Barley Sprout Extract and Luteolin Mitigate LPS-Mediated Inflammation in RAW264.7 Murine Macrophages via Histone Acetyltrasferase Activity Inhibition

This study aimed to assess the anti-inflammatory activity and the mechanism of anti-inflammatory action of barley sprout (Hordeum vulgare L.). Barley sprout powder (BSP), barley sprout ethanol extract (BSE), and barley sprout water extract (BSW) were prepared, and the inhibitory effects of the samples on nitric oxide (NO) production were evaluated. The results showed that the inhibitory activity of BSE and BSW on NO production was greater compared to BSP. Among the active compounds found in barley sprouts, luteolin exhibited greater inhibition of NO production and histone acetyltransferase (HAT) activity compared to the other compounds. Luteolin significantly (P<0.05) attenuated lipopolysaccharide (LPS)-mediated inflammatory mediators, including interleukin-6, tumor necrosis factor-, inducible nitric oxide synthase, and cyclooxygenase-2 in RAW264.7 cells. Luteolin also significantly inhibited in vitro specific HATs (p300, CBP, PCAF) as well as total HAT, which was also observed in the nuclear fraction of LPS-treated RAW264.7 cells. The anti-inflammatory activity of luteolin was attributed to total and specific HAT inhibition. Collectively, the anti-inflammatory activity of barley sprouts could be attributed to luteolin via HAT inhibition.