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The flavonoid-rich natural products exert a wide range of pharmacological properties. This investigation aimed at obtaining extracts from tobacco cultivars and waste enriched with flavonoids and purified from nicotine and phenolic acids, and evaluating their radical scavenging potential. Extraction with a mixture of ethyl acetate-methanol (1:1, v/v) was employed resulting in 100% yield for flavonoids and 36% yield for phenolic acids. The crude extracts were purified using preparative column chromatography on silica gel. The content of flavonoids in the purified extracts varied from 8.8 ± 1.1% to 14.3 ± 1.8%. Nicotine was not detected in amounts higher than 0.3 μg mL(-1). The content of phenolic acids was lower than 1.0%. The radical scavenging potential of extracts from tobacco cultivars exhibited values from IC50 = 35.0 ± 3.1 to 64.6 ± 7.5 μg mL(-1). The extracts obtained by the proposed procedure are enriched with flavonoids with high radical scavenging potential and are purified from nicotine and phenolic acids. They can be regarded as potential biopharmaceuticals.

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Abstract:The N-acyliminium intermediates of 3,4-dihydroisoquinoline and salts of isoquinoline with acyl chlorides were successfully used as amidoalkylating reagents toward synthesis of heterocyclic aromatics as indole, pyrrole, thiophene and pyrazine.

A number of 1-substituted 3,4-dihydro-9H-β-carboline derivatives (4) with high purity and yields have been synthesized by treating of tryptamine (1) with carboxylic acids (2) in polyphosphoric acid. 3,4-Dihydro-9H-β-carbolines (4) were successfully transformed to 1,2,3,4-tetrahydro-9H-β-carbolines (5) and 9H-β-carbolines (6).