(-)-Calcaridine B, a new chiral aminoimidazole-containing alkaloid from the marine sponge Leucetta chagosensis

Abstract

LC-DAD/MS-based dereplication of organic extract of a calcareous sponge Leucetta chagosensis afforded one new chiral aminoimidazole-containing alkaloid, (-)-calcaridine B (1), along with one achiral imidazole analog leucettamine E (2) as well as one known imidazole derivative (2E, 9E)-pyronaamidine-9-(N-methylimine) (3). Their structures were elucidated on the basis of NMR spectroscopic analyses, and comparing with the literature. The cytotoxic activities of all isolates were evaluated against three human cancer cell lines, and compounds 1 and 3 exhibited mild cytotoxicities toward the MCF-7 cell line with IC₅₀ values of 25.3–24.2 μM, respectively.

Graphical Abstract

Keywords:

• Marine sponge
• Leucetta chagosensis
• chiral imidazole alkaloid
• cytotoxicities

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was financially supported by the National Natural Science Fund of China under Grants (41506149, 81741151, 81502936, 41106127, 81072573, 41476121, U1605221, and 41576130).