Analysis and identification of phenolic compounds with antiproliferative activity from Chinese olive (Canarium album L.) fruit extract by HPLC-DAD-SPE-TT-NMR.

Chinese olives (Canarium album L.) are rich in phenolic compounds, exhibiting a broad spectrum of potential clinical applications. This study is the first report on the isolation and elucidation of bioactive compounds with high antiproliferative activity from the ethyl acetate fraction of a Chinese olive fruit methanolic extract (CO-EtOAc). We used the WST-1 assay to determine which subfractions of CO-EtOAc had significant antiproliferative activity using the murine colon cancer cell line CT26. Subsequently, the functional compounds were characterized by the hyphenated technique and high-performance liquid chromatography-diode array detector-solid phase extraction-transfer tube-nuclear magnetic resonance (HPLC-DAD-SPE-TT-NMR). Thirteen phenolic constituents were identified from the antiproliferation-enhancing subfractions of CO-EtOAc, including two new compounds, 2,4-didehydrochebulic acid 1,7-dimethyl ester (5) and 1-hydroxybrevifolin (7), which were further purified and found to exhibit marked antiproliferative activity. Chebulic acid dimethyl ester (2), which was isolated from C. album for the first time, also possessed antiproliferative activity.