molecules Article New Acetophenones and Chromenes from the Leaves of Melicope barbigera A. Gray Kim-Thao Le 1, Jan J. Bandolik 2 , Matthias U. Kassack 2 , Kenneth R. Wood 3 , Claudia Paetzold 4,5, Marc S. Appelhans 4 and Claus M. Passreiter 1,* 1 Institute of Pharmaceutical Biology and Biotechnology, Heinrich-Heine-University Duesseldorf, 40225 Duesseldorf, Germany;
[email protected] 2 Institute for Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-University Duesseldorf, 40225 Duesseldorf, Germany;
[email protected] (J.J.B.);
[email protected] (M.U.K.) 3 National Tropical Botanical Garden, 3530 Papalina Road, Kalaheo, HI 96741, USA;
[email protected] 4 Institute of Systematics, Biodiversity and Evolution of Plants, Georg-August-University Goettingen, 37073 Goettingen, Germany;
[email protected] (C.P.);
[email protected] (M.S.A.) 5 Division Botany and Molecular Evolution, Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, 60325 Frankfurt am Main, Germany * Correspondence:
[email protected]; Tel.: +49-211-81-14472 Abstract: The dichloromethane extract from leaves of Melicope barbigera (Rutaceae), endemic to the Hawaiian island of Kaua’i, yielded four new and three previously known acetophenones and 2H-chromenes, all found for the first time in M. barbigera. The structures of the new compounds obtained from the dichloromethane extract after purification by chromatographic methods were unambiguously elucidated by spectroscopic analyses including 1D/2D NMR spectroscopy and HRESIMS. The absolute configuration was determined by modified Mosher’s method. Compounds 2, 4 and the mixture of 6 and 7 exhibited moderate cytotoxic activities against the human ovarian Citation: Le, K.-T.; Bandolik, J.J.; cancer cell line A2780 with IC50 values of 30.0 and 75.7 µM for 2 and 4, respectively, in a nuclear Kassack, M.U.; Wood, K.R.; Paetzold, shrinkage cytotoxicity assay.