Cytotoxic scalarane-type sesterterpenes from the Saudi Red Sea sponge Hyrtios erectus

Abstract

The CHCl₃/MeOH extract of the marine sponge Hyrtios erectus showed cytotoxicity against three cancer cell lines HepG2, A549, and PC-3 with IC₅₀ 0.055, 0.044, and 0.023 μg/ml, respectively. The CH₂Cl₂ soluble fraction afforded three scalarane sesterterpenes (1–3) along with a cholestane derivative (4) and an indole alkaloid (5). Chemical structures were established by spectroscopic techniques and comparison with data reported in the literature. Scalarinol (1) was found as a new metabolite, while heteronemin (2) and 12-O-deacetyl-19-deoxyscalarin (3) are known compounds. 1–3 exhibited cytotoxic activity against the cancer cell lines with IC₅₀ values ranging from 14 to 230 μM. The molecular affinity to the DNA was employed as marker to examine the proposed mechanism of cytotoxic activities. Compound 2, with IC₅₀ 28 μg/ml, displayed the highest affinity to the DNA.

Keywords:

• Marine sponges
• sesterterpenes
• cytotoxicity
• scalarinol
• Hyrtios erectus

Acknowledgments

The authors, therefore, thank DSR technical and financial support. Thanks are due to Dr Mohsen El-Sherbiny, Marine Biology Department, Faculty of Marine Sciences, King Abdulaziz University, for identification of the sponge sample.

Disclosure statement

No potential conflict of interest was reported by the authors.