Abstract: Indicaxanthin is a betalain that is abundant in Opuntia ficus-indica orange fruit and has antioxidative and anti-inflammatory effects. Nevertheless, very little is known about the neuroprotective potential of indicaxanthin. This study investigated the impact of indicaxanthin on neuronal damage and gut microbiota dysbiosis induced by a high-fat diet in mice. The mice were divided into three groups according to different diets: the negative control group was fed a standard diet; the high-fat diet group was fed a high-fat diet; and the high-fat diet + indicaxanthin group was fed a high-fat diet and received indicaxanthin orally (0.86 mg/kg per day) for 4 weeks. Brain apoptosis, redox status, inflammation, and the gut microbiota composition were compared among the different animal groups. The results demonstrated that indicaxanthin treatment reduced neuronal apoptosis by downregulating the expression of proapoptotic genes and increasing the expression of antiapoptotic genes. Indicaxanthin also markedly decreased the expression of neuroinflammatory proteins and genes and inhibited high-fat diet–induced neuronal oxidative stress by reducing reactive oxygen and nitrogen species, malondialdehyde, and nitric oxide levels. In addition, indicaxanthin treatment improved the microflora composition by increasing the abundance of healthy bacterial genera, known as producers of short-chain fatty acids (Lachnospiraceae, Alloprovetella, and Lactobacillus), and by reducing bacteria related to unhealthy profiles (Blautia, Faecalibaculum, Romboutsia and Bilophila). In conclusion, indicaxanthin has a positive effect on high-fat diet–induced neuronal damage and on the gut microbiota composition in obese mice.

Key words: gut microbiota dysbiosis, high-fat diet, indicaxanthin, microflora, neuronal apoptosis, neurodegeneration, neuroinflammation, obesity, Opuntia ficus-indica fruit