Antioxidant Activity Of Jute Leaf Extract And The Synthesis Mechanism Of Flavonoids In Jute

Plants with bioactive specialized metabolites,also referred to as medicinal plants,have been used by humans and other primates for thousands of years.Recently,researchers focusing on plant bioactive compounds due to being easily accessible and are believed to be effective with fewer side effects in comparison with modern drugs in the treatment of different diseases.Jute leaves are rich in secondary metabolites such as flavonoids and polyphenols,which have high medicinal value and are used to treat different diseases.The accumulation levels of bioactive compounds inside the plant are highly influenced by variety.However,the specific stage of growth and tissues at which the most prominent bioactive contents and biological activities are yet to be elucidated.In addition,there has no information about the optimization of extraction,how to biosynthetic pathway alters the flavonoids accumulation with different growth stages.Because of that,the present study was carried out to optimize the extraction condition,screen out the superior variety for phenolic compound and antioxidant activities,quantification of the phenolic compounds in different growth stages and parts,as well as the molecular mechanism of flavonoid biosynthesis,accumulation,and regulation at different growth stages,was initially revealed.The major findings of this study were summarized as follows:1.Ultrasound-Assisted Extraction(UAE)of Corchorous olitorius Leaves:Process Optimization,and Antioxidant ActivitiesThis study employed ultrasound-assisted extraction(UAE)through response surface methodology(RSM)to optimize the extraction parameters of flavonoids and polyphenols from jute leaf extracts.Based on single-factor investigations,a four-factors-five-level Central Composite Design(CCD),including 30experimental runs,has been applied to optimize the extraction conditions via ultrasound-assisted extraction(UAE).Results demonstrated that all models were significant polynomial quadratic equations(p<0.05),with a non-significant lack of fit at p>0.05 and R²in excess of 0.90.The maximum yield of the total flavonoid content(7.81 mg RE/g DW)and total phenolic compound(14.56 mg GAE/g)were recorded at the independent parameters combination(ethanol concentration,temperature,and ultrasound irradiation time 80%,55?,and 45 min,respectively).Under these optimized conditions,TFC(6.97±0.16 mg QE/100g DW)and TPC(14.46±0.46 mg GAE/g)were closely correlated with the predicted value and significantly superior to the heat reflux extraction(HRE)(3.63±0.22 mg QE/100 g DW,11.60±0.90 mg GAE/g).While the modeled equation suits the data,it suggests that the experimental appraisals are consistent with the results of response surface methodology models.Furthermore,the antioxidant test of the sample extract revealed a good DPPH.ABTS,hydroxyl Radical scavenging activities with IC₅₀values of 313.35,199.53,and 642.33?g/mL,respectively.It is the first attempt to optimize UAE extraction variables of phenolic compounds.Results indicate that the developed UAE technique is a powerful,rapid,and straightforward approach of flavonoids and polyphenols with antioxidant activity.2.Analysis of Active Components,Mineral Content and Antioxidant Activity of Leaves Extracts from Different Jute varietiesIn addition to fiber,Corchorus spp(jute)leaf is also rich in secondary metabolites and is used in folk medicine in jute-producing communities.It has been reported that jute halts the progression of and helps manage different chronic diseases like tumors,obesity,diabetes,and cardiovascular diseases.Various phytochemical,mineral,and antioxidant potency properties of 30 varieties belonging to Corchorus capsularis and Corchorus olitorius were evaluated in the current study.The results demonstrate that total flavonoids and polyphenols range were 3.04 to 13.66 mg rutin equivalent(RE)/g and 5.12 to 7.78 mg gallic acid equivalent(GAE)/g DW,respectively.Total tannin and saponin content in both species was13.08 to 26.95 mg tannic acid(TAE)/g and 34.45 to 114.59 mg tea saponin(TSE)/g DW,respectively,when analysed for the first time.Moreover,this study sincerely establishes that jute leaf is an excellent source of mineral elements(magnesium,zinc,and selenium)and could also be a good energy source.The antioxidant properties of samples were examined with three unique strategies,including DPPH,FRAP,and ABT values of leaf extract ranged from 206.42 to 351.77?g/mL(IC₅₀),16.69 to 94.69 mmol Fe(?)/g DW,and 50.27 to149.90 mmol Trolox equivalent(TE)/g DW,respectively.A principal component analysis(PCA)explained 58.52%of the variance of studied parameters,while a hierarchical cluster analysis(HCA)was performed to construct five distinct groups based on their secondary metabolites content and antioxidant activities.Therefore,this study facilitates the selection of the excellent varieties that might be used as new materials for developing industrial and medicinal uses and sorting varieties for future genetic engineering purposes to enhance a particular bioactive compound and its natural antioxidants beneficial for human health.3.Phenolic profiling of leaves extracts from different stages of leaves,stem,and root of C.capsularis&C.olitoriusC.capsularis and C.olitorius possess a wide range of natural compounds with a variety of distinct biological features.The phytochemical components and antioxidant activities of various parts extract of C.capsularis and C.olitorius at different growth stages were studied in this work.Total phenols and flavonoids,content from leaves,stem,and root extracts were evaluated spectrophotometrically.For leaves,stems,and roots,the flavonoid content ranged from 3.93-7.02,0.68-3.70,0.8-3.25 mg RE/g DW,respectively.Total polyphenol content varied from 5.78-10.25 mg GAE/g for leaf,0.52-5.08 mg GAE/g DW for the stem,and 0.50-6.34 mg GAE/g DW for root.The highest contents of total phenols,flavonoids,were determined in the leaves at the 3^rd(pre-flowering)stage,followed by the 4th stage(post-flowering),whereas stems and roots displayed the content changes vice-verse with growth stages.This investigation indicates that quantitative changes in phytochemical component concentrations and antioxidant capacity occur in different parts and growth phases.Combined analysis of GC/MS and HPLC demonstrated the presence of six major phenolics compounds,including chlorogenic acid,isoquercitrin,hyperoside,adhyperforin,1,3-di-O-caffeoyquinic acid,and 3,4-di-O-caffeoyquinic acid were determined by a corresponding conversion of the peak area and their elution times were 19.30,33.9,34.4,35.9,37.3 and39.1 min,respectively.Antioxidant capacity was significantly affected by growth stages,and the leaves of both species had more antioxidant potential than stems.This study established that the plant's parts and developmental phases influence the phytoconstituents and antioxidant capacity of C.olitorius and C.capsularis.4.Comparative Transcriptome Analysis of C.olitorius leaf reveals the Molecular Mechanism of Flavonoid Biosynthesis,Accumulation,and regulation during different growth stagesFlavonoids are the main chemical compounds in leaves of C.olitorius.However,the genetic molecular mechanisms of flavonoid biosynthesis are not well understood.This study performed comparative transcriptome technology to investigate the molecular mechanism of flavonoids biosynthesis and accumulation-related genes in C.olitorius from four different growth stages.The total flavonoid contents at different growth stages were also analyzed.Illumine Hiseq 2000 platform averagely generated about 6.53 Gb bases per sample,average mapping ratio with reference genome is 89.10%,and 24,658genes were identified,of which 22,982 of them are known and 1,687 of them are novel genes.Of these,10398 were annotated in the Gene Ontology(GO)database,and 4203 were annotated in the KEGG database.Thirty-one of the DEGs annotated by the KEGG database were involved in the flavonoid pathway.The resultant WGCNA co-expression network included 19 co-expression modules,identified several hub genes related to the flavonoid biosynthesis and regulation.In the comparative analysis of both varieties,it was observed that 31 DEGs encoded 11 key enzymes were associated with flavonoid biosynthesis.The expression levels of PAL,4CL,HCT,and FLS gradually increased from stage 1^st(H1)and reached a peak in stage 4^th(H4)in the V1 variety.On the other hand,in V2,variety is highly expressed in the 3^rd(L3)stage.F3H and DFR exhibited a similar trend in both varieties and were highly expressed at the 3rd stage.These results provide insights into the molecular mechanism of flavonoid biosynthesis,accumulation,and regulation in C.olitorius,which laid the foundation for mining candidate genes for flavonoid synthesis.