| Cranberry,one of the "Three traditional fruits" in North America,is a low calorie,high fiber fruit with rich nutrients.It is very popular in the United States,and the cranberry products are gradually being introduced into China market today.There is a growing public interest for the cranberry as a functional food because of its abundant physiological active substances,especially for the A-type cranberry proanthocyanidins,which is effective for prevention of urinary tract infection.In this study,we analyzed the main chemical constituents of A-type proanthocyanidins(PACs)-rich cranberry concentrate(CBC)and its comparison with B-type PACs-rich grape seed extract(GSE),then investigated the redox state regulation and anti-aging effects in vivo by them.Results showed that the CBC,whose main bioactive substances are PACs dimer A,had good anti-aging effects from regulating redox state and protecting telomeres in vivo,it showed better effects on promoting GSH-Px activity and inhibiting the telomere shortening compared with GSE,whose main bioactive substances are epicatechin and PACs dimer B,indicating CBC has great potential to be an anti-aging functional food.Detailed research contents and conclusions were presented as follows:1.Using national standard method,the total flavonoids,total PACs,ascorbic acid and a-tocopherol in CBC and GSE were measured for the analysis of bioactive components,the moisture content,ash content,fat content,protein content were measured as the constituent parts of CBC and GSE.Results showed that the main bioactive components in CBC and GSE were PACs.The content of PACs in CBC was 15.6 g/kg while in GSE was 309.0 g/kg.2.Using the Q-Extractive quadrupole/orbitrap high resolution mass spectrometry,PACs dimer A and B were identified as predominant phenolic compounds of CBC and GSE,respectively,while epicatechin was present in both extracts.3.Using the D-galactose-induced aging mice model,effects of both CBC and GSE(15 mg/kg/d,30 mg/kg/d、60 mg/kg/d,calculated as PACs)were investigated via an 8-week oral gavage administration considering water-soluble vitamin E as the positive control.Results showed that both CBC and GSE reduced hepatic and brain thiobarbituric acid reactive substances(TBARS),presented as malonaldehyde(MDA)equivalents and plasma 8-isoprostane levels by 30-57%,24-30%and 11-62%,respectively,and decreased brain and plasma monoamine oxidase(MAO)activities by 27-59%and 65-71%,respectively.CBC(60 mg/kg/d)could improve hepatic glutathione peroxidase(GSH-Px)activity by 42%,while GSE(30 mg/kg/d)increased hepatic superoxide dismutase(SOD)activity by 13%(p<0.05).Therefore,CBC/GSE exerted anti-aging effects probably via regulating in vivo redox state.A-type linked PACs regulated GSH-Px activities obviously while B-type PACs had no effect on it,and neither generated any effect on catalase(CAT)activities.4.Using real-time quantitative PCR(RT-PCR)to measure the telomere length(TL)of liver and testis,results showed that CBC(15 mg/kg/d)can inhibit the telomere shortening caused by D-galactose in liver and testis(p<0.05),but GSE had no effect on keeping the telomere length.Expression of tert and sirt6 were detected by Western Blot.We found that both CBC(30 mg/kg/d and 60 mg/kg/d)and GSE(15 mg/kg/d)reduced the expression of tert in testis(p<0.05),but only CBC(15 mg/kg/d)had significant effect on tert in liver(p<0.05),this result demonstrated that CBC and GSE could decrease telomerase activity to prevent carcinogenesis,but they had differerent targets.About sirt6,which can stabilize genomes and telomeres and prevents cells from premature senescence,both CBC(all groups)and GSE(30 mg/kg/d)could promote the expression of its protein(p<0.05),so we concluded that CBC and GSE could protect the DNA and prevent cells from senescence. |
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