•Near-infrared spectroscopy was applied for on-line monitoring of extraction process of TCM on the production scale.•A new algorithm of synergy interval PLS with genetic algorithm Si-GA-PLS was firstly proposed.•Si-GA-PLS model was superior to other PLS models in the prediction accuracy.There is a growing need for the effective on-line process monitoring during the manufacture of traditional Chinese medicine to ensure quality consistency. In this study, the potential of near infrared (NIR) spectroscopy technique to monitor the extraction process of Flos Lonicerae Japonicae was investigated. A new algorithm of synergy interval PLS with genetic algorithm (Si-GA-PLS) was proposed for modeling. Four different PLS models, namely Full-PLS, Si-PLS, GA-PLS, and Si-GA-PLS, were established, and their performances in predicting two quality parameters (viz. total acid and soluble solid contents) were compared. In conclusion, Si-GA-PLS model got the best results due to the combination of superiority of Si-PLS and GA. For Si-GA-PLS, the determination coefficient (Rp2) and root-mean-square error for the prediction set (RMSEP) were 0.9561 and 147.6544 μg/ml for total acid, 0.9062 and 0.1078% for soluble solid contents, correspondingly. The overall results demonstrated that the NIR spectroscopy technique combined with Si-GA-PLS calibration is a reliable and non-destructive alternative method for on-line monitoring of the extraction process of TCM on the production scale.Download high-res image (189KB)Download full-size image

•RTRT and NIR were combined to improve the quality control efficiency of TCM materials.•We established reliable NIR models for both quantitative and qualitative RTRT of Rhizoma paridis.•The quantitative RTRT outperformed qualitative RTRT with higher accuracy.Raw material examination is a critical process in the industrial production of traditional Chinese medicine (TCM); high accuracy and minimal time consumption are both required. In this study, near-infrared (NIR) spectroscopy was applied to improve the quality control efficiency of Rhizoma paridis. Partial least squares regression (PLSR) was first used to develop quantitative calibration models, and the discriminant analysis model was established to qualitatively discriminate the qualified samples from the unqualified samples. These two established NIR models were applied for real-time release testing (RTRT) of R. paridis. R. paridis saponins (RPS) ≥ 0.6% and moisture ≤ 12% were used as the quantitative releasing criteria of RTRT according to the Chinese Pharmacopoeia. Qualified samples classified by the discriminant analysis model were deemed to meet the qualitative releasing criterion of RTRT. Using the established quantitative model, 24 samples were allowed to be released to the subsequent production processes with 100% accuracy. For the qualitative RTRT analysis, three samples were misclassified as the unqualified class and were released unsuccessfully, the accuracy of the qualitative RTRT was 90%. Therefore, the quantitative RTRT was more feasible for actual manufacturing processes. Based on this study, a rapid and effective quantitative NIR spectroscopic method was proposed for the RTRT of R. paridis. The combination of RTRT and NIR spectroscopy could be a potential tool to improve the quality control efficiency of R. paridis.Graphical abstract

The application of near-infrared (NIR) spectroscopy for on-line monitoring of the extraction process of red paeony root was investigated. For NIR measurements, two fiber optic probes designed to transmit NIR radiation through a 2 mm pathlength flow cell were employed to collect spectra in real-time. Partial least squares regression (PLSR) calibration models were developed for the parameters of interest: total solid, paeoniflorin, and benzoic acid. The influences of flow rate and air bubble on the NIR spectra and calibration models were also investigated. The established models were used for on-line and real-time monitoring of extraction process, and a model updating method was proposed for the long-term usage of the developed models. Furthermore, both the moving block of standard deviation (MBSD) and relative concentration changing rate (RCCR) methods were used to identify the end point of extraction process. The results of this particular application of implementing NIR spectroscopy to monitor extraction process are very encouraging. Successful models have been built and applied on-line, which proffers real-time data and instant feedback about the extraction course, and in turn, provides improved control.

Nowadays supercritical fluid extraction (SFE) as an alternative is popular in food and pharmaceutical industries but its large scale application is often restricted economically by the confliction between recovery efficiency and selectivity. In this article, a simple but novel and efficient combined method was investigated for separating coumarins from Angelica dahurica. The experimental results showed that combining SFE and liquid–liquid extraction could improve both extraction selectivity and separation efficiency, enriching easily coumarins from 0.144% in the herb to as much as 41.68% in the concentrate.Graphical abstractResearch highlights▶ SFE was used to extract coumarins from Angelica dahurica. ▶ RIC was calculated to judge the separation efficiency. ▶ Petroleum ether/water extraction was designed to remove low polar impurities. ▶ Petroleum ether/60% methanol extraction was designed to purify the coumarins.

The solubility of imperatorin in ethyl acetate, ethanol, methanol, n-hexane, and petroleum ether was measured at temperatures ranging from (278.2 to 318.2) K at atmospheric pressure. The solubility of imperatorin in the above solvents decreased in the order ethyl acetate > methanol > ethanol > n-hexane and petroleum ether. The solubility data were well correlated with a modified Apelblat equation.

Nowadays supercritical fluid extraction (SFE) as an alternative is popular in food and pharmaceutical industries but its large scale application is often restricted economically by the confliction between recovery efficiency and selectivity. In this article, a simple but novel and efficient combined method was investigated for separating coumarins from Angelica dahurica. The experimental results showed that combining SFE and liquid–liquid extraction could improve both extraction selectivity and separation efficiency, enriching easily coumarins from 0.144% in the herb to as much as 41.68% in the concentrate.Graphical abstractDownload full-size imageResearch highlights▶ SFE was used to extract coumarins from Angelica dahurica. ▶ RIC was calculated to judge the separation efficiency. ▶ Petroleum ether/water extraction was designed to remove low polar impurities. ▶ Petroleum ether/60% methanol extraction was designed to purify the coumarins.