| Paeonia suffruticasa Andrews.is a perennial deciduous shrub of the Sect.Moutan DC.of Paeonia L.in the family Paeoniaeeae.This group includes two subgroups of leathery discs and fleshy discs,with a total of nine wild peony species,one subspecies and one variety.P.suffruticasa is a unique resource plant in our country,with important ornamental value,oil value,medicinal value and edible value.In this study,nine different wild species of peony,Paeonia jishanensis,P.qiui,P.ostii,P.rockii,P.decomposita,P.potanini,P.delavayi,P.lutea and P.ludlowii,were used as test materials,and the functional components of their seed kernels were used as the entry point to systematically study the nutritional profile,chemical composition,oil characteristics,antioxidant activity and antibacterial activity of the seed kernels.A series of chemometric studies such as correlation analysis,hierarchical clustering score,principal component analysis and discriminant analysis were further conducted to evaluate the quality of nine wild peony resources with a view to discovering the best wild peony germplasm resources and providing a theoretical basis for the targeted breeding of new peony varieties,quality control and innovative development and utilization of their functional food and drug products.The main research conclusions were as follows:(1)The 100-grain weight,kernel yield and crude fat content of P.ludlowii were significantly higher than those of other wild species and P.ostii ‘Fengdan’(P < 0.05).The 100-grain weight of P.ludlowii was 54 g,the kernel yield was 77.89%,and the crude fat content was 23.6%.(2)The soluble protein and soluble sugar contents of P.delavayi seed kernels were significantly higher than those of other wild species,with the values of 15.69%and 87 mg/g.(3)A total of 27 fatty acids were identified and isolated from nine types of wild peony seed oil,including 12 saturated fatty acids(SFA),namely octanoate,decanoate,dodecanoate,tridecanoate,myristate,palmitate,heptadecanoate,stearate,arachidate,heneicosanoate,tricosanoate,tetracosanoate.There are 15 types of unsaturated fatty acids(UFA),including 6 monounsaturated fatty acids,namely myristoleate,methyl palmitoleate,cis-10-heptadecenoate,oleate,cis-11-Eicosenoic acid ester,and erucate.There are nine polyunsaturated fatty acids(PUFA),namely linoleate,γ-linolenate,α-linolenate,cis-11,14-Eicosadienoic acid ester,cis-8,11,14-Eicosatrienoic acid ester,cis-11,14,17-Eicosatrienoic acid ester,cis-5,8,11,14,17-Eicosapentaenoic acid ester,cis-13,16-Docosadienoic acid ester,cis-4,7,10,13,16,19-Docosahexaenoic acid ester.octanoate,myristoleate,cis-11,14-Eicosadienoic acid ester,cis-11,14,17-Eicosatrienoic acid ester,cis-5,8,11,14,17-Eicosapentaenoic acid ester,cis-13,16-Docosadienoic acid ester,cis-4,7,10,13,16,19-Docosahexaenoic acid ester,erucate,tricosanoate and tetracosanoate were detected in peony seed oil for the first time.Unsaturated fatty acids account for a larger proportion of peony seed oil(87.99%～97.02%)compared to saturated fatty acids.Except for P.rockii and P.ludlowii,the unsaturated fatty acid content of seed oil of all wild species was higher than that of cultivated species P.ostii‘Fengdan’,which had certain development potential.(4)A total of twenty-seven chemical constituents were identified in nine wild peony seeds.One of them was phenylalanine,and the content ranged from 31791.726 to 138815.169 μg/g.And 5 flavonoids were detected: apigenin,myricetin,quercetin,isorhamnetin,and kaempferol.Three kinds of isoflavones were detected: genistein,mangiferin and biochanin A.Nine kinds of flavonoid glycosides were detected:quercetin,vitexin/isovitexin,chrysin,rutin,luteolin,taxifolin,quercetin 3-O-glucoside,luteolin-7-O-glucoside and naringin.One type of flavanones was detected: butin;one type of chalcone and dihydrochalcone was detected: isoliquiritigenin.Seven kinds of phenolic acids were detected: p-coumaric acid and ferulic acid belong to hydroxycinnamic acid,eriodictyol,naringenin,catechin,epicatechin,(-)-epigallocatechin belongs to flavans.The highest content was flavonoid glycosides,and the content ranged from 9321.035 to 77006.855 μg/g.Followed by flavans,the content range was 271.457～917.436 μg/g.The third was flavonoids,the content range was122.232～898.528 μg/g.The fourth was hydroxycinnamic acid,the content range was167.565～647.319 μg/g.(5)Using DPPH method,ABTS method and FRAP method to determine the antioxidant activity of the chemical constituents of the seed kernel,the results showed that the seed oil,total flavonoids extract and total phenolic extract of nine species of wild peony had good antioxidant capacity.The seed oils of P.ludlowii and P.ostii had superior antioxidant activity,the total flavonoid extracts from the seed kernels of P.delavayi and P.ludlowii had better antioxidant activity,and the total phenolic extracts from the seeds and kernels of P.potanini and P.ostii had better antioxidant activities.(6)In the process of antibacterial experiments on 6 strains,it was found that 9kinds of wild peony seed oils only had certain antibacterial activity against S.aureus and E.cloacae,and the diameters of the inhibition zones were 11.7～15.65 mm,7.28～9.37 mm.The total flavonoids and total phenolic extracts of 9 wild peony seeds have inhibitory effects on 6 strains of S.aureus,K.pneumoniae,B.subtilis,Escherichia coli,E.cloacae,and C.albicans.Collectively,the antibacterial activity of the seed kernel extract of P.jishanensis was the best.(7)Through a series of experimental studies and integrated analysis of the data,the following results are obtained.From the perspective of yield traits and oil characteristics,P.ludlowii has high quality.Judging from the contents of flavonoids and their bioactivities,P.ludlowii,P.jishanensis,P.rockii have high quality.Judging from the contents of phenolic and bioactivities,P.ostii and P.potanini have high quality.This was consistent with the quality assessment results based on chemometric analysis.Therefore,wild peonies can be exploited as a valuable functional resource plant. |
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