Biologically Active Acetylenic Amino Alcohol and <i>N</i>‑Hydroxylated 1,2,3,4-Tetrahydro-β-carboline Constituents of the New Zealand Ascidian <i>Pseudodistoma opacum</i>

The first occurrence of an acetylenic 1-amino-2-alcohol, distaminolyne A (<b>1</b>), isolated from the New Zealand ascidian <i>Pseudodistoma opacum</i>, is reported. The isolation and structure elucidation of <b>1</b> and assignment of absolute configuration using the exciton coupled circular dichroism technique are described. In addition, a new N-9 hydroxy analogue (<b>2</b>) of the known <i>P. opacum</i> metabolite 7-bromohomotrypargine is also reported. Antimicrobial screening identified modest activity of <b>1</b> toward <i>Escherichia coli</i>, <i>Staphylococcus aureus</i>, and <i>Mycobacterim tuberculosis</i>, while <b>2</b> exhibited a moderate antimalarial activity (IC₅₀ 3.82 μM) toward a chloroquine-resistant strain (FcB1) of <i>Plasmodium falciparum</i>