Abstract
Background Eleutherol (1) and Eleutherol C (2) are naphthalene derivative compounds from Bawang Tiwai Bulb Eleutherine bulbosa with moderate cytotoxic activity against MCF-7 breast cancer cells.
Objectives This research was conducted to evaluate cytotoxic activity against MCF-7 breast cancer cells, the compounds Eleutherol (1) and Eleutherol C (2) are naphthalene derivatives from Eleutherine bulbosa, where previously it has been reported that naphthalene derivative compounds have activity against breast cancer cells, especially MCF-7.
Methods After isolating the compounds Eleutherol (1) and Eleutherol C (2) from the EtOH extract of Bawang Tiwai Bulb Eleutherine bulbosa using conventional chromatography methods, their cytotoxic activity was tested against MCF-7 breast cancer cells in vitro. Their chemical structures were elucidated based on spectroscopic analysis including IR, HR-TOFMS, 1D, and 2D NMR, and by comparison to those related spectra previously reported.
Results Two naphthalene derivatives named Eleutherol (1) and Eleutherol C (2) have been isolated from the Bawang Tiwai Bulb of Eleutherine bulbosa. Compounds 1 and 2 were tested for their cytotoxic effects against MCF-7 breast cancer cells and showed moderate cytotoxicity against MCF-7 breast cancer cells with IC50 values 153.05 and 103.45 µM, respectively, compared with cisplatin 53.7 µM.
Conclusion This research shows moderate cytotoxic activity of the compounds Eleutherol (1) and Eleutherol C (2) from the EtOH extract of Bawang Tiwai Bulb Eleutherine bulbosa. Testing of the cytotoxic effects on MCF-7 breast cancer cells of compounds 1 and 2 of naphthalene derivatives was first reported.

Key words: Eleutherine bulbosa, Eleutherol, Eleutherol C, MCF-7 breast cancer, Borneo