IL6 and major depressive disorder: Salvianolic acid B relieves cerebral injury by reducing IL-6 expression (Fan et al., 2018) Leonurine, baicalin, geniposide and ferulic acid (Jia et al., 2017; Zhao Y. et al., 2018; Guo et al., 2019; Zheng et al., 2019) reduce IL-6 expression to treat depression (Kim et al., 2016).