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Phycocyanin is a well-known natural colorant with a blue hue, utilized extensively in food and beverage applications. However, phycocyanin displays poor colloidal stability and precipitates from solution under acidic conditions, resulting in loss of blue color. In this study, gelatin (0.1%-1.0%w/v) was used to protect the colloidal and color stability of phycocyanin while also enhancing its antioxidant activity. Zeta-potential, particle size, and SEM results indicated that suitable concentrations of gelatin could form complexes with phycocyanin. This was induced by surface patch binding (SPB), making phycocyanin more electrostatically repulsive to overcome protein aggregation. Free radical scavenging experiments showed that phycocyanin-gelatin binding promoted the antioxidant activity of phycocyanin. UV–vis absorption, fluorescence spectra, and Fourier transform infrared spectroscopy results showed that gelatin could stabilizing the tertiary structure of phycocyanin and the tetrapyrrole chromophore through hydrophobic interactions and hydrogen bonds formation. Circular dichroism further revealed that gelatin could preserve the native secondary structure of phycocyanin, particularly the α-helix, thereby stabilizing the chromophore and protecting the blue color. This study showed that gelatin has a beneficial role in recovering acidified phycocyanin structure and color, facilitating the potential application of phycocyanin in foods and beverages as a natural pigment. [Display omitted] • Gelatin (Gel) was used to improve the stability of phycocyanin (PC) at pH 3.0. • Electrostatic attraction existed between PC and Gel at pH 3 due to SPB. • Gel inhibited the precipitation of PC and protected its blue color. • PC's tertiary structure and secondary structure were protected by complexation. • Electrostatic, hydrogen bond and hydrophobic interactions were main driving forces. [ABSTRACT FROM AUTHOR]

Effective treatments for non-healing burn wounds are an unmet need for 95% of burn sufferers. Approaches currently available to treat non-healing burn wounds are not satisfactory due to undesirable side-effects or expense. The anti-oxidation and antibacterial activities of walnuts are recommended for treating chronic diseases. Walnut ointment has been developed and successfully applied to treat non-healing burn wounds in our hospital for decades. We report herein a detailed retrospective case review examining patients' response to the walnut ointment. The walnut ointment has shortened healing time of non-healing burn wounds and improved clinical outcomes. In order to investigate the mechanism of action, walnut ointment has been applied on wounds of porcine full-thickness burn wound models. Histological and immunohistochemical analysis indicated our walnut ointment supports wound healing through promoting keratinocyte proliferation and differentiation. Taken together, we recommend the walnut ointment offers an effective and economical treatment for patients presenting with non-healing burn wounds. [ABSTRACT FROM AUTHOR]

Osteoporotic osteoarthritis is a phenotype of osteoarthritis (OA) manifested as fragile and osteoporotic subchondral bone. However, the ultrastructural features of subchondral bone in osteoporosis OA have not been determined. The study was aimed to investigate the ultrastructural dynamic changes of subchondral bone in osteoporotic OA model and how the ultrastructural damage in the subchondral bone caused by osteoporosis deteriorated the cartilage damage in OA. Eighteen rabbits were equally randomized to three groups, including the control, the OA and the osteoporotic OA groups. The structural changes of cartilage were evaluated by HE and safranin-O fast green staining, the Mankin’s grading system was used to assess the stage of OA progression. And microstructural or ultrastructural changes in subchondral bone were assessed by micro-computed tomography or by scanning electron microscopy. According to the changes of cartilage histopathology, the OA group was in the early pathological stage of OA while the osteoporotic OA group was in the middle stage of OA based on Mankin’s grading system. In addition, the damage of cartilage surface, reduction in the number of chondrocytes and the matrix staining were more increased in the osteoporotic OA group compared to the OA group. Compared to the OA group, the subchondral bone in the microstructure and ultrastructure in the osteoporotic OA group showed more microfracture changes in trabecular bone with more destructions of the tree-like mesh. Moreover, the collagen fibers were random rough with a fewer amount of bone lacunae in subchondral cortical plate in the osteoporotic OA group compared to the OA group. These findings indicated that the subchondral bone ultrastructure in the osteoporotic OA model was characterized by the destruction of the network structure and collagen fibers. The subchondral bone ultrastructural damage caused by osteoporosis may change mechanical properties of the upper cartilage and aggravate OA cartilage. Therefore, early diagnosis and treatment of osteoporosis is of great significance to prevent early OA from further developing osteoporotic OA. [ABSTRACT FROM AUTHOR]