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The protective effects of oleanolic acid (OA) on carbon tetrachloride (CCl₄)-induced liver mitochondrial damage and the possible mechanisms were investigated. Pretreatment with OA prior to the administration of CCl₄ significantly suppressed the increases of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) (4.2- and 19.9-fold, respectively) in a dose-dependent manner in mice. The dissipation of mitochondrial membrane potential (14.8%) and intra-mitochondrial Ca²⁺ overload (2.1-fold) in livers of CCl₄-insulted mice were also dose-dependently prevented by pretreatment with 20, 50 or 100 mg/kg OA. In addition, the effects of OA on liver mitochondria permeability transition (MPT) induced by Ca²⁺ were assessed by measuring the change in mitochondrial membrane potential, release of matrix Ca²⁺ and mitochondrial swelling in vitro. The results showed that preincubation with 50 or 100 μg/ml OA obviously inhibited the Ca²⁺-induced mitochondrial swelling, mitochondrial membrane depolarization and intra-mitochondrial Ca²⁺ release. It could be concluded that OA has protective effects on liver mitochondria and the mechanisms underlying its protection may be related to its inhibitory action on MPT.

Radix Glycyrrhizae (RG) is a medicinal herb extensively utilized in numerous Chinese medical formulae for coordinating the actions of various components in the recipes and strengthening the body functions. In this report, we demonstrate that the aqueous extract of Radix Glycyrrhizae is capable of stimulating the c-Jun N-terminal kinase and p38 subgroups of mitogen-activated protein kinases (MAPKs), and the nuclear factor-κB (NFκB) in Jurkat T-lymphocytes. The activation magnitudes of MAPKs and NFκB were dose-dependent (EC₅₀ ≈ 1 mg/ml) and time-dependent (maximal around 15–30 minutes). Stimulations of MAPKs and NFκB were not associated with changes in intracellular Ca²⁺ mobilization. Similar activation profiles of MAPK and NFκB were obtained from THP-1 monocytes treated with the extract. In terms of chemotactic activity, the SDF-induced chemotaxis of Jurkat cells and THP-1 cells were inhibited by RG extract at 1–10 mg/ml, while a lower RG concentration (0.1–0.3 mg/ml) potentiated the SDF-induced chemotaxis for the former, but not the latter cell type. Given the fact that MAPKs and NFκB are important signaling intermediates for lymphocyte activities, our results suggest that Radix Glycyrrhizae may contain active constituents capable of modulating immuno-responses through various intracellular signaling pathways.