Sesquiterpenoids and Diterpenoids from the Flowers of Nicotiana tabacum L. and Their Antifungal Activity

Abstract

Two new guaiane-type sesquiterpenoids, nicotiasesquiterpenes A (1) and B (2), and seven known cembrane-type diterpenoids (3−9), were isolated from glandular trichome secretions of fresh flowers of Nicotiana tabacum L. These new chemical structures were established by extensive analyses of HRESIMS and 1D and 2D NMR data, while the other structures were elucidated by comparison of 1D NMR data with those reported in the literature. All of the isolated compounds were tested for their antiphytopathogenic fungal activity against Valsa mali var. mali, Alternaria porri, and Botrytis cinerea at a concentration of 10 μg/mL. Compounds 3, 4, and 5 exhibited medium antifungal effects against Valsa mali var. mali, with inhibitory rates of 45.3±16.1, 53.4± 4.6, and 40.1±4.5%, respectively, while the other compounds showed only insignificant activities.