Cytotoxicity of diplodiatoxin, dipmatol and diplonine, metabolites synthesized by Stenocarpella maydis

The cytotoxicity of three Stenocarpella maydis metabolites (diplodiatoxin, dipmatol and diplonine) was investigated on Neuro-2a, CHO-K1 and MDBK cell lines. Diplodiatoxin was the most cytotoxic followed by dipmatol. Conversely, diplonine was not cytotoxic. Diplodiatoxin and dipmatol affected mitochondrial succinate dehydrogenase (MTT assay) and the overall viability of cells as assessed in real-time (xCELLigence assay). The results obtained so far indicate that diplodiatoxin and dipmatol exert their toxicity possibly via the necrotic cell death pathway.National Research Foundation (NRF), International Foundation for Science (IFS) and the Joy Liebenberg Trust Fund.http://www.elsevier.com/locate/toxiconhb201

Geigerin-induced cytotoxicity in a murine myoblast cell line (C2C12)

Geigeria poisoning in sheep, locally known as ‘vermeersiekte’, is an economically important plant poisoning in southern Africa. The toxic principles contained by the toxic plants are believed to be several sesquiterpene lactones, such as geigerin, vermeeric acid and vermeerin, which cause striated muscle lesions in small stock. Because of ethical issues surrounding the use of live animals in toxicity studies, there is currently a dire need to establish an in vitro model that can be used to replace traditional animal experimentation. The objective of this study was to determine the cytotoxicity of geigerin in a murine myoblast cell line (C2C12) using methyl-thiazol-tetrazolium (MTT) and lactate dehydrogenase (LDH) assays, annexin V and propidium iodide (PI) flow cytometry and transmission electron microscopy (TEM). Mouse myoblasts were exposed to 2.0 mM, 2.5 mM and 5.0 mM geigerin for 24, 48 and 72 h. A concentration-dependent cytotoxic response was observed. Apoptosis was detected by means of annexin V flow cytometry during the first 24 h and apoptotic bodies were also visible on TEM. According to the LDH and PI flow cytometry results, myoblast cell membranes were not injured. We concluded that the murine myoblast cell line (C2C12) is a suitable model for future studies planned to evaluate the cytotoxicity of other and combinations of sesquiterpene lactones, with and without metabolic activation, implicated in ‘vermeersiekte’ and to elucidate the subcellular effects of these myotoxins on cultured myoblasts