Secretion of Specific Cytotoxic Products by Plant Storage Organs after Wound-Desiccation Stress

After a wound-desiccation stress, plant tissues can secrete products that have specific cytotoxicity against melanoma B16 cells. Healthy plant or animal cells were not susceptible to these products. Secretion of the active product varied with the plant species and the plant organs. The secretion of tubers of yam (Dioscorea cayenensis Lam), cassava (Manihot esculenta), Jerusalem artichoke (Helianthus tuberosus), ginger (Zingiber officinale) and potato (Solanum tuberosum L.) showed activity against murine melanoma B16 cells, but not against immortalized fibroblast L929 cells. A decrease of 20 to 30% of the B16 clonogenicity was observed, while the treated L929 fibroblast cells did not show any significant difference with the control cell colonies. In contrast, the secreted products of roots of beet (Beta vulgaris) and tubers of sweet potato (Ipomoea batatas) only showed slight cytotoxicity. Secretion of the active product was associated with the storage tissues. The physiology of the plant, such as the light growth conditions (for hypocotyls of sunflower, Helianthus annuus L., and tomato, Lycopersicon esculentum Mill), or dormancy (for Jerusalem artichoke tubers, Helianthus tuberosus L.), was involved in the secretion process of an active product. The active agent was associated with a protein complex. The secretion of the cytotoxic products against melanoma B16 cells, thus, can be performed through a specific stress on the storage organs of plants usually cultivated. _____________________________________________________________________________________________________________