| Objective:To investigate the effects of plant growth regulators and processing methods on the quality of Platycodon grandiflorum by setting up a field experiment of plant growth regulators in Niuyingzi Town,Karqin Qi,Chifeng city,using the appearance characters,extracts,polysaccharides and content of Platycodon grandiflorum saponin D as evaluation indexes.At the same time,different growth years of radix platycodon were collected to investigate the effect of growth years on quality of radix platycodon.It provides scientific basis for comprehensive evaluation of the quality of Platycodon grandiflorum and standardization of collection and processing.Methods:（1）The process of planting Platycodon grandiflorum and the use of plant growth regulator（Zhuang genling）were investigated,and the field experiment of plant growth regulator（Zhuang genling）was established in the local area.（2）26 possible chemical constituents in Zhuanggenling were detected by HPLC-MS/MS.（3）Taking root length,root diameter and root branches of Platycodon grandiflorum as evaluation indexes,the appearance characters of Platycodon grandiflorum with different application concentrations in the experimental field were compared and analyzed.（4）The content of Platycodon grandiflorum extract and Platycodon grandiflorum saponin D in test field were determined according to the method of Ch.P 2020 edition.（5）Using the yield of Platycodon grandiflorum polysaccharide as evaluation index,the optimal extraction conditions of Platycodon grandiflorum polysaccharide were determined by single factor examination.（6）Molecular weight distribution and polysaccharide content of Platycodon grandiflorum polysaccharide were determined by HPSEC-MALLS-RID equipped with 18-angle laser light scatterer.（7）The contents of extract,polysaccharide and saponin D in radix platycodon from different producing areas were compared and analyzed.（8）The extract and saponin D content of Platycodon grandiflorum in different growth years were compared and analyzed,as well as the molecular weight distribution and polysaccharide content of Platycodon grandiflorum in different growth years.Results:（1）Randomized block design was used in the experiment,and the administration group and the blank group were randomly arranged in blocks.Referring to the local farmers’conventional application concentration,the application group was set with high,medium and low concentrations,and the blank plot was set without fertilization.In the second year of Platycodon grandiflorum planting,two sprayings were carried out at the interval of half a month in the flowering period of Platycodon grandiflorum.Three months after the second sprayings,samples were collected and dried.（2）Using Phenomenex Kinetex 2.6u C18 100A column,using mobile phase A:Under the gradient elution condition of 1mmol·L-1ammonium formate solution（containing 0.1%formic acid）,mobile phase B:methanol,the linear correlation coefficients r of 26 components were all greater than 0.99 in the range of 0.05～10 mg·L-1,and the detection limits were 0.03～31.60μg·L-1.Zhuang genling was detected by this method.The results showed that 26 chemical components were not detected.（3）The order of root length and root diameter of Platycodon grandiflorum was high concentration>medium concentration>low concentration>blank.The order of branch proportion of Platycodon grandiflorum was high concentration>blank>low concentration>medium concentration.The samples with medium concentration were smooth,large and had the least branches.（4）The data of the content of Platycodon grandiflorum extract and saponin D in different concentrations were obtained.The average content of Platycodon grandiflorum extract was 18.6%in blank test,26.7%in low concentration,30.9%in medium concentration and 36.2%in high concentration.The content of Platycodon grandiflorum extract was positively correlated with the application concentration of plant growth regulator.The average content of Platycodon grandiflorum saponin D in radix Platycodon grandiflorum was 0.27%in blank test,0.24%in low concentration,0.22%in medium concentration and0.19%in high concentration.The application concentration was negatively correlated with the content of Platycodon grandiflorum saponin D.（5）When the extraction parameters of polysaccharides from Platycodon grandiflorum were as follows:ultrasonic power 300W（40k Hz）,ultrasonic time 30 min,enzymolysis temperature 50℃,p H=5,compound enzyme dosage 3%,compound enzyme（cellulase:pectinase）ratio 1:2 and proteinization times 3,the yield of polysaccharides from Platycodon grandiflorum was the highest.（6）The molecular weight distribution trend of polysaccharides of Platycodon grandiflorum at different concentrations was similar.The mass fraction of polysaccharides with molecular weight less than 10k Da was greater than 90%,and that with molecular weight more than 300k Da was less than 10%.The mass fraction of small molecular polysaccharides of Platycodon grandiflorum at medium and high concentrations was greater than 96%.The average content of Platycodon grandiflorum polysaccharide in blank test was 13.63%and low concentration was 14.95%.The medium concentration was 15.83%.The high concentration was 16.63%,and the application concentration was positively correlated with the polysaccharide content of Platycodon grandiflorum.（7）The contents of radix Platycodon grandiflorum extract,radix platycodon saponin D and radix platycodon polysaccharide and their molecular weight distribution in different processing methods were obtained.The average contents of radix Platycodon grandiflorum extract were 24.6%without peeling and 33.5%without peeling.The average content of saponin D in Platycodon grandiflorum was 0.12%and 0.22%respectively.The molecular weight of polysaccharides was between 300k and 950k Da,and the average content was 15.48%.The molecular weight of polysaccharides from unpeeled Platycodon grandiflorum ranged from 600k to 4200k Da,and the average content was 15.84%.The contents of extract,saponin D,polysaccharide and molecular weight of radix platycodon without peeling were higher than those of radix platycodon without peeling.（8）The contents of radix Platycodon grandiflorum saponin D,polysaccharides and molecular weight distribution of radix Platycodon grandiflorum in different growth years were obtained.The average contents of radix Platycodon grandiflorum extract were 17.7%for one-year,14.2%for two-year and 15.7%for three-year.The average content of unpeeled Platycodon grandiflorum extract was 26.2%for annual and 26.5%for biennial.The content of Platycodon grandiflorum saponin D in peeling Platycodon grandiflorum did not change with growth years,and the content was about 0.12%.The average content of Platycodon grandiflorum saponin D in unpeeled Platycodon grandiflorum was 0.14%in annual and0.19%in biennial.The average content of polysaccharides was 15.75%,and the molecular weight of polysaccharides ranged from 120k to 2500k Da.The average content of biennial polysaccharides was 22.45%,and the molecular weight of polysaccharides ranged from 160k to 250k Da.The average content of three-year polysaccharides was 21.28%,and the molecular weight of polysaccharides ranged from 360k to 1300k Da.The results showed that there was no significant difference in the extract content of Radix platycodon in different growth years.The content of Platycodon grandiflorum Saponin D did not change with growing age.The content of Platycodon grandiflorum Saponin D increased with growth years.The content of polysaccharide was the highest in the biennial radix platycodonis.The molecular weight is minimal.Conclusion:The effects of plant growth regulators on the quality of Platycodon grandiflorum in this area can be comprehensively evaluated through the above studies.At the same time,the samples of Platycodon grandiflorum from different producing areas were systematically compared and studied,and a scientific and reasonable quality evaluation system was established to optimize the harvest year and standardize the processing method of producing areas,so as to ensure the quality of medicinal materials.The results of this study will serve as a demonstration for standardized planting of Platycodon grandiflorum and the establishment of safety production and quality evaluation system. |
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