Saponins from Panax japonicus attenuate age-related neuroinflammation via regulation of the mitogen-activated protein kinase and nuclear factor kappa B signaling pathways.

Neuroinflammation is recognized as an important pathogenic factor for aging and related cognitive disorders. Mitogen-activated protein kinase and nuclear factor kappa B signaling pathways may mediate neuroinflammation. Saponins from Panax japonicus are the most abundant and bioactive members in rhizomes of Panax japonicus, and show anti-inflammatory activity. However, it is not known whether saponin from Panax japonicus has an anti-inflammatory effect in the aging brain, and likewise its underlying mechanisms. Sprague-Dawley rats were divided into control groups (3-, 9-, 15-, and 24-month-old groups) and saponins from Panax japonicus-treated groups. Saponins from Panax japonicus-treated groups were orally administrated saponins from Panax japonicus at three doses of 10, 30, and 60 mg/kg once daily for 6 months until the rats were 24 months old. Immunohistochemical staining and western blot assay results demonstrated that many microglia were activated in 24-month-old rats compared with 3- and 9-month-old rats. Expression of interleukin-1ß, tumor necrosis factor-α, cyclooxygenase-2, and inducible nitric oxide synthase increased. Each dose of saponins from Panax japonicus visibly suppressed microglial activation in the aging rat brain, and inhibited expression levels of the above factors. Each dose of saponins from Panax japonicus markedly diminished levels of nuclear factor kappa B, IκBα, extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38. These results confirm that saponins from Panax japonicus can mitigate neuroinflammation in the aging rat brain by inhibition of the mitogen-activated protein kinase and nuclear factor kappa B signaling pathways.

Chikusetsusaponin V attenuates lipopolysaccharide-induced liver injury in mice.

Chikusetsusaponin V (CsV), a saponin from Panax japonicus, has been reported to inhibit inflammatory responses in lipopolysaccharide (LPS)-induced macrophage cells. However, whether CsV could alleviate LPS-induced liver injury in vivo and the potential mechanisms involved remain unclear. In the present study, we investigated the anti-inflammatory effects of CsV on LPS-induced acute liver injury in mice and further explored the potential mechanisms involved. Our results showed that CsV significantly attenuated elevation of alanine transaminase (ALT) and aspartate aminotransferase (AST) levels and improved liver histopathological changes in LPS-induced mice. In addition, CsV decreased serum tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) levels and inhibited mRNA expressions of inducible nitric oxide synthase (iNOS), TNF-α and IL-1ß in LPS challenged mice. Furthermore, CsV inhibited nuclear factor kappa B (NF-κB) activation by downregulating phosphorylated NF-κB, IκB-α, ERK, c-Jun N-terminal kinase (JNK) and p38 levels in the liver tissue, which ultimately decreased nucleus NF-κB protein level. In conclusion, our data suggested that CsV could be a promising drug for preventing LPS challenged liver injury since it attenuated LPS-induced inflammatory responses, partly via inhibiting NF-κB and MAPK signaling pathways.

[Study on protective effect of total saponins of Panax japonicus on LPS-induced RAW264. 7 cell inflammation through NF-kappaB pathway].

OBJECTIVE: To observe the anti-inflammatory effect of total saponins of Panax japonicus on LPS-induced RAW264. 7 macrophages. METHOD: The effect of total saponins of P. japonicus of different concentrations on RAW264. 7 cell viability was determined with the MTT method. The NO kit assay was adopted to detect the NO release of total saponins of P. japonicus to LPS-induced RAW264. 7 cells. The enzyme linked immunosorbent assay (ELISA) was used to detect the secretion of tumor necrosis factor-alpha (TNF-alpha) and interleukin 1-beta (IL-1beta). The reverse transeriptase-polymerase chain reaction (RT-PCR) was used to determine the expression of inducible nitric oxide synthase (iNOS) ,TNF-alpha,IL-1beta. The protein expression of nuclear transcription factor-kappaB p65 (NF-kappaB p65) was tested by Western blot. RESULT: The safe medication range of total saponins of P. japonicus was less than 80 mg x L(-1). Compared with the LPS model group, total saponins of P. japonicus high, middle and low dose groups (0.1, 1, 10, 40 mg x L(-1)) could significantly reduce the secretion of NO, TNF-alpha, IL-1beta of LPS-induced RAW264. 7 cells, and inhibit the expressions of iNOS, TNF-alpha and IL-1beta mRNA and the protein expression of NF-kappaB p65. CONCLUSION: This study preliminarily proves the protective effect of total saponins of P. japonicus on LPS-induced RAW264.7 macrophages. Its action mechanism may be related to NF-kappaB signal pathway.

Chikusetsu saponin V attenuates MPP+-induced neurotoxicity in SH-SY5Y cells via regulation of Sirt1/Mn-SOD and GRP78/caspase-12 pathways.

Studies have shown that saponins from Panax japonicus (SPJ) possess neuroprotective effects. However, whether Chikusetsu saponin V (CsV), the most abundant member of SPJ, can exert neuroprotective effects against 1-methyl-4-phenylpyridinium ion (MPP+)-induced cytotoxicity is not known. In this study, we aimed to investigate the neuroprotective effects of CsV on MPP+-induced cytotoxicity in human neuroblastoma SH-SY5Y cells and explore its possible mechanisms. Our results show that CsV attenuates MPP+-induced cytotoxicity, inhibits ROS accumulation, and increases mitochondrial membrane potential dose-dependently. We also found that levels of Sirt1 protein and Mn-SOD mRNA significantly decreased in MPP+-treated group but were restored with CsV treatment in a dose-dependent manner. Furthermore, GRP78 protein and Caspase-12 mRNA levels were elevated by MPP+ exposure but reversed by CsV treatment. CsV inhibited the MPP+-induced downregulation of Bcl-2 and up-regulation of Bax in a dose-dependent manner and, thus, increased the ratio of Bcl-2/Bax. Overall, these results suggest that Sirt1/Mn-SOD and GRP78/Caspase-12 pathways might be involved in the CsV-mediated neuroprotective effects.