[Studies on anti-tumor activity of crude drugs. III. The effects of decreasing resistance of cancer cell in long-term in vitro screening test with aqueous extracts of some crude drugs].
When human cancer cell (JTC-26) was subjected to aqueous extracts of some crude drugs for a long time, its drug resistance against the cancer cell decreased. However, the cancer cell with decreased resistance recovered its proliferative power completely when cultured without the addition of the specimens. This revealed that the drug resistance-decreasing action or cytostatic action was entirely reversible. On the other hand, chemical anticancer agents increased cancer cell resistance, but the cancer cell did not recover itself and then perished when damage was given to it to a certain extent. Normal cell showed no decrease in resistance to the aqueous extracts.