New anticancer agents: in vitro and in vivo evaluation of the antitumor and antimetastatic actions of various compounds isolated from medicinal plants.

In this review, in the search for the development of new anticancer drugs, the effects of compounds isolated from various medicinal plants on tumor growth and metastasis, using mice bearing a highly metastatic drug-resistant mouse tumor, were studied. The antitumor and antimetastatic actions of stilbene derivatives isolated from Polygonum and Cassia species were examined. Among the stilbene derivatives, resveratrol and cassiagrol A (stilbene dimer) displayed antitumor and antimetastatic actions through the inhibition of tumor-induced neovascularization in in vitro and in vivo models. It was found that two chalcone derivatives from Angelica keiskei roots also inhibited tumor growth and metastasis in tumor-bearing mice through the inhibition of tumor-induced neovascularization and/or the inhibition of immune suppression caused by tumors. Recently, basidiomycete fungi have been used for the treatment of cancer. Then, the low molecular weight substances were isolated from Agaricus blazei and Ganoderma lucidum as antitumor and antimetastatic substances. It is suggested that these substances of basidiomycete also inhibited tumor growth and metastasis to the lung through the inhibition of tumor-induced neovascularization and/or the inhibition of immune suppression caused by tumors.