Recurvataside, a new saponin from aerial parts of Mussaenda recurvata

Abstract

A new glycoside, recurvataside (1) and six known compounds, quinovic acid (2), quinovic acid 28-O-β-D-glucopyranosyl ester (3), 3-O-β-D-glucopyranosylquinovic acid (4), 3-O-β-D-glucopyranosylquinovic acid 28-O-β-D-glucopyranosyl ester (5), pomolic acid (6), and ursolic acid (7) were isolated from aerial parts of Mussaenda recurvata. The structure of compound 1 was identified from its spectroscopic data and by comparison with the literature. Recurvataside represents the first occurrence of δ-oleanolic acid saponin bearing two D-glucose units at C-3 and C-28 in nature. This is the first time δ-oleanane-type saponin reported in the genus Mussaenda. Compounds 1-7 were evaluated the cytotoxicity against two cancer cell lines MCF-7 and HepG2. Among them, only compound 7 exhibited moderate activity against MCF-7 and HepG2 cell lines with IC₅₀ value of 16.97 ± 1.55 and 20.28 ± 1.00 μM, respectively. Compounds 1–7 were also tested for their inhibitory NO production in LPS-stimulated RAW264.7 cells. Compounds 3, 5, and 7 showed significant reduction of nitrite accumulation in LPS-stimulated RAW 264.7 cells with the IC₅₀ values of 8.81 ± 0.48, 13.42 ± 0.84, and 18.37 ± 0.67 μM, respectively.

Graphical Abstract

Keywords:

• Rubiaceae
• Mussaenda recurvata
• glycoside
• recurvataside
• saponin

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research is funded by Vietnam National Foundation for Science and Technology Development (NAFOSTED) under grant number 104.01-2018.353.