Zanthoxylum zanthoxyloides (Z. zanthoxyloides) is a plant used in West Africa to treat diseases such as stomach ache, toothache and malaria. Extract and bioactives from the rootbark of Z. zanthoxyloides have been suggested to have anti-inflammatory activity (1 and 2). In cerebral malaria, the accumulation of malaria pigment hemozoin induces inflammation leading to excessive production of pro-inflammatory cytokines which contributes to its pathology (3). However, whether Z. zanthoxyloides could suppress hemozoin-induced neuroinflammation remains unclear. In this study, we investigated the effect of Z. zanthoxyloides in hemozoin-induced BV2 microglia. Cultured BV2 microglia cells were treated with 4, 6 and 8 µg/ml of Z. zanthoxyloides 30 minutes before stimulation with hemozoin (400 μg/ml) for a further 24 hours. Levels of TNFα, IL-1β, IL-6, IL-10 released were measured using ELISA while PGE2 production was measured by enzyme immunoassay. Nitric oxide (NO) production was determined using the Griess assay. Z. zanthoxyloides (4, 6 and 8 µg/ml) significantly (p<0.05) reduced the production of TNF α (40±5%), IL-1β (40±2%), IL-6 (50±2%), NO (40±3%) and PGE2 (40±2%). Western blot experiments showed that Z. zanthoxyloides reduced levels of iNOS (45±5%), COX-2 (50±5%), phospho-p65 (50±5%) and phospho-IҡBα (40±5%) in comparision with hemozoin control. These results suggest that Zanthoxylum zanthoxyloides might be inhibiting neuroinflammation in hemozoin induced microglia cells by targeting NF-kB signalling. These results have significant implications in cerebral malaria.
References
- Prempeh, A.B.A. and Mensah-Attipoe, J., 2009. Inhibition of vascular response in inflammation by crude aqueous extract of the root bark of Zanthoxylum Xanthoxyloides. Ghana medical journal, 43(2).
- Oriowo MA. (1982) Anti-inflammatory activity of piperonyl-4-acrylic isobutyl amide, an extractive from Zanthoxylum zanthoxyloides. Planta Medica 44: 54-56
- Sultan, S. and Irfan, S.M., 2015. Intraleukocytic hemozoin pigments in complicated Plasmodium falciparum cerebral malaria. Blood research, 50(2), pp.72-72.