The antitumor activity of a branched
beta-1,3-glucan "
grifolan LE" purified from liquid cultures of Grifola frondosa (Ohno et al. Chem. Pharm. Bull., 34, 1709-1715 (1986] was examined on an allogeneic murine
tumor system. By intraperitoneal (i.p.) administration (100-200 micrograms/mouse/d X 5) at days 1 to 9 from the
tumor transplantation,
grifolan LE showed marked inhibitory activity on the growth of solid form
sarcoma 180 in ICR mice. Significant activity was also observed in intravenous (i.v.) or intratumoral (i.t.) administrations. However, the oral (p.o.) administration of
grifolan LE was not effective. I.p. administration of
grifolan LE at a dose of 100 micrograms/mouse/d X 5 before the
tumor transplantation showed significant inhibition of
tumor growth. I.p. administration of
grifolan LE at day +11 to +19 was also effective.
Grifolan LE was not effective on the
ascites form of
sarcoma 180. The pretreatment of
sarcoma 180 cell with
grifolan LE in vitro did not affect
tumor growth. The mice cured from the solid form of
sarcoma 180 by administration of
grifolan LE had the ability to reject the same
tumor cell. From these results, it is suggested that the antitumor activity of
grifolan LE occurred by modification of
biological responses.