The following valepotriates: valtrate and didrovaltrate, isolated from the roots of Valeriana wallichii D. C., as well as baldrinal, a degradation product of the valtrate, were tested for their cytotoxic and antitumor activities, respectively in vitro on cultured rat hepatoma cells (HTC line), and in vivo, on female mice KREBS II ascitic tumors. It appears that the three valepotriates are very potent cytotoxic agents for the HTC hepatoma cells, and that the didrovaltrate induces a perceptible high per cent definitive remissions of the KREBS II ascitic tumors.
We have shown that the planar formula of the polyindoline alkaloids (C, B, E and D) isolated from the leaves of Psychotria forsteriana agree respectively with Quadrigemine A, Quadrigemine B, Psychotridine, and Isopsychotndine C. Their cytotoxic activity on cultured rat hepatoma cells (HTC line) is reported in this paper. These alkaloids showed a higher toxicity on HTC cells than vincristine, a bisindole alkaloid currently used in antitumor chemotherapy.
Valtrate, didrovaltrate and deoxido-didrovaltrate were compared for toxicity on cultured rat hepatoma cells (HTC strain) and for their effects on the synthesis of DNA and proteins.Despite lacking the epoxide function in C8-C11 position in its molecular structure, deoxido-didrovaltrate has a similar cytotoxicity to didrovaltrate. The toxicity of both these drugs is two times lower than that of valtrate.Incorporation tests with 3H-thymidine and 3H-leucine on cultured HTC cells revealed that a low dose of valtrate, rapidly and extensively inhibits the synthesis of both DNA and proteins.Didrovaltrate and deoxido-didrovaltrate have the same effect, but at double the dose.
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