| Research Abstract |
In our screening program on immunosuppressive principles of mushrooms (Basidiomycetes), we fractionated the crude extracts of Lactarius flavidulus, Pisolithus tinctorius, Microporus flabelliformis and Lenzites betulina under moniroting their immunosuppressive actibities against mitogen-induced proliferation ( ; lastogenesis) of mouse spleen lymphocytes, and isolated their immunosupperssive principles. Three immunosuppressive vomponents from L.flavidulus tentatively named LF-1, -2 and -3 were indentified with geranylphenols, flavidulols A, B and C, respectively, which had formerly been isolated from the same mushroom (flavidulol A had formerly been isolated as an anti-microbial pronciple from the mushroom). Five immunosuppressive components from P.tinctorius tentatively named PT-1, -2, -3, -4 and -5 were also characterized as follows. PT-1 and -2 were deduced to be 24-methyllanosta-8, 24(28)-diene-3beta, 22zeta-diol and pisolactone ](22S)-24-methllanosta-8-en-22, 28-epoxy-3beta-ol-28-one], which were formerly isolated from the same nushroom. PT-3 was deduced tove a mixture of two novel isomeric compounds related to pisolactone. PT-4 and -5, which were identical with immunosuppressive components from both M.flabelliformis and L.betulina, were identified with ergosterol peroxide and 9(11)-dehydroergosterol peroxide, respectively. These seven components except for ergosterol perxide were isolated spectively. These seven components except for ergosterol peroxide were isolated this time as immunosuppressive principles for the first time. Structure-activity relatioonship on these eight immunosuppressive components was also investigated.
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