Synthesis of aminopyridinium‐grafted starch derivatives and evaluation of their antioxidant property

Abstract

In order to improve the bioactivity of starch, novel starch derivatives were developed including 2-(2-aminopyridinium)acetyl starch (2APASC), 2-(3-aminopyridinium)acetyl starch (3APASC), 2-(4-aminopyridinium)acetyl starch (4APASC), 2-(2,3-diaminopyridinium)acetyl starch (2,3DAPASC), 2-(2,6-diaminopyridinium)acetyl starch (2,6DAPASC), and 2-(3,4-diaminopyridinium)acetyl starch (3,4DAPASC). The in vitro antioxidant capacities against hydroxyl-radical, DPPH-radical, and superoxide-radical for all synthesized starch derivatives were evaluated using free radicals scavenging assays. The results showed that the scavenging effect of starch derivatives bearing aminopyridinium groups was better than starch. Especially, 2,3DAPASC and 2,6DAPASC could scavenge hydroxyl-radicals completely at 0.4 mg/mL. Moreover, the antioxidant property of synthesized starch derivatives was affected by the different positions and the number of amino groups on pyridinium rings. Because the aminopyridinium acetyl starch derivatives could be synthesized conveniently and also possessed significantly strong antioxidant activity, this synthetic strategy might provide an effective tool to broaden further utilization of starch.

Novel 1,2,3-triazolium-functionalized inulin derivatives: synthesis, free radical-scavenging activity, and antifungal activity

“…33 Tan synthesized aminopyridinium-graed starch derivative and found antioxidant property of synthesized starch derivatives was affected by the different positions and the number of amino groups on pyridinium rings. 34 The experimental data above and related literature demonstrated that the chemical modication of polysaccharides was conducive to improving the free radical scavenging activity of them.…”

Synthesis, characterization, and biological activities of folic acid conjugates with polyvinyl alcohol, chitosan, and cellulose

“…The reaction mixture was warmed in an oil bath at 100°C for 3 days (tlc) and the solvent was removed under vacuum. The products were collected by Buchner filtration using vacuum pump, washed several times with acetone, ethanol, and dried in drying oven at 50°C for 2 days 59 …”

Preparation of starch derivatives bearing urea groups and the evaluation of antioxidant, antifungal, and antibacterial activities

“…In the FT-IR spectra of TUCAST, MTUCAST, and PTUCAST, the vibration peaks at 786 cm À1 confirm that the existence of CACl becomes weaker and new peaks appear at about 1550 cm À1 , 1510 cm À1 , and 670 cm À1 , indicating that CACl bonds were replaced by some new groups bearing aromatic rings. Exactly, the peaks at 1550 cm À1 and 1510 cm À1 are the characteristic signals of pyridine [22,26] as well as the peak at 670 cm À1 is the characteristic signal of thiadiazole [27,28]. Moreover, the FT-IR spectrum of PTUCAST shows absorption at 771 cm À1 , which can be assigned to the typical absorption of benzene.…”

“…The degrees of substitution (DS) of CAST were estimated from the 1 H NMR spectrum by using relative change in the ratio of integral of the hydrogen atom bonded to Carbon 1 of the glucopyranose ring and hydrogen atoms corresponding to chloroacetyl group [22]. The DS of CAST were calculated according to the following equation:…”

“…The superoxide-radical scavenging ability was assessed following the model of Tan's methods [22]. The reaction mixture, involving test samples (5 mg/mL, 0.06, 0.12, 0.24, 0.48, and 0.96 mL), phenazine methosulfate (PMS, 30 lM), nitro blue tetrazolium (NBT, 72 lM), and nicotinamide adenine dinucleotide reduced (NADH, 338 lM) in Tris-HCl buffer (16 mM, pH 8.0), was incubated 5 min at r.t..…”