Two new dimethylpyranoflavanones from the roots of Melodorum fruticosum

Abstract

Two previously unreported dimethylpyranoflavanones, pyronomelodorones A and B (1 and 2), along with five known compounds, 7-O-methyldihydrowogonin (3), 5,6,7-trimethoxyflavanone (4), 5,6-dihydroxy-7-methoxy-dihydroflavone (5), 5,7,8-trimethoxydihydroflavone (6), and pinostrobin (7), were isolated from the roots of Melodorum fruticosum. The structures of all isolates were fully characterized using spectroscopic data and comparison with the previous literature. All isolates were evaluated for their in vitro α-glucosidase inhibition and their cytotoxicity against KB, HepG2, and MCF7 cell lines. Among the isolates, compound 1 exhibited the most inhibitory activity against α-glucosidase and was superior to the positive control with an IC₅₀ value of 1.32 μM. Compounds 1 and 2 showed weak cytotoxicity against the three human cancer cell lines, with IC₅₀ values in the range of 53.3–79.0 μM.

Keywords:

• Annonaceae
• Melodorum fruticosum
• pyronomelodorones A and B
• dimethylpyranoflavanones
• α-glucosidase inhibition
• cytotoxicity

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by Nafosted (National Foundation for Science and Technology Development) (Granted no. 104.01-2018.324).