Evaluation of the antioxidant activities of fatty polyhydroquinolines synthesized by Hantzsch multicomponent reactions

• Published in: RSC advances Vol. 9; no. 43; pp. 24688 - 24698
• Main Authors: Brinkerhoff, Rafael Centuriao, Santa-Helena, Eduarda, do Amaral, Paulo C, Cabrera, Diego da C, Ongaratto, Renata F, de Oliveira, Patrick M, Da Ros Montes D'Oca, Caroline, Neves Gonçalves, Carla A, Maia Nery, Luiz E, Montes D'Oca, Marcelo G
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 08-08-2019; The Royal Society of Chemistry
• Subjects: Additives; Alcohol; Antioxidants; Aromatic compounds; Chemistry; Derivatives; Fatty acids; Nitrogen dioxide; NMR; Nuclear magnetic resonance; Oleyl alcohol; Substitutes
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c9ra04758a

Polyhydroquinolines (PHQs) are the unsymmetrical Hantzsch derivatives of 1,4-dihydropyridines with several biological applications. In this work, new fatty 2- and 3-substituted PHQ derivatives from different fatty acids and fatty alcohol feedstocks were synthesized at good yields
via
a four-component reaction (4CR). The antioxidant activities of fatty PHQs were investigated using three different antioxidant methods. The experiments showed that the compounds derived from 2-nitrobenzaldehyde and fatty palmitic (C16:0) and oleic (C18:1) chains showed better antioxidant activity. This revealed that combining the
ortho
NO
2
group in the aromatic ring with the insertion of fatty chains in the PHQ core contributed to the antioxidant activity. However, among all the fatty PHQs tested, the fatty 2-substituted compound derived from oleyl alcohol and 2-nitrobenzaldehyde showed the highest antioxidant activity (EC
50
, 2.11-4.69 μM), which was similar to those of the antioxidant standards butylated hydroxytoluene (EC
50
, 1.98-6.47 μM) and vitamin E (EC
50
, 1.19-5.88 μM). In addition, this lipophilic compound showed higher antioxidant activity than the antihypertensive drug nifedipine (EC
50
, 49.25-126.86 μM). These results indicate that the new fatty PHQs may find novel applications as antioxidant additives.
The insertion of a fatty long chain into polyhydroquinoline (PHQ) core contributes to antioxidant potential, the new fatty PHQs showed activities similar to commercial antioxidants.