Synergistic effect of chitosan and ß-carotene in inhibiting MNU-induced retinitis pigmentosa.

In this study, N-Methyl-N-nitrosourea (MNU) was intraperitoneally injected to construct a mouse retinitis pigmentosa (RP) model to evaluate the protective effect of chitosan and ß-carotene on RP. The results demonstrated that chitosan synergized with ß-carotene significantly reduced retinal histopathological structural damage in RP mice. The co-treatment group of ß-carotene and chitosan restored the retinal thickness and outer nuclear layer thickness better than the group treated with the two alone, and the thickness reached the normal level. The content of ß-carotene and retinoids in the liver of chitosan and ß-carotene co-treated group increased by 46.75 % and 20.69 %, respectively, compared to the ß-carotene group. Chitosan and ß-carotene supplement suppressed the expressions of Bax, Calpain2, Caspase3, NF-κB, TNF-α, IL-6, and IL-1ß, and promoted the up-regulation of Bcl2. Chitosan and ß-carotene interventions remarkably contributed to the content of SCFAs and enhanced the abundance of Ruminococcaceae, Rikenellaceae, Odoribacteraceae and Helicobacteraceae. Correlation analysis demonstrated a strong association between gut microbiota and improvement in retinitis pigmentosa. This study will provide a reference for the study of the gut-eye axis.

Polysaccharides affect the utilization of ß-carotene through gut microbiota investigated by in vitro and in vivo experiments.

This study aimed to evaluate the effects of six polysaccharides on the utilization of ß-carotene from the perspective of gut microbiota using both in vitro simulated anaerobic fermentation systems and in vivo animal experiments. In the in vitro experiments, the addition of arabinoxylan, arabinogalactan, mannan, inulin, chitosan, and glucan led to a 31.07-79.12% decrease in ß-carotene retention and a significant increase in retinol content (0.21-0.99-fold) compared to ß-carotene alone. Among them, the addition of chitosan produced the highest level of retinol. In the in vivo experiments, mice treated with the six polysaccharides exhibited a significant increase (2.51-5.78-fold) in serum ß-carotene content compared to the group treated with ß-carotene alone. The accumulation of retinoids in the serum, liver, and small intestine increased by 13.56-21.61%, 12.64-56.27%, and 7.9%-71.69%, respectively. The expression of ß-carotene cleavage enzymes was increased in the liver. Genetic analysis of small intestinal tissue revealed no significant enhancement in the expression of genes related to ß-carotene metabolism. In the gut microbiota environment, the addition of polysaccharides generated more SCFAs and altered the structure and composition of the gut microbiota. The correlation analysis revealed a strong association between gut microbes (Ruminococcaceae and Odoribacteraceae) and ß-carotene metabolism and absorption. Collectively, our findings suggest that the addition of polysaccharides may improve ß-carotene utilization by modulating the gut microbiota.

Lutein combined with EGCG improved retinitis pigmentosa against N-methyl-N nitrosourea-induced.

In order to investigate the synergistic improving effect of lutein (LUT) and epigallocatechin-3-gallate (EGCG) treatment on retinitis pigmentosa (RP), an N-methyl-N-nitrosourea (MNU)-induced mouse model was conducted in the present study. Compared to the LUT alone treatment group, in the LUT combined with EGCG (LUT-EGCG) treatment group, the accumulation content of LUT was significantly increased by 50.24% in the liver. The morphological results indicated that LUT-EGCG treatment significantly improved the retina structure with the thickness of the outer nuclear layer restored to 185.28 ± 0.29 µm, showing no significant difference compared to the control group. The LUT-EGCG treatment also increased the production of short-chain fatty acids, such as acetic and propionic acids. Compared with the LUT alone treatment, the LUT-EGCG treatment significantly increased the relative abundance of Lachnospiraceae and Helicobacteraceae. RT-qPCR results indicated that LUT-EGCG treatment significantly increased the antiapoptotic gene Bcl-2 expression. In addition, the expression of IL-6 was significantly down-regulated in the LUT-EGCG group, while there was no significance in NF-κß, TNF-α, IL-1ß, and IL-18 compared with the LUT group. Correlation analysis supported the conclusion that LUT combined with EGCG may improve RP by modulating antiapoptotic gene expression and regulating the abundance of gut microbiota. However, the underlying mechanism still needs further research.

Identification of carotenoids from fruits and vegetables with or without saponification and evaluation of their antioxidant activities.

This study investigates the composition and form of carotenoids in typical fruits and vegetables obtained through saponification or non-saponification and evaluates the correlation between carotenoids and antioxidant capacity. The results showed that the content of the total carotenoids in non-saponified broccoli was the highest, reaching 1505.93 ± 71.99 µg/g d.w. The content of the total carotenoids in pumpkin flesh and broccoli after saponification was reduced by 71.82% and 52.02%, respectively. The content of lutein in spinach decreased by 24.4% after saponification, but the content of ß-carotene increased compared to non-saponification. After saponification, the total antioxidant activities of apple peel, radish peel, radish flesh, and maize were significantly increased by 30.26%, 91.74%, 425.30%, and 242.88%, respectively. Saponification also improved the antioxidant activities of carotenoids in maize under six different antioxidant assays. The highest correlation was found between the total amount of carotenoids and oxygen radical absorbance capacity (R = 0.945), whereas the correlation coefficients among reducing power, 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid), hydroxyl and superoxide radical scavenging activity, and total carotenoids' content were 0.935, 0.851, 0.872, 0.885, and 0.777, respectively, all showing significant correlations. The study demonstrates that saponification can increase the total carotenoid content and antioxidation for apple peel, radish peel, radish flesh, and maize. Moreover, carotenoids were significantly positively correlated with most in vitro antioxidant assays. This study provides a theoretical basis for improving the postharvest added value of fruits and vegetables and rationally utilizing their byproducts.