Chemical Components And Antioxidant Activity Of Jujube Honey

Jujube honey,one of the significant monofloral honeys in China,is deeply loved by consumers owing to its amber color,sticky texture and unique flavor.In this paper,we studied Shaanxi,Henan,Shandong,Shanxi,Xinjiang and Hebei jujube honey,established the phenolic fingerprint of jujube honey by HPLC-DAD technology.By HPLC/ESI-Q-TOF-MS,the phenolic compounds were detected in the samples and the volatile components of jujube honey were determined by HS-SPME-GC-MS.Then,the antioxidant activity in vitro of jujube honey collected from different regions were investigated as well as their effect in protecting plasmid p BR322 against hydroxyl radical-induced oxidative DNA damage and protecting mouse lymphocytes against oxidative DNA damage induced by hydrogen peroxide（H₂O₂）.The paper including four chapters,and the contents are as follows:1.The chromatographic fingerprint of jujube honeys were established by the HPLC-DAD technology.The result showed that the phenolic fingerprint of jujube honey from same regions were similar,and the maker peaks from different areas jujube honey were extracted.By HPLC/ESI-Q-TOF-MS,a total of seventeen phenolic compounds were detected in the samples.The content of protocatechuic acid were higher than other phenolic compounds.There are differences in the types and contents of phenolic compounds in different areas.2.Seven types volatile components were identified from jujube honey by HS-SPME-GC-MS,with aldehydes,alkanes and esters as the main substances.The content of methyl nonanoate,nonanal,decanal and caryophyllene were higher than other volatile components,and octenal and 2-ethylhexanol could be used as maker components of jujube honey.Methyl nonoate was the distinctive compounds of Henan jujube honey.3.The antioxidant experiments in vitro and comet assay were used to evaluate the in vitro antioxidant activity of jujube honey.The results showed that the total phenol content of jujube honey was 243.67-357.43 mg/kg,jujube honey had strong 1,1-diphenyl-2-trinitrophenylhydrazine（DPPH）radical scavenging capacity with a half maximal inhibitory concentration(IC₅₀)（0.083-0.225 g/m L）,ferrous ion chelating activity（0.54-1.15 mg/kg）and ferric reducing power（147.05-262.75 mg/kg）.Furthermore,jujube honey ferric reducing power and DPPH radical scavenging capacity are significantly related to its total phenol content（P<0.01）.Jujube honey had a protective effect against oxidative DNA damage in plasmid p BR322 induced by hydroxyl radical,the protective effect of Shaanxi jujube honey on plasmid DNA was 58.34%.And jujube honey could significantly reduced oxidative DNA damage induced by H₂O₂ in mouse lymphocytes.