The effect of water-soluble chitosan, a natural polymer derived from chitin, on indices of oxidative stress was investigated in normal volunteers. Treatment with chitosan for 4 weeks produced a significant decrease in levels of plasma glucose, atherogenic index and led to increase in high density lipoprotein cholesterol (HDL). Chitosan treatment also lowered the ratio of oxidized to reduced albumin and increased total plasma antioxidant activity (TPA). There was good correlation between TPA and oxidized albumin ratio. The results indicate that oxidized albumin ratio represents a potentially useful marker of oxidative stress. In in vitro studies, albumin carbonyls and hydroperoxides were significantly decreased in a time-dependent manner in the presence of chitosan, compared with controls (p<0.05). Chitosan also reduced two stable radicals in a dose- and time-dependent manner. The results suggest that chitosan has a direct antioxidant activity in systemic circulation by lowering the indices of oxidative stress in both in vitro and in vivo studies. This may confer benefits additional to the reduction in plasma carbohydrate and increase in HDL levels. It may also inhibit oxidation of serum albumin commonly observed in patients undergoing hemodialysis, resulting in reduction of oxidative stress associated with uremia.
"It dictates numerous advantage properties, such as biodegradability (Shigemasa et al., 1994), biocompatibility (Risbud and Bhonde, 2000), bioactivity (Dumitriu et al., 1989) and non-toxicity (Denkbas and Odabasi, 2002). Several studies have proposed CS as a biomaterial for pharmaceutics (Kim et al., 2008), tissue engineering (Li et al., 2005), cosmetics (Kim et al., 2006), food preservation (Kanatt et al., 2008) and dietary (Anraku et al., 2009). The amino (–NH 2 ) and hydroxyl (–OH) groups of CS at C-2 and C-6 positions not only provide reactive sites for functionalization but also exhibit strong metal ion chelation (Guibal, 2004), oil absorption (Sokkera et al., 2011), antimicrobial (Park et al., 2004), and antioxidant activities (Yang and Mau, 2008). "
[Show abstract][Hide abstract] ABSTRACT: The idea of preparing water-soluble chitosan and observing its nanostructural morphology are proposed using irradiation process. The water-soluble chitosan nanoparticles (WSCS-NPs) properties were assessed for a possible use as an antioxidant and reducing agent for a green synthesis of gold nanoparticles (AuNPs). The characteristics of WSCS-NPs were verified using FT-IR, XRD, C H N analyzer and TGA. The nanostructural morphology was investigated using SEM and TEM. The number average molecular weight of WSCS-NPs was as low as 3800 g/mol with narrow polydispersity of 1.26. The average hydrodynamic diameter of WSCS-NPs was 15.40 ± 0.47 nm. The 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging activity of WSCS-NPs at 0.1 mg/mL was up to 80%, while the original CS exhibited no antioxidant activity. An effective concentration of WSCS-NPs to reduce DPPH free radicals (150μM) by 50% is as low as 0.025 mg/mL. The in vitro cytotoxicity test by MTT assay demonstrated that WSCS-NPs are non-toxic with an IC50 of 2000 μg/mL. The WSCS-NPs are efficient reducing and stabilizing agent for producing stable colloidal AuNPs. The achievement of the WSCS-NPs and its ability to create AuNPs would be a part of growing interest of green nanotechnology in biomedicine.
"Similarly, it was reported that the injection of chitosan inhibits glycerol-induced renal oxidative damage in rats by Yoon et al. in, 2008 . In a previous study, we also showed that the administration of LMW chitosan to human volunteers prevented the oxidation of HSA in vivo (Anraku et al., 2009) . Therefore, given the likelihood that LMW chitosans have antioxidative properties, they would be potentially useful as components of extended-release systems for use in drug delivery. "
[Show abstract][Hide abstract] ABSTRACT: The antioxidant properties of different low molecular weight (LMW) chitosans (CS1; 22 kDa, CS2; 38 kDa, CS3; 52 kDa, CS4; 81 kDa) were examined for possible use in extended-release tablets. The criteria used were the ability of the chitosans to reduce Cu2+, and hydroxyl and superoxide radicals and N-centered radicals derived from 1,1'-diphenyl-2-picrylhydrazyl, via the use of ESR spectrometry. CS2 showed the highest scavenging activity. CS1 and CS3, however, were much less effective and CS4 was not a viable antioxidant. The results suggest that CS2 could be useful in combating the development of oxidative stress. A series of chitosan tablets were prepared using a spray drying method and evaluated as an extended-release matrix tablet using theophylline (TPH) as a model drug. The release of TPH from the different MW chitosan tablets increased with increasing MW of the chitosan used. CS2, CS3 and CS4 showed a reasonable release activity, but CS1 showed the shortest release activity. Moreover, the CS2-TPH tablet showed the highest scavenging activity of the three chitosan tablets (CS2-CS4) using 2,2’-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) radicals. These results suggest that a CS2-TPH tablet could be potentially useful in an extended-release matrix tablet with a high antioxidant activity.
[Show abstract][Hide abstract] ABSTRACT: Most of the reports to date on the antioxidant capacity of chitosans and chitooligosaccharides (COS) are based on strictly chemical methods. When studying antioxidants with potential in vivo applications, the method used to evaluate the antioxidant activity should be representative of the conditions in which the antioxidant might have a protective effect. In this work we evaluate the antioxidant activity of two COS mixtures and a low MW chitosan (LMWC) upon two biological oxidizable substrates – erythrocytes and phages, subjected to accelerated oxidation conditions.Our results suggest that COS/LMWC can be used as antioxidants in biological systems. All the tested compounds reduced either the hemolytic and DNA damage, by inhibiting H2O2- and AAPH-radicals. However, the results obtained for these biological assays did not reveal a dose dependence, contrary to the chemical assay, suggesting that the protective concentrations should be established, in order to prevent enhancement of the oxidative damage – i.e. a prooxidant effect.
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