Two novel flavonoids from the leaves of Rhododendron dauricum L. with their inhibition of TNF-α production in LPS-induced RAW 264.7 cells

Abstract

Two new flavonoids, (2S)-6,8-dimethyl-5,7,3′,4′-tetrahydroxyflavanone 4′-O-β-D-glucopyranoside (1) and quercetin 3-O-β-D-(6′′-p-methoxybenzoyl)-galactopyranoside (2), together with ten known flavonoids (3–12) were isolated from the leaves of Rhododendron dauricum L. The structures of the flavonoids were characterized from spectroscopic data (1D and 2D NMR and HR-ESI-MS). The isolated flavonoids were evaluated for their inhibitory effects on the production of tumour necrosis factor (TNF)-α in LPS-stimulated RAW 264.7 cells. Compound 11 exhibited inhibitory activity against TNF-α production with an IC₅₀ value of 46.2 ± 1.2 µM.

Keywords:

• Rhododendron dauricum
• Ericaceae
• flavonoid
• TNF-α

Disclosure statement

No potential conflict of interests was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China under Grant numbers 81660699, 81660579 and 81760627. We thank Renee Mosi, PhD, from Liwen Bianji, Edanz Group China (www.liwenbianji.cn/ac), for editing the English text of a draft of this manuscript.