The new isoflavone glucoside vavain 3'-O-β-D-glucoside (1) and its aglycon, vavain (2), were isolated from the bark of Ceiba pentandra, together with the known flavan-3-ol, (+)-catechin. These novel structures were elucidated by one- and two-dimensional NMR experiments and by MS, IR, and UV spectroscopy as 5-hydroxy-7,4',5'-trimethoxyisoflavone 3'-O-β-D-glucoside (1) and 5,3'-dihydroxy-7,4',5'-trimethoxyisoflavone (2), respectively. The compounds were isolated following bioactivity-directed fractionation, using a cyclooxygenase-1-catalyzed prostaglandin biosynthesis assay in vitro, in which compounds 1 and 2 and (+)-catechin exhibited IC50 values of 381, 97, and 80 μM, respectively (standard: indomethacin, IC50 1.1 μM). When further tested for their inhibitory effects on cyclooxygenase-2-catalyzed prostaglandin biosynthesis, 1 and 2 were found to be inactive (IC50 > 1200 and > 900 μM, respectively).
Ceiba pentandra, catechin, cyclooxygenase 1, cyclooxygenase 2, flavanol derivative, indometacin, isoflavone derivative, plant extract
NCBI PubMed ID: 9461647Publication DOI: 10.1021/np970198+Journal NLM ID: 7906882Publisher: American Society of Pharmacognosy
Correspondence: Bohlin L
Institutions: Division of Pharmacognosy, Department of Pharmacy, Biomedical Centre, Uppsala University, Uppsala, Sweden
Methods: 13C NMR, 1H NMR, IR, FAB-MS, inhibition studies, TLC, acid hydrolysis, UV, extraction, optical rotation measurement, HMBC, DEPT, COSY, MPLC, HSCCC
Found