TY - JOUR
T1 - Antioxidant and nitric oxide production inhibitory activities of galacturonyl hydroxamic acid
AU - Liu, Yuh Hwa
AU - Lin, Shyr Yi
AU - Lee, Chi Ching
AU - Hou, Wen Chi
PY - 2008/7/1
Y1 - 2008/7/1
N2 - The self-prepared pectin hydroxamic acid has been reported to have antioxidant activities [Yang, S. S., Cheng, K. D., Lin, Y. S., Liu, Y. W., & Hou, W. C. (2004). Pectin hydroxamic acids exhibit antioxidant activities in vitro. Journal of Agricultural and Food Chemistry, 52, 4270-4273]. In this study, the galacturonic acid (GalA), the monomer unit of the pectin polymer, was esterified with acidic methanol (1 N HCl) at 4 °C with gentle stirring for 5 days to get galacturonic acid methyl ester which was further reacted with alkaline hydroxylamine to get galacturonyl hydroxamic acid (GalA-NHOH). The GalA-NHOH was used to test the antioxidant and antiradical activities in the comparison with GalA. The scavenging activities of GalA-NHOH against DPPH radicals (half-inhibition concentration, IC50, was 82 μM), hydroxyl radicals detected by electron spin resonance (IC50 was 0.227 nM in the comparison with Trolox of 0.433 μM), superoxide radicals (IC50 was 830 μM) were determined. The protection activities of GalA-NHOH against hydroxyl radicals-mediated calf thymus DNA damages, linoleic acid peroxidation and peroxynitrite-mediated dihydrorhodamine 123 oxidations were also investigated. It was found that the GalA-NHOH exhibited dose-dependently antioxidant activity and few or none was found in GalA. The GalA-NHOH was used to evaluate the suppressed activity of nitric oxide (NO) productions of RAW264.7 cells in the presence of lipopolysaccharide (LPS, 100 ng/ml) as inducers. It was found that GalA-NHOH (0.02-0.1 mg/ml) could dose-dependently suppress the NO productions (expressed as nitrite concentrations) in RAW264.7 cells without significant cytotoxicity.
AB - The self-prepared pectin hydroxamic acid has been reported to have antioxidant activities [Yang, S. S., Cheng, K. D., Lin, Y. S., Liu, Y. W., & Hou, W. C. (2004). Pectin hydroxamic acids exhibit antioxidant activities in vitro. Journal of Agricultural and Food Chemistry, 52, 4270-4273]. In this study, the galacturonic acid (GalA), the monomer unit of the pectin polymer, was esterified with acidic methanol (1 N HCl) at 4 °C with gentle stirring for 5 days to get galacturonic acid methyl ester which was further reacted with alkaline hydroxylamine to get galacturonyl hydroxamic acid (GalA-NHOH). The GalA-NHOH was used to test the antioxidant and antiradical activities in the comparison with GalA. The scavenging activities of GalA-NHOH against DPPH radicals (half-inhibition concentration, IC50, was 82 μM), hydroxyl radicals detected by electron spin resonance (IC50 was 0.227 nM in the comparison with Trolox of 0.433 μM), superoxide radicals (IC50 was 830 μM) were determined. The protection activities of GalA-NHOH against hydroxyl radicals-mediated calf thymus DNA damages, linoleic acid peroxidation and peroxynitrite-mediated dihydrorhodamine 123 oxidations were also investigated. It was found that the GalA-NHOH exhibited dose-dependently antioxidant activity and few or none was found in GalA. The GalA-NHOH was used to evaluate the suppressed activity of nitric oxide (NO) productions of RAW264.7 cells in the presence of lipopolysaccharide (LPS, 100 ng/ml) as inducers. It was found that GalA-NHOH (0.02-0.1 mg/ml) could dose-dependently suppress the NO productions (expressed as nitrite concentrations) in RAW264.7 cells without significant cytotoxicity.
KW - Antioxidant activity
KW - Electron spin resonance (ESR)
KW - Galacturonylhydroxamic acid (GalA-NHOH)
KW - Nitric oxide
KW - RAW264.7 cells
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U2 - 10.1016/j.foodchem.2007.12.055
DO - 10.1016/j.foodchem.2007.12.055
M3 - Article
AN - SCOPUS:39149130314
SN - 0308-8146
VL - 109
SP - 159
EP - 166
JO - Food Chemistry
JF - Food Chemistry
IS - 1
ER -