Dendropanax morbifera Léveille extract ameliorates cadmium-induced impairment in memory and hippocampal neurogenesis in rats.

BACKGROUND: Cadmium leads to learning and memory impairment. Dendropanax morbifera Léveille stem extract (DMS) reduces cadmium-induced oxidative stress in the hippocampus. We investigated the effects of DMS on cadmium-induced impairments in memory in rats. METHODS: Cadmium (2 mg/kg), with or without DMS (100 mg/kg), was orally administered to 7-week-old Sprague-Dawley rats for 28 days. Galantamine (5 mg/kg), an acetylcholinesterase inhibitor, was intraperitoneally administered as a positive control. A novel-object recognition test was conducted 2 h after the final administration. Cell proliferation and neuroblast differentiation were assessed by immunohistochemistry for Ki67 and doublecortin, respectively. Acetylcholinesterase activity in the synaptosomes of the hippocampus was also measured based on the formation of 5,5'-dithio-bis-acid nitrobenzoic acid. RESULTS: An increase in the preferential exploration time of new objects was observed in both vehicle-treated and cadmium-treated rats. In addition, DMS administration increased cell proliferation and neuroblast differentiation in the dentate gyrus of vehicle-treated and cadmium-treated rats. Acetylcholinesterase activity in the hippocampal synaptosomes was also significantly higher in the DMS-treated group than in the vehicle-treated group. The effect of DMS on cadmium-induced memory impairment and cell proliferation in the hippocampus was comparable to that of galantamine. CONCLUSIONS: These results suggest that DMS ameliorates cadmium-induced memory impairment via increase in cell proliferation, neuroblast differentiation, and acetylcholinesterase activity in the hippocampus. The consumption of DMS may reduce cadmium-induced neurotoxicity in animals or humans.

Eleutherococcus senticosus extract attenuates LPS-induced iNOS expression through the inhibition of Akt and JNK pathways in murine macrophage.

Eleutherococcus senticosus (Araliaceae) is immunological modulator which has been successfully used for anti-inflammatory effectors on anti-rheumatic diseases in oriental medicine. Mitogen-activated protein kinases (MAPKs) and Akt modulate the transcription of many genes involved in the inflammatory process. In this study, we investigated the inhibitory effects of Eleutherococcus senticosus on the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in lipopolysaccharides (LPS)-activated macrophages. Finally, we studied the involvement of MAPKs and Akt signaling in the protective effect of Eleutherococcus senticosus in LPS-activated macrophages. Eleutherococcus senticosus significantly attenuated LPS-induced iNOS expression but not COX-2 expression. In using the standard inhibitors (MAPKs and Akt), our results show that Eleutherococcus senticosus downregulates inflammatory iNOS expression by blocking JNK and Akt activation.