Proteasome-inhibitory and cytotoxic constituents of Garcinia lateriflora: absolute configuration of caged xanthones.
A new biflavonoid (1), a new xanthone enantiomer (2), five new caged xanthones (3-7), and several known compounds were isolated from the stem bark of Garcinia lateriflora, collected in Indonesia. The structures of the new compounds were determined by analysis of spectroscopic data, and the absolute configuration of the caged xanthones was shown for the first time at carbons 5, 7, 8, 8a, 10a, and 27, by analysis of COSY and NOESY NMR and ECD spectra. The biflavonoids exhibited proteasome inhibitory activity, and the known compound, morelloflavone (8) was found to have the greatest potency (IC(50) = 1.3 muM). The caged xanthones were cytotoxic towards HT-29 cells, with the known compound, morellic acid (10) being the most active (ED(50) = 0.36 muM). However, when tested in an in vivo hollow fiber assay, it was inactive at the highest dose tested (20 mg/kg).
Ren
Yulin
Y
Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio 43210, USA.
Lantvit
Daniel D
DD
Carcache de Blanco
Esperanza J
EJ
Kardono
Leonardus B S
LB
Riswan
Soedarsono
S
Chai
Heebyung
H
Cottrell
Charles E
CE
Farnsworth
Norman R
NR
Swanson
Steven M
SM
Ding
Yuanqing
Y
Li
Xing-Cong
XC
Marais
Jannie P J
JP
Ferreira
Daneel
D
Kinghorn
A Douglas
AD