Inhibitory activity of lignanamides isolated from hemp seed hulls(Cannabis sativa L.) against soluble epoxide hydrolase

Inhibitory Activity of Glycosides from Elsholtzia ciliata against Soluble Epoxide Hydrolase and Cytokines in RAW264.7 Cells

Soluble epoxide hydrolase (sEH) and pro-inflammatory cytokines are associated with the development of inhibitors for cardiovascular and inflammatory diseases. Here, we report on four natural sEH inhibitors isolated from the aerial parts of Elsholtzia ciliata (Thunb.) Hyl.. The four compounds, 1-4, were identified as luteolin-7-O-glucoside (1), yuanhuanin (2), apigenin-7-O-glucoside (3), and butein-4'-O-glucoside (4). Among them, compounds 2 and 4 are reported for the first time from this plant. In vitro and in silico, they showed inhibitory activity towards sEH at micromole concentrations. Moreover, they suppressed pro-inflammatory cytokines in polyinosinic:polycytidylic acid (poly(I:C))-stimulated RAW264.7 cells. Notably, 4 significantly downregulated the sEH catalytic reaction, NO and PGE2 production, and the expression levels of iNOS, COX-2, IL-6 mRNA, and sEH mRNA. Therefore, butein-4'-O-glucoside (4) is a potential sEH inhibitor that may be suitable for treating inflammation and cardiovascular diseases caused by infection.

The Inhibition Activity of Natural Methoxyflavonoid from Inula britannica on Soluble Epoxide Hydrolase and NO Production in RAW264.7 Cells

Soluble epoxide hydrolase (sEH) is an enzyme targeted for the treatment of inflammation and cardiovascular diseases. Activated inflammatory cells produce nitric oxide (NO), which induces oxidative stress and exacerbates inflammation. We identify an inhibitor able to suppress sEH and thus NO production. Five flavonoids 1-5 isolated from Inula britannica flowers were evaluated for their abilities to inhibit sEH with IC50 values of 12.1 ± 0.1 to 62.8 ± 1.8 µM and for their effects on enzyme kinetics. A simulation study using computational chemistry was conducted as well. Furthermore, five inhibitors (1-5) were confirmed to suppress NO levels at 10 µM. The results showed that flavonoids 1-5 exhibited inhibitory activity in all tests, with compound 3 exhibiting the most significant efficacy. Thus, in the development of anti-inflammatory inhibitors, compound 3 is a promising natural candidate.