Immune-Enhancing Effects of Red Platycodon grandiflorus Root Extract via p38 MAPK-Mediated NF-κB Activation

Euonymus alatus (Thunb.) Siebold leaf extract enhanced immunostimulatory effects in a cyclophosphamide-induced immunosuppressed rat model

Background

Euonymus alatus (Thunb.) Siebold (EA) is a medicinal plant used in some Asian countries to treat various diseases, including cancer, hyperglycemia, diabetes, urticaria, dysmenorrhea, and arthritis. Owing to the wide range of pharmacological applications of EA, various roles of EA are being studied.

Objective

We evaluated the immune-enhancing effect of EA treatment in a cyclophosphamide (Cy)-induced immunosuppressed rat model.

Design

We analyzed the immune enhancement effect of EA on macrophages by western blotting. In addition, cell viability and natural killer (NK) cell activity were analyzed in splenocytes following EA treatment. For in vivo studies, analysis of weekly body weight, spleen weight, immune cell count, cytokine levels, and spleen histological findings was performed following EA administration in Cy-induced immunocompromised rats.

Results

EA significantly increased cell viability and phospho-nuclear factor-kappa B and phospho-extracellular signal-regulated kinase protein levels in the macrophages. EA significantly increased NK cell activity in splenocytes compared with the control group. In Cy-induced immunosuppressed rats, EA administration increased spleen tissue weight and the contents of leukocytes, lymphocytes, granulocytes, intermediate cells, and plasma cytokines (tumor necrosis factor-α and interferon-γ). In addition, improvement in the damaged spleen tissue was observed.

Conclusions

These findings confirm that EA exerts an immune-enhancing effect, thereby suggesting its potential as an immunostimulatory agent or functional food.

Antioxidant and Immune Stimulating Effects of Allium hookeri Extracts in the RAW 264.7 Cells and Immune-Depressed C57BL/6 Mice

We investigated the antioxidant and immune-enhancing effects of the extracts from Allium hookeri leaves and roots (AHL and AHR) in in vitro and in vivo models. Their antioxidant effects were determined by total phenolic content (TPC), DPPH and ABTS radical scavenging activities, and superoxide dismutase and catalase activities. The immunomodulatory effects were evaluated by nitric oxide (NO) production and cytokine concentrations produced from RAW 264.7, and by serum IgA and IgG levels, cytokine levels, and NK cell activities in the immunosuppressed C57BL/6 mice. AHL and AHR extracts improved antioxidant activities and productions of NO and cytokines without cytotoxicity in the RAW 264.7 cells. AHL and AHR groups showed significantly higher serum IgA and IgG levels, Th1 cytokine concentrations, splenocyte proliferations, and NK cell activities than the NC group which was not treated with AHL or AHR extract. AHR extract showed higher values than AHL extract in the factors evaluated in this study. The results show that they have high antioxidant and immunomodulatory effects and can be used as novel potential therapeutic candidates to treat related diseases and to improve public health.

Immune-Enhancing Effects of Co-treatment With Kalopanax pictus Nakai Bark and Nelumbo nucifera Gaertner Leaf Extract in a Cyclophosphamide-Induced Immunosuppressed Rat Model

Objective

Immune system disorders can result in various pathological conditions, such as infections and cancer. Identifying therapies that enhance the immune response might be crucial for immunocompromised individuals. Therefore, we assessed the immune-enhancing effect of co-treatment with Kalopanax pictus Nakai Bark and Nelumbo nucifera Gaertner leaf extract (KPNN) in a cyclophosphamide (Cy)-induced immunosuppressed rat model.

Materials and Methods

For in vitro studies, macrophages and splenocytes were treated with various KPNN doses in the presence or absence of Cy. Macrophage viability, nitric oxide production, splenocyte viability, cytokine production and natural killer (NK) cell activity were analyzed. For in vivo studies, analysis of weekly body weight, dietary intake, tissue weight, immune-related blood cell count, cytokine levels, and spleen biopsy was performed in a Cy-induced immunocompromised animal model.

Results

KPNN significantly increased phospho-NF-κB and phospho-ERK protein levels and cell viability in macrophages. KPNN significantly increased the NK cell activity in splenocytes compared to that in the control. Cy treatment decreased tumor necrosis factor (TNF)-α, interleukin (IL)-6, and interferon-γ production. In the Cy-induced immunosuppression rat model, KPNN-treated rats had significantly higher body weights and tissue weights than the Cy-treated rats. Additionally, KPNN treatment restored the immune-related factors, such as total leukocyte, lymphocyte, and intermediate cell contents, to their normal levels in the blood. The blood cytokines (TNF-α and IL-6) were increased, and spleen tissue damage was significantly alleviated.

Conclusions

Collectively, KPNN exerts an immune-enhancing effect suggesting their potential as an immunostimulatory agent or functional food.

An 8-week randomized, double-blind, placebo-controlled study to evaluate the efficacy and safety of red Platycodon grandiflorus root extract on enhancement of immune function

BACKGROUND

The immune-enhancing effects of red Platycodon grandiflorus root extract (RPGE) has been reported in vitro and in vivo, but there are few studies on humans. Therefore, this study aimed to investigate the efficacy and safety of RPGE in enhancing immune function in healthy subjects.

SUBJECTS AND METHODS

An 8-week randomized, double-blind, parallel, placebo-controlled clinical trial was conducted at the Gachon University Gil Medical Center, Incheon, South Korea. A total of 100 adults aged 20-75 years with white blood cell counts of 3000-10,000 cell/µL were randomly divided into two groups (RPGE group, 50 and placebo group, 50) using a computer-generated random list with a 1:1 allocation ratio. The subjects consumed RPGE (2 times/day, 2 tablets/time, 375 mg RPGE powder/tablet) or placebo for 8 weeks. All test foods for the human study were coded and administered under double-blind conditions. The primary outcome was a change in the NK cell activity after 8 weeks of treatment compared to the baseline.

RESULTS

Among 100 subjects enrolled for the study, 87 completed the study. NK cell activity (p = 0.005) and IFN-γ level (p = 0.003) of the RPGE group (n = 41) were higher than those of the placebo group (n = 46). The findings of the safety assessment revealed absence of clinically significant changes in any test and serious adverse events throughout the study.

CONCLUSION

In conclusion, these results demonstrate the efficacy and safety of RPGE, suggesting it to be a beneficial agent for enhancing immune function in humans.

TRIAL REGISTRATION

CRIS Registration Number KCT0005945, https://cris.nih.go.kr.

Anti-Inflammatory Effects of Fermented Lotus Root and Linoleic Acid in Lipopolysaccharide-Induced RAW 264.7 Cells

Inflammation is a protective response of the innate immune system. However, aberrant inflammatory responses lead to various diseases. Lotus root, the edible rhizome of Nelumbo nucifera, is a popular traditional herbal medicine in East Asia. In a previous study, we reported that fermented lotus root (FLR) alleviated ethanol/HCl-induced gastric ulcers in rats by modulating inflammation-related genes. However, the mechanisms underlying the anti-inflammatory effects of FLR and its major constituent, linoleic acid (LA), are still largely unknown. In this study, we investigated the anti-inflammatory effects of FLR and LA on lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 murine macrophages. We found that FLR inhibited LPS-induced expression of inflammatory mediators through down-regulation of NF-κB activity. Similarly, LA also attenuated LPS-induced inflammatory responses and reduced LPS-induced phosphorylation of proteins associated with NF-κB signaling, such as ERK, JNK, and p38. Overall, our results suggested that FLR and LA may effectively ameliorate inflammatory diseases.