Splenocyte-mediated immune enhancing activity of Sargassum horneri extracts / 한국영양학회지

PURPOSE: This study examined the immunological activity and optimized the mixture conditions of Sargassum horneri (S. horneri) extracts in vitro and in vivo models.METHODS: S. horneri was extracted using three different methods: hot water extraction (HWE), 50% ethanol extraction (EE), and supercritical fluid extraction (SFE). Splenocyte proliferation and cytokine production (Interleukin-2 and Interferon-γ) were measured using a WST-1 assay and enzyme-linked immunosorbent assay, respectively. The levels of nitric oxide and T cell activation production were measured using a Griess assay and flow cytometry, respectively. The natural killer (NK) cell activity was determined using an EZ-LDH kit.RESULTS: Among the three different types of extracts, HWE showed the highest levels of splenocyte proliferation and cytokine production in vitro. In the animal model, three different types of extracts were administrated for 14 days (once/day) at 50 and 100 mg/kg body weight. HWE and SFE showed a high level of splenocyte proliferation and cytokine production in the with and without mitogen-treated groups, whereas EE administration did not induce the splenocyte activation. When RAW264.7 macrophage cells were treated with different mixtures (HWE with 5, 10, 15, 20% of SFE) to determine the optimal mixture ratio of HWE and SFE, the levels of nitric oxide and cytokine production increased strongly in the HWE with 5% and 10% of SFE containing group. In the animal model, HWE with 5% and 10% of SFE mixture administration increased the levels of splenocyte proliferation, cytokine production, and activated CD4⁺ cell population significantly, with the highest level observed in the HWE with 5% of SFE group. Moreover, the NK cell activity was increased significantly in the HWE with 5% of SFE mixture-treated group compared to the control group.CONCLUSION: The optimal mixture condition of S. horneri with immune-enhancing activity is the HWE with 5% of SFE mixture. These results confirmed that the extracts of S. horneri and its mixtures are potential candidate materials for immune enhancement.

Immunomodulating activity of Sargassum horneri extracts in RAW264.7 macrophages / 한국영양학회지

PURPOSE: Sargassum horneri (S. horneri) is a species of brown macroalgae that is common along the coast of Japan and Korea. The present study investigated the immuno-modulatory effects of different types of S. horneri extracts in RAW264.7 macrophages. METHODS: S. horneri was extracted by three different methods, hot water extraction, 50% ethanol extraction, and supercritical fluid extraction. Cell viability was then measured by MTT assay, while the production levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and nitric oxide (NO) were measured by enzyme-linked immunosorbent assay and Griess assay, respectively. The expression and activation levels of inducible NO synthase (iNOS), mitogen-activated protein kinase (MAPK) and nuclear factor κB (NF-κB) were examined by western blot analysis. RESULTS: The three different S. horneri extracts were nontoxic against RAW 264.7 cells up to 50 µg/mL, among which treatment with hot water extract (HWE) of S. horneri significantly enhanced the production of TNF-α, IL-6, and NO in a dose-dependent manner. Hot water extract of S. horneri also increased the expression level of iNOS, suggesting that up-regulation of iNOS expression by HWE of S. horneri was responsible for the induction of NO production. In addition, treatment of RAW 264.7 macrophages with HWE of S. horneri increased the phosphorylation levels of ERK, p38 and JNK. Furthermore, the activation and subsequent nuclear translocation of NF-κB was enhanced upon treatment with HWE of S. horneri, indicating that HWE of S. horneri activates macrophages to secrete TNF-α, IL-6 and NO and induces iNOS expression via activation of the NF-κB and MAPKs signaling pathways. CONCLUSION: Taken together, these findings suggest that HWE of S. horneri possesses potential as a functional food with immunomodulatory activity.