Study on the anti-hyperuricemic bioactivity and chemical components of Sterculiae lychnophorae Semen

Abstract

Sterculiae lychnophorae Semen is an edible and medicinal resource and is widely used in functional foods in China. In the previous study, the S. lychnophorae′ function of anti-hyperuricemia was found, but its main functional ingredients have not been clarified. In this study, the major functional ingredients of S. lychnophorae with anti-hyperuricemic effect were determined under activity guided screening through the intervention for xanthine oxidase (XO) enzymatic reaction in vitro. The results showed EtOAc fraction (EF) of S. lychnophorae had the strongest inhibitory activity among all fractions with the inhibition rate 94.94%. Since hyperuricemia could trigger inflammation reaction, the anti-inflammation effect of mainly functional ingredient (EF) was also researched through a cell inflammation model established by using uric acid (UA) to stimulate HK-2 cells. The results showed that the expression levels of inflammatory cytokines IL-6, IL-1β and TNF-α were decreased after treatment with EF. On the meanwhile, molecular mechanistic studies revealed that EF could downregulate the phosphorylation levels of PI3K, AKT, IκBα, NF-κB proteins in HK-2 cells. These results showed that EF could potentially lower UA level and combat inflammation by inhibiting the PI3K/AKT/NF-κB signal pathway. Furthermore, the chemical components of EF were also clarified. As a result, two new compounds, ethyl 2, 3-dihydro-1, 4-benzodioxin-6-carboxylate (1) and ethyl 3-(butyryloxy)-4-hydroxybenzoate (2), together with 15 known compounds were identified from EF by extensive NMR experiments and comparison with the data reported in the literature. The XO inhibitory effects of all the compounds were analyzed. With the determination of the anti-hyperuricemic mechanism and chemical component of EF, it can be used as a raw material to develop functional foods against hyperuricemia in the future.