Two New Sesquiterpenes from Leaves of Nicotiana tabacum and their Antibacterial Activity

Two new sesquiterpenes, nicosesquites A and B ( 1 and 2 ) as well as four known sesquiterpenes ( 3–6 ) were isolated from the leaves of Nicotiana tabacum. Their structures were determined mainly by spectroscopic methods, including extensive 1D and 2D NMR techniques. Compounds 1 and 2 were tested for their antimethicillin-resistant Staphylococcus aureus (anti-MRSA) activity. The results revealed that compounds 1 and 2 showed good inhibition with IZD of 13.4 ± 2.2, and 14.6 ± 2.4 mm, respectively. In addition, compounds 1 and 2 also have weak floral fragrances, and they have the potential value for use as an essence for cigarettes.