Ergosterol Peroxide from the Egyptian Red Lingzhi or Reishi Mushroom, Ganoderma resinaceum (Agaricomycetes), Showed Preferred Inhibition of MCF-7 over MDA-MB-231 Breast Cancer Cell Lines

   Ergosterol peroxide and ganoderic acid AM1 were isolated forthe first time from the mycelium of the Egyptian Ganoderma resinaceum mushroom. The structure of these two metabolites was established by detailed analysis of of 1D and 2D NMR. The isolated compounds were tested for their antitumor in vitro activities in MCF-7 and
MDA-MB-231 breast cancer cell lines. Ergosterol peroxide showed preferred inhibition of MCF-7 (ER +ve) cell lines
relative to MDA-MB-231 (ER -ve) cell lines with an IC50 of 1.18 μM and 12.82 μM respectively. Our data suggest that
ergosterol peroxide targets estrogen receptors.