Antivirus isoindolinone alkaloids with rare oxocyclopenta[f]isoindole frameworks isolated from the stems of flue cured tobacco

Abstract Background Since Nicotiana tabacum (tobacco) has important significance to humans for their medicinal uses, find antivirus activities inhibitors from tobacco, increase its value, and comprehensive utilization of by-products, our group had investigated the chemical constituents stems Y-202, a cultivar tobacco which high resistance mosaic virus (TMV). Results Four new isoindolinone-type alkaloids, nicoisoindoles A–D ( 1 – 4 ), along with four known isoindole derivatives 5 8 ) were isolated. Compounds represent subclass isoindolinone alkaloids rare cyclopenta[ f ]isoindole-1-one frameworks. Among them, nicoisoindole C 3 possesses an unusual N -2-(5-methoxy-6-methylpyridin-2-yl) ethyl moiety, while D novel -(3-methyl-6-oxo-1,6-dihydropyridin-2-yl)methyl substituent. Interestingly, compounds , 3, showed anti-TMV inhibition rates 43.8%, 58.8%, 67.8% at concentration 20 ?M, IC 50 values 23.6, 19.5 15.4 respectively, even more potent than that positive control. Conclusions The successful isolation structure identification oxocyclopenta[ ]isoindole-1-ones provide materials screening inhibitors, contribute development waste cultivation. Graphical