Sialic acid is an essential moiety of mucin as a hydroxyl radical scavenger

Abstract

In this work, we examined the antioxidant role of mucin, a typical sialic acid containing high-molecular weight glycoprotein. The function of mucin as a hydroxyl radical ( Å OH) scavenger was characterized using bovine submaxillary gland mucin (BSM). Non-treated BSM effectively protected DNA from the attack of Å OH; however, desialylated BSM lost this potential. Moreover, we estimated the scavenging effects of BSM against Å OH generated by UV irradiation of hydrogen peroxide using ESR analysis. Our results indicate that BSM has Å OH scavenging ability the and sialic acid in mucin is an essential moiety to scavenge Å OH.

Synthesis and cardiovascular protective effects of quercetin 7‐O‐sialic acid

“…Presently, studies investigating the correlation between serum total sialic acid and the severity of atherosclerosis have presented conflicting results. It is noteworthy that recent studies have demonstrated that sialic acid could scavenge ROS 13, 14, 15 and may be applied as therapeutic option in some diseases 16, 17, 18.…”

Erythrocyte membrane bound and plasma sialic acid during aging

“…One of important functions of sialic acid is 'molecular mimicry', in which successful microbial pathogens decorate themselves with sialic acids, assisting in evasion of host immunity (Vimr et al 2004). Mucin, which contains high-molecular-weight glycoprotein (containing sialic acid), functions as hydroxyl radical scavenger and loses its ability when desialylated; thus mucin has the ability to protect cells from oxidants (Ogasawaraa et al 2007). Since oxidative stress is known to increase with age in humans (Rizvi & Maurya 2006, 2007 and our present results also substantiate this in rats, we presume that loss of sialic acid could also contribute to decreased ability of mucin to protect against oxidants.…”

“…The most common member of this group is N-acetylneuraminic acid (NANA). Sialylated conjugates in mammals perform important roles in cellular recognition, signalling, hydroxyl radical scavenging, neuronal development and host-pathogen interaction (Ogasawaraa et al 2007;Varki 2008). Sialic acids are also the ligands for the Siglec family of cell adhesion molecules, which appear to be involved in regulating the immune response (Varki & Angata 2006;Crocker et al 2007;Varki 2007).…”

Selective Detection of Hydroxyl Radical Scavenging Capacity Based on Electrogenerated Chemiluminescence Detection Using Tris(2,2'-bipyridine)ruthenium(III) by Flow Injection Analysis

“…18) Tris(2,2Ј-bipyridine)ruthenium(III), or Ru(bpy) 3 3ϩ , has been shown to be an important chemiluminescence reagent. When coupled with flow injection analysis (FIA), 19) 3 3ϩ and · OH are in contact in the spiral cell in the detector, and thus, the chemiluminescence is continuously maintained. Constant chemiluminescence is generated and recorded as the background emission.…”

“…When · OH is generated in excess and the cellular antioxidant defense is deficient, some free radical chain reactions can attack proteins, lipids, and nucleic acids, leading to cellular damage. [1][2][3] Living systems contain complex enzymatic antioxidants such as superoxide dismutase, glutathione peroxidase, and catalase. These enzymes can block the initiation of · OH and the free radical chain reaction.…”