| Isatidis radix is the dried root of Isatis indigotica Fort.which has antibacterial and antiviral effects,among which the pharmacological effect of anti-influenza virus is especially obvious,resulting in increasing market demand.However,the market control of its quality is not comprehensive enough,often through the "long,thick,solid body is better" and other experience to determine its quality,lack of science,which seriously affects the clinical safety of Isatidis radix.Therefore,it is important to objectify the trait parameters of Isatidis radix and integrate the trait parameters and chemical composition to evaluate the quality of Isatidis radix and improve its evaluation criteria.At present,there is a lack of systematic research on the objectification of trait parameters of Isatidis radix and whether the appearance of traits can reflect the content of intrinsic components,resulting in the uneven quality of Isatidis radix in the market.In this study,based on the traditional empirical theory of "identification of symptoms and quality",intelligent sensory technology(color difference meter and electronic nose)was applied to objectify the trait parameters of Isatidis radix herbs,and the identification model of color difference meter and electronic nose was established to provide a method for rapid identification of the quality of Isatidis radix herbs,while the content of chemical components of Isatidis radix was quantitatively analyzed by using modern technology.The quantitative analysis of the content of chemical components of Isatidis radix was carried out,and multiple indicators such as apparent traits,color,odor and chemical composition were synthesized to comprehensively evaluate the quality of Isatidis radix herbs.The results of the study were as follows:1.Quantitative analysis of the chemical composition of Isatidis radix samples from different origins in Gansu Province revealed that there were differences in the contents of(R,S)-Goitrin,nucleoside components and total polysaccharides of Isatidis radix samples from different origins,among which the content of nucleoside components in Minle County was higher than that in Jinta County,and compared with Jinta County,there were significant differences in uridine content(P<0.05)and highly significant differences in adenosine(P<0.01).The content of(R,S)-Goitrin and total polysaccharide was lower in Minle County than in Jinta County,but there was no significant difference.2.The apparent properties of the samples of Isatidis radix from different origins in Gansu Province were measured and analyzed,and it was found that the mean values of branch number,root dry mass,diameter at the thickest point and main root length were smaller in Minle County than in Jinta County,and there were no significant differences;while the longest root length and diameter at 2 cm below the rut were larger in Minle County than in Jinta County,and there were no significant differences.The correlation analysis showed that the root dry mass was significantly and positively correlated with uridine and guanosine;the main root length was significantly and positively correlated with uridine,guanosine and(R,S)-Goitrin;the diameter at 2 cm below the rut were significantly and positively correlated with(R,S)-Goitrin and the thickest diameter showed highly significant positive correlation with(R,S)-Goitrin;the number of branches was significantly and positively correlated with the total polysaccharide content,and negatively correlated with guanosine,while the longest root length was not correlated with the chemical composition.3.The powder color of the samples from different origins of Isatidis radix was measured and analyzed,and the results showed that the color of the samples from Jinta County was brighter and more yellow compared to Minle County.And the color of Minle County was more reddish compared to Jinta County.In addition there was no significant difference in the total color difference between the 29 origins.PCA analysis could not effectively distinguish the differences of samples between origins,OPLS-DA could effectively distinguish the differences between origins,and this model could be used to analyze the samples of different origins of Isatidis radix.The VIP analysis showed that ΔE and Δa* dominated among the four parameters of chromaticity values.And by correlation analysis,it was found that ΔL* showed highly significant positive correlation with uridine and adenosine,Δa* showed significant positive correlation and highly significant positive correlation with uridine and adenosine,respectively,and ΔE showed significant positive correlation with adenosine.4.The odor of Isatidis radix samples of different origins were quantified and their response values were analyzed,and it was found that there were differences in the odor response values of Isatidis radix samples of different origins.W1 S,W1W,W2 S,W2W sensors were more sensitive to the odor of Isatidis radix samples,where compared to Minle County,W1 S and W2 S sensors from Jinta County had highly significant differences in odor response values(P<0.01)and W2 W had significant differences(P<0.05).PCA analysis can basically distinguish different origins based on sample odor,but OPLS-DA cannot distinguish origins.LDA can completely separate origins from production areas.It is possible to distinguish different origins of Isatidis radix samples by establishing LDA Isatidis radix odor discrimination model..Combined with Loadings and VIP analysis,it was found that the electronic nose with 10 sensors W5 C,W3C,W3 S,W1S and W2 W contributed more to distinguish the origin by odor.By Pearson correlation analysis,uridine and guanosine showed significant positive correlation with W2 W,but not with any other sensors;adenosine showed significant positive correlation with W1 S and W3 S,and highly significant positive correlation with W2S;(R,S)-Goitrin showed significant positive correlation with W1 W and W2W;total polysaccharide of Isatidis radix not correlated with its odor information.5.The model for rapid evaluation of the quality of Isatidis radix was constructed by entropy weight TOPSIS analysis,and it was concluded that alkanes,sulfur compounds,aromatic compounds,and organic compounds of sulfur dominated in the process of evaluating the quality of Isatidis radix.Secondly,the overall sample quality of Minle County was slightly better compared with Jinta County,while the best quality was found in Xia Zha Zhai Village,Minlian Town,Minle County and Beitan Jinshan Village,Liuba Town.In conclusion,the root surface properties of the samples from different origins were in accordance with the traditional identification method of "long,thick and solid strips are better".Secondly,the color and odor of Isatidis radix are not very obvious in the traditional empirical identification,but the objective analysis found that there are differences in color and odor between different origins of Isatidis radix,and the odor of Isatidis radix samples can be preferentially chosen to achieve rapid discrimination of the quality of Isatidis radix,which provides a new method and idea for the quality identification of Isatidis radix. |
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