IDENTIFICATION OF 2 NOVEL DIHYDROXYSTEROLS FROM PAVLOVA

Pavlova gyrans and P. lutheri were cultured, and the dihydroxysterols were isolated from the free sterol and the polar sterol fractions. Fou r dihydroxysterols were detected in amounts greater than 1% of total s terol by gas chromatography and were analyzed by gas chromatography/ma ss spectrometry. The two principal sterols were isolated by chromatogr aphy on alumina followed by hydrophobic Sephadex column chromatography . The two sterols appeared to differ by having either a methyl or an e thyl group at C-24; they were termed ''methylpavlovol'' and ''ethylpav lovol.'' Analysis by 400 MHz nuclear magnetic resonance showed that me thylpavlovol is 4alpha,24beta-dimethylcholestan-3beta,4beta-diol and e thylpavlovol is pha-methyl,24beta-ethylcholestan-3beta,4beta-diol. The 4alpha-methyl, 4beta-hydroxy configuration has not been observed prev iously in a natural sterol. Dihydroxysterols make up approximately one -third of the total sterols in these Pavlova species. Neither the bios ynthetic origin of these dihydroxysterols nor their role in the bioche mistry of Pavlova is known.