Figure 3.

Three complement activation pathways and the role of fucoidan in complement activation. Fucoidan inhibits complement activation through the classical pathway by preventing active C1 formation, inhibiting C4 activity by forming a complex with C4, and preventing the binding of C4b and C2a (Blondin et al., 1994; Tissot, Montdargent, et al., 2003). Fucoidan also inhibits complement activation through the alternative pathway by preventing the binding of factor B to C3b (Blondin et al., 1994). The figure was created with BioRender.com.