A new triterpenoid from the leaves of Rhodomyrtus tomentosa (Ait.) Hassk

Abstract

A new triterpenoid, 2α, 3β, 23α, 29-tetrahydroxyolean-11, 13 (18)-dien-28, 19β-olide, named as rhodotomoside A (1), together with six known triterpenoids (2–7), were isolated from the leaves of Rhodomyrtus tomentosa (Ait.) Hassk by column chromatography on silica gel, reversed-phase C₁₈ silica gel and semi-preparative HPLC. Their structures were elucidated on the basis of spectroscopic methods, including extensive 1D NMR, 2D NMR and MS spectra. The inhibition rates of α-glucosidase of compound 1 was 77.82%, and exhibited inhibitory activity against α-glucosidase with IC₅₀ value at 0.213 ± 0.016 mg/mL.

Graphical Abstract

KEYWORDS:

• Myrtaceae
• Rhodomyrtus tomentosa
• triterpenoids
• α-glucosidase

Acknowledgement

We are grateful to Kunming Institute of Botany, Chinese Academy of Sciences, Guangxi Normal University, for measuring the IR, UV, MS and NMR spectra.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the [National Natural Science Foundation of China] under Grant [No. 31560100; No. 81860621]; [Natural Science Fund of Guangxi Province] under Grant [No. 2017GXNSFAA198242; No. 2018GXNSFBA281032; No. 2018GXNSFAA28110; No. 2018GXNSFBA281079], and [State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources] (Guangxi Normal University) under Grant [No. CHEMR2017-B15].