Moleules 213, 18, 1229-124; doi:1.339/moleules1811229 OPEN ACCESS moleules ISSN 142-349 www.mdpi.om/journl/moleules Artile Yields, Phenoli Profiles nd Antioxidnt Ativities of Ziziphus jujue Mill. in Response to Different Fertiliztion Tretments Chun-Sen Wu 1, Qing-Hn Go 2, Roger Keith Kjelgren 3, Xu-Dn Guo 4 nd Min Wng 1, * 1 2 3 4 College of Food Siene nd Engineering, Northwest A & F University, Yngling 7121, Shnxi, Chin; E-Mil: wuhunsen@126.om Shool of Puli Helth, Ningxi Medil University, Yinhun 754, Ningxi, Chin; E-Mil: goqinghn85@126.om Deprtment of Plnts, Soils, nd Climte, College of Agriulture, Uth Stte University, Logn, UT 84322, USA; E-Mil: roger.kjelgren@usu.edu Chinese Cerels nd Oils Assoition, Beijing 137, Chin; E-Mil: guoxudn123@126.om * Author to whom orrespondene should e ddressed; E-Mil: wngmin2566@nwsuf.edu.n or wngmin2566@163.om; Tel.: +86-29-879-2816; Fx: +86-29-879-2486. Reeived: 21 August 213; in revised form: 1 Septemer 213 / Aepted: 17 Septemer 213 / Pulished: 27 Septemer 213 Astrt: Inresing demnd for more jujue (Ziziphus jujue Mill.) prodution requires understnding the speifi fertiliztion needs of jujue trees. This study ws onduted to ompre fruit yields, phenoli profiles nd ntioxidnt tivity of jujue in response to different fertilizers. Applition of orgni fertilizer ppered to enhne the phenolis nd ntioxidnt tivity umultion of jujues, ompred to onventionl fertilized jujues. Amongst inorgni fertilizers, supplementl potssium s n individul nutrient improved the umultion of phenolis in jujues. Our results demonstrte tht phenolis levels nd ntioxidnt tivity of jujue n e mnipulted through fertilizer mngement nd trked y following pronthoynidin onentrtions. In prtil prodution ontext, the omintion of orgni fertilizers nd inorgni fertilizers suh s more supplementl individul potssium, nd less supplementl individul nitrogen nd phosphorus, might e the est mngement omintion for hieving higher phenoli onentrtion, stronger ntioxidnt tivity nd good hrvest. Keywords: jujue; orgni fertilizer; inorgni fertilizer; phenolis; ntioxidnt tivity
Moleules 213, 18 123 1. Introdution Jujue (Ziziphus jujue Mill.) hs een known s ntive fruit in Chin for t lest 4, yers [1]. Nowdys, jujues hve flourished nd re widely distriuted in Asi, Austrli nd Europe [2]. This fruit is not only flvorful, ut lso ommonly used in Trditionl Chinese Mediine for detoxifition, preventing nemi, nlepti, pllitive nd immunity improvements [1]. Beside the designted uses, jujues trees re ttrtive to reserhers nd produers for their drought tolerne to severe wter defiits [3,4]. In Chin, jujue is eing more populr for offering perennil woody speies tht redues soil erosion while produing n eonomi rop following the government poliy of onverting smll grin prodution to onservtion forestry on the Loess Plteu. For more jujue prodution, there is n urgent need for the speifi fertiliztion of jujue trees. Trditionl intensive griulture imed t mximum produtivity with lrge mounts of inorgni fertilizers nd pestiides re now eing lmed for delining soil fertility nd negtive environmentl effets [5]. The optiml pplition of pproprite fertilizers for sustinle soil mngement nd eonomi yield is very importnt for jujue prodution. The presene of undnt phenolis in jujue my explin the helth-promoting effets oserved in vitro, in vivo, nd in nutritionl trils with humns [2]. In the effort to improve dietry ntioxidnt ontents, phenolis hve often een the trget for enhnement. We hve previously reported the effets of vrieties, ripening stges nd proessing methods on the umultion of phenolis in jujue [6 8]. Phenolis in plnt tissues might lso e ffeted y environmentl ftors suh s fertilizers (nutrient supply) [9]. It hs een postulted tht reltive differenes in relese of nutrients from vrious fertilizers ould led to different ron/nitrogen rtios nd onsequently differenes in the prodution of seondry metolites (suh s phenolis) in plnts [1]. This topi is of high relevne to phenoli prodution in plnts nd there is prtiulr interest in understnding the potentil effets of fertilizers. Severl previous studies hve oserved phenoli vrition in strwerry, tomto nd se ukthorn erry grown with different fertilizers, ut were somewht inonlusive [11 13]. To the est of our knowledge, there is sene of informtion out the effets of different fertilizers on the phenolis nd ntioxidnt tivity of jujue fruit. In the present work, populr fresh-eten ultivr of Ziziphus jujue Mill., lled per-jujue or Lizo ws seleted s the experimentl plnt. The gol of our study ws to evlute the effet of different fertilizers on the vrition in totl phenoli ontent (TPC), totl flvonoid ontent (TFC), totl pronthoynidin ontent (TPA), ntioxidnt tivity nd individul phenoli ompounds in jujue (Ziziphus jujue Mill. v. Lizo). Thus, in the present work, orgni fertilizer [iogs residue fertilizer (BRF) nd deomposed soyen mel fertilizer (DSM)] were ompred with inorgni fertilizer [omplete NPK fertilizer (NPK)] nd n unfertilized ontrol (CK) on the umultion of phenolis nd ntioxidnt properties in jujue. Moreover, the omprisons of NPK to the individul inorgni nutrients [nitrogen (N), phosphorus (P), potssium (K)] were studied. Furthermore, we investigted the reltionship etween ntioxidnt tivity nd phenolis.
Moleules 213, 18 1231 2. Results nd Disussion In the present study, jujues grown with different fertilizers were evluted nd ompred for their yields, TPC, TFC, TPA, ntioxidnt tivity nd phenoli ompounds for the first time. As otined, jujue ws undnt in phenolis nd displyed signifint ntioxidnt tivity, similr to our previous studies [6 8]. Tle 1 presents tht jujue yields signifintly inresed with ll fertilizer pplition in respet of CK, whih is similr to the results of previous study in priot [14]. Complex NPK fertilizer is the most effiient fertilizer in the yields of jujue trees (Tle 1), while orgni fertilizer is not so effiient. These results re in greement with previously pulished informtion on plm [15] nd priot [14]. Applition of individul potssium to jujue trees produes muh higher yield thn phosphorus input (Tle 1). The enefiil tion of potssium hs een disovered on the itrus tree [16]. Tle 1. The experimentl fertilizer mngement nd yields of jujue trees. Plots Tretment Fertilizing mount (g/tree) Yields (kg/tree) Nitrogenous Fertilizer (N) 545 g (Nitrogen) 11.56 ± 1.26 Phosphti Fertilizer (P) 12 g (Phosphorus) 1.51 ±.7 Potssi Fertilizer (K) 251 g (Potssium) 11.98 ± 1.15 Inorgni Fertilizer Orgni Fertilizer Complete NPK Fertilizer (NPK) Biogs Residue Fertilizer (BRF) 22 g (Nitrogen) 12 g (Phosphorus) 251 g (Potssium) 5g (orgni mtter: 5.65 g/kg FW; N: 3.6 g/kg FW; P: 4.96 g/kg; K: 12.14 g/kg) 13.22 ± 1.5 1.77 ± 1.19 Deomposed Soyen Mel (DSM) 4 g (orgni mtter: 76.9 g/kg FW; N:41.31 g/kg FW; P: 9.8 g/kg; K: 15.74 g/kg) 11.21 ± 1.2 CK unfertilized ontrol (CK) 8.33 ±.43 Dt expressed s the men ± SD (n = 3). Mens within the sme olumn followed y different letters were signifintly different t p <.5. Phenolis, espeilly the pronthoynidins in fruits, re of gret interest y onsumers nd reserhers euse of their potent ntioxidnt pity nd possile protetive effets in humn helth [11]. TPC, TFC nd TPA levels of jujue in response to different fertilizer tretments re presented in Figure 1. Jujues with fertilizer tretment displyed drmtilly lower TPC, TFC nd TPA thn CK (Figure 1). The CK jujue trees grown in the lol nturl environment resulted in higher phenoli ontent in the fruit ompred to the fertiliztion tretments, ut growing jujue nturlly on the infertile Loess Plteu without fertiliztion redues yields sustntilly. Aundnt phenolis in CK jujues re prtilly due to the infertile soil indued n unfvorle growing environment, nd so tht jujue lloted more resoures to synthesize defensive phenolis to protet limited nutrient resoures from diseses or insets [17,18]. Consumers often pereive tht orgnilly grown fruits re of etter qulity, helthier nd more nutritious thn onventionlly-produed ounterprts [19]. When ompring jujues grown with orgni fertilizer (BRF nd DSM) to onventionl hemil fertilizer (omplete NPK), orgni fertilizer is effiient in umulting TPC, TFC nd TPA (Figure 1). These results re in greement with previous oservtions tht higher phenoli onentrtions our in orgnilly fertilized peh
Moleules 213, 18 1232 nd per [2], mrionerry [21], strwerry [22] nd tomto [12]. The ove result my e prtilly ttriuted to the differenes in nutrient soures etween orgni nd the omplete NPK inorgni fertilizer. The orgni fertilizers BRF nd DSM hve lrge mounts of ron-rih orgni mtter (i.e., humi id or humus) tht ould replenish the soil orgni mtter nd improve soil struture nd fertility [23,24]. As known, the lne of ron to nitrogen is neessry to produe phenolis in plnts [1]. Due to the plnts nnot llote the resoures to growth simultneously, dded orgni fertilizer with undnt ron my push jujue tree to llote more resoures to synthesize phenolis [18,25]. Figure 1. Chnges of totl phenol, flvonoid nd pronthoynidin ontent of jujue produed with different fertilizer tretments. Totl phenoli ontent (mg gli id eq./1g FW) 75 6 45 3 15 e A de d Totl flvonoid ontent (mg Rutin eq./1g FW) 4 35 3 25 2 15 1 5 de e B d Fertilizer tretment Fertilizer tretment 45 C The pronthoynidin ontent (mg gli id eq./1g FW) 4 35 3 25 2 15 1 5 d d Fertilizer tretment A: totl phenoli ontent; B: totl flvonoid ontent; C: totl pronthoynidin ontent. Inorgni fertilizer tretments (N, P, K nd NPK), orgni fertilizer tretments (BRF nd DSM) nd CK (unfertilized ontrol). The vertil rs represent the SD (n = 3) nd rs mrked with no letters in ommon re signifintly different (p <.5). Inorgni fertilizer is onstntly used in fruit prodution euse it is hep nd hs high impt on the yields of jujue trees. Supplementl potssium s n individul nutrient improved the umultion of TPC, TFC nd TPA (Figure 1), similr to wht ws seen in priot fruit [26]. Suh n impt ould e prtilly due to potssium tivting physiologil metolism retions in plnts nd plying n importnt role in growth nd wter-use effiieny [27]. The individul nutrient nitrogen pplition deresed the TPC, TFC nd TPA (Figure 1), onsistent with studies of Aridopsis thlin [28] nd
Moleules 213, 18 1233 rooli heds [29]. Negtive effets of nitrogen on phenolis n possily e ttriuted to ompetition for phenyllnine, whih n either e used in phenoli synthesis, or e inorported into protein syntheti pthwys [3,31]. Menwhile, nitrogen is effiient in improving the protein umultion [28,29], nd so phenoli levels re deresed for ertin mount of phenyllnine. As evluted in our study, phosphorus showed negtive impts on the umultion of phenolis in jujue, exept for prototehui id. This response is in ontrst to findings on grden sge [32], ut suh inonsisteny ould e ttriuted to speies differenes. Finlly, the miniml impt of the omplete NPK fertilizer ould e due to the synergisti effets of supplementl nitrogen, phosphorus nd potssium. The ddition of nitrogen nd phosphorus my redue the umultion of phenolis in jujues. We elieve tht more potssium with less phosphorus nd nitrogen dded re enefiil to the phenolis in jujues. The detiled intertions mong the ville nutrients nd other environmentl onditions will e explored in our future work. A lrge sreening study of fruit extrts from numer of speies reported vrile onentrtions of ntioxidnt ompounds, whih sometimes did not orrelte with ntioxidnt tivity [33], owing to mixture of their synergisti nd ntgonisti intertions. For omprehensive understnding, four ssys inluding eletron or rdil svenging nd lipid peroxidtions were estlished to evlute the ntioxidnt tivity indued y jujue trees fertilized y different fertilizers. The pttern of DPPH nd reduing power mong ll these fertilizer tretments somewht mirrored the ove tendeny, with the CK hving the highest, followed y the two orgni tretments nd K tretment (Figure 2). However, ABTS + svenging tivity of ll tretments (Figure 2) re hnged signifintly, nd the orgni fertilizer tretments BRF nd DSM re the highest, followed y the CK nd K tretments. In ddition, the impt of fertiliztion tretments on ntioxidnt tivity oeffiient (AAC) showed the fewest differenes nd did not follow n existing pttern (Figure 2). As known, the β-rotene-linolei id ssy determines the lipid peroxidtions of ntioxidnts [34]. Therefore, this pttern of AAC suggested tht the phenolis sujet to lipid peroxidtions in jujues were not hnged oviously following different fertilizer tretments. As for individul phenoli ompounds, prototehui id, tehin, epitehin nd rutin in jujues were refully monitored nd their responses to different fertilizers ompred (Tle 2). As reported in Tle 2, the hnges in phenoli ompounds were omplited nd inonsistent. Unexpetedly, only rutin hnges follow TPC, TFC nd TPA. Orgni fertilizer BRF nd DSM tretments resulted in higher ontents of the four phenoli ompounds thn omplete NPK tretment. Menwhile, the tehin, epitehin nd rutin ontents of K-fertilized jujue were remrkle in the inorgni fertilizer tretments. Jujues produed y different fertilizers differ in their ntioxidnt pity nd phenoli omposition. As evluted in our study, levels of quntified phenolis ould not explin ll the hnges of ntioxidnt tivity with the different fertilizer tretments. This finding ws ttriuted to the synergisti nd ntgonisti effets from individul phenolis on their expressed ntioxidnt tivity [35,36]. Therefore, the orreltions mongst the TFC, TPC, TPA nd ntioxidnt tivity were evluted in this study (Tle 3). Interestingly, TPA showed remrkle orreltions to TPC, TFC nd ntioxidnt tivity. Evluted in our study, pronthoynidins might e one of the mjor phenoli ompounds ffeted y fertilizers. In other words, phenolis nd ntioxidnt tivity of jujue n e mnipulted through fertilizer mngement nd trked y following pronthoynidin onentrtions.
Moleules 213, 18 1234 Figure 2. The ntioxidnt tivity of jujue fruit produed y different fertilizers. 1 A 7 B DPPH svenging tivity (mmol Trolox eq./1g FW) 9 8 7 6 5 4 3 2 1 e d de d ABTS.+ svengin tivity (mmol Trolox eq./1g FW) 6 5 4 3 2 1 d d Fertilizer tretment Fertilizer tretment Antioxidnt tivity oeffiient (AAC) 1 9 8 7 6 5 4 3 2 1 d C Fertilizer tretment Reduing power (mg Vitmin C eq./1g FW) 1 9 8 7 6 5 4 3 2 1 D Fertilizer tretment A: DPPH svenging tivity; B: ABTS + svenging tivity; C: ntioxidnt tivity oeffiient; D: reduing power. Inorgni fertilizer tretments (N, P, K nd omplete NPK), orgni fertilizer tretments (BRF nd DSM) nd CK. The vertil rs represent the SD (n = 3) nd rs mrked with no letters in ommon re signifintly different (p <.5). Tle 2. Phenoli ompounds in the jujue fruit grown y different fertilizers (mg/1g FW). Tretment Prototehui id (+)-Ctehin ( )-Epitehin Rutin N 3.82 ±.68 22.48 ± 4.79 33.18 ± 6.7 3.49 ±.44 d P 7.18 ± 1.31 28.38 ± 1.76 42.62 ± 3.65 3.34 ± 1.17 d K 4.82 ±.67 34.11 ± 3.89 47.36 ± 8.2 6.18 ±.24 NPK 4.3 ±.58 29.56 ±.43 42.66 ± 5.97 3.98 ±.72 d BRF 5.7 ±.93 3.97 ± 2.82 49.13 ± 7.3 5.78 ±.51 DSM 6.4 ±.2 33.68 ± 3.13 54.19 ± 2.55 8.52 ± 1.17 CK 14.8 ± 2.36 28.5 ± 3.6 43.57 ± 7.31 11.52 ± 1.8 Inorgni fertilizer tretment (N, P, K nd NPK), orgni fertilizer tretment (BRF nd DSM) nd CK. Dt expressed s the men ± SD (n = 3) nd mirogrms per 1 grm of fresh weight. Mens within the sme olumn followed y different letters were signifintly different t p <.5.
Moleules 213, 18 1235 Tle 3. Correltion nlysis mong TPC, TFC, TPA, ntioxidnt tivity nd phenoli ompounds. TPC TFC TPA DPPH ABTS AAC Reduing power TPC 1.99 **.92 **.95 **.75.711.943 ** TFC.99 ** 1.977 **.828 *.851 *.793 *.976 ** TPA.92 **.977 ** 1.775 *.97 **.828 *.926 ** Prototehui id.641.637.58.86 *.175.51.745 (+)-Ctehin.562.483.617.471.738.66.381 ( )-Epitehin.559.569.66.473.822 *.751.443 Rutin.963 **.928 **.875**.925 **.654.716.978 ** ** Correltion is signifint t the.1 level (2-tiled, p <.5); * Correltion is signifint t the.5 level (2-tiled, p <.5). In this Tle, TPC: totl phenoli ontent; TFC: totl flvonoid ontent; TPA: totl pronthoynidins ontent; DPPH: DPPH svenging pity; ABTS: ABTS + svenging tivity; AAC: ntioxidnt tivity oeffiient in β-rotene-linolei id model. 3. Experimentl 3.1. Fruit Tree Orhrds The experimentl orhrds were loted t the Northwest Agriulture nd Forestry University Experimentl Sttion in mid-shnxi Provine on the Loess Plteu (Mizhi County-Yulin, 11 17'E, 37 36'N; verge elevtion, 1,49 m). The orhrds hd Loess soil profile (ulk density: 1.2 g/m3; ville nitrogen: 34.7 mg/kg; ville phosphorus: 2.9 mg/kg; ville potssium: 11.9 mg/kg; orgni mtter: 2.1 g/kg; ph: 8.6). Men nnul preipittion for this re ws roughly 393 mm, flling lrgely from July to Septemer. A populr fresh-eten jujue (Ziziphus jujue Mill.) ultivr lled per-jujue or Lizo ws seleted in this study. All the experimentl dwrfed five-yer-old per-jujue trees seleted were pproximtely 2 m high, helthy nd uniform, plnted y the rndomized lok design in 3 m within-row nd 2 m etween row sping. Jujue trees were drip irrigted to mintin optimum plnt wter sttus. These trees were minly irrigted t flow rte of 4 L/h for 4 h in the looming, fruit setting nd developing stges, respetively. Six fertilizer tretments were rndomly pplied to ten single-tree replites per tretment: two orgni (BRF nd DSM) nd four inorgni (omplete NPK, individul N, P, K) in ddition to the unfertilized ontrol (CK). Fertilizer rtes (Tle 1) were suffiient nd optiml for jujue prodution in this re ording to previous studies nd prties over severl yers. No pestiides were used in our experiments. Fertilizer tretments were repeted for yers 28 nd 29. To void potentil onfounding effets of previous prodution prties t this lotion, fruit ws nlyzed from the seond-yer s hrvest. 3.2. Smple Preprtion Jujue fruit ws seleted from four sides (est, south, west nd north) of eh experimentl tree. Fruit smples were delivered to the refrigertor immeditely fter hrvest nd storge t C 4 C for susequent extrtion nlyses in two dys. The moisture ontent of the jujue ws 8.6%. Antioxidnts in jujue were extrted ording to previously desried lortory proedure [7,8]. Representtive homogenized smples (2 g) were extrted with queous methnol (6 ml, 8%, v/v)
Moleules 213, 18 1236 under ultrsoni irrdition for 2 min. Superntnts were olleted nd residue ws repetedly extrted twie. All the olleted superntnts were evported t 45 C, rought to finl volume of 25 ml with solute methnol, nd then stored t 2 C until further nlysis. 3.3. Totl Phenoli, Flvonoid, Pronthoynidins Determintion The totl phenoli ontent (TPC) in jujue ws ssessed using the Folin-Ciolteu phenol method [7,8]. Results were expressed s glli id equivlents in mg per 1 g of fresh weight (mg glli id eqution/1g FW). The totl flvonoid ontent (TFC) ws determined following modified olorimetri method desried y our lortory [7,8]. TFC ws expressed s rutin equivlents in mg per 1 g of fresh weight (mg rutin eqution/1g FW). The totl pronthoynidins ontent (TPA) ws determined using the n-buoh/hcl method s modified y our lortory [7,8]. Results were expressed s grpeseed pronthoynidins extrt (GSPE) equivlents in mg per 1 g of fresh weight (mg GSPE eqution/1g FW). 3.4. Antioxidnt Ativity Anlysis DPPH Svenging Ativity. The DPPH free rdil svenging pity of jujue extrts ws evluted ording to previously desried lortory proedure [7,8]. The extrts with n ddition of DPPH regent solution ws left to ret in the drk for 3 min. After this durtion, the sorne of the mixture ws mesured t 517 nm ginst methnol lnk. The DPPH svenging tivity of ntioxidnt extrts ws expressed s mmol of Trolox equivlent per 1 g of fresh weight (mmol Trolox eqution/1g FW). ABTS + Svenging Ativity. The ABTS + svenging tivity of jujue extrts ws evluted ording to previously reported protool [7,8]. A mixture of ABTS + solution (5 mm ) nd exess mngnese dioxide ws left to inute in the drk for 48 h to form the ABTS + rdil tion. The mixture ws then filtered nd diluted with phosphte uffer solution (.5 mol/l, ph 7.4) to n sorne of.7 t 734 nm. The finl retion mixture ontined ABTS + solution nd the extrts. Asorne of the mixture t 734 nm ws determined fter 1 min. Results were expressed in terms of mmol Trolox equivlents per 1 g fresh weight (mmol Trolox eqution/1g FW). β-crotene-linolei Aid Assy. The ntioxidnt tivity of the extrts ws tested in β-rotene-linolei id system using previously desried method [7,8]. β-crotene (2 mg), linolei id (45 mg) nd Tween-4 (35 mg) were dissolved nd mde up to volume of 1 ml with hloroform. The hloroform ws then removed through the rottory evportion, nd oxygen-sturted distilled wter ws dded to form n emulsion. Extrts were lended with the emulsion nd inuted for 6 min t 5 C. Asorne ws red t 47 nm using spetrophotometer ginst lnk (emulsion with no β-rotene) t min nd 6 min. Antioxidnt tivity mesured in the β-rotene-linolei id ssy ws expressed s ntioxidnt tivity oeffiient (AAC) lulted using the following eqution: AAC = A A 1 A 6 6 S C 6 C A C, where A 6 S is the sorne of the smple t 6 min, A C is the sorne of the ontrol smple t min nd A 6 C is the sorne of the ontrol smple t 6 min.
Moleules 213, 18 1237 Reduing Power Determintion. The reduing power model ws estlished ording to previously reported version [7,8]. Jujue extrt ws mixed with phosphte uffer (.2 mol/l, ph 6.6) nd potssium ferriynide (1%, w/v) nd inuted t 5 C for 2 min. Afterwrd, trihloroeti id (1%, w/v) ws dded to the mixture to stop the retion. A portion (1 ml) of the retion mixture ws then lended with distilled wter nd ferri trihloride solution (.1%, w/v). The resulting mixture ws inuted in the drk for 3 min, nd sorne ws mesured t 7 nm. Results were expressed in terms of vitmin C equivlents in milligrms per 1 g fresh weight (mg vitmin C eqution/1g FW). 3.5. Phenoli Compounds Anlysis Phenoli ompounds were evluted using previously reported lortory proedure with slight modifitions [7,8]. Fresh jujue fruit (2 g) from eh tretment ws extrted with ethyl ette (AR, 4 ml). The mixture ws extrted in wter under ultrsoni irrdition for 3 min nd entrifuged t 4, rpm for 1 min. Superntnt ws olleted nd the residue ws re-extrted twie. All the olleted superntnts were evported to dryness t 35 C. The residue ws then rought to 5 ml volume with solute methnol. The extrts were stored in the drk t 2 C nd susequently nlyzed y high-performne liquid hromtogrphy (HPLC). HPLC nlysis ws performed on LC-21AHT hromtogrph instrument equipped with UV-vis detetor (Shimdzu Corp., Kyoto, Jpn). Smples were injeted t mient temperture (3 C) into reverse phse Wters symmetry C18 olumn (4.6 mm 15 mm, prtile size 5 µm) with grdient of solvent A(1% methnol)nd solvent B (ph 2.6: ultrpure wter idified with phosphte) t flow rte of.8 ml/min. The solvent grdient ws progrmmed s follows: t min, 15% A; t 15 25 min, 25% A; t 65 min, 75% A; t 7 min, 15% A. Phenoli ompounds in the eluents were monitored t 28 nm. Seven phenoli ompounds, glli id; prototehui id; (+)-tehin; hlorogeni id; ffei id; ( )-epitehin; rutin nd innmi id, were supposed to e present in jujue [37,38]. Identifition of the phenoli ompounds ws omplished y ompring the retention times nd spetr in smples to those of phenoli ompounds stndrds. Eh smple ws nlyzed three times y HPLC. 3.6. Sttistil Anlysis Dt from this study were expressed s men ± stndrd devitions (SD) for the single-tree replite determintions of eh fertilizer tretment. Vrine mong dt ws ompred y Dunn s test, nd Person orreltion test etween mens ws nlyzed y PASW Sttistis 18 (SPSS In., Chigo, IL, USA). Sttistil signifine ws delred t p<.5. 4. Conlusions Jujue fruit produed y different fertilizers differ in their ntioxidnt pity nd phenoli omposition. Nturl growing prties indue high phenoli onentrtion nd strong ntioxidnt tivity t the ost of muh lower yields. Orgni fertilizers nd inorgni fertilizers suh s more potssium, less nitrogen nd phosphorus re effiient in simultneously improving yields, phenolis
Moleules 213, 18 1238 levels nd ntioxidnt tivity. Pronthoynidins ould e the mjor ompounds mong the phenolis ffeted y fertilizers nd were used s proxy to estimte the effets of fertilizers on the phenoli onentrtion nd ntioxidnt tivity. These results lerly demonstrte tht phenolis nd ntioxidnt tivity in jujues depend on fertilizer type nd ould e trked y following pronthoynidin onentrtions. In orhrds, phenolis nd ntioxidnt tivity of jujues ould e mnipulted through fertilizer mngement. Aknowledgments We re grteful to Zheng Guo nd Fu-Li Xu for providing the per-jujue smples nd Yu-Tng Wng for exellent tehnil ssistne. We lso ppreite the suggestions nd ssistnes of Pu-Te Wu in this study. This reserh ws supported y the Ntionl Tehnology Support Projet with federl grnt numer 27BAD88B5 nd 211BAD29B4, People s Repuli of Chin. Conflits of Interest The uthors delre no onflit of interest. Referenes 1. Go, Q.H.; Wu, C.S.; Wng, M. The jujue (Ziziphus juju Mill.) fruit: A review of urrent knowledge of fruit omposition nd helth enefits. J. Agri. Food Chem. 213, 61, 3351 3363. 2. Hung, Y.-L.; Yen, G.-C.; Sheu, F.; Chu, C.-F. Effets of wter-solule rohydrte onentrte from Chinese jujue on different intestinl nd fel indies. J. Agri. Food Chem. 28, 56, 1734 1739. 3. Cruz, Z.N.; Rodríguez, P.; Glindo, A.; Torreills, E.; Ondoño, S.; Mellisho, C.D.; Torreills, A. Lef mehnisms for drought resistne in Zizyphus juju trees. Plnt Si. 212, 197, 77 83. 4. Colldo-González, J.; Cruz, Z.N.; Rodríguez, P.; Glindo, A.; Díz-Bños, F.G.; Grí de l Torre, J.; Ferreres, F.; Medin, S.; Torreills, A.; Gil-Izquierdo, A. Effet of wter defiit nd domesti storge on the proynidin profile, size, nd ggregtion proess in per-jujue (Z. juju) fruits. J. Agri. Food Chem. 213, 61, 6187 6197. 5. Jnvier, C.; Villeneuve, F.; Alouvette, C.; Edel-Hermnn, V.; Mteille, T.; Steinerg, C. Soil helth through soil disese suppression: Whih strtegy from desriptors to inditors? Soil Biol. Biohem. 27, 39, 1 23. 6. Go, Q.-H.; Wu, C.-S.; Wng, M.; Xu, B.-N.; Du, L.-J. Effet of drying of jujues (Ziziphus juju Mill.) on the ontents of sugrs, orgni ids, lph-toopherol, et-rotene, nd phenoli ompounds. J. Agri. Food Chem. 212, 6, 9642 9648. 7. Wu, C.-S.; Go, Q.-H.; Guo, X.-D.; Yu, J.-G.; Wng, M. Effet of ripening stge on physiohemil properties nd ntioxidnt profiles of promising tle fruit per-jujue (Zizyphus juju Mill.). Si. Horti. 212, 148, 177 184. 8. Go, Q.H.; Wu, C.S.; Yu, J.G.; Wng, M.; M, Y.J.; Li, C.L. Texturl hrteristi, ntioxidnt tivity, sugr, orgni id, nd phenoli profiles of 1 promising jujue (Ziziphus juju Mill.) Seletions. J. Food Si. 212, 77, 1218 1225.
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