The Flavonoid Composition In Lotus Petal And Pollen

Lotus,a perennial aquatic plant,belongs to Nymphaeaceae family Nelumbo genus,which consists only two species,Chinese lotus(N.nucifera Garetn.)and American lotus(N.lutea Pers.).In this study,we used UPLC-MS to investigate the composition and content of flavonoid in petal of 28 lotus cultivars of hybridizated parents and 26 hybrids,and that in pollen of 50 lotus cultivars.The differences of the flavonoid composition among different samples were analyzed.We choosed several samples which were suitable to produce flower tea or pollen product and also discussed the flavonoid synthesis in lotus petal and pollen.We establishmented and optimizated the UPLC analysis methods of lotus flavonoid.The UPLC methods for analyzing the flavonoid in lotus petal and pollen were developed by optimizing analytical conditions,such as the solvent system,columns,elution gradient,temperature,flow rate and so on.We established the best conditions of quantitative analysis flavonoids in lotus petal and pollen within 7 minutes.Twenty six flavonoids components in petal were detected,among which four flavonoids were firstly reported in lotus,that is,one anthocyanin,peonidin 3-O-glucuronide(Pn3GIcA),three kinds of flavonols,isorhamnetin 3-O-galactoside(Is3Gal),myricetin 3-O-arabinopyranosyl-(1?2)-galactopyranoside(My3AraGal)and isorhamnetin 3-O-rhamnopyranosyl-(1?6)-galactopyranoside(Is3Rob).Four flavonoids were firstly reported in lotus petal,including three kinds of flavonols and one kind of flavone:quercetin 3-O-rhamnopyranosyl-(1?2)-glucopyranoside(Qu3Neo),quercetin 3-O-xylopyranosyl-(1?2)-glucopyranoside(Qu3Sam),isorhamnetin 3-O-hexose(Is3Hex)and diosmetin 7-O-rhamnopyranosyl-(1?6)-glucopyranoside(Di7Rut).The total content of anthocyanins(TA)was greatly different among different samples,ranging from 0.00 to 228.15 mg/100g.Malvidin 3-O-glucoside(Mv3Glc)and delphindin 3-O-glucoside(Dp3Glc)were higher in lotus petal than other anthocyanins.Similarly,the total content of flavones and flavonols(TF)ranged from 904.27 to 3417.73 mg/100g.Quercetin and kaempferol glycosides were the main composition and can together reached more than 75%of TF.Isorhamnetin,myricetin,syringetin presented in all samples.Diosmetin was low in the petal,and existed only in a small number of samples.We detected and presumed 15 flavonoids in lotus pollen,including two kinds of flavone glycosides and 13 kinds of flavonol glycosides,which were all firstly reported in the lotus pollen.The TF in different cultivars was quite different,which fluctuated between 82.64 and 281.08 mg/100g.Three quercetin glycosides,quercetin 3-O-glucuronide(Qu3GlcA),quercetin 3-O-rhamnopyranosyl-(1?2)-glucopyranoside(Qu3Neo)and quercetin 3-O-arabinopyranosyl-(1?2)-galactopyranoside(Qu3AraGal)were higher in lotus pollen than other flavonoids.Three kaempferol glycosides were detected in only several cultivars and the content were not the same.Diosmetin glucoside and isorhamnetin glycosides presented in all detected cultivars and the content of diosmetin glycoside in pollen was very low.We detected lower syringetin-3-O-glucoside(Sy3Glc)in some cultivars.We screened all the samples for flower tea and pollen product.The TA in '12B'?'12F'and '12E' were higher,and their color were much deeper,thus these three samples were probably suitable to flower bud tea.The TF of 'Wu-Fei-Lian','Huang-Bai-Lian','5A' and'Shou-Xing-Tao' were higher,which were all above 2500 mg/100g,but their color were not deep enough,so these four samples were suitable to mixed flower tea production.The TA of 'Hong-Mu-Dan','Zhong-Ri-You-Yi-Lian','Shu-Hong-Lian' were lower than that of'12B','12F' and '12E',and their TF were lower than that of 'Wu-Fei-Lian'.Considering both TA and TF,'Hong-Mu-Dan','Zhong-Ri-You-Yi-Lian' and 'Shu-Hong-Lian' were the most suitable samples for lotus flower tea products.What's more,we clustered all 50 cultivars by using the sorts of flavonoids which were detected in lotus pollen.Results showed that cultivars in group A and group B had more sorts of flavonoids.The TF of'Xi-Hu-Hong-Lian','You-Yi-Hong-3-Hao','Gu-Dai-Lian','Fei-Yun-Qian-Ye' and'Bo-Li-Xiao-Jie' were higher,both were higher than 220 mg/100g.These five cultivars are single petal lotus and have larger quantity of pollen,compared with semidouble lotus and double lotus.So we choosed 'Xi-Hu-Hong-Lian','You-Yi-Hong-3-Hao','Gu-Dai-Lian','Fei-Yun-Qian-Ye' and 'Bo-Li-Xiao-Jie'as pollen using cultivars.