Influence of Copigmentation on the Stability and Oxidative Stress of Anthocyanins from Purple Corn and Camu-Camu

Alzheimer's disease (AD) involves oxidative stress in brain tissue, creating a need for stable neuroprotective agents. Anthocyanins are potent antioxidants, but they are highly susceptible to degradation. This study evaluated anthocyanins from purple corn (PCA) and camu-camu (CCA) and the copigmentation effects of the phenolic acids cinnamic (C), ferulic acid (F), resveratrol (R) and polyaspartic acid (P) on the stability and neuroprotective capacity of these anthocyanins. HPLC-MS analysis identified twelve anthocyanins in PCA, including a new one (petunidin sophoroside). Copigmentation was assessed via UV-Vis spectroscopy, FTIR, TG, and stability tests at pH 7.4. The TBARS assay evaluated protection against oxidative stress in brain tissue. Copigment R provided the strongest hyperchromic effect for PCA, while P was most effective for CCA. TG analysis showed that copigmentation with R significantly improved the thermal and pH stability of both anthocyanin sources. All single copigmented samples showed improved stability of anthocyanins in physiological conditions. Furthermore, R-copigmented anthocyanins exhibited the most potent neuroprotective effects, significantly inhibiting lipid peroxidation. Thus, copigmentation, particularly with R, is a highly effective strategy for stabilizing anthocyanins and enhancing their potential as neuroprotective agents against oxidative stress.