C (PKC), which regulates different signal transduction pathways. Interference with the activity of PKC affects a number of processes including phospholipid and protein synthesis, enzyme activities, DNA synthesis, phosphorylation of proteins, cell differentiation and gene expression (Goel at al., 2007;Devappa et al, 2010b;EFSA CONTAM Panel, 2015).…”

“…With reference to the toxicity of PEs, the Panel noted that an NOAEL (no observed adverse effect level) of 0.4 mg/kg bw per day was identified in a subchronic study in pigs by EFSA CONTAM Panel (2015). This study (described by Li et al, 2015) was specifically designed to investigate the use of defatted Jatropha kernel meal to replace soybean meal in the diet of growing pigs.…”