Effect of betulin and betulonic acid on isolated rat liver mitochondria and liposomes.

The paper considers the effects of plant triterpenoid betulin and its derivative betulonic acid on rat liver mitochondria and liposomes. It was found that betulonic acid and, to a lesser extent, betulin, activate mitochondrial respiration in states 2 and 4 and inhibit ADP- and DNP-stimulated (uncoupled) respiration. The effect of betulonic acid resulted in a significant decrease of the respiratory control and ADP/O ratios and decrease in Δψ.

Synthesis and antimalarial activity of 3'-trifluoromethylated 1,2,4-trioxolanes and 1,2,4,5-tetraoxane based on deoxycholic acid.

A series of new steroidal peroxides - 3'-trifluoromethylated 1,2,4-trioxolanes and 1,2,4,5-tetraoxanes based on deoxycholic acid were prepared via the reactions of the Griesbaum coozonolysis and peroxycondensation, respectively. 1,2,4-Trioxolanes were synthesized by the interaction of methyl O-methyl-3-oximino-12α-acetoxy-deoxycholate with CFC(O)CH or CFC(O)Ph and O as the mixtures of four possible stereoisomers at ratios of 1:2:2:1 and in yields of 50% and 38%, respectively. The major diastereomer of methyl 12α-acetoxy-5β-cholan-24-oate-3-spiro-5'-(3'-methyl-3'-trifluoromethyl-1',2',4'-trioxolane) was isolated via crystallization of a mixture of stereoisomers from hexane and its (3S,3'R)-configuration was determined using X-ray crystallographic analysis.