Bioactive Bis(indole) Alkaloids from a Spongosorites sp. Sponge

Area of Science:

• Marine Natural Products Chemistry
• Medicinal Chemistry
• Organic Chemistry

Background:

• Marine sponges are a rich source of structurally diverse bioactive compounds.
• Bis(indole) alkaloids, particularly from the topsentin class, have demonstrated significant pharmacological potential.
• The exploration of marine biodiversity from unique geographical locations, like Korea, is crucial for discovering novel chemical entities.

Purpose of the Study:

• To isolate and characterize new bis(indole) alkaloids from a Korean *Spongosorites* sp. sponge.
• To elucidate the structures and absolute configurations of the newly discovered compounds.
• To evaluate the biological activities of the isolated compounds against bacterial pathogens, cancer cell lines, and bacterial enzymes.

Main Methods:

• Isolation of compounds using chromatographic techniques.
• Structure elucidation through comprehensive spectroscopic analyses (NMR, MS).
• Determination of absolute configurations using electronic circular dichroism (ECD) computation.

Main Results:

• Six new bis(indole) alkaloids, spongosoritins A-D (1-4) and spongocarbamides A-B (5-6), were identified.
• Spongosoritins A-D feature a 2-methoxy-1-imidazole-5-one core linking indole moieties.
• Spongocarbamides A-B possess a linear urea bridge connecting the indole moieties.
• The new compounds demonstrated moderate inhibition against transpeptidase sortase A.
• Weak inhibitory activity was observed against human pathogenic bacteria and A549 and K562 cancer cell lines.

Conclusions:

• The study successfully identified novel bis(indole) alkaloids with unique structural features from a Korean marine sponge.
• The determined structures and absolute configurations provide valuable insights into the chemical diversity of marine natural products.
• The isolated compounds exhibit preliminary biological activities, suggesting potential for further drug development.