Bioassay-guided isolation of sesamin and fargesin from the hydroalcoholic stem extract of Zanthoxylum armatum DC. inhibited inflammation in CpG-stimulated conventional type 1 dendritic cells

Introduction Zanthoxylum armatum DC. is renowned for its medicinal values. All the plant parts have been used to treat tooth- and gum-related problems, gastro-intestinal problems, inflammation, rheumatism, and pain by the indigenous people of Nepal, India, China, and other South East Asian countries. Bioassay-guided isolation of active compounds from medicinal plants is recognized as a promising approach for the discovery of novel drug candidates. The objective of this study was to examine the main constituents of Zanthoxylum armatum DC. stems through bio-guided isolation and to explore their anti-inflammatory potential. Method Sequential fractions were prepared from the hydromethanolic stem extract of Z. armatum DC. Afterward, bioassay-guided isolation was conducted using a combination of column chromatography, heat-induced hemolysis inhibition assay, and albumin denaturation inhibition assay. The structures of the isolated compounds were elucidated through single crystal XRD and NMR. The anti-inflammatory activity of the compounds was evaluated in vitro by measuring the expression levels of IL12 and CD80 using flow cytometry. Results Sequential ethyl acetate fraction showed the highest protein anti-denaturation and membrane stabilization activities. Afterward, sesamin and fargesin were isolated from the sequential ethyl acetate fraction. Both of them showed activity against IL12 production by conventional type 1 dendritic cells. Moreover, fargesin significantly inhibited the expression of CD80. Conclusion The results identified bioactive compounds with potential against the pro-inflammatory dendritic cells for the first time. The findings justified the traditional use of Z. armatum DC. as an anti-inflammatory agent.