| Background:Asparagus（Asparagus officinalis L.）is a perennial persistent herb in the Liliaceae family.The main edible part of asparagus is tender stem,which is rich in saponins,flavonoids,polyphenols,polysaccharides,amino acids,proteins and other active ingredients,with various effects such as anti-tumor,anti-inflammatory,hypolipidemic,hypoglycemic,antioxidant and other.The asparagus cultivation and production scale of China has now reached the first in the world,and the large amount of waste is generated during its production and processing,such as old stems,skins,leaves and roots,has been accumulated in large quantities,resulting in resources waste and environmental pollution.It has been found that these wastes are also rich in saponins,flavonoids,polysaccharides,amino acids and other components,which have considerable utilization value.Purpose:Asparagus old stems,a waste material from the production and processing of asparagus,the effect of aqueous extract of old stems on the natural aging life span of w118Drosophila melanogaster was studied.Preliminary investigation of the mechanism of aqueous extract of old stems of asparagus to retard aging in Drosophila melanogaster by metabolomics as well as network pharmacology techniques.The aqueous extract of old stems of asparagus was made into spray-dried powder by spray drying technology,and its feeding conditions,powder quality,physicochemical properties and chemical composition were investigated.The above studies provided the basis for the development and utilization of asparagus waste resources.Methods:1)The aqueous extract of old asparagus stems was concentrated to 100 mg/m L（AE）,and 0.5 m L,2.0 m L,3.5 m L,5.0 m L and 6.5 m L were added to 100 m L of Drosophila basal medium to obtain five dosing concentrations of 0.5%AE,2.0%AE,3.5%AE,5.0%AE and 6.5%AE,while the basal medium without dosing was set as blank control group（CON）;the administration time was set as youth-aged（15-30 d）and late-aged（30-45 d）.The optimal dosing times and doses for both female and male Drosophila were screened by natural aging lifespan assay and climbing assay.2)Biomarkers and metabolic pathways were analyzed by LC-MS in male Drosophila group（40 d CON vs.40 d 5.0%AE）,and in female Drosophila group（40 d CON vs.40 d 2.0%AE）respectively.3)Screening of asparagus component target genes and aging target genes by using network pharmacology,and combining the differential metabolite related genes screened by metabolomics,the intersection of component-disease genes and metabolite genes were taken into concatenation.KEGG pathway analysis and PPI network construction were performed on the concatenated genes,and node ranking was performed using maximal clique centrality（MCC）,and the top 10 core targets were finally screened.4)The spray drying process of asparagus old stem aqueous extract was optimized by examining the air inlet temperature,sample flow rate and feed liquid density.The physicochemical properties such as solubility,wettability and moisture content of the spray powder produced under the optimal process conditions were analyzed and determined,and the chemical composition in the spray dried powder was identified using UHPLC-Q-TOF-MS/MS.Results:1)The lifespan graphs showed that the survival rate of both female and male groups of Drosophila youth-aged administration was overall lower than the old-aged administration.Therefore,the optimal administration time for the aqueous extract of old stems of asparagus should be selected for the old-aged（30-45 d）.Further screening of old-aged dosing concentrations by climbing experiments,the optimal dose of 5.0%AE was finally determined for the male group,5.0%AE increased the mean,median and maximum lifespan of Drosophila by 6.35%,3.58%,6.80%（P<0.05）,and increased the climbing ability by 71.60%（P<0.01）;the optimal dose for the female group was determined as2.0%AE,2.0%AE increased the mean,median and maximum lifespan of Drosophila by10.63%（P<0.05）,9.91%（P<0.05）,4.32%,and increased climbing ability by 71.83%（P<0.01）.2)48 and 42 biomarkers with significant backregulation were found in male（40 d CON vs.40 d 5.0%AE）and female（40 d CON vs.40 d 2.0%AE）Drosophila,respectively.A total of 12 metabolic pathways related to anti-aging were identified in male Drosophila,mainly including phenylalanine-tyrosine-tryptophan biosynthesis,phenylalanine metabolism,purine metabolism,arginine biosynthesis,arginine and proline metabolism.In the female group of Drosophila,a total of 6 aging-related metabolic pathways were identified,including phenylalanine-tyrosine-tryptophan biosynthesis,tryptophan metabolism,phenylalanine metabolism,fructose and mannose metabolism,amino sugar and nucleotide sugar metabolism,and arginine biosynthesis.3)Through network pharmacology techniques,ten core targets of aqueous extract of old asparagus stems were found to act on male and female Drosophila senescence in the same way,including AMPD1,AMPD2,NT5C1A,NT5E,NT5C1B,NT5C2,NT5C,ENTPD8,ENTPD1,ENTPD3,which involved purine metabolism and nucleotide metabolism.Combined with the metabolomics results,it was found that the aqueous extract of asparagus old stems retarded aging in male Drosophila mainly by regulating purine metabolism,while it had less effect on female Drosophila.4)Through single-factor experiments,the optimal conditions for spray drying of asparagus old stems aqueous extract were determined as the air inlet temperature of130℃,the sample flow rate of 350 m L·h-1,and the feed liquid density of 1.07 g·cm-3.The experimentally obtained spray powder was delicate,dispersed,with less sticky wall,low water content,high yield,and the solubility,wettability,and moisture content were in accordance with the relevant regulations.A total of 46 chemical components such as shatavarinⅨ,rutin and isorhamnetin were detected in the spray-dried powder of asparagus old stems aqueous extract,indicating that the active ingredients in asparagus were well retained by this method.Conclusion:This study demonstrated that the aqueous extract of old stems of asparagus had good aging retarding effects on both male and female Drosophila,and the mechanism may be related to purine metabolism.It shows that the mechanism of the aqueous extract from old stems of asparagus is conserved,and has excellent medicinal value and health effects.Secondly,the spray-dried powder made from the aqueous extract of asparagus old stems is rich in nutrients,delicate,high yield,and has the unique flavor of asparagus.This study provides new ideas for the development and utilization of asparagus waste resources and the development of asparagus industry. |
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