Chitosan‐hydroxycinnamic acid conjugates: Synthesis, photostability and phytotoxicity to seed germination of barley

Abstract

Chitosan‐caffeic and chitosan‐ferulic acid conjugates are synthesized by carbodiimide method and characterized by UV, FTIR, and NMR spectroscopy. There are two obtained forms of conjugates: freshly synthesized and reconstituted freeze‐dried. A comparative study of the stability of various conjugate forms over time and under UV irradiation has been carried out. It has been shown that the absorption intensity of an aqueous solution of the freshly synthesized chitosan‐caffeic acid conjugate decrease in ~2 times during 20 weeks of storage, while the maximum rate of intensity decrease is observed during the first 40 days. The absorption intensity of the chitosan‐ferulic acid conjugate decrease by 6–7% during the entire storage period. It has been found that freeze‐dried powders of chitosan‐caffeic and chitosan‐ferulic acid conjugates are stable for at least 1 year. It has been established that freeze‐dried chitosan‐caffeic and chitosan‐ferulic acid conjugates are more stable under UV irradiation (in 4–8 and 1.4–1.9 times, respectively) compared to freshly synthesized ones. A comparative study of the influence of conjugates on barley seedlings (Hordeum vulgare L.) growth has been carried out.

Design of Highly Porous Materials Based on Chitosan/Pectin Interpolyelectrolyte Complex for Wound Healing Application

“…FTIR spectra of Chit30 acetate, original Pect, AF-Pect, and Chit30/AF-Pect (1 : 1) sponge in the range from 4,000 to 400 cm −1 are presented in Figure 3. In the spectrum of Chit30 acetate, the characteristic bands at 3,440 (O─H and N─H stretching), 2,923 and 2,886 (C─H symmetric and asymmetric stretching), 1,630 (C═O stretching vibrations, amide I), 1,335 (C─N stretching, amide III), and 1,153 and 898 cm −1 (ν as (C─O─C bridge) and C─H bending vibrations of glucopyranose ring) were detected [61,62]. In addition, three bands at 1,564, 1,411, and 1,384 cm −1 assigned to N─H bending vibrations (amide II) and the deformation of─CH 2 and CH 3 groups, respectively, were observed [62,63].…”

Chitosan-based Maillard self-reaction products: Formation, characterization, antioxidant and antimicrobial potential

“…3). (Guimarães et al, 2020;Mauricio-Sánchez et al, 2018;Nikalaichuk et al, 2022;Tran et al, 2019). In addition, the spectrum of chitosan acetate is distinguished by two strong bands at 1536 and 1404 cm − 1 .…”

“…Thus, the introduction of additional functional groups into chitosan leads to enhance its antiviral and antibacterial activity, increase its immunostimulatory, adjuvant, adaptogenic, antihypoxic, radioprotective and hemostatic effects (Bakshi et al, 2020;Muzzarelli et al, 2014;Verlee et al, 2017), as well as improve its antioxidant (Alexandrova et al, 2016) and mucoadhesive (Ways et al, 2018) properties. The conjugation of chitosan is most often carried out by the standard carbodiimide method (Nikalaichuk et al, 2022), the drawback of which is the high cost of reagents for carbodiimide activation of functional groups. At the same time, carbonyl-amine interactions can occur under the influence of temperature, for example, when amino acids are heated with sugars, i.e.…”