Chemical Constituents of the Leaves of Desmos cochinchinensis var. fulvescens Ban by Tung-Ying Wu a ), Yuan-Bin Cheng a ), Fu-Ting Cheng a ), Yu-Ming Hsu a ), Thang Tran Dinh b ), Fang-Rong Chang* a ), and Yang-Chang Wu* a ) c ) d ) e ) a )Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (phone: þ 886-7-312-1101 ext. 2162; fax: þ 886-07-311-4773; e-mail: aaronfrc@kmu.edu.tw) b )Department of Chemistry, Vinh University, Vinh 42000, Vietnam c )School of Pharmacy, College of Pharmacy, China Medical University, Taichung 40402, Taiwan d ) Chinese Medicine Research and Development Center, China Medical University Hospital, Taichung 40402, Taiwan e )Center for Molecular Medicine, China Medical University Hospital, Taichung 40402, Taiwan A phytochemical investigation of MeOH extract of Desmos cochinchinensis var. fulvescens Ban afforded two new compounds, 1b,7a-dihydroxyeudesman-4-one (1) and 5aH-megastigm-7-ene- 3a,4a,6b,9-tetrol (2), together with nine known terpenoids. The structures of the new compounds were elucidated by 1D- and 2D-NMR spectroscopic analysis. Their relative configurations were assigned by NOESY experiments. Introduction. – The genus of Desmos , belonging to the family Annonaceae, is a climbing or upright shrub. About 42 species have been found in Oceania and in tropic and subtropic Asia. The phytochemical studies of genus Desmos resulted in the isolation of triterpenoids [1], alkaloids [2 – 3], chalcones [4 – 6], flavonoids, and a cyclopeptide [7]. Some of these components showed cytotoxic [7], antiplasmodial [2], and anti-HIV [8] activities. In some folk-medicine records, D. cochinchinensis was used to treat malaria in the south part of China. D. cochinchinensis var. fulvescens Ban is a rare species growing in the coastal forest of Vietnam and has never been phytochemi- cally studied. In our preliminary bioactivity test, the MeOH extract of D. cochinchi- nensis var. fulvescens not only showed cytotoxic activities against Hep G2, Hep 3B, and MCF-7 cell lines (all IC 50 values < 20 mg/ml) but also exhibited anti-inflammatory effects in fMLP-induced superoxide and elastase-release assays. Herein, we report the isolation and structure elucidation of two new natural products, 1b,7a-dihydroxyeudes- man-4-one (1) and 5aH-megastigm-7-ene-3a,4a,6b,9-tetrol (2) , along with nine known sesquiterpenes, i.e. , selin-4(15)-ene-1b,11-diol ( 3) [9] [10], 4-epicryptomeridiol (4), cryptomeridiol (5) [11], 11-hydroxy-4a-methoxyselinane (6) [12], 4b,10a-dihydrox- yaromadendrane (7), 4b,10b-dihydroxyaromadendrane (8) [13], pipelol A (9) [14], 10b-hydroxyisodauc-6-en-14-al (10) [15], and alismoxide (11) [16] from an MeOH extract of the leaves of D. cochinchinensis var. fulvescens Ban. The structures of all compounds were established by interpretation of their spectroscopic data, especially 2D-NMR. The relative configurations of new structures were assigned by NOESY experiments. Helvetica Chimica Acta – Vol. 97 (2014) 1714  2014 Verlag Helvetica Chimica Acta AG, Zürich