New biphenyl derivatives from the leaves of Nicotiana tabacum and their cytotoxic activity

- Three new (1-3) biphenyls were isolated from Nicotiana tabacum.
- Four known (4-7) biphenyls were also obtained from the title plant.
- 1-7 were tested for their cytotoxicity.
- 1-7 showed moderate or weak activities with IC50 values ranging from 2.8 to 9.4 μM.

With the aim of searching for new bioactive metabolites from medicinal plants, three new biphenyls, tababiphenyls G-I (1-3), together with four known ones (4-7) were isolated from the leaves of Nicotiana tabacum. Their structures were elucidated by extensive NMR and MS spectroscopic analyses. All the isolated compounds were evaluated for their cytotoxicity against NB4, A549, SHSY5Y, PC3, and MCF7 human cancer cell lines, and some of them showed moderate inhibitory activities against several human tumor cell lines with IC50 values ranging from 2.8 to 9.4 μM.