Structure elucidation at the nanomole scale. 3. Phorbasides G-I from Phorbas sp

Area of Science:

• Marine Natural Products Chemistry
• Organic Chemistry
• Biotechnology

Background:

• Marine sponges are a rich source of structurally diverse bioactive compounds.
• Phorbasides A and B are known macrolide glycosides with potential biological activities.
• The Phorbas genus continues to yield novel chemical entities.

Purpose of the Study:

• To isolate and characterize new macrolide glycosides from the marine sponge Phorbas sp.
• To elucidate the structures and absolute configurations of the novel compounds.
• To expand the known chemical diversity of chlorocyclopropyl ene-yne macrolides.

Main Methods:

• Isolation of compounds using chromatographic techniques.
• Structure elucidation via mass spectrometry (MS), circular dichroism (CD), and microcryoprobe Nuclear Magnetic Resonance (NMR) spectroscopy.
• Determination of absolute configurations through Rotating-frame Overhauser Effect SpectroscopY (ROESY) and CD correlation with known compounds.

Main Results:

• Three new phorbasides, designated G-I, were successfully isolated from Phorbas sp.
• The new compounds are chlorocyclopropyl ene-yne macrolide glycosides, differing only in their sugar moieties.
• Yields of 7-9.5 µg were obtained for the new phorbasides.
• Complete structural characterization and absolute configuration determination were achieved.

Conclusions:

• The study successfully identified and characterized three novel phorbasides (G-I) from Phorbas sp.
• The structural variations primarily lie in the glycosidic components, highlighting the chemo-diversity within this compound class.
• The findings contribute to the understanding of marine natural products and provide new leads for drug discovery.