2 research outputs found
Plakortinic Acids A and B: Cytotoxic Cycloperoxides with a Bicyclo[4.2.0]octene Unit from Sponges of the Genera <i>Plakortis</i> and <i>Xestospongia</i>
Plakortinic acids A (<b>2</b>) and B (<b>3</b>), two
polyketide endoperoxides with a bicyclo[4.2.0]octene unit, were isolated
as minor constituents from the sponge–sponge symbiotic association <i>Plakortis halichondrioides</i>–<i>Xestospongia deweerdtae</i>, along with known epiplakinic acid F (<b>1</b>). The structures
of the mixture of two inseparable compounds were determined by spectroscopic
analysis. Screening for cytotoxic activity of the mixture against
two human tumor cell lines revealed that these compounds are very
active at sub-micromolar concentration
Exploring the Sponge Consortium <i>Plakortis symbiotica–Xestospongia deweerdtae</i> as a Potential Source of Antimicrobial Compounds and Probing the Pharmacophore for Antituberculosis Activity of Smenothiazole A by Diverted Total Synthesis
Fractionation of the bioactive CHCl<sub>3</sub>–MeOH (1:1)
extracts obtained from two collections of the sponge consortium <i>Plakortis symbiotica</i>–<i>Xestospongia deweerdtae</i> from Puerto Rico provided two new plakinidone analogues, designated
as plakinidone B (<b>2</b>) and plakinidone C (<b>3</b>), as well as the known plakinidone (<b>1</b>), plakortolide
F (<b>4</b>), and smenothiazole A (<b>5</b>). The structures
of <b>1</b>–<b>5</b> were characterized on the
basis of 1D and 2D NMR spectroscopic, IR, UV, and HRMS analysis. The
absolute configurations of plakinidones <b>2</b> and <b>3</b> were established through chemical correlation methods, VCD/ECD experiments,
and spectroscopic data comparisons. When assayed in vitro against <i>Mycobacterium tuberculosis</i> H<sub>37</sub>Rv, none of the
plakinidones <b>1</b>–<b>3</b> displayed significant
activity, whereas smenothiazole A (<b>5</b>) was the most active
compound, exhibiting an MIC value of 4.1 μg/mL. Synthesis and
subsequent biological screening of <b>8</b>, a dechlorinated
version of smenothiazole A, revealed that the chlorine atom in <b>5</b> is indispensable for anti-TB activity