DNA protective activity of triterpenoids isolated from medicinal mushroom Fomitopsis betulina

Eleven 31-methylenlanostane triterpenoids, i.e., seven 21- and four 26-oic acids, as well a lupane triterpenoid betulin, isolated from the fruiting bodies of mushroom Fomitopsis betulina, were tested for in vitro protective effect on chromosome aberrations peripheral human lymphocytes using cytochalasin-B blocked micronucleus (CBMN) assay. Most compounds showed beneficial by reducing DNA damage more effectively than amifostine, radioprotective agent, used positive control. All decreased MN frequency concentration dependent manner, with 2.0 ?g mL-1 being most effective ? increase activity slightly decreases. The structure?activity relationship (SAR) studies indicated that lanostanes containing conjugated 7,9 (11)-diene system exhibit lower ?8-analogues. It was also demonstrated activities within ?8-lanostane-26-oic acid group are affected substitution position 3 pattern. In ?8 series oxygenation at C-12 or 16 functionality proved chromosomal aberrations. Betulin exhibited lowest activity, but it is still comparable to amifostine.