Aureanin: a new iridoid from the leaves of Tabebuia aurea (Silva Manso) Benth. & Hook.f. ex S.Moore

Abstract

One new iridoid named aureanin (1) was isolated from the leaves of Tabebuia aurea (Silva Manso) Benth. & Hook.f. ex S.Moore, together with eight known compounds, isoquercetin (2), astragalin (3), callicoside B (4), amphipaniculoside E (5), rehmaglutin D (6), quercetin-3-sambubioside (7), rutin (8), kaempferol-3-O-rutinoside (9). The structures of the isolated compounds were elucidated and confirmed by spectroscopic methods, including 1 D and 2 D NMR experiments, as well as HR-ESI-MS. Compounds 1-9 were evaluated for their in vitro cytotoxic activity against three human cancer cell lines (A549, HepG2, and MCF-7) and Leishmania major. Compound 4 showed activity against A549 (IC₅₀: 36.8 ± 1.5 μg/mL, etoposide (positive control): 28.1 ± 4.2 μg/mL), however, none of the compounds were active against L. major.

Graphical Abstract

Keywords:

• Tabebuia aurea (Silva Manso) Benth. & Hook.f. ex S.Moore
• Bignoniaceae
• iridoid
• aureanin
• cytotoxicity
• antileishmania

Acknowledgments

The authors are grateful for access to the superconducting NMR instrument and ESI-MS at the Natural Science Center for Basic Research and Development (N-BARD) of the Graduate School of Biomedical and Health Sciences, Hiroshima University.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by JSPS KAKENHI Grant Number 22K06678. It was also supported by Ministry of Higher Education, Egypt, through the Scientific Mission System.