Flavonoid content and antioxidant capacity of spinach genotypes determined by high-performance liquid chromatography/mass spectrometry

BACKGROUND: Flavonoids in different spinach genotypes were separated, identified, and quantified by a high-performance liquid chromatographic method with photodiode array and mass spectrometric detection. The antioxidant capacities of the genotypes were also measured using two antioxidant assays-oxygen radical absorbance capacity (ORAC(FL)) and photochemiluminescence (PCL)-which measure the response to the peroxyl and superoxide anion radicals, respectively. RESULTS: Eighteen flavonoids representing glucuronides and acylated di- and triglycosides of methylated and methylene dioxide derivatives of 6-oxygenated flavonols were identified (patuletin, spinacetin, spinatoside, jaceidin). The total flavonoids ranged from 1805 to 3703 mg kg(-1), indicating 2.0-fold variation among genotypes. The ORACFL and PCL values ranged from 48.7 to 84.4 mmol kg(-1) and from 9.0 to 14.0 mmol kg(-1), respectively, representing as much as 1.7-fold variation among genotypes. CONCLUSION: The ORACFL and PCL values were highly correlated with total flavonoid content (r(xy)=0.96). (c) 2008 Society of Chemical Industry.