TOXICITY ASSESSMENT OF TOXINS T-514 AND T-544 OF BUCKTHORN (KARWINSKIA-HUMBOLDTIANA) IN PRIMARY SKIN AND LIVER-CELL CULTURES

The present study was undertaken to assess and compare thc in vitro cytotoxicity of toxins T-514 and T-544 of Buckthorn (Karvinskia humboldtiana) using primary cultures of rat hepatocytes and keratinocytes. Cell cultures were exposed to 6, 12, 25 and 50-mu-M concentrations of the toxins for 2, 4, 6 and 24-h periods. Cytotoxicity was determined by release of the cytoplasmic enzyme, lactate dehydrogenase (LDH), in culture media, methylthiazoltetrazolium (MTT) reduction and neutral red (NR) uptake. An increase in LDH leakage was observed in liver cell cultures as early as 2 h with 50-mu-M T-544 and with 6-mu-M T-514 and T-544 at 6 h and 24 h, respectively. In the NR assay the toxicity was evident at 2 h with 12-mu-M T-514 and T-544 and with 6-mu-M concentrations of both toxins at 6 h. On the other hand, a decrease in MTT reduction was detected at 4 h with 50-mu-M concentrations of both toxins and with 25-mu-M T-544 and 12-mu-M T-514 at 6 h and 6-mu-M T-514 and T-544 at 24 h. Both toxins were shown to be highly hepatotoxic; T-514 was more toxic than T-544. In the skin cell cultures, the toxicity of the toxins was not as severe and was not expressed until 12 h of exposure.