Use of novel compounds from fruiting body of Antrodia camphorata for stimulating immune response

A method of stimulating production of TNF-α or inhibiting production of IL6, comprising administering to a subject in need thereof an effective amount of an isolated compound or a pharmaceutically acceptable salt thereof, wherein the compound is selected from the group consisting of trans-3-isobutyl-4-[4-(3-methyl-2-butenyloxy)phenyl]pyrrolidine-2,5-dione, trans-1-hydroxy-3-(4-hydroxyphenyl)-4-isobutylpyrrolidine-2,5-dione, cis-3-(4-hydroxyphenyl)-4-isobutyldihydrofuran-2,5-dione, 3-(4-hydroxyphenyl)-4-isobutyl-1H-pyrrole-2,5-dione, and dimethyl 2-(4-hydroxyphenyl)-3-isobutylmaleate.