Attention has already been directed to the antitumor action of plant glycosides, but the involved mechanism of action is unknown.
In this experimental study, the effect of glycyrrhizin in inhibiting growth of a cultured cell of salivary gland tumor induced by 20-methylcholanthrene (cultured S. G. tumor cell) was investigated.
The following results were obtained:
1) Glycyrrhizin inhibited the growth of the cultured S. G. tumor cell.
2) Glycyrrhizin inhibited growth at concentrations over 0.4mg/ml. Growth inhibition at 0.4-0.6mg/ml of glycyrrhizin was comparable to that at 0.5 μg/ml of actinomycin D.
3) Histopathologically, cultured S. G. tumor cells treated with glycyrrhizin showed signs of degeneration and destruction such as cell atrophy and pyknosis.
4) Ultramorphologically, microvilli and branching processes of the cell surface of the cultured S. G. tumor cells were poorly developed and the nucleus was apparently decreased in size.
5) Flow cytometric analysis of cultured S. G. tumor cells after 24 hr. of exposure to glycyrrhizin revealed that glycyrrhizin treatment led to marked accumulation of cells in G1phase, suggesting that growth inhibition was the result of a block during G1 which did not permit the cells to enter S phase.
