Five 3-formyl-2-arylbenzofuran derivatives, including three new compounds (1-3) and two known analogues (4-5), were identified from the 95% EtOH extract of Itea yunnanensis. Extensive spectroscopic analyses were performed for the structure elucidation of all new benzofurans, and single-crystal X-ray diffraction analyses were further employed for the structure verification of iteafuranals C (1) and D (2). In MTT assay, iteafuranal E (3) and iteafuranal A (4) displayed significant growth inhibition effect on SK-Hep-1 cells with IC 50 values of 5.365 μM and 6.013 μM, respectively.The colony formation assay of 3 and 4 further confirmed their remarkable inhibitory effect on cell growth. Preliminary mechanism study demonstrated that 3 remarkably down-regulated the phosphorylation level of ERK, which suggested 3 could inhibit cell growth and induce apoptosis of SK-Hep-1 cells by blocking RAS/RAF/MEK/ERK signaling pathway. This study highlighted the potential of 3-fomyl-2-benzofuran derivatives as novel lead compounds to treat Hepatocellular carcinoma.

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C20H26O3, orthorhombic, P21212 (no. 18), a = 10.0361(11) Å, b = 18.542(2) Å, c = 9.7357(12) Å, V = 1811.7(4) Å3, Z = 4, R gt (F) = 0.0535, wR ref (F 2) = 0.1553, T = 273(2) K.

C18H16O8, monoclinic, P21/n (no. 14), a = 14.5762(6) Å, b = 6.6791(3) Å, c = 17.4240(7) Å, β = 103.5820(10)°, V = 1648.89(12) Å3, Z = 4, R gt (F) = 0.0436, wR ref (F 2) = 0.1218, T = 293(2) K.

C18H14O3, monoclinic, P21/n (no. 14), a = 11.115(4) Å, b = 6.878(3) Å, c = 18.024(7) Å, β = 99.964(8)°, V = 1357.1(9) Å3, Z = 4, Rgt(F) = 0.0601, wRref(F2) = 0.1892, T = 173 K.