Effects of covalent conjugation with quercetin and its glycosides on the structure and allergenicity of Bra c p from bee pollen.

Profilin family members are potential pan-allergens in foods, presenting public health hazards. However, studies on the allergenicity modification of profilin allergens are limited. Herein, quercetin and its glycosides (isoquercitrin and rutin) were applied to modify the allergenicity of a profilin allergen (Bra c p) from Brassica campestris bee pollen. Results showed that only quercetin can be closely covalently bound to Bra c p among the three, and the binding site was located at the Cys98 residue. After covalently conjunction, the relative content of α-helix structure in Bra c p was reduced by 40.05%, while random coil was increased by 42.89%; moreover, the Tyr and Phe residues in Bra c p were masked. These structural changes could alter the conformational antigenic epitopes of Bra c p, resulting in its allergenicity reduction. Our findings might provide a technical foundation for reducing the allergenicity of bee pollen and foods containing profilin family allergens.

Natural Carotenoids as Neuroprotective Agents for Alzheimer's Disease: An Evidence-Based Comprehensive Review.

Alzheimer's disease (AD) is a neurodegenerative disorder of an ever-increasing aging population with various pathological features such as ß-amyloid (Aß) aggregation, oxidative stress, an impaired cholinergic system, and neuroinflammation. Several therapeutic drugs have been introduced to slow the progression of AD by targeting the above-mentioned pathways. In addition, emerging evidence suggests that naturally occurring compounds have the potential to serve as adjuvant therapies to alleviate AD symptoms. Carotenoids, a group of natural pigments with antioxidative and anti-inflammatory properties, are proposed to be implicated in neuroprotection. To obtain a comprehensive picture of the effect of carotenoids on AD prevention and development, we critically reviewed and discussed recent evidence from in silico, in vitro, in vivo, and human studies in databases including PubMed, Web of Science, Google Scholar, and Cochrane (CENTRAL). After analyzing the existing evidence, we found that high-quality randomized controlled trials (RCTs) are lacking to explore the neuroprotective role of carotenoids in AD pathogenesis and symptoms, especially carotenoids with solid preclinical evidence such as astaxanthin, fucoxanthin, macular carotenoids, and crocin, in order to develop effective preventive dietary supplements for AD patients to ameliorate the symptoms. This review points out directions for future studies to advance the knowledge in this field.