Antitumor activity of aqueous extracts of edible mushrooms.

Aqueous extracts of seven species of edible mushrooms were tested for their antitumor activity against transplanted Sarcoma 180 in Swiss albino mice. All of the aqueous extracts except that of Auricularia auricula-judae (Bull. cx Fr.) QUé1. highly inhibited the growth of transplanted tumors. The active antitumor component of Lentinus edodes (Berk.) Sing. was not adsorbed by the acetate form of a weak ly basic ion-exchange resin. It was nondialyzable and precipi tated with the addition of ethanol or acetone. The active anti tumor material was suggested by chemical analysis to be a polysaccharide. Introduction. The antitumor activities of high molecular weight substances of some wild Basidiomycetes for trans planted Sarcoma 180 in Swiss albino mice were reported in previous papers (1, 4). The suggestion was made that the anti tumor activities were due to indirect host-mediated effects (2, 3, 5—7). In this study we are using the same bioassay method that was described previously (1) to determine the antitumor activi ties of aqueous extracts of seven species of edible mushrooms occurring in Japan. Materials and Methods. The method of Nakahara and co workers (2, 3) was used as an assay for antitumor activity. Seven-day-old Sarcoma 180 ascites tumor cells were implanted subcutaneously into the right groin of Swiss albino mice. After 24 hours, these mice were injected intraperitoneally with 200 mgJkgJday doses of sample materials for 10 days. After observ ing the tumor growth for 5 weeks, the tumor weights of treated mice were compared with those of untreated mice. One kg of mushrooms was extracted for 4.5 hours with two liters of water maintained at 95—97°Cby a boiling water bath, and the extracts were evaporated under reduced pressure and then freeze-dried. The yield was 5.4% in Lentinus edodes (Berk.) Sing. Ten gm of the extract of Lentinus edodes (Berk.) Sing. was dissolved in about 200 ml of water and purified by passage through a 6 x 50 cm column of Duolite A-7 or 5-30 (acetateform)ion-exchange r sin.Thecolumnwaselutedwith 3 liters of water, and the eluate was evaporated to a volume of