ABSTRACT
A new bis-aporphine alkaloid, cerasoidine (1), was isolated from the root extract of Polyalthia cerasoides together with the known bis-aporphine bidebiline E (2) during screening for compounds with Wnt signal inhibitory activities. The structure of cerasoidine (1) was established by X-ray analysis and shown by chiral HPLC analyses and electronic circular dichroism to be a 57:43 mixture of R(-)- and S(+)-atropisomers. Bidebiline E (2) exhibited inhibition of transcriptional activity of TCF/ß-catenin with an IC50 value of 20.2 µM and was also found to inhibit Wnt signaling by decreasing nuclear ß-catenin.
Subject(s)
Alkaloids/isolation & purification , Aporphines/isolation & purification , Aporphines/pharmacology , Polyalthia/chemistry , Wnt Proteins/drug effects , Alkaloids/chemistry , Alkaloids/pharmacology , Aporphines/chemistry , Humans , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Plant Roots/chemistry , T Cell Transcription Factor 1/antagonists & inhibitors , Thailand , beta Catenin/antagonists & inhibitorsABSTRACT
The Wnt signal pathway modulates numerous biological processes, and its aberrant activation is related to various diseases. Therefore, inhibition of the Wnt signal may provide an effective (or efficient) strategy for these diseases. Cell-based luciferase assay targeting the Wnt signal (TOP assay) revealed that Hibiscus ficulneus extract inhibited the Wnt signal. The activity-guided isolation of the MeOH extract of H. ficulneus stems yielded four known (1-4) lignans along with myriceric acid (5). Compounds 1-4 potently inhibited the Wnt signal with TOPflash IC50 values of 1.0, 4.5, 6.3, and 1.9 µM, respectively. Compound 1 exhibited cytotoxicity against both Wnt-dependent (HCT116) and Wnt-independent (RKO) cells. Western blot analysis showed that 1 decreased the expression of full, cytosolic and nuclear ß-catenin along with c-myc in STF/293 cells. Our results suggested that 1 may have inhibited the Wnt signal by decreasing ß-catenin levels.
