Research on the antineoplastic action of a new drug of plant origin: "Vincaleukoblastin"

Abstract

The action of the Vincaleukoblastine sulphate has been studied on some experimental tumours. In the ascites tumour, Ehrlich adenocarcinoma of the mouse and ascites myeloma of the rat, the agent showed a marked antineoplastic activity, with increase of the average survival and reduction of the tumour growth. On the other hand, it proved to be scarcely effective or ineffective on the Oberling-Guérin-Guérin solid tumour. The cytologic examination showed a blocking in the very early mitotic stages, with very high values of the mitotic index in the first hours after introduction of the substance (up to the 14 per cent about) and very severe morphologic alterations of the neoplastic cells (increased vacuolization, cytoplasmic buddings, breaking up of nuclear chromatin with formation of micronuclei, monster cells). The most sensitive to the drug action were demonstrated to be the most atypical and indifferentiated tumour elements belonging to the reticuloendothelial system. As a matter of fact, the ascites myeloma underwent a tumour growth inhibition of the 97 per cent following VLB introduction. VLB, which is promptly and rapidly eliminated, showed rather moderate and reversible toxic effects, which reflect mainly on the bone marrow, with a rapid and transient decrease in number of granuloblasts and erythroblasts.