Structure elucidation of two new bisbenzylisoquinoline alkaloids and NMR assignments of the alkaloids from the fruits of Tiliacora racemosa

Besides three known biphenyldibenzodioxinbisbenzylisoquinoline alkaloids, two novel alkaloids of the same group have been isolated from the fruits of Tiliacora racemosa. The structures of these new compounds designated tiliaimine and nordinklacorine were established on the basis of 1D and 2D NMR spectroscopy, including COSY, TOCSY, ROESY, HMBC and HSQC experiments. Preliminary antibacterial activity studies on the known compounds (tiliarine, 2′-nortiliacorinine, 2′-nortiliacorine) from the fruits of the plant showed strong activity against three bacterial strains viz. Escherichia coli strain VT3 (Verotoxigenic E.coli), Staphylococcus aureus ATCC 25923 and Bacillus subtilis ATCC 6623 but were inactive against the strains Vibrio cholerae O1 (NB2) and Pseudomonas aeruginosa ATCC 15442. Copyright © 2010 John Wiley & Sons, Ltd.