Two new 5,6-epoxysterols from calcareous marine sponge Leucetta chagosensis

Abstract

Chemical investigation on CH₂Cl₂ extract of the marine sponge Leucetta chagosensis, collected from the South China Sea, afforded two new 5,6-epoxysterols, 5α,6α-epoxycholesta-8(14),22(E)-diene-3β,7α-diol (1) and (24R)-24-ethyl-5α,6α-epoxycholesta-8(14),22(E)-diene-3β,7α-diol (2) along with ten known related steroid analogs (3–12). Their structures were elucidated on the basis of NMR spectroscopic analyses, and comparison with the literature. All isolates were tested for cytotoxicity against three tumor cell lines only known compounds 11 and 12 exhibited notable cytotoxic activity against A549 (IC₅₀: 3.0 and 5.6 μM), PC9 (2.0 and 15.6 μM), and MCF-7 (9.4 and 11.8 μM) cell lines, respectively.

Graphical Abstract

Keywords:

• 5,6-epoxysterols
• steroids
• cytotoxicity
• Leucetta chagosensis

Acknowledgements

We thank Huping Zhu at Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, for NMR spectroscopic measurements.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was supported by the National Natural Science Fund of China under Grants[41506149, 81502936, 81741151, 41106127, 81072573, 41476121, U1605221, and 41576130], and The National Key Research and Development Program of China (2018 YFC0310900).