Fucosterol is a plant sterol found in algae that has diverse biological activities including antioxidant, anti-inflammatory, anticancer, and antidiabetic properties among others.[1] It decreases markers of oxidative damage and increases antioxidative enzyme activity in vitro.[2] It reduces the expression of TNF-α and IL-6 following LPS administration by halting NF-κB and p38 MAPK signaling in RAW 264.7 murine macrophages.[3] In HEK293, MCF-7, and SiHa cells, fucosterol decreases proliferation (IC50s = 185.4, 43.3, and 34.0 μg/ml, respectively).[4] It also has anticancer activity in HL-60 leukemia cells, where it inhibits cell growth, halts the cell cycle at the G2/M transition, and induces apoptosis with maximally increased caspase-9, -8, and -3 expression at 68.8 μM.[5] In a streptozotocin rat model of diabetes, it decreases serum glucose concentrations when administered at 30 mg/kg.[6]

Reference:
[1]. Abdul, Q.A., Choi, R.J., Jung, H.A., et al. Health benefit of fucosterol from marine algae: A review J. Sci. Food Agric. 96(6), 1856-1866 (2015).
[2]. Lee, S., Lee, Y.S., Jung, S.H., et al. Anti-oxidant activities of fucosterol from the marine algae Pelvetia siliquosa Arch. Pharm. Res. 26(9), 719-722 (2003).
[3]. Yoo, M.S., Shin, J.S., Choi, H.E., et al. Fucosterol isolated from Undaria pinnatifida inhibits lipopolysaccharide-induced production of nitric oxide and pro-inflammatory cytokines via the inactivation of nuclear factor-κB and p38 mitogen-activated protein kinase in RAW264.7 macrophages Food Chem. 135(3), 967-975 (2012).
[4]. Caamal-Fuentes, E., Moo-Puc, R., Freile-Pelegrin, Y., et al. Cytotoxic and antiproliferative constituents from Dictyota ciliolata, Padina sanctae-crucis and Turbinaria tricostata Pharm. Biol. 52(10), 1244-1248 (2014).
[5]. Yi, Y.B., Ji, C.F., and Yue, L. Study on human promyelocytic leukemia HL-60 cells apoptosis induced by fucosterol Biomed. Mater. Eng. 24(1), 845-851 (2014).
[6]. Lee, Y.S., Shin, K.H., Kim, B.K., et al. Anti-diabetic activities of fucosterol from Pelvetia siliquosa Arch. Pharm. Res. 27(11), 1120-1122 (2004).