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- b utyl-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.