Anti-Inflammatory Activity of Fucoidan Extracts In Vitro

Abstract

Fucoidans are sulfated, complex, fucose-rich polymers found in brown seaweeds. Fucoidans have been shown to have multiple bioactivities, including anti-inflammatory effects, and are known to inhibit inflammatory processes via a number of pathways such as selectin blockade and enzyme inhibition, and have demonstrated inhibition of inflammatory pathologies in vivo. In this current investigation, fucoidan extracts from Undaria pinnatifida, Fucus vesiculosus, Macrocystis pyrifera, Ascophyllum nodosum, and Laminaria japonica were assessed for modulation of pro-inflammatory cytokine production (TNF-α, IL-1β, and IL-6) by human peripheral blood mononuclear cells (PBMCs) and in a human macrophage line (THP-1). Fucoidan extracts exhibited no signs of cytotoxicity in THP-1 cells after incubation of 48 h. Additionally, all fucoidan extracts reduced cytokine production in LPS stimulated PBMCs and human THP-1 cells in a dose-dependent fashion. Notably, the 5-30 kDa subfraction from Macrocystis pyrifera was a highly effective inhibitor at lower concentrations. Fucoidan extracts from all species had significant anti-inflammatory effects, but the lowest molecular weight subfractions had maximal effects at low concentrations. These observations on various fucoidan extracts offer insight into strategies that improve their efficacy against inflammation-related pathology. Further studies should be conducted to elucidate the mechanism of action of these extracts.

Keywords: Ascophyllum nodosum; Fucus vesiculosus; Laminaria japonica; Macrocystis pyrifera; PBMCs; THP-1; TNF-α, IL-1β, and IL-6; Undaria pinnatifida; fucoidan.

Figure 1

Effects of fucoidan extracts on THP-1 cell viability. Cells were treated with the specified concentrations of fucoidan extract UPF (A), FVF (B) and MPF (C) for 48 h and assessed by MTT reduction assays. Results expressed OD of treated cells vs. vehicle control. Data represented as means ± SEM. Statistical analyses were carried out using one-way ANOVA followed by Tukey’s multiple comparison test of three independent experiments run in triplicates (n = 3). A p-value of <0.05 was considered significant.

Figure 2

Pre-treatment of fucoidan extracts on pro-inflammatory cytokines, TNF-α, IL-1β, and IL-6 in LPS-stimulated human PBMC cells. Cells were pre-treated with the indicated doses UPF (A–C) and FVF (D–F) for 1 h followed by LPS stimulation for 24 h. The amounts of TNF-α, IL-1β, and IL-6 were measured from the supernatant using ELISA. Data represented as means ± SEM. Statistical analyses were carried out using one-way ANOVA followed by Tukey’s multiple comparison test of three independent experiments run in triplicates (n = 3) A p-value of <0.05 was considered significant. * p < 0.05, ** p < 0.001, *** p < 0.0001 and **** p < 0.00001.

Figure 3

Effects of multiple fucoidan extracts on LPS induced pro-inflammatory cytokine TNF-α in human THP-1. Cells were pre-treated with several fucoidan extracts. UPF and its derived extracts (A–C), FVF and its derived extracts (D–F), MPF and derived extracts (G–I), FVC (J), ANF (K) and LJF (L) with indicated doses (10, 50, 100, and 200 µg/mL) for 24 h before LPS treatment (0.5 µg/mL), supernatants were isolated, and the amounts of TNF-α was measured. Data represented as means ± SEM. Statistical analyses were carried out using one-way ANOVA followed by Tukey’s multiple comparison test of three independent experiments run in triplicates (n = 3). A p-value of <0.05 was considered significant. * p < 0.05, ** p < 0.001, *** p < 0.0001, and **** p < 0.00001.

Figure 4

Effects of multiple fucoidan extracts on LPS induced pro-inflammatory cytokine, IL-1β in human THP-1 monocyte cells. Cells were pre-treated with several fucoidan extracts. UPF and its derived extracts (A–C), FVF and its derived extracts (D–F), MPF and derived extracts (G–I), FVC (J), ANF (K) and LJF (L) with indicated doses (10, 50, 100, and 200 µg/mL) for 24 h before LPS treatment for 24 h (0.5 µg/mL), supernatants were isolated, and the amounts of TNF-α were subsequently measured. Data represented as means ± SEM. Statistical analyses were carried out using one-way ANOVA followed by Tukey’s multiple comparison test of three independent experiments run in triplicates (n = 3). A p-value of < 0.05 was considered significant. * p < 0.05, ** p < 0.001, and *** p < 0.0001.