Chemical constituents in leaves and aroma products of Nicotiana rustica L. tobacco

Abstract

Nicotiana rustica L. (Aztec tobacco) is the only Nicotiana species, except common tobacco (N. tabacum L.), which is cultivated for tabacco products. The leaves of N. rustica, however, accumulate various specialized metabolites of potential interest. Therefore, the objective of this study was to evaluate certain classes of metabolites (by HPLC and GC-MS) in the leaves, the essential oil (EO), concrete and resinoid of N. rustica. Three pentacyclic triterpenes were identified in the leaves (by HPLC): betulin (252.78 µg g^-1), betulinic (182.53 µg g^-1) and oleanolic  (69.44 µg g^-1) acids. The dominant free phenolic acids in the leaves (by HPLC) were rosmarinic (4257.38 µg g^-1) and chlorogenic (1714.40 µg g^-1), and conjugated forms of vanillic (3445.71 µg g^-1), sinapic (1963.11 µg g^-1), and syringic (1784.96 µg g^-1). The major flavonoids in the leaves were luteolin (960.44 µg g^-1), apigenin (880.66 µg g^-1) and hyperosid (780.72 µg g^-1). The GS-MS profiling of the EO identified 19 components and the major ones were phytol (43.68 %), solanone (5.54 %), cis-5-butyl-4-methyldihydrofuran-2(3H)-one (5.23 %), dihydro-β-ionone (4.25 %), α-ionene (3.54 %),and β-damascenone (3.03 %). The major volatiles in the concrete were  isoamyl alcohol (28.82 %), oxynicotine (9.02 %), phytol (7.80 %), 4-mеthyl-1-penthanol (6.33 %), cotinine (5.55 %) and 3-metyl-3-penthanol (4.09 %). Resinoid composition was dominant by nicotine (39.75 %), phytol (11.23 %), eicosane (4.88 %), diethyl phthalate (4.19 %), dibutyl phthalate (3.48 %) and solanone (3.27 %). Concrete and resinoid showed weak antibacterial activity . These results create grounds for considering N. rustica as a source to obtain aroma or other bioproducts.