Isolation and characterization of immunosuppressive components of three mushrooms, Pisolithus tinctorius, Microporus flabelliformis and Lenzites betulina.

Two components having an immunosuppressive activity were isolated together with non-active pisolactone from Pisolithus tinctorius, and they were deduced to the 24-methyllanosta-8,24(28)-diene-3 beta,22 zeta-diol and a mixture of two new compounds, (22S,24R)-24-methyllanosta-8-en-22,28-epoxy-3 beta,28 alpha-diol and (22S,24S)-24-methyllanosta-8-en-22,28-epoxy-3 beta,28 beta-diol, respectively. Among them, pisolactone and 24-methyllanosta-8,24(28)-diene-3 beta,22 zeta-diol have previously been isolated from the same mushroom. Ergosterol peroxide and 9(11)-dehydroergosterol peroxide were also isolated as active components from this mushroom in small amounts, and from Microporus flabelliformis and Lenzites betulina. The IC50 values of these components were evaluated against proliferation of mouse spleen lymphocytes stimulated with concanavalin A and lipopolysaccharide.