[Antitumor activities of bamboo leaf extracts (BLE) and its lignin (BLL)]

Antitumor activity of bamboo leaf against various transplantable mouse tumor strains, such as Sarcoma 180 and Ehrlich ascites carcinoma has previously been demonstrated by Sakai et al.7) and Yammamoto et al.9). The present investigation was undertaken to determine the antitumor activities of BLE and BLL against the spontaneous tumor induced by benzopyrene (BP) and 4-nitroquinoline-1-oxide (4NQO) in mice and rats. The possible mechanism of antitumor action was also discussed as related to Kada's Rec-assay and Ames test in vitro. The in vivo antitumor test was performed using 16 groups of mice given the following solutions ad libitum for 120 days; Groups 1-4, 5-8, 9-12 and 13-16 were given water, 1% and 10% BLe, 0.1% BLL, and each respective group was treated with no injection (control), oil/s.c., BP 1 mg/s.c., and 4NQO 0.5 mg/s.c. Rat respective group was treated 30 days after in initiation of experiment with no injection (control), oil/s.c., BP 2.4 mg/s.c. Antitumor activities of the BLE and BLL were determined by the tumor incidence index and average weight of tumor. In vitro Rec-assay, cold incubation method, and Ames test were performed in the usual manner. Antitumor activity against BP induced tumor was the highest with 1.0% BLE (0.71 mg/ml), but no significant difference was found between the groups of the 10% BLE, 0.1% BL and control. A weak trend toward DNA damage was seen in the case of BLE, in the Rec-assay. His+ revertants with S-9 mix on Salmonella typhimurium TA98 were found in the case of BLL. It was concluded that antitumor activity against BP- and 4NQO-induced tumors was the highest with 1% BLE (0.71 mg/ml), and a direct action of BLE on tumor cells was indicated.