Flavonoids From the Whole Plants of Leptopus clarkei and Their In Vitro Anti-inflammatory Activities

Our previous research has confirmed that the Leptopus genus plants possess significant anti-tumor and hepatoprotective effects, and over 50 triterpenoids were isolated from these plants. In the present work, the anti-inflammatory activities of four Leptopus genus plants were evaluated before phytochemical experiments. Subsequently, eight flavonoids (1-8) including two previously undescribed prenylated flavonoids (1-2) were isolated from the whole plants of Leptopus clarkei. The structures of these new compounds were unequivocally elucidated by high-resolution electrospray ionization mass spectrometry and one-/two-dimensional nuclear magnetic resonance data. Additionally, all isolates were evaluated for their anti-inflammatory activities. Among these compounds, 1 exhibited moderate anti-inflammatory activity with a minimum inhibitory concentration value of 26.5 ± 1.2 µM on nitric oxide production in lipopolysaccharide-induced RAW264.7 cells.