| Summary: | 碩士 === 國立宜蘭大學 === 食品科學系碩士班 === 99 === Kumquat (Fortunella margarita Swingle) contains many bioactive phenolic compounds, which have obvious effects on oxidation restraining. Previous study revealed yeast fermented kumquat juice could significantly improved the total contents of polyphenol and flavonoids and also the antioxidant capacity. HPLC analysis demonstrated three unknown compounds, designated as UN1-3, in the fermented kumquat juice, and these compounds, consequently isolated and collected with a semi-preparative column. Their molecular weight were determined to be 598.18, 446.12 and 446.12 Da, respectively, by liquid chromatography mass spectrometry (LC-MS). Antibacterial test showed that UN1-3 had the ability to inhibit S. aureus (BCRC 10780 and BCRC 10781) and E. coli (BCRC 10314 and BCRC 10675). Oxygen radical absorbance ability (ORAC) showed that these compounds had good antioxidant activity. Besides, in vitro cellular test revealed that UN1-3 could protect cells from the oxidant damage caused by AAPH (2,2-azobis (2-amidinopropane) di- hydrochloride). In addition, they also show significant suppression on the LPS-induced NO in RAW264.7 cell. Western blot and RT-PCR analysis exhibited UN1-3 could effectively suppress the expression of iNOS protein and mRNA, respectively. UN2 and UN3, but not UN1, showed down-regulation on NF-B activity at the concentration of 50 g/mL.
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