2 research outputs found
Penicillipyrones A and B, Meroterpenoids from a Marine-Derived <i>Penicillium</i> sp. Fungus
Penicillipyrones
A (<b>1</b>) and B (<b>2</b>), two novel meroterpenoids,
were isolated from the marine-derived fungus <i>Penicillium</i> sp. On the basis of the results of combined spectroscopic analyses,
these compounds were structurally elucidated to be sesquiterpene γ-pyrones
from a new skeletal class derived from a unique linkage pattern between
the drimane sesquiterpene and pyrone moieties. Compound <b>2</b> elicited significant induction of quinone reductase
Ohmyungsamycins A and B: Cytotoxic and Antimicrobial Cyclic Peptides Produced by <i>Streptomyces</i> sp. from a Volcanic Island
Ohmyungsamycins
A and B (<b>1</b> and <b>2</b>), which
are new cyclic peptides, were isolated from a marine bacterial strain
belonging to the <i>Streptomyces</i> genus collected from
a sand beach on Jeju, a volcanic island in the Republic of Korea.
Based on the interpretation of the NMR, UV, and IR spectroscopic and
MS data, the planar structures of <b>1</b> and <b>2</b> were elucidated as cyclic depsipeptides bearing unusual amino acid
units, including <i>N</i>-methyl-4-methoxytrytophan, β-hydroxyphenylalanine,
and <i>N</i>,<i>N</i>-dimethylvaline. The absolute
configurations of the α-carbons of the amino acid residues were
determined using the advanced Marfey’s method. The configurations
of the additional stereogenic centers at the β-carbons of the
threonine, <i>N</i>-methylthreonine, and β-hydroxyphenylalanine
units were assigned by GITC (2,3,4,6-tetra-<i>O</i>-acetyl-β-d-glucopyranosyl isothiocyanate) derivatization and the modified
Mosher’s method. We have developed a new method utilizing PGME
(phenylglycine methyl ester) derivatization coupled with chromatographic
analysis to determine the absolute configuration of <i>N</i>,<i>N</i>-dimethylvaline. Our first successful establishment
of the absolute configuration of <i>N</i>,<i>N</i>-dimethylvaline using PGME will provide a general and convenient
analytical method for determining the absolute configurations of amino
acids with fully substituted amine groups. Ohmyungsamycins A and B
showed significant inhibitory activities against diverse cancer cells
as well as antibacterial effects