Defensin protein from sweet potato (Ipomoea batatas [L.] Lam ‘Tainong 57’) storage roots exhibits antioxidant activities in vitro and ex vivo

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Title:	Defensin protein from sweet potato (Ipomoea batatas [L.] Lam ‘Tainong 57’) storage roots exhibits antioxidant activities in vitro and ex vivo
Authors:	Guan-Jhong Huang;Jeng-Shyan Deng;Hsien-Jung Chen;Shyh-Shyun Huang;Jung-Chun Liao;Wen-Chi Hou;Yaw-Huei Lin
Contributors:	保健營養生技學系
Keywords:	Sweet potato;Defensin;Antioxidant
Date:	2012-04
Issue Date:	2012-11-26 02:32:36 (UTC+0)
Abstract:	This study was designed to investigate the antioxidant activities of sweet potato defensin (SPD1) in vitro and ex vivo. Antioxidant status [2,2'-azinobis[3-ethylbenzthiazoline-6-sulphonic acid (ABTS) assay], scavenging activity against DPPH (1,1-dipheny-2-picrylhydrazyl) radical method, reducing power method, Fe(2+)-chelating ability, FTC (ferric thiocyanate) method, and protection of calf thymus DNA against hydroxyl radical-induced damage were studied in vitro. The ex vivo experiments revealed that SPD1 could decrease the production of intracellular peroxide in HepG2 cells. Four peptides, namely GFR, GPCSR, CFCTKPC and MCESASSK for testing antioxidative activity, were synthesized according to tryptic hydrolysis simulation. In the TEAC assay CFCTKPC performed the best (13.5±0.3μmol TE/g dw), even better than reduced glutathione (7.3±0.2μmol TE/g dw). In the DPPH radical assay (%), [IC(50) (μM) (the concentration required for scavenging 50% activity)] CFCTKPC again had the highest antioxidant activity (IC(50) is 11.3±3.2μM) even better than reduced glutathione (IC(50) is 74.3±2.4μM). In the lipid peroxidation assay, once again CFCTKPC performed the best, with an IC(50) value of 0.5±0.0μM better than reduced glutathione (1.2±0.1μM). These findings mean that cysteine residue is most important in antioxidant activities. It was suggested that SPD1 might contribute its antioxidant activities against hydroxyl and peroxyl radicals.
Relation:	FOOD CHEMISTRY, 135(3):861-867.
Appears in Collections:	[Department of Food Nutrition and Healthy Biotechnology] Journal Article

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