Heat treatment enhances the NO-suppressing and peroxynitrite-intercepting activities of kumquat (Fortunella margarita Swingle) peel

Chih-Cheng Lin; Pi-Fang Hung; Su-Chen Ho

doi:10.1016/j.foodchem.2007.12.053

Heat treatment enhances the NO-suppressing and peroxynitrite-intercepting activities of kumquat (Fortunella margarita Swingle) peel

Food Chem. 2008 Jul 1;109(1):95-103. doi: 10.1016/j.foodchem.2007.12.053. Epub 2007 Dec 25.

Authors

Chih-Cheng Lin¹, Pi-Fang Hung¹, Su-Chen Ho²

Affiliations

¹ Department of Biotechnology, Yuanpei University, Hsinchu, Taiwan, ROC.
² Department of Food Science, Yuanpei University, No. 306, Yuanpei Street, Hsinchu 30015, Taiwan, ROC. Electronic address: sche@mail.ypu.edu.tw.

PMID: 26054269
DOI: 10.1016/j.foodchem.2007.12.053

Abstract

In Taiwan, folk remedies containing dried kumquats (Fortunella margarita Swingle) are used to cure inflammatory respiratory disorders. The induction of inducible nitric oxide (NO) synthase in inflammatory cells and increased airway production of NO and peroxynitrite, its derivative, are key events in such disorders. Although heat is known to affect the antioxidant activity of citrus peels, the effects of dehydration and heating on NO suppression and on the interception of peroxynitrite are unclear. We determined the NO-suppressing activities of freeze-dried, oven-dried, and heat-treated kumquat extracts by measuring their inhibition of NO production in lipopolysaccharide-activated RAW 264.7 macrophages. Furthermore, we evaluated the attenuation of peroxynitrite-mediated nitrotyrosine formation in albumin. Heating, but not oven drying, enhanced the ability of kumquat peels to suppress NO and intercept peroxynitrite, as compared with freeze drying. However, heat treatment and oven drying of kumquat flesh attenuated these activities; these effects were at least partially attributed to heat-susceptible ascorbate.

Keywords: Antioxidant; Citrus fruit; Heat treatment; Nitric oxide; Peroxynitrite.