不同炮制时间的荆芥炭色度值与多项指标的相关性研究

Study on Correlation of Chromaticity Value with Multiple Indicators in Schizonepeta tenuifolia Charcoal of Different Processing Time

目的:研究不同炮制时间(0~40 min,下同)的荆芥炭色度值与多项指标的相关性,揭示荆芥炭在炮制过程中的质量变化规律,确定炮制终点时间。方法:测定不同炮制时间的荆芥炭饮片中醇溶性浸出物的含量;建立荆芥饮片及不同炮制时间荆芥炭饮片的超高效液相色谱(UPLC)指纹图谱并进行相似度评价,通过与对照品比对确认色谱峰;采用相同的UPLC条件测定不同炮制时间荆芥炭饮片中指标成分(橙皮苷、迷迭香酸、胡薄荷酮)的含量;运用色差仪测定不同炮制时间荆芥炭饮片的色度值,以炮制0 min样品为对照,计算总色值(E)和总色差值(ΔE)。对荆芥炭饮片中醇溶性浸出物、指标成分含量及色谱峰峰面积与色度值参数进行Pearson相关性分析、聚类分析和正交偏最小二乘法判别分析。确定荆芥炭炮制终点时间并验证。结果:随着炮制时间的延长,荆芥炭饮片中醇溶性浸出物的含量逐渐降低。12批荆芥饮片中共标定17个色谱峰,与对照指纹图谱的相似度均大于0.9。不同炮制时间荆芥炭饮片中共标定21个色谱峰,与炮制0 min样品图谱的相似度随着炮制时间延长而降低,其中炮制18 min后的相似度均低于0.9。确认色谱峰峰9为橙皮苷、峰10为迷迭香酸、峰17为胡薄荷酮。含量和色度值测定结果显示,随着炮制时间的延长,橙皮苷、迷迭香酸、胡薄荷酮含量均逐渐降低,荆芥炭饮片粉末颜色L、b、E值均逐渐减小,a、ΔE值均逐渐增大。Pearson相关性分析显示,荆芥炭饮片中醇溶性浸出物含量、橙皮苷含量、迷迭香酸含量、胡薄荷酮含量以及15个色谱峰(峰2、7~15、17~21)的峰面积与E值成显著正相关(P<0.01),5个色谱峰(峰1、3~6)的峰面积与E值成显著负相关(P<0.01),而峰16的峰面积与E值无关(P>0.05)。聚类分析结果显示,不同炮制时间的荆芥炭饮片被分成2类,炮制0~16 min为第1类、18~40 min为第2类。正交偏最小二乘法判别分析结果显示,荆芥炭饮片的峰6峰面积(2.800 75)、L值(2.327 54)、峰3峰面积(1.793 39)、b值(1.735 78)、峰5峰面积(1.244 04)的变量投影重要性(VIP值)均大于1。荆芥炭炮制终点时间为18 min;3次验证实验结果显示,荆芥炭饮片的L、a、b值分别为20.22~22.00、4.44~7.67、9.78~13.00,ΔE为13.50~14.12。结论:不同炮制时间荆芥炭饮片的色度值与其醇溶性浸出物含量、橙皮苷含量、迷迭香酸含量、胡薄荷酮含量以及20个色谱峰的峰面积密切相关。建议荆芥炭炮制终点时间为18 min。

OBJECTIVE:To study the correlation of the chromaticity value of Schizonepeta tenuifolia charcoal of different processing time(0-40 min,similarly hereinafter)with multiple indicators,and to reveal the quality change law of S.tenuifolia charcoal during processing and confirm the terminal time.METHODS:The contents of ethanol-soluble extracts from S.tenuifolia charcoal decoction pieces of different processing time were determined.UPLC fingerprint of S.tenuifolia decoction pieces and S.tenuifolia charcoal decoction pieces of different processing time were established,and the similarity evaluation was also conducted.The chromatographic peaks were confirmed by comparison with substance control.The same UPLC conditions were used to determine the contents of index components(hesperidin,rosmarinic acid,menthone)in S.tenuifolia charcoal decoction pieces of different processing time.The colorimetric method was used to measure the chromaticity value of S.tenuifolia charcoal decoction pieces of different processing time.Meanwhile,sample of processing 0 min was used as a control to calculate the total color value(E)and the total color difference value(ΔE).Pearson correlation analysis,cluster analysis and orthogonal partial least squares discriminant analysis(OPLS-DA)were performed on the ethanol-soluble extracts,index component contents,chromatographic peak area and chromaticity value.The terminal time of processing S.tenuifolia charcoal was confirmed,and validation test was also conducted.RESULTS:With the extension of processing time,the content of ethanol-soluble extract in S.tenuifolia charcoal decoction pieces gradually decreased.A total of 17 chromatographic peaks were identified in 12 batches of S.tenuifolia decoction piece,and its similarity with the control fingerprint was greater than 0.9.21 chromatographic peaks were identified in S.tenuifolia charcoal decoction pieces of different processing time,and its similarity with the chromatogram of sample of processing 0 min decreased with the processing time,and the similarity after 18 min was lower than 0.9.The chromatographic peak 9 was hesperidin,peak 10 was rosmarinic acid and peak 17 was menthone.The determination of content and chromaticity value showed that with the extension of processing time,the contents of hesperidin,rosmarinic acid and menthone decreased gradually;the color L,b and E values of S.tenuifolia charcoal decoction piece powder decreased gradually,and the a andΔE values increased gradually.Pearson correlation analysis showed that the contents of ethanol-soluble extract,hesperidin,rosmarinic acid and menthone,the peak areas of 15 chromatographic peaks(peak2,7-15,17-21)were significantly positively correlated with E value(P<0.01);the peak areas of 5 chromatographic peaks(peak1,3-6)were significantly negatively correlated with E value(P<0.01),but peak area of peak 16 was not related to E value(P>0.05).Results of cluster analysis showed that S.tenuifolia charcoal decoction pieces of different processing time were divided into 2 categories;the first category was processed for 0-16 min,and the second category was processed for 18-40 min.The results of OPLS-DA showed that the VIP values of peak 6 area(2.80075),L value(2.32754),peak 3 area(1.79339),b value(1.73578)and peak 5 area(1.24404)were greater than 1.The final processing time of S.tenuifolia charcoal was 18 min.The results of validation experiment showed that the L,a and b values of S.tenuifolia charcoal decoction piece were 20.22-22.00,4.44-7.67,9.78-13.00,andΔE were 13.50-14.12,respectively.CONCLUSIONS:The chromaticity value of S.tenuifolia charcoal decoction pieces of different processing time is closely related to the contents of ethanol-soluble extract,hesperidin,rosmarinic acid,menthone and the area of 20 chromatographic peaks.It is suggested that the terminal time of processing S.tenuifolia is 18 min.