ABSTRACT
Anthocyanins are colored water-soluble plant pigments. Upon consumption, anthocyanins are quickly absorbed and can penetrate the blood-brain barrier (BBB). Research based on population studies suggests that including anthocyanin-rich sources in the diet lowers the risk of neurodegenerative diseases. The copigmentation caused by copigments is considered an effective way to stabilize anthocyanins against adverse environmental conditions. This is attributed to the covalent and noncovalent interactions between colored forms of anthocyanins (flavylium ions and quinoidal bases) and colorless or pale-yellow organic molecules (copigments). The present work carried out a theoretical study of the copigmentation process between cyanidin and resveratrol (CINRES). We used three levels of density functional theory: M06-2x/6-31g+(d,p) (d3bj); ωB97X-D/6-31+(d,p); APFD/6-31+(d,p), implemented in the Gaussian16W package. In a vacuum, the CINRES was found at a copigmentation distance of 3.54 Å between cyanidin and resveratrol. In water, a binding free energy ∆G was calculated, rendering -3.31, -1.68, and -6.91 kcal/mol, at M06-2x/6-31g+(d,p) (d3bj), ωB97X-D/6-31+(d,p), and APFD/6-31+(d,p) levels of theory, respectively. A time-dependent density functional theory (TD-DFT) was used to calculate the UV spectra of the complexes and then compared to its parent molecules, resulting in a lower energy gap at forming complexes. Excited states' properties were analyzed with the ωB97X-D functional. Finally, Shannon aromaticity indices were calculated and isosurfaces of non-covalent interactions were evaluated.
Subject(s)
Anthocyanins , Density Functional Theory , Resveratrol , Anthocyanins/chemistry , Resveratrol/chemistry , Thermodynamics , Models, Molecular , Water/chemistryABSTRACT
Abstract Compound usnic acid (1), isolated from lichen Evernia prunastri (Cajamarca-Peru) and the synthesis and characterization of its acyl-hydrazone (2), from the condensation reaction between usnic acid and isoniazid in an ethanol solution under reflux, giving an overall yield of 95%, were evaluated. Both compounds were evaluated and compared with isoniazid according to its anti-Mycobacterium tuberculosis activity based on the tetrazolium microplate assay (TEMA). Compound 1 had MIC (minimal inhibitory concentration) value of 16.0 μg/mL in each test of H37Rv (susceptible type), TB DM 97 (resistant wild type) and MDR DM 1098 (multi drug resistances type) strains. In similar tests, compound 2 MIC values were 2.0, 64.0 and 64.0 μg/mL respectively.
Resumen Se evaluó el ácido úsnico (1), aislado del liquen Evernia prunastri (Cajamarca-Perú), producto natural conocido por sus actividades biológicas, y, del mismo modo, se evaluó la síntesis de su derivado acil-hidrazona (2), obtenido a partir de una reacción de condensación entre el ácido úsnico y la isoniazida en solución etanólica a reflujo, con un rendimiento global de 95%. Ambos compuestos fueron evaluados y comparados con la isoniazida según su actividad anti-Mycobacterium tuberculosis basada en el ensayo de susceptibilidad mediante el método TEMA. Los resultados mostraron que el compuesto 1 presenta valores de MIC de 16,0 μg/mL frente a las cepas H37Rv, TB DM 97 y MDR DM 1098, mientras que el compuesto 2 presenta valores de MIC de 2,0; 64,0 y 64,0 μg/mL respectivamente.
Resumo Foi avaliado o ácido úsnico (1), um produto natural conhecido pelas suas atividades biológicas, isolado a partir do líquen Evernia prunastri (Cajamarca-Peru), assim mesmo foi avaliada a síntese do seu derivado, a acil-hidrazona (2), obtido a partir de uma reação de condensação com refluxo entre o ácido úsnico e a isoniazida em solução etanólica, com um rendimento global de 95%. A atividade anti-Mycobacterium tuberculosis de ambos compostos foi avaliada e comparada com a isoniazida mediante testes de sensibilidade obtidos pelo método TEMA. Os resultados mostraram que o composto 1 apresenta o valor de MIC de 16,0 μg/mL contra variedades H37Rv, TB DM 97 e MDR DM 1098; enquanto que para o composto 2 os valores de MIC são de 2,0; 64,0 e 64,0 μg/mL, respectivamente.
