Magdy M. D. Mohammed, Nabaweya A Ibrahim, Ming Chen and Lin Zhai
Leaves of Ixora undulata Roxb. were investigated phytochemically for the first time for its alkaloidal content, which resulted in the isolation of a novel unusual thiazepine alkaloid glycoside identified as 7-[(β-D-glucopyranosyl)oxy]-6-hydroxy-2-methoxy-4,5-dihydro-1,3-thiazepine and trivially named as Rubiothiazepine. Its structure was determined on the basis of 1D and 2D NMR (1H-, 13C-NMR, 1H-1H COSY, 1H-13C HETCOR, 1H-13C HMBC, 1H-15N HMBC and DIFNOE), high resolution ESI-CID-MS/MS, UV and IR spectroscopy. The isolated compound showed cytotoxic activity against EL4 (Murine Leukemia) with IC50 >100 μg/mL, and also showed cytotoxic and HIV-1 activity against MT-4 and HIV-1IIIB with CC50 >100 μg/mL and EC50 >100 μg/mL, respectively