Cytotoxic furanosesquiterpenoids and steroids from Ircinia mutans sponges

Abstract

Context

Ircinia mutans Wilson (Irciniidae) is a sponge with antimicrobial and cytotoxic constituents.

Objective

Our objective was to characterise the cytotoxic constituents of two seasonal collections of I. mutans.

Materials and methods

The sponges were extracted in methanol-dichloromethane and their constituents were purified and characterised using column chromatography, GC-MS, 1 D and 2 D NMR. Anti-proliferative activities of the compounds, were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay (0.25–100 μg/mL, 72 h) against leukaemia (MOLT-4), breast (MCF-7) and colon cancer (HT-29) human cells.

Results

Three furanosesquiterpoids; furodysin (1), ent-furodysinin (2) and furoircin (3) and ten sterols were characterised in I. mutans, for the first time. Cholesterol (4), cholesta-5, 7-dien-3β-ol (5) and ergosterol (6) were determined in the sponge from the winter collections, while cholesta-5, 22-dien-3β-ol (7), 24-methyldesmosterol (8), campesterol (9), stigmasterol (10), γ-ergostenol (11), chondrillasterol (12) and γ-sitosterol (13) were detected in the summer samples. The steroids from the winter collection exhibited cytotoxic activity with IC₅₀ values of 13.0 ± 0.9, 11.1 ± 1.7 and 1.1 ± 0.4 µg/mL, against the mentioned cancer cell lines, respectively, while those from the summer sample, showed greater activity, IC₅₀ = 1.1 ± 0.2 μg/mL against MOLT-4. The purified steroids showed potent MOLT-4 cytotoxic activity, IC₅₀ values = 2.3–7.8 µg/mL.

Discussion and conclusion

The present study suggests that I. mutans is a rich source of cytotoxic steroids, and introduces 3 as new natural product. Considering the high cytotoxic activity of the steroids, these structures could be candidates for anticancer drug development in future research.

Keywords:

• Furanosesquiterpenes
• marine sponge
• cholesterol
• ergosterol
• stigmasterol
• γ-sitosterol

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research was funded by the University of Hormozgan, Bandar Abbas; the Shiraz University of Medical Sciences; Vice-Provosts for Researches and the Alexander von Humboldt foundation for a research group linkage program grant [3.4 - IRN/1101775].