Development of cell culture techniques for assessment of the toxicity of plant products.

Plant products consumed by humans contain a wide variety of both beneficial and toxic compounds. Studies have been undertaken to explore the utility of cell culture techniques in testing plant products for toxicity and antitoxicity. Preliminary results are reported on the cytotoxic effects of aqueous and methanol extracts of a range of conventional and herb teas and a variety of vegetables. The teas were tested in primary cultures of rat hepatocytes, using lactate dehydrogenase release and inhibition of protein synthesis as endpoints of cytotoxicity. Toxicity was detected in aqueous preparations but not in methanol extracts. Korean green tea and a conventional black tea were more toxic than herb teas such as comfrey and ragwort, which are thought to contain hepatotoxic pyrrolizidine alkaloids. Extracts of five vegetables were tested using the same assays and also the MTT assay in hepatocytes and the Kenacid blue assay in Chinese hamster ovary (CHO) cells. Toxicity to hepatocytes was low but most extracts were more toxic to CHO cells. The toxicity of cabbage was reduced by cooking and that of potato was increased by greening, which increases the levels of glycoalkaloids and other toxins in the tubers. The results suggest a number of ways in which cell culture tests may be useful for detecting and assessing the effects of toxins and antitoxins in plant products.