10.

Chemical Constituents from the Roots of Clausena excavata and Their Cytotoxicity

Tawanun Sripisut, Sarot Cheenpracha, Thunwadee Ritthiwigrom, Uma Prawat, Surat Laphookhieo

Natural Products Research Laboratory, School of Science, Mae Fah Luang University, Tasud, Muang, Chiang Rai 57100, Thailand

School of Science, University of Phayao, Maeka, Muang, Phayao 56000, Thailand

Department of Chemistry, Faculty Science, Chiang Mai University, Sutep, Muang, Chiang Mai, 50200, Thailand

Laboratory of Natural Products Research Faculty of Science and Technology, Phuket Rajabhat University, Rassada, Muang, Phuket 83000, Thailand

Abstract: Six coumarins (1-6) and twelve alkaloids (7-18) were isolated from the roots of Clausena excavata. Their structures were elucidated on the basis of spectroscopic methods. This is the first report on the isolation of compounds 1, 7 and 17 from C. excavata. Compound 1 is also the first example of an unsymmetrical dimer coumarin isolated from Clausena species. The completed assignment of 13C NMR spectral data of 1 as well as HMBC spectral data is also reported here for the first time. Compounds 2-7, 11-16 and 18 were evaluated for their cytotoxicity against three human cancer cell lines, oral cavity cancer (KB), breast cancer (MCF7) and small cell lung cancer (NCI-H187). The results showed that compounds 4, 11 and 18 exhibited highest cytotoxicity against KB, MCF7 and NCI-H187 cell lines with IC 50 values of 5.95, 3.76 and 5.65 µg/mL, respectively.

Keywords: Clausena excavata ; Rutaceae; coumarins; alkaloids; cytotoxicity.