Abstract
Carrageenan oligosaccharides (COS) have been reported to possess excellent antioxidant activities, but the underlying mechanism remains poorly understood. In this study, H2O2 was applied to trigger oxidative stress. The results showed that the addition of COS could effectively extend the lifespan of female Drosophila, which was associated with improvements by COS on the antioxidant defense system, including a decrease in MDA, the enhanced activities of SOD and CAT, the reduction of ROS in intestinal epithelial cells, and the up-regulation of antioxidant-relevant genes (GCL, GSTs, Nrf2, SOD). Meanwhile, the axenic female Drosophila fed with COS showed almost no improvement in the above measurements after H2O2 treatment, which highlighted the antioxidant mechanism of COS was closely related to intestinal microorganisms. Then, 16S rDNA high-throughput sequencing was applied and the result showed that the addition of COS in diets contributed to the diversity and abundance of intestinal flora in H2O2 induced female Drosophila. Moreover, COS significantly inhibited the expression of gene mTOR, elevated its downstream gene 4E-BP, and further inhibited autophagy-relevant genes (AMPKα, Atg1, Atg5, Atg8a) in H2O2 induced female Drosophila. The inhibition of the mTOR pathway and the activation of autophagy was probably mediated by the antioxidant effects of COS. These results provide potential evidence for further understanding of COS as an intestinal antioxidant.
Highlights
Oxidative stress, the unbalanced biological reactions which cause the number of free radicals to increase in the body, which in turn damage biological macromolecules such as DNA, lipids and proteins, plays an important role in the pathogenesis of many chronicdegenerative disorders [1,2]
Compared with male flies, the results showed that Carrageenan oligosaccharides (COS) was more beneficial to the oxidative stress resistance of female flies, especially in extending lifespan and improving antioxidant defense system (SOD and CAT activities, and CAT content)
To better investigate the influence of gut flora related to COS antioxidant capability, the authors focused on the female of Drosophila in this study
Summary
The unbalanced biological reactions which cause the number of free radicals to increase in the body, which in turn damage biological macromolecules such as DNA, lipids and proteins, plays an important role in the pathogenesis of many chronicdegenerative disorders [1,2]. Due to modern lifestyles, such as processed foods, exposure to various toxic species, and lack of exercise, oxidative stress damage inevitably occurs. The gut is an important source of reactive oxygen species (ROS) due to its inevitable exposure to foreign substances and microbial pathogens [3,4,5]. When external harmful substances stimulate the intestine to cause oxidative stress, the intestinal epithelial cells will act as the first barrier to create a direct immune response. Attention is more focused on safe antioxidants ingested through the diet
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
