Anti-Inflammatory Effect of Xanthones from Hypericum beanii on Macrophage RAW 264.7 Cells through Reduced NO Production and TNF-α, IL-1β, IL-6, and COX-2 Expression

<i>Hypericum beanii</i> N. Robson, a perennial upright herb, predominantly inhabits temperate regions. This species has been utilized for the treatment of various inflammation-related diseases. One new xanthone 3,7-dihydroxy-1,6-dimethoxyxanthone (<b>1</b>) and twenty-three known xanthones (<b>2</b>-<b>24</b>) were isolated from the aerial parts of <i>H. beanii</i>. The structure of the new compound was determined based on high-resolution electrospray ionization mass spectroscopy (HR-ESIMS), nuclear magnetic resonance (NMR), Infrared Spectroscopy (IR), ultraviolet spectrophotometry (UV) spectroscopic data. The anti-inflammatory effects of all the isolates were assessed by measuring the inhibitory effect on nitric oxide (NO) production in LPS-stimulated RAW 264.7 macrophages. Compounds 3,4-dihydroxy-2-methoxyxanthone (<b>15</b>), 1,3,5,6-tetrahydroxyxanthone (<b>19</b>), and 1,3,6,7-tetrahydroxyxanthone (<b>22</b>) exhibited significant anti-inflammatory effects at a concentration of 10 <i>μ</i>M with higher potency compared to the positive control quercetin. Furthermore, compounds <b>15</b>, <b>19</b>, and <b>22</b> reduced inducible NO synthase (iNOS), tumor necrosis factor alpha (TNF-<i>α</i>), interleukin-1<i>β (</i>IL-1<i>β</i>), IL-6, and cyclooxygenase 2 (COX-2) mRNA expression in the LPS-stimulated RAW 264.7 macrophages, suggesting that these compounds may mitigate the synthesis of the aforementioned molecules at the transcriptional level, provisionally confirming their anti-inflammatory efficacy.