Probing the interaction of caffeic acid with ZnO nanoparticles

Abstract

The binding of ZnO nanoparticles (NPs) and caffeic acid (CFA) was investigated using fluorescence quenching, UV/vis absorption spectrscopy, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and dynamic light scattering (DLS) at different temperatures. The study results indicated fluorescence quenching between ZnO NPs and CFA rationalized in terms of a static quenching mechanism or the formation of non-fluorescent CFA-ZnO. From fluorescence quenching spectral analysis, the binding constant (K(a)), number of binding sites (n) and thermodynamic properties were determined. Values of the quenching (K(SV)) and binding (K(a)) constants decrease with increasing temperature and the number of binding sites n = 2. The thermodynamic parameters determined using Van't Hoff equation indicated that binding occurs spontaneously involving the hydrogen bond, and van der Waal's forces played a major role in the reaction of ZnO NPs with CFA. The FTIR, TEM and DLS measurements also indicated differences in the structure, morphology and size of CFA, ZnO NPs and their corresponding CFA-ZnO.

Antitumor and Radiosensitizing Effects of Zinc Oxide-Caffeic Acid Nanoparticles against Solid Ehrlich Carcinoma in Female Mice

“…FT-IR spectra of CA, handling KBr discs, revealed that the spectral assignments were carried out based on data from the literature. [28][29][30][50][51][52] The bands at: 3431 and 3350 cm −1 are appointed to -O-H stretching vibration of OH aromatic, 3231 cm −1 is appointed to =C-H stretching vibration of phenol ring, 3057, 3026, and 2988 cm −1 are appointed to C-H stretching vibration of phenol ring, 2837-2565 cm −1 are appointed to -O-H stretching vibration of COOH (acid), 1645 cm −1 is appointed to -C=O stretching vibration of -O-C=O, 1526 and 1451 cm −1 are appointed to C=C stretching vibration of phenol ring, 1354 and 1218 cm −1 are appointed to -O-H in-plane bending vibration of phenolic OH, 972 cm −1 is appointed to =C-H out-plane bending vibration of Ar-C=C, 851 cm −1 is appointed to out-plane bending vibration of CH in the aromatic ring with 2 neighboring hydrogen atoms, 816 cm −1 is appointed to in-plane bending vibration of C=O, 698 cm −1 is appointed to outplane bending vibration of C=O. [50][51][52] FT-IR spectra of ZnO NPs demonstrated that the distinguished bands detected around 471 and 521 cm −1 resulted from the stretching vibration of Zn-O bond in tetrahedral coordination.…”

“…26 Moreover, ZnO NPs were conjugated with caffeic acid. [27][28][29] Caffeic acid (CA, 3,4-dihydroxyphenyl-2-propenoic acid or 3,4-dihydroxycinnamic acid, C 9 H 8 O 4 ; molecular weight (M.wt) 180. 16) is a near molecular analog of dihydroxyphenylalanine (DOPA).…”

“…26 Moreover, ZnO NPs were conjugated with caffeic acid. 27-29 Caffeic acid (CA, 3,4-dihydroxyphenyl-2-propenoic acid or 3,4-dihydroxycinnamic acid, C 9 H 8 O 4 ; molecular weight (M.wt) 180.16) is a near molecular analog of dihydroxyphenylalanine (DOPA). 27 CA is a natural phytochemical phenolic constituent in plants found in high concentrations in coffee, wine, and tea as well as in propolis.…”

Size Dependent Uptake and Hemolytic Effect of Zinc Oxide Nanoparticles on Erythrocytes and Biomedical Potential of ZnO-Ferulic acid Conjugates

“…On the other hand, ZnONPs with FA cause minimal DNA damage. Previous study reported that the interaction of ZnONPs with caffeic acid, which is a precursor of FA 43 , in presence of FA could results in the formation of ZnONPs-ferulate conjugate through the interaction with FA which alleviate its affinity to DNA and protect the cell from DNA damage and cell death. Raman spectra carried out to ascertain the effect of ZnONPs and ZnONPs with FA.…”

Polydimethylsiloxane Membranes Incorporating Metal–Organic Frameworks for the Sustained Release of Antibacterial Agents

“…14 The other absorption band peaks of CA in the region of 1600−1700 cm −1 were due to the CO stretching vibration, and a strong and isolated peak at 1447 cm −1 was due to the CC−C aromatic ring stretching. 53 The two parallel peaks located at 1200−1280 cm −1 represented the bending vibration of the OH group on the benzene ring. 54,55 In CA@Ag@CD-MOF, the bending vibration of the OH group on the CA benzene ring and the CC−C aromatic ring stretching of the aromatic ring could be observed and a certain deviation appeared, while the partial weakening of most characteristic peaks of CA may be due to the presence of CA in the cavity of the CD-MOF and thus being covered by CD-MOF.…”