Characterization of the pro-inflammatory potencies of purified Jatropha phorbol esters by a gene expression-based in vitro bioassay |
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Authors: | Guillaume Pelletier Bhaja Krushna Padhi Mahsa Hamzeh Annamaria Halasz Manjeet Singh Jalal Hawari |
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Institution: | 1. Hazard Identification Division, Environmental Health Science and Research Bureau, Health Canada, Environmental Health Centre, Ottawa, Canada;2. National Research Council of Canada, Montreal, Canada;3. Department of Civil Engineering, Geology and Mining, Polytechnique Montréal, Montreal, Canada |
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Abstract: | The oil extracted from Jatropha seeds is an emerging biodiesel feedstock that also contains several pro-inflammatory phorbol esters. These phorbol esters can elicit adverse inflammatory responses through activation of the protein kinase C, as previously described for the prototypical phorbol ester 12-O-tetradecanoylphorbol-13-acetate. We extracted and purified the six phorbol esters identified in Jatropha oil and assessed their pro-inflammatory activities using a recently developed gene expression-based bioassay. Borrowing from an approach used for the assessment of dioxin toxicity, we expressed their pro-inflammatory potencies in relation to the potency of 12-O-tetradecanoylphorbol-13-acetate (in terms of 12-O-tetradecanoylphorbol-13-acetate toxic equivalency factors). The pro-inflammatory potencies of Jatropha phorbol esters were orders of magnitudes below the potency of 12-O-tetradecanoylphorbol-13-acetate. Interestingly, the cytotoxicity of phorbol esters did not appear to be directly related to their pro-inflammatory potencies. Calculations based on phorbol ester potencies and concentrations led to overestimation of the pro-inflammatory activity of Jatropha oil, as measured by the same gene expression-based bioassay. The preliminary results presented here suggest that further work on the described approach may lead to the development of valuable tools and metrics to quantify and predict the pro-inflammatory activities of complex phorbol ester mixtures. |
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Keywords: | In vitro assay MDCK cells Jatropha oil phorbol ester toxic equivalency factor |
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