Two new sesquiterpenoids and two new diterpenoids from Croton lauioides with anti-inflammatory and cytotoxic activities.

Abstract

Two new tropolone-bearing sesquiterpenoids (1-2), two new dolabrane-type diterpenoids (3-4) along with eight known compounds as ionone-type sesquiterpenoid (5), oleanane triterpenoid (6), vanillin and its derivative (7-8), neolignan (9), two lignans (10-11), flavanonol glycoside (12) were isolated from whole plants of Croton lauioides Radcl.-Sm. & Govaerts. The structures of all isolated compounds were elucidated by extensive spectral data including 1D, 2D NMR, HR-ESI-MS, and by comparing their NMR data with those of previously reported compounds. The experimental and calculated electronic circular dichroism data were used to determine their absolute configurations. All new compounds (1-4) were evaluated for their anti-inflammatory activity on LPS-induced RAW264.7 macrophages, and cytotoxicity against five human cancer cell lines (HepG2, A-549, MDA-MB-231, HL-60, and SW-480). Compound 2 showed signicant inhibitory activity against NO production with an IC₅₀ value of 16.41 ± 0.48 μM, better than that of L-NMMA (positive control, IC₅₀ = 42.83 ± 0.80 μM), while compound 1 exhibited comparable anti-inflammatory activity with IC₅₀ value of 47.50 ± 0.46 μM. Furthermore, compound 1 was also found to display selective cytotoxicity against human cancer cell line HepG2 with an inhibition rate of 79.09 % at 40.0 μM.