Molecules (May 2012)
Phaeophytin Analogues from<em> Ligularia knorringiana</em>
Abstract
A new phaeophytin, ligulariaphytin A, together with five known phaeophytins, were isolated from the aerial parts of <em>Ligularia knorringiana</em>. The structure of ligulariaphytin A was elucidated as 13<sup>1</sup>-hydroxy-13<sup>1</sup>,13<sup>2</sup>-peroxyphaeophorbide A ethyl ester (<strong>1</strong>), and the five known compounds were identified as 13<sup>2</sup>-hydroxyphaeophorbide A ethyl ester (<strong>2</strong>), 17<sup>3</sup>-ethoxyphaeophorbide A (<strong>3</strong>), phaeophytin B (<strong>4</strong>), phaeophytin A (<strong>5</strong>), and phaeophorbide B ethyl ester (<strong>6</strong>), respectively, based on spectroscopic analysis and by comparison of their spectral data with those reported previously in the literature. All compounds were evaluated for their<em> in vitro</em> cytotoxic activities against cultured Hela cell, and were found to show only very weak cytotoxicity.
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