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Article

Effects of Different Processing Methods Based on Different Drying Conditions on the Active Ingredients of Salvia miltiorrhiza Bunge

by
Liuwei Zhang
1,2,†,
Xuemei Zhang
1,†,
Naheeda Begum
3,
Pengguo Xia
4,
Jingling Liu
5 and
Zongsuo Liang
4,5,*
1
College of Chemistry and Pharmacy, Northwest A&F University, Yangling 712100, China
2
Shandong (Linyi) Institute of Modern Agriculture, Zhejiang University, Linyi 276000, China
3
National Center for Soybean Improvement, Key Laboratory of Biology and Genetics and Breeding for Soybean, Ministry of Agriculture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China
4
College of Life Science and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
5
College of Life Science, Northwest A&F University, Yangling 712100, China
*
Author to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Molecules 2022, 27(15), 4860; https://doi.org/10.3390/molecules27154860
Submission received: 1 July 2022 / Revised: 26 July 2022 / Accepted: 27 July 2022 / Published: 29 July 2022
(This article belongs to the Collection Qualitative and Quantitative Analysis of Bioactive Natural Products)
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Abstract

:
Compared to the traditional processing method, fresh processing can significantly enhance the preservation of biologically active ingredients and reduce processing time. This study evaluated the influences of fresh and traditional processing based on different drying conditions (sun drying, oven drying and shade drying) on the active ingredients in the roots and rhizomes of S. miltiorrhiza. High-performance liquid chromatography (HPLC) was utilized to determine the contents of six active ingredients in the roots and rhizomes of S. miltiorrhiza. The data were analyzed by fingerprint similarity evaluation, hierarchical cluster analysis (HCA) and principal component analysis (PCA). The results suggest that compared to the traditional processing method, the fresh processing method may significantly increase the preservation of biologically active ingredients. Furthermore, the findings demonstrated that among the three drying methods under fresh processing conditions, the shade-drying (21.02–26.38%) method is most beneficial for retaining the active ingredients in the roots and rhizomes of S. miltiorrhiza. Moreover, the fingerprint analysis identified 17 common peaks, and the similarity of fingerprints among samples processed by different methods ranged from 0.989 to 1.000. Collectively, these results suggest novel processing methods that may improve the yield of active ingredients for S. miltiorrhiza and may be implemented for industrial production.

1. Introduction

Salvia miltiorrhiza Bunge, from the Lamiaceae family of plants, is a well-known traditional Chinese medicine (TCM) [1] (Figure 1). The dried roots and rhizomes of S. miltiorrhiza promote blood circulation, relieve dysmenorrhea and reduce swelling [2]. More than 70 compounds in S. miltiorrhiza have been isolated and identified [3,4]. There are two groups of main bioactive ingredients: water-soluble phenolic acids, such as rosmarinic acid (Figure 2A) and salvianolic acid B (Figure 2B), and lipid-soluble terpenoid ingredients, such as dihydrotanshinone I (Figure 2C), cryptotanshinone (Figure 2D), tanshinone I (Figure 2E) and tanshinone IIA (Figure 2F) [5,6,7]. Recent studies have demonstrated that tanshinones have various biological functions, including antitumor, antibacterial, antioxidant and anti-inflammatory activities [8,9], and tanshinones are widely employed to treat multiple cardiovascular and cerebrovascular diseases and breast cancer [10,11,12,13]. Furthermore, hydrophilic phenolic acid derivatives have vital roles in the treatment of cardiovascular diseases, inflammation [14,15,16], angina pectoris and dysmenorrhea [17,18], due to their antithrombic, anticoagulation, cytoprotective, antiviral, anti-inflammatory and antioxidant effects [19,20,21]. In addition, it was recently reported that salvianolic acid B can inhibit the viropexis of 2019-nCoV spike pseudovirus [22]. Due to the excellent curative effects of S. miltiorrhiza, it is widely applied as a raw material in Chinese patent medicine, such as compound S. miltiorrhiza tablets and dripping pills, and in food additives and cosmetics in Asian countries [23]. Consequently, the demand for S. miltiorrhiza has steadily increased in recent years. China consumes an estimated 20 million kilograms of S. miltiorrhiza annually [24,25,26]. Due to the low contents of active ingredients, long growth cycle and severe quality degradation of S. miltiorrhiza [27], enhancement of the contents of active ingredients in S. miltiorrhiza has recently become an active area of research.
Many factors affect the quality of TCMs, such as growth years, harvest time, pest control, germplasm quality and postharvest processing [28,29,30]. Among them, postharvest processing is one of the most important factors. Postharvest processing may lead to changes in active ingredients that directly affect clinical efficacy and stability [31]. It has been recently reported that in the traditional postharvest processing of S. miltiorrhiza, its roots and rhizomes are dried after harvesting in the production area. After entering the market as a TCM, the roots and rhizomes are washed, softened, cut and then dried again. It thus undergoes two drying steps (a first drying step after harvesting and a second after sectioning) and a softening process. Previous findings demonstrated that the whole process is time-consuming and laborious, and the active ingredients are easily lost in the softening process [32]. Recently, it was reported that salvianolic acid B and rosmarinic acid are very soluble in water and that a longer exposure time of S. miltiorrhiza to water during the softening process leads to a more severe loss of ingredients [33]. Therefore, it is necessary to optimize the traditional processing technology of S. miltiorrhiza to reduce the loss of water-soluble phenolic acids during postharvest processing. A general approach has been to reduce the time of contact with water as much as possible. One proposed strategy is to cut fresh S. miltiorrhiza into thick pieces postharvest in the planting area [34]. In recent years, fresh processing technology for some Chinese medicines, such as Panax notoginseng (Burk.) F.H. Chen [35], Scutellaria baicalensis Georgi [36] and Angelica sinensis [37], has been explored.
Drying is one of the most important processing methods for TCMs. Drying can decrease the volume and weight of TCMs and reduce the costs of storage, transportation and packaging [38]. More importantly, it may maintain active ingredients and extend the preservation time of TCMs [39,40,41]. However, the contents and species of active ingredients can be modified during the postharvest drying period due to anti-dehydration stress [42]. There are numerous drying methods for TCMs, including microwave drying, freeze drying, steam drying, shade drying, sun drying, vacuum drying, etc. [43,44,45,46,47]. Different drying methods have different effects on the active ingredients of TCMs [48]. Sun drying, oven drying and shade drying have been reported to be the most common drying methods in the postharvest processing of TCMs [49,50]. However, comprehensive research on the processing of S. miltiorrhiza by different drying methods is lacking, and studies on the fresh processing and traditional processing of S. miltiorrhiza based on different drying conditions have not been reported. Thus, the differences in active ingredient contents and overall quality among S. miltiorrhiza materials processed with different methods remain largely unknown.
The aim of our study was to evaluate the differences between fresh processing and traditional processing, and demonstrate the feasibility of fresh processing by using HPLC to determine the contents of the active ingredients of S. miltiorrhiza processed via different methods. Meanwhile, the differences in the contents of active ingredients among different drying conditions under fresh processing were studied. In addition, to further study the impacts of different processing methods on S. miltiorrhiza, we carried out fingerprinting evaluation, HCA and PCA.

2. Results

2.1. Effects of Fresh and Traditional Processing Methods on the Contents of the Main Active Ingredients in the Roots and Rhizomes of S. miltiorrhiza

To investigate the effects of fresh and traditional processing on the active ingredients of S. miltiorrhiza roots and rhizomes, HPLC was employed to determine the contents of the active ingredients under fresh and conventional processing for each drying method (Table 1). In the samples processed by the shade-drying method, the content of total tanshinones in S2 was lower than that in S14, and the contents of salvianolic acid B, rosmarinic acid and total tanshinones in S1, S3, S4 and S5 were significantly higher than those in S14 (p < 0.05, Figure 3A), except for total tanshinone content in S1. The contents of salvianolic acid B, rosmarinic acid and total tanshinones in samples processed by the sun-drying method were significantly higher in S1, S6, S7, S8 and S9 than those in S14 (p < 0.05, Figure 3B). For the samples treated by the oven-drying method, the contents of salvianolic acid B and rosmarinic acid in S1, S10, S11, S12 and S13 were significantly higher than that in S16 (p < 0.05, Figure 3C). For the total tanshinones, there was no significant differences between S1 or S10 and S16, whereas the contents of S11, S12 and S13 were significantly higher than those of S16 (p < 0.05, Figure 3C). These results demonstrated that the fresh processing method could retain much of the contents of the active ingredients and was superior to traditional processing.

2.2. Differences in the Contents of the Main Active Ingredients among Different Drying Conditions under Fresh Processing (S1–S13)

To further reveal the effect of drying conditions on the active ingredients under fresh processing, we analyzed the differences in active ingredients among the conditions of shade drying, sun drying and oven drying (60 °C) with different moisture contents. When the moisture content was high (S1,S2, S1–S6, S1–S10), the content of salvianolic acid B decreased in the order shade drying, sun drying and oven drying. In shade-dried (S2–S5), sun-dried (S6–S9) and oven-dried (S10–S13) samples, with the extension of drying time, moisture content gradually decreased, and the content of salvianolic acid B increased (Figure 4A). For rosmarinic acid, when the moisture content was high (S1,S2, S1–S6, S1–S11), the content of rosmarinic acid decreased in the order shade drying, sun drying and oven drying. In shade-dried (S2–S5), sun-dried (S6–S9) and oven-dried (S11–S13) samples, with the extension of drying time, moisture content gradually decreased, and the content of rosmarinic acid increased (Figure 4B). The contents of the shade-dried (S4,S5) and sun-dried (S8,S9) samples were greater than those of the other processed samples. However, for the samples processed by the oven-drying method, which yielded the highest contents of rosmarinic acid and salvianolic acid B (S13), the differences from the undried sample (S1) were not significant. These results indicated that for the fresh processing method, shade drying (S4,S5) and sun drying (S8,S9) were beneficial for preserving the contents of rosmarinic acid and salvianolic acid B, while oven drying was not.
For total tanshinones, with the extension of drying time, the moisture contents gradually decreased. The content of total tanshinones under the shade drying and oven drying methods showed irregular trends. However, compared to that in S1, the contents of total tanshinones in the shade-dried (S3–S5) and oven-dried (S11–S13) samples were high. During the sun-drying process, the contents of total tanshinones continuously decreased (S1–S8); although the content of total tanshinones (S8,S9) increased, it remains less than that in S1 (Figure 4C). The contents of the shade-dried (S3–S5) and oven-dried (S11–S13) samples were greater than those of the other processed samples. However, the highest total tanshinone content was observed in the sun-dried samples (S6), although it was lower than that of the undried sample (S1). The results suggested that for the fresh processing method, shade drying (S3–S5) and oven drying (S11–S13) were beneficial for preserving the contents of total tanshinones, while sun drying was not.
Therefore, in the fresh processing method, as moisture content decreased over the drying process, the contents of salvianolic acid B, rosmarinic acid and total tanshinones changed (increased or decreased). From these results, we inferred that the shade-drying method (S4–S5) might be the best drying method for preserving the main active ingredients.

2.3. HPLC Fingerprinting and SA of S. miltiorrhiza Treated by Different Processing Methods

To further comprehensively explore the effects of different processing methods on S. miltiorrhiza, HPLC fingerprints of the sixteen groups of S. miltiorrhiza processed via different drying and cutting methods were established. The chromatographic data were analyzed using the software Similarity Evaluation System for Chromatographic Fingerprints of Traditional Chinese Medicine (Version 2012). There were a total of 17 common peaks (accounting for more than 90% of the total PA) in the HPLC fingerprint, which appeared in the 16 samples (Figure S1, see Supplementary Materials); the six reference chromatograms are shown in Figure 5A. By comparing the tR and HPLC-UV spectrum of each peak with those of the mixed standard compound, the six ingredients were marked as peak 7 (rosmarinic acid), peak 9 (salvianolic acid B), peak 12 (dihydrotanshinone I), peak 14 (cryptotanshinone), peak 15 (tanshinone I) and peak 17 (tanshinone IIA). Peak 17 (tanshinone IIA), with a large PA and stable peak time, was assigned as the reference peak to calculate the relative retention area and relative tR of the other sixteen common peaks. As shown in Tables S1 and S2, the relative tR R.S.D. of each common peak ranged from 0.036–1.640%, and the relative PA R.S.D. ranged from 7.772–64.680%. There were significant differences in the content of each ingredient of S. miltiorrhiza among different processing methods. The similarity values are shown in Table S3. The similarity values of the 16 batches of samples with the reference fingerprint ranged from 0.989–1.000, which showed that all samples had high similarity. Based on these findings, it was concluded that the different treatment methods did not significantly affect the category of bioactive ingredients of S. miltiorrhiza.

2.4. HCA of S. miltiorrhiza

HCA is a multivariate analysis method that provides visual information about raw data [51]. The relative PAs of the 17 common peaks of 16 batches of S. miltiorrhiza samples were imported into IBM SPSS 26 software to perform cluster analysis with the between-group connection method and the Euclidean square distance as the classification basis. As shown in Figure 6, the 16 batches of samples could be divided into three groups. Samples S1, S2, S3, S6, S7, S10, S11, S12, S13 and S14 were assembled into the first group; samples S4, S5, S8 and S9 were clustered into the second group; and S15, S16 were clustered into the third group. The groups were classified according to the contents of the active ingredients (Table 1). The sample sources comprised one-year-old S. miltiorrhiza plants from Tongchuan, but they belonged to different types, which may have been related to the different processing methods of TCM. The findings showed that the type of processing method can affect the quality of the TCM.

2.5. PCA of S. miltiorrhiza

PCA is a commonly used method of multivariate analysis and is usually employed in HPLC fingerprinting research [52,53]. In this study, the PA of 17 unique peaks in 16 groups of samples, as described above, was submitted to SPSS 26 for PCA. The best principal components were defined as those with eigenvalues λ > 1, and four principal components were extracted. The eigenvalues of the first four principal components were 6.843, 4.447, 1.902 and 1.452, and the cumulative contribution rate was 86.145% (Table S4), which satisfied the requirement of cumulative percentage of variance (CPV) > 70–85% for PCA. Therefore, the four principal components contained most of the information in the variables. PC1 had positive factor loadings for 10 peaks: A4, A7, A9, A10, A11, A12, A13 (cryptotanshinone), A14 (tanshinone I), A16 (tanshinone IIA) and A17 (salvianolic acid B). PC2 had positive factor loadings for 8 peaks: A1, A2, A6, A12, A13 (cryptotanshinone), A14 (tanshinone I), A15 and A16 (tanshinone IIA) (Table S5). Accordingly, the score plot of the first and second principal components, PC1 and PC2, showed apparent differences among all samples (S1–S16). As shown in the score plot of the PCA results (Figure 7), differences between S10–S13 and S6–S9 are evident on both the positive and negative sides. S16 and S14 are more closely located. S2–S5 are on the right side except for S2. The PCA clearly demonstrates substantial differences between the oven-dried and sun-dried samples, and differences among drying methods and even among moisture contents within a drying method.

3. Discussion

3.1. Fresh Processing May Be Widely Adopted for S. miltiorrhiza Processing in the Future

In the present study, we compared fresh and traditional methods of processing S. miltiorrhiza. The investigation revealed that the fresh processing method is favorable for the preservation of salvianolic acid B and rosmarinic acid. Fresh processing can avoid the washing and softening steps of traditional processing, thereby reducing the damage to the water-soluble ingredients salvianolic acid B and rosmarinic acid. For preserving tanshinones, fresh processing was generally better than traditional processing. The fingerprint SA showed that the fingerprints of the traditional and fresh processing methods are very similar, which indicates that the types of 17 active ingredients are not substantially changed under fresh processing compared with traditional processing. In general, the new technology of fresh processing offers cost and energy savings, and can maximize the retention of active ingredients, and it has fundamental significance for the processing of TCMs. Fresh processing technology for S. miltiorrhiza may become a mainstream processing technology in the future.

3.2. The Contents of Active Ingredients Changed during Processing

Changes in the contents of active ingredients during TCM processing have become a very important issue. Previous studies have suggested that the active ingredients of medicinal plants form and accumulate before harvest and that their contents decrease following harvest [54]. In the present research, we investigated whether the contents of total tanshinones, salvianolic acid B and rosmarinic acid in newly harvested plant roots and rhizomes increased after harvest. Consistent with our findings, other studies have revealed significant increases in the contents of total tanshinones and salvianolic acid B in the roots of S. miltiorrhiza in the early drying process after harvest [55,56]. One explanation for this phenomenon is that newly harvested plant materials (especially roots) still have physiological activity and that the antidehydration response of the plant is induced in the early stage of drying and dehydration after harvest [57,58]. By inducing endogenous antioxidant enzymes to produce active ingredients, the antioxidant activity of plants can be improved [59,60,61]. As both salvianolic acid B and total tanshinones in S. miltiorrhiza are effective oxygen free radical (OFR) scavengers, they play important roles in the resistance of plants to dehydration stress [62]. Therefore, the total tanshinone, salvianolic acid B and rosmarinic acid contents in S. miltiorrhiza might result from the remobilization and transformation of preharvest stored carbohydrates in roots and rhizomes by a series of primary and secondary metabolic reactions under dehydration stress.

3.3. Effects of Different Drying Conditions on the Contents of Salvianolic Acid B and Rosmarinic Acid during Fresh Processing

For the fresh processing method, shade drying (S4–S5) and sun drying (S8–S9) were beneficial for preserving the contents of rosmarinic acid and salvianolic acid B, while the other treatments were not. This result may be related to the enzymes in S. miltiorrhiza. Polyphenol oxidase (PPO) is widely distributed in plant cells and is a key enzyme causing browning [63]. There are three conditions for enzymatic browning: substrate, oxygen and enzyme. Under normal circumstances, PPO cannot directly contact phenolic substances due to the regional distribution of the membrane system. PPO primarily exists in the cytoplasm, while phenols exist in vacuoles. Therefore, enzymatic browning will not occur even in the presence of oxygen [64]. However, when S. miltiorrhiza is cut under fresh conditions, a large number of phenolic acids in vacuoles come into contact with PPO due to cell structure damage [65]. In the presence of oxygen, PPO can oxidize o-diquinone in phenolic acids by molecular oxygen [66], resulting in decreased contents of salvianolic acid B and rosmarinic acid. Therefore, it is speculated that in the present study, regardless of the drying method, PPO enzyme activity was very high when the water content was high (greater than 34%). When the water content was below 26%, PPO activity may have been greatly reduced, limiting the oxidation of salvianolic acid B and rosmarinic acid. Moreover, compared with the shade drying and sun drying methods, oven drying at 60 °C was not favorable to the preservation of rosmarinic acid and salvianolic acid B; in this process, S. miltiorrhiza was cut into thick slices regardless of water content, and the contents of active ingredients after drying were very low. Rosmarinic acid and salvianolic acid B have catechol and Ar-CH=CH-COOR structures, which are easily oxidized at high temperatures [67]. During the first oven-drying process, the temperature was not very high, but with the extension of drying time, the roots and rhizomes were also not cut into thick slices, resulting in continuous heating inside the roots and rhizomes. The internal heat was not dispersed, creating strong conditions for a series of complex enzymatic, oxidation, polymerization and other biochemical reactions, so the contents of the oven-dried samples were consistently very low. Therefore, the use of the shade-drying method (moisture content: 21.02–26.38%) or the sun-drying method (moisture content: 13.88–22.91%) may reduce the damage to rosmarinic acid and salvianolic acid B.

3.4. Effects of Different Drying Conditions on Total Tanshinone Contents during Fresh Processing

The contents of total tanshinones under the sun-drying method were significantly lower than those under the other two methods. Total tanshinones and other fat-soluble active ingredients are distributed around the periderm of the roots and rhizomes of S. miltiorrhiza [68]. Therefore, total tanshinone ingredients are sensitive to light and unstable and are thus easily decomposed under light conditions. In the sun-drying process, the materials were exposed to the sun for a long time, and due to the existence of autogenous enzymes, some functional ingredients easily decomposed, causing a severe loss of total tanshinones. However, the use of the shade-drying method (moisture content: 21.02–34.57%) or the oven-drying method (moisture content: 18.01–49.79%) may reduce the damage to total tanshinones.

4. Materials and Methods

4.1. Chemicals and Plant Materials

HPLC-grade acetonitrile was purchased from Merck Co., Inc. (Darmstadt, Germany). HPLC-grade phosphoric acid and analytical-grade methanol were purchased from Tianjin Komiou Chemical Reagent Co., Ltd. (Tianjin, China). Six reference compounds (rosmarinic acid, salvianolic acid B, dihydrotanshinone I, cryptotanshinone, tanshinone I and tanshinone IIA, HPLC ≥ 98%) were purchased from Shanghai Yuan ye Bio-Technology Co., Ltd. (Shanghai, China). Ultrapure water was generated with a You pu Ultrapure Water System (Chengdu, China).
The fresh roots and rhizomes of one-year-old S. miltiorrhiza plants were harvested in 2020 in Tongchuan (Tongchuan, China) in April, the best time of year for the harvest of the medicinal parts of S. miltiorrhiza, and were identified by Professor Zongsuo Liang (Zhejiang Sci-tech University). After removing soil and impurities, the samples were divided into 16 batches according to their weight, size and thickness.

4.2. Sample Processing

4.2.1. Fresh Processing

The roots and rhizomes of the freshly harvested S. miltiorrhiza plants were divided into 13 groups (Codes S1–S13). As shown in Table 2, different drying conditions were applied. S. miltiorrhiza roots and rhizomes were dried for different durations to achieve different moisture contents (Table 2). Then, the samples (S1–S13) were cut into 2–4 mm thick slices, and the slices were dried in an oven at 60 °C until they were completely dry (≤13.0%). All treatments were replicated three times (Figure 8).

4.2.2. Traditional Processing

The roots and rhizomes of the freshly harvested S. miltiorrhiza plants were divided into 3 groups (codes S14–S16). As shown in Table 1, different drying conditions were applied. S. miltiorrhiza roots and rhizomes were dried until they were completely dry (≤13.0%, Table 2). Then, after being washed and softened, the samples (S14–S16) were cut into 2–4 mm thick slices, and the slices were dried in an oven at 60 °C until they were completely dry (≤13.0%). All treatments were replicated three times (Figure 8).

4.2.3. Shade Drying

This method was carried out in a dark room. The S2–S5 and S14 samples were spread out in a dark, ventilated room without direct sunlight. The average temperature of the room was 13.5 °C, and the relative humidity was 55% ± 5%.

4.2.4. Sun Drying

This method was performed in an open environment. S6–S9 and S15 samples were placed on a hardboard with exposure to direct sunlight. The average temperature was 16.8 °C (mid-late March to mid-April).

4.2.5. Oven Drying

An electric constant-temperature blast-drying oven (DHG-9240A, Shanghai Jing Hong Laboratory Instrument Co., Ltd., Shanghai, China) was used to dry samples (S10–S13, S16) at 60 °C.

4.3. Preparation of Samples and Reference Standards

The dried samples were sieved through a Standard Chinese Pharmacopeia sieve-3 (355 ± 13 μm). A total of 0.5 g of each sample was accurately weighed and then placed in a 50 mL centrifuge tube. After immersion in 70% methanol for approximately 12 h, the sample was subjected to ultrasonic extraction with 20 mL of 70% methanol for 60 min at room temperature and centrifuged for 25 min at 7830 rpm. The supernatant was filtered through a 0.22 μm membrane. The samples were stored in a refrigerator at 4 °C before HPLC-PDA analysis.
An appropriate amount of each of six reference standards of rosmarinic acid, salvianolic acid B, dihydrotanshinone I, cryptotanshinone, tanshinone I and tanshinone IIA was dissolved in methanol (99.8%) to obtain the desired final contents (715.00, 3360.00, 94.500, 102.50, 135.50 and 215.00 µg·mL−1 of the mixed reference standard solution), and the mixed solution was sealed and stored in a refrigerator at 4 °C.

4.4. Instrumentation and HPLC Conditions

Fingerprinting analysis of S. miltiorrhiza was performed on a Waters 1525 HPLC system (Waters Corp., Milford, MA, USA) consisting of a binary pump, a 2996 photodiode array detector, a column temperature controller and a manual injector. Data acquisition and system control were supported by Empower 2 software. Chromatographic separation was performed on a Waters Symmetry C18 column (4.6 mm × 250 mm, 5 µm). A gradient elution of A (acetonitrile) and B (0.02% phosphoric acid solution) was utilized as follows: 0–10 min: 5–20% A; 10–15 min: 20–25% A; 15–20 min: 25% A; 20–25 min: 25–20% A; 25–28 min: 20–30% A; 28–40 min: 30% A; 40–45 min: 30–45% A; 45–50 min: 45–50% A; 50–58 min: 50–58% A; 58–67 min: 58–55% A; 67–70 min: 55–60% A; 70–80 min: 60–65% A; 80–87 min: 65% A; 87–91 min: 65–100% A. The flow rate was set to 1 mL·min−1, and the column temperature was set to 30 °C. The chromatographic peak area (PA) was monitored via the HPLC-PDA detector at wavelengths of 288 nm (rosmarinic acid, salvianolic acid B) and 270 nm (dihydrotanshinone I, cryptotanshinone, tanshinone I and tanshinone IIA). The peak information at 270 nm was applied for HPLC fingerprinting analysis.

4.5. Determination of Water Content in Sample

The moisture content was determined according to the drying method in the fourth part of the Chinese Pharmacopoeia of the 2020 version [69].

4.6. Main Peak Identification and Sample Content Determination

Under the HPLC conditions described in Section 2.4, the reference standard solution was injected into the HPLC system, and the tR and PA of the reference standard were recorded. The active ingredients of all samples were identified by comparing the tR values with those of the reference standards. The contents of the active ingredients were calculated according to the reference standard contents and PAs.

4.7. Similarity Evaluation and Statistical Analysis

HPLC fingerprint similarity analysis (SA) was evaluated with Similarity Evaluation System for Chromatographic Fingerprint (Version 2012) software, which was developed and recommended by the Chinese Pharmacopoeia Committee. HCA and PCA of all samples were performed using the Statistical Program for Social Sciences (SPSS) 26 software (SPSS Inc., Cary, NC, USA).

5. Conclusions

In this study, fresh processing and traditional processing methods based on different drying conditions were utilized to explore their effects on the active ingredients in the roots and rhizomes of S. miltiorrhiza. We used HPLC fingerprinting, SA, HCA and PCA to examine the differences in salvianolic acid B, rosmarinic acid and total tanshinone contents among S. miltiorrhiza roots and rhizomes processed by different methods. Four conclusions were drawn from the results: (1) the fingerprinting and other analyses revealed significant differences in the content of each ingredient of S. miltiorrhiza among different processing methods. (2) The fresh processing method yielded significantly greater preservation of phenolic acids and tanshinones than the traditional processing method. (3) Among the different drying conditions during fresh processing, the shade-drying method (moisture content: 21.02–26.38%) was most beneficial for retaining the active ingredients in the roots and rhizomes of S. miltiorrhiza. (4) For preserving total tanshinone ingredients in particular, due to the constant temperature and short drying time, the oven-drying method (moisture content: 18.01–49.79%) might be the most suitable drying method. For preserving the contents of rosmarinic acid and salvianolic acid B, the sun-drying method (moisture content: 13.88–22.91%) might be the most suitable drying method because it is not limited by site. These results provide a reference for improving the yield of active ingredients in the industrial production of S. miltiorrhiza. Furthermore, we hope that the current findings lead to new ideas and insights for the processing of other TCMs.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/molecules27154860/s1, Figure S1: HPLC fingerprints of all active ingredients of 16 batches of different processing S. miltiorrhiza.; Table S1: The relative retention time of the common peaks of the 16 batches of S. miltiorrhiza with different processing. Table S2: The relative peak area of the common peaks of the 16 batches of S. miltiorrhiza with different processing. Table S3: The similarity results of the common peaks of the 16 batches of S. miltiorrhiza with different processing. Table S4: Principal components initial eigenvalue and contribution rate. Table S5: Factor loading matrix after rotation. Table S6: Linear relationships table of six active ingredients. Table S7: Analytical results of precision, repeatability of six ingredients. Table S8: Analytical results of stability and recovery tests of six ingredients.

Author Contributions

L.Z.: Data curation, Formal analysis, Investigation, Methodology, Validation, Visualization, Writing—original draft, Writing—review and editing. X.Z.: Data curation, Formal analysis, Investigation, Methodology, Validation, Visualization, Writing—original draft, Writing—review and editing. N.B.: Writing—review and editing. P.X.: Validation. J.L.: Supervision. Z.L.: Conceptualization, Methodology, Writing—review and editing, Supervision. All authors have read and agreed to the published version of the manuscript.

Funding

This work was supported by Shaanxi Province Key R&D Project (2017TSCL-SF-11-2, 2020ZDLSF05-02). The funder had no role in data collection and analysis, decision to publish or preparation of the manuscript.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Conflicts of Interest

The authors declare no conflict of interest.

Sample Availability

Samples of the compounds are available from the authors.

References

  1. Peng, K.Y.; Gu, J.F.; Su, S.L.; Zhu, Y.; Guo, J.M.; Qian, D.W.; Duan, J.A. Salvia miltiorrhiza stems and leaves total phenolic acids combination with tanshinone protect against DSS-induced ulcerative colitis through inhibiting TLR4/PI3K/AKT/mTOR signaling pathway in mice. J. Ethnopharmacol. 2021, 264, 113052. [Google Scholar] [CrossRef] [PubMed]
  2. National Pharmacopoeia Commission. The Pharmacopoeia of the People’s Republic of China (Part I); China Medical Science and Technology Press: Beijing, China, 2020; pp. 77–79. [Google Scholar]
  3. Li, M.H.; Chen, J.M.; Peng, Y.; Wu, Q.L.; Xiao, P.G. Investigation of Denshen and related medicinal plants in China. J. Ethnopharmcol. 2008, 120, 419–426. [Google Scholar] [CrossRef] [PubMed]
  4. Ozdemir, N.; Ozgen, Y.; Kiralan, M.; Bayrak, A.; Arslan, N.; Ramadan, M.F. Effect of different drying methods on the essential oil yield, composition and antioxidant activity of Origanum vulgare L. and Origanum onites L. J. Food Meas. Charact. 2018, 825, 12–820. [Google Scholar] [CrossRef]
  5. Wang, X.; Susan, L.; Natschke, M.; Lee, K.H. New developments in the chemistry and biology of the bioactive constituents of Tanshen. Med. Res. Rev. 2010, 27, 133–148. [Google Scholar] [CrossRef] [PubMed]
  6. Zhou, L.M.; Zuo, Z.C.; Moses, S.S. Danshen: An overview of its chemistry, phsrmscology, phsrmscokinetics, and cilinical use. J. Clinpharmacol. 2005, 45, 1345–1359. [Google Scholar]
  7. Zhou, W.; Huang, Q.; Wu, X.; Zhou, Z.; Ding, M.; Shi, M.; Kai, G. Comprehensive transcriptome profiling of Salvia miltiorrhiza for discovery of genes associated with the biosynthesis of tanshinones and phenolic acids. Sci. Rep. 2017, 7, 10554. [Google Scholar] [CrossRef] [Green Version]
  8. Li, X.X.; Zheng, X.; Liu, Z.; Xu, Q.; Tang, H.; Feng, J.; Yang, S.; Vong, C.T.; Gao, H.; Wang, Y. CryptoTanshinone from Salvia miltiorrhiza Bunge (Danshen) inhibited inflammatory responses via TLR4/MyD88 signaling pathway. Chin. Med. 2020, 15, 120–325. [Google Scholar] [CrossRef] [Green Version]
  9. Wang, X.Y.; Yang, Y.; Liu, X.; Gao, X.M. Pharmacological properties of Tanshinones, the natural products from Salvia miltiorrhiza. Adv. Pharmacol. 2020, 87, 43–70. [Google Scholar]
  10. Lin, Y.S.; Shen, Y.C.; Wu, C.Y.; Tsai, Y.Y.; Yang, Y.H.; Lin, Y.Y.; Kuan, F.C.; Lu, C.N.; Chang, G.H.; Tsai, M.S.; et al. Danshen improves survival of patients with breast cancer and dihydroiso tanshinoneI induces ferroptosis and a poptosis of breast cancer cells. Front. Pharmacol. 2019, 10, 1226. [Google Scholar] [CrossRef] [Green Version]
  11. Xu, H.; Zhang, L.; Zhou, C.C.; Xiao, J.B.; Liao, P.; Kai, G.Y. Metabolic regulation and genetic engineering of pharmaceutical component Tanshinone biosynthesis in Salvia miltiorrhiza. J. Med. Plant Res. 2019, 4, 2591–2597. [Google Scholar]
  12. Kai, G.; Liao, P.; Xu, H.; Wang, J.; Zhou, C.C.; Zhou, W.; Qi, Y.P.; Xiao, J.B.; Wang, Y.L.; Zhang, L. Molecular mechanism of elicitor-induced Tanshinone accumulation in Salvia miltiorrhiza hairy roots cultures. Acta Physiol. Plant 2012, 1433, 34–1421. [Google Scholar]
  13. Xiao, Y.Q.; Li, L.; Liu, Y.; Ma, Y.L.; Yu, D.R. Development and innovation of traditional Chinese medicine processing discipline and Chinese herbal pieces industry. China J. Chin. Mater. Med. 2016, 41, 24–27. [Google Scholar]
  14. Petersen, M.; Simmonds, M.S. Rosmarinic acid. Phytochemistry 2003, 62, 121–125. [Google Scholar] [CrossRef]
  15. Xu, L.L.; Deng, Y.P.; Feng, L.X.; Li, D.F.; Chen, X.Y.; Ma, C.; Liu, X.; Yin, J.; Yang, M.; Teng, F.K.; et al. Cardio-protection of salvianolic Acid B through ingibition of apoptosis network. PLoS ONE 2011, 6, e24036. [Google Scholar]
  16. Zhang, Y.; Li, X.; Wang, Z.Z. Antioxidant activities of leaf extract of Salvia miltiorrhiza Bunge and related phenolic constituents. Food Chem. Toxicol. 2010, 48, 2656–2662. [Google Scholar] [CrossRef]
  17. Hu, P.; Luo, G.A.; Zhao, Z.Z.; Jiang, Z.H. Quality assessment of Radix Salviae miltiorrhizae. Chem. Pharm. Bull. 2005, 53, 481–486. [Google Scholar] [CrossRef] [Green Version]
  18. Xu, X.B.; Jiang, Q.H.; Ma, X.Y.; Ying, Q.C.; Shen, B.; Qian, Y.S.; Song, H.M.; Wang, H.Z. Deep sequencing identifies tissues-specific microRNAs and their target genes involving in the biosynthesis of tanshinones in Salvia miltiorrhiza. PLoS ONE 2014, 9, e111679. [Google Scholar] [CrossRef] [Green Version]
  19. Du, G.; Song, J.; Du, L.; Zhang, L.; Qiang, G.F.; Wang, S.B.; Yang, X.Y.; Fang, L.H. Chemical and pharmacological research on the polyphenol acids isolated from Danshen: A review of salvianolic acids. Adv. Pharmacol. 2020, 87, 1–41. [Google Scholar]
  20. Liu, Y.; Chen, J.F.; Xu, N.; Lin, W.G.; Liu, Y.M.; Chen, M.L.; Liu, D.B. Effects of fresh-cut on drying rate and quality of Panax notoginseng. China J. Chin. Mater. Med. 2019, 44, 1381–1391. [Google Scholar]
  21. Wu, Y.B.; Ni, Z.Y.; Shi, Q.W.; Dong, M.; Kiyota, H.; Gu, Y.C.; Cong, B. Constituents from salvia species and their biological activities. Chem Rev. 2012, 112, 5967–6062. [Google Scholar] [CrossRef]
  22. Hu, S.L.; Wang, J.; Zhang, Y.J.; Bai, H.Y.; Wang, C.; Wang, N.; He, L.C. Three salvianolic acids inhibit 2019-nCoV spike pseudovirus viropexis by binding to both its RBD and receptor ACE2. J. Med. Virol. 2021, 93, 3143–3151. [Google Scholar] [CrossRef]
  23. Mdadiko, C.M.; Bongo, G.N.; Mindele, L.U.; Ngbolua, K.; Mpiana, P.T.; Ngombe, N.K.; Mbemba, T.F. Effect of drying on the composition of secondary metabolites in extracts from floral parts of Curcuma longa L. Asian J. Res. Biol. Pharm. Bot. 2019, 2, 1–6. [Google Scholar]
  24. Chakraborty, R.; Dey, T. Drying protocols for traditional medicinal herbs: A critical review. Int. J. Eng. Technol. Manag. Appl. Sci. 2016, 4, 312–319. [Google Scholar]
  25. Figiel, A.; Michalska, A. Overall quality of fruits and vegetables products affected by the drying processes with the assistance of vacuum-microwaves. Int. J. Mol. Sci. 2016, 18, 71. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  26. Zhang, C.L.; Yang, D.F.; Liang, Z.S.; Liu, J.L.; Yan, K.J.; Zhu, Y.H.; Yang, S.S. Climatic factors control the geospatial distribution of active ingredients in Salvia miltiorrhiza Bunge in China. Sci. Rep. 2019, 9, 904. [Google Scholar] [CrossRef] [PubMed]
  27. Zhou, W.; Shen, Y.F.; Chen, J.F.; Dai, L.M.; Kai, G.Y.; Zhou, G.Y. Research and development of biotechnology of Salvia miltiorrhiza Bunge. J. Biol. 2007, 24, 48–51. [Google Scholar]
  28. He, C.E.; Wei, J.H.; Jin, Y.; Chen, S.L. Bioactive components of the roots of Salvia miltiorrhizae: Changes related to harvest time and germplasm line. Ind. Crop. Prod. 2010, 32, 313–317. [Google Scholar] [CrossRef]
  29. Wu, X.; Wang, S.P.; Lu, J.R.; Jing, Y.; Li, M.X.; Cao, J.L.; Bian, B.L.; Hu, C.J. Seeing the unseen of Chinese herbal medicine processing (Paozhi): Advances in new perspectives. Chin. Med. 2018, 13, 4. [Google Scholar] [CrossRef]
  30. Zhao, Z.; Liang, Z.; Chan, K.; Lu, G.; Lee, E.L.; Chen, H.; Li, L. A unique issue in the standardization of Chinese Materia Medica: Processing. Planta Med. 2010, 76, 1975–1986. [Google Scholar] [CrossRef]
  31. Zhang, X.M.; Zhang, L.W.; Zuo, X.R.; Xia, P.G.; Liang, Z.S. Study on fresh processing of Scutellaria baicalensis based on HPLC fingerprint and multi-index quantification. Chin. Tradit. Herb. Drugs 2021, 21, 45–51. [Google Scholar]
  32. Wei, G.F.; Li, C.; Liu, Q.; Li, J.; Zhang, Y.Q. Influence of washing before drying on active components of Salvia miltiorrhizae Radix et rhizoma. Chin. Tradit. Herb. Drugs 2015, 46, 2467–2470. [Google Scholar]
  33. Wang, C.; Zhang, C.X.; Shao, C.F.; Li, C.W.; Liu, S.H.; Peng, X.P.; Xu, Y.Q. Chemical fingerprint analysis for the quality evaluation of deepure instant pu-erh tea by HPLC combined with chemometrics. Food Anal. Methods 2016, 9, 3298–3309. [Google Scholar] [CrossRef]
  34. Zhao, Z.G.; Gao, S.R.; Yan, B.B.; Xie, J.; Zhang, X.M.; Li, J.; Hou, J.L.; Wang, W.Q. Study on feasibility of cutting fresh Radix et rhizoma Salviae miltiorrhizae in planting area. China J. Tradit. Chin. Med. Pharm. 2017, 32, 797–800. [Google Scholar]
  35. Liu, H.M.; Ma, S.L.; Xia, H.R.; Lou, H.X.; Zhu, F.L.; Sun, L.R. Anti-inflammatory activities and potential mechanisms of phenolic acids isolated from Salvia miltiorrhiza f. alba roots in THP-1 macrophages. J. Ethnopharmacol. 2018, 222, 201–207. [Google Scholar] [CrossRef]
  36. Bai, C.; Yang, J.; Cao, B.; Xue, Y.; Gao, P.; Liang, H.; Li, G. Growth years and post-harvest processing methods have critical roles on the contents of medicinal active ingredients of Scutellaria baicalensis. Ind. Crops Prod. 2020, 158, 112985. [Google Scholar] [CrossRef]
  37. Tang, L.Y.; Wang, Z.J.; Song, B.S.; He, Z.Q.; Wu, H.W.; Huang, L.Q. Study on feasibility of cutting process of fresh Angelica sinensis Radix. China J. Chin. Mater. Med. 2010, 35, 3147–3150. [Google Scholar]
  38. Doymaz, İ. Drying of pomegranate seeds using infrared radiation. Food Sci. Biotechnol. 2012, 21, 1269–1275. [Google Scholar] [CrossRef]
  39. Bruni, R.; Sacchetti, G. Factors affecting polyphenol biosynthesis in wild and field Grown St. John’s wort (Hypericum perforatum L. hypericaceae/guttiferae). Molecules 2009, 14, 682–725. [Google Scholar] [CrossRef] [Green Version]
  40. Li, J.; Li, C.L.; Lu, S.F. Systematic analysis of DEMETER-like DNA glycosylase genes shows lineage-specific Smi-miR7972 involved in SmDML1 regulation in Salvia miltiorrhiza. Sci. Rep. 2018, 8, 7143. [Google Scholar] [CrossRef]
  41. Tanko, H.; Carrier, D.J.; Duan, L.J.; Clausen, E. Pre- and post-harvest processing of medicinal plants. Plant Genet. Resour. 2005, 3, 304–313. [Google Scholar] [CrossRef]
  42. Chao, J.; Dai, Y.; Cheng, H.Y.; Lam, W.; Cheng, Y.C.; Li, K.; Peng, W.H.; Pao, L.H.; Hsieh, M.T.; Qin, X.M.; et al. Improving the concentrations of the active components in the herbal tea ingredient, uraria crinita: The effect of post-harvest oven-drying processing. Sci. Rep. 2017, 7, 38763. [Google Scholar] [CrossRef]
  43. Rocha, R.P.; Melo, E.C.; Radünz, L.L. Influence of drying process on the quality of medicinal plants: A review. J. Med. Plants Res. 2011, 5, 7076–7084. [Google Scholar] [CrossRef]
  44. Tian, Y.H.; Du, H.Z.; Qing, X.H.; Zhang, L.W. Effects of picking time and drying methods on contents of eight flavonoids and antioxidant activity of leaves of Diospyros lotus L. J. Food Meas. Charact. 2020, 14, 1461–1469. [Google Scholar] [CrossRef]
  45. Kong, L.S.; Yu, L.; Feng, T.; Yin, X.J.; Liu, T.J.; Dong, L. Physicochemical characterization of the polysaccharide from Bletilla striata: Effect of drying method. Carbohydr. Polym. 2015, 125, 1–8. [Google Scholar] [CrossRef] [PubMed]
  46. Su, X.Y.; Wu, Y.J.; Li, Y.; Huang, Y.F.; Liu, Y.; Luo, P.; Zhang, Z.F. Effect of different post-harvest processing methods on the chemical constituents of notopterygium franchetii by an UHPLC-QTOF-MS-MS metabolomics approach. Molecules 2019, 24, 3188. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  47. Abascal, K.; Ganora, L.; Yarnell, E. The effect of freeze-drying and its implications for botanical medicine: A review. Phytother Res. 2005, 19, 655–660. [Google Scholar] [CrossRef] [PubMed]
  48. Nozad, M.; Khojastehpour, M.; Tabasizadeh, M.; Azizi, M.; Miraei Ashtiani, S.; Salarikia, A. Characterization of hot-air drying and infrared drying of spearmint (Mentha spicata L.) leaves. J. Food Meas. Charact. 2016, 10, 466–473. [Google Scholar] [CrossRef]
  49. Marie, C.K.; Petit, J.; Zimmer, D.; Djantou, E.B.; Scher, I. Effects of drying and grinding in production of fruit and vegetable powders: A review. J. Food Eng. 2016, 188, 32–49. [Google Scholar]
  50. Li, Y.G.; Song, L.; Liu, M.; Hu, Z.B.; Wang, Z.T. Advancement in analysis of Salviae miltiorrhizae Radix et Rhizoma (Danshen). J. Chromatogr. A 2009, 1216, 1941–1953. [Google Scholar] [CrossRef]
  51. Kim, S.; Kim, K.Y.; Han, C.S.; Ki, K.S.; Min, K.J.; Zhang, X.D.; Whang, W.K. Simultaneous analysis of six major compounds in Osterici Radix and Notopterygii Rhizoma et Radix by HPLC and discrimination of their origins from chemical fingerprint analysis. Arch. Pharmacal. Res. 2012, 35, 691–699. [Google Scholar] [CrossRef]
  52. Xia, P.G.; Bai, Z.Q.; Liang, T.Y.; Yang, D.F.; Liang, Z.S.; Yan, X.J.; Liu, Y. High-performance liquid chromatography based chemical fingerprint analysis and chemometric approaches for the identification and distinction of three endangered Panax plants in Southeast Asia. J. Sep. Sci. 2016, 39, 3880–3888. [Google Scholar] [CrossRef]
  53. Sabir, A.; Rafi, M.; Darusman, L.K. Discrimination of red and white rice bran from Indonesia using HPLC fingerprint analysis combined with chemometrics. Food Chem. 2017, 221, 1717–1722. [Google Scholar] [CrossRef]
  54. Yabar, E.; Pedreschi, R.; Chirinos, R.; Campos, D. Glucosinolate content and myrosinase activity evolution in three maca (Lepidium meyenii Walp.) ecotypes during preharvest, harvest and post-harvest drying. Food Chem. 2011, 127, 1576–1583. [Google Scholar] [CrossRef]
  55. Zhou, G.J.; Wang, W.; Xie, X.M.; Qin, M.J.; Kuai, B.K.; Zhou, T.S. Post-harvest induced production of salvianolic acids and significant promotion of antioxidant properties in roots of Salvia miltiorrhiza (Danshen). Molecules 2014, 19, 7207–7222. [Google Scholar] [CrossRef] [Green Version]
  56. Li, X.B.; Wei, W.; Zhou, G.J.; Li, Y.; Xie, X.M.; Zhou, T.S. Production of salvianolic acid B in roots of Salvia miltiorrhiza (Danshen) during the post-harvest drying process. Molecules 2012, 17, 2388–2407. [Google Scholar] [CrossRef]
  57. Briskin, D.P. Medicinal plants and phytomedicines. Linking plant biochemistry and physiology to human health. Plant Physiol. 2000, 124, 507–514. [Google Scholar] [CrossRef] [Green Version]
  58. Hartmann, T. From waste products to ecochemicals: Fifty years research of plant secondary metabolism. Phytochemistry 2007, 68, 2831–2846. [Google Scholar] [CrossRef]
  59. Dewanto, V.; Wu, X.Z.; Adom, K.K.; Liu, R.H. Thermal processing enhances the nutritional value of tomatoes by increasing total antioxidant activity. J. Agric. Food Chem. 2002, 50, 3010–3014. [Google Scholar] [CrossRef]
  60. Dewanto, V.; Wu, X.Z.; Liu, R.H. Processed sweet corn has higher antioxidant activity. J. Agric. Food Chem. 2002, 50, 4959–4964. [Google Scholar] [CrossRef]
  61. Tomaino, A.; Cimino, F.; Zimbalatti, V.; Venuti, V.; Sulfaro, V.; De Pasquale, A.; Saija, A. Influence of heating on antioxidant activity and the chemical composition of some spice essential oils. Food Chem. 2005, 89, 549–554. [Google Scholar] [CrossRef]
  62. Sun, Y.S.; Zhu, H.F.; Wang, J.H.; Liu, Z.B.; Bi, J.J. Isolation and purification of salvianolic acid A and salvianolic acid B from Salvia miltiorrhiza by high-speed counter-current chromatography and comparison of their antioxidant activity. J. Chromatogr. B 2009, 877, 733–737. [Google Scholar] [CrossRef]
  63. Massolo, J.F.; Concellon, A.; Chaves, A.R.; Vicente, A.R. 1-Methylcyclopropene (1-MCP)delays senescence, maintains quality and reduces browning of non-climacteric eggplant (Solanum melongena L.) fruit. Postharvest Biol. Technol. 2011, 59, 10–15. [Google Scholar] [CrossRef]
  64. Ye, M. Research progress of plant tissue browning. J. Chongqing Technol. Bus. Univ. (Nat. Sci. Ed.) 2005, 22, 326–329. [Google Scholar]
  65. Mayer, A.M.; Harel, E. Polyphenol oxidases in plants. Phytochemistry 1979, 18, 193–215. [Google Scholar] [CrossRef]
  66. Thipyapong, P.; Stout, M.; Attajarusit, J. Functional analysis of polyphenol oxidases by antisense/sense technology. Molecules 2007, 12, 1569–1595. [Google Scholar] [CrossRef]
  67. Zhang, X.B.; Zhao, J.H.; Cao, H.T.; Wang, X.Y. Effects of different drying methods and infiltration time on effective component of Taihang mountain Salvia Miltiorrhiza. Chin. J. Rat. Drug Use 2017, 14, 1–3+7. [Google Scholar]
  68. He, J.J.; Li, Z.H. Discussion on the distribution of effective components of Danshen in crude drugs and the idea of extraction process. Drug Stand. China 2000, 2, 27–28. [Google Scholar]
  69. National Pharmacopoeia Commission. The Pharmacopoeia of the People’s Republic of China (Part IV); China Medical Science and Technology Press: Beijing, China, 2020; p. 114. [Google Scholar]
Molecules 27 04860 g001 550
Figure 1. The plant and main medicinal material of S. miltiorrhiza used in the pharmaceutical industry. From left to right: whole plants, leaves, stems, flowers, roots and pieces.
Figure 1. The plant and main medicinal material of S. miltiorrhiza used in the pharmaceutical industry. From left to right: whole plants, leaves, stems, flowers, roots and pieces.
Molecules 27 04860 g001
Molecules 27 04860 g002a 550Molecules 27 04860 g002b 550
Figure 2. The structures of six active ingredients: (A)—rosmarinic acid, (B)—salvianolic acid B, (C)—dihydrotanshinone I, (D)—cryptotanshinone, (E)—tanshinone I, (F)—tanshinone IIA.
Figure 2. The structures of six active ingredients: (A)—rosmarinic acid, (B)—salvianolic acid B, (C)—dihydrotanshinone I, (D)—cryptotanshinone, (E)—tanshinone I, (F)—tanshinone IIA.
Molecules 27 04860 g002aMolecules 27 04860 g002b
Molecules 27 04860 g003 550
Figure 3. Changes in S. miltiorrhiza ingredient contents under different processing methods. (A) Shade drying; (B) sun drying; (C) oven drying. Note: p < 0.05.
Figure 3. Changes in S. miltiorrhiza ingredient contents under different processing methods. (A) Shade drying; (B) sun drying; (C) oven drying. Note: p < 0.05.
Molecules 27 04860 g003
Molecules 27 04860 g004a 550Molecules 27 04860 g004b 550
Figure 4. Changes in S. miltiorrhiza ingredient contents in different drying conditions during fresh processing. (A) Salvianolic acid B; (B) rosmarinic acid; (C) total tanshinones.
Figure 4. Changes in S. miltiorrhiza ingredient contents in different drying conditions during fresh processing. (A) Salvianolic acid B; (B) rosmarinic acid; (C) total tanshinones.
Molecules 27 04860 g004aMolecules 27 04860 g004b
Molecules 27 04860 g005 550
Figure 5. Typical chromatograms of standard mixed solution (A) and samples (B). 7-rosmarinic acid; 9-salvianolic acid B; 12-dihydrotanshinone I; 14-cryptotanshinone; 15-tanshinone I; 17-tanshinone IIA.
Figure 5. Typical chromatograms of standard mixed solution (A) and samples (B). 7-rosmarinic acid; 9-salvianolic acid B; 12-dihydrotanshinone I; 14-cryptotanshinone; 15-tanshinone I; 17-tanshinone IIA.
Molecules 27 04860 g005
Molecules 27 04860 g006 550
Figure 6. The cluster dendrogram of all active ingredients of 16 batches of different processing methods of S. miltiorrhiza.
Figure 6. The cluster dendrogram of all active ingredients of 16 batches of different processing methods of S. miltiorrhiza.
Molecules 27 04860 g006
Molecules 27 04860 g007 550
Figure 7. The 2D score plot of all active ingredients of 16 batches of different processing methods of S. miltiorrhiza with the first two three principal components.
Figure 7. The 2D score plot of all active ingredients of 16 batches of different processing methods of S. miltiorrhiza with the first two three principal components.
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Molecules 27 04860 g008 550
Figure 8. The process flow of S. miltiorrhiza roots and rhizome.
Figure 8. The process flow of S. miltiorrhiza roots and rhizome.
Molecules 27 04860 g008
Table
Table 1. Contents of six active ingredients in S1–S16.
Table 1. Contents of six active ingredients in S1–S16.
Sample CodeRosmarinic Acid (mg·g−1)Salvianolic Acid B (mg·g−1)Total Tanshinones (mg·g−1)
S12.806 ± 0.051 *#&57.033 ± 1.706 *#&3.560 ± 0.098 #&
S22.247 ± 0.025 *47.840 ± 0.4653.056 ± 0.023 *
S32.446 ± 0.072 *52.759 ± 0.486 *4.294 ± 0.030 *
S43.214 ± 0.053 *69.814 ± 0.620 *5.152 ± 0.006 *
S54.207 ± 0.116 *70.288 ± 1.288 *4.850 ± 0.007 *
S62.399 ± 0.121 #51.263 ± 0.433 #3.364 ± 0.053 #
S72.486 ± 0.124 #52.499 ± 1.566 #3.054 ± 0.090 #
S83.439 ± 0.098 #64.003 ± 0.749 #2.446 ± 0.050 #
S94.495 ± 0.054 #70.027 ± 0.346 #2.662 ± 0.020 #
S102.348 ± 0.068 &46.016 ± 0.457 &3.952 ± 0.049
S112.235 ± 0.064 &52.701 ± 1.305 &4.819 ± 0.079 &
S122.451 ± 0.021 &53.341 ± 1.604 &4.174 ± 0.121 &
S132.942 ± 0.078 &54.250 ± 0.379 &4.839 ± 0.079 &
S142.094 ± 0.10447.397 ± 0.6833.655 ± 0.181
S151.623 ± 0.08141.554 ± 0.1911.946 ± 0.014
S161.388 ± 0.01739.515 ± 1.2283.760 ± 0.102
* p < 0.05 vs. S14, # p < 0.05 vs. S15, & p < 0.05 vs. S16.
Table
Table 2. Different processing treatment methods.
Table 2. Different processing treatment methods.
Sample CodeRaw Weight (g)Raw Size (cm)Raw Thickness (mm)Drying ConditionsMoisture Content
before Cutting (%)		Moisture Content
after Drying (%)
S149.67 ± 1.1313.50 ± 0.039.18 ± 0.06No drying 78.946.11
S249.29 ± 1.4713.59 ± 0.628.11 ± 0.13Shade drying 72 h55.216.23
S352.44 ± 0.9414.76 ± 0.407.48 ± 0.10Shade drying 120 h34.574.31
S452.11 ± 1.5115.17 ± 0.298.97 ± 0.15Shade drying 144 h26.384.20
S556.57 ± 0.5615.39 ± 0.149.80 ± 0.02Shade drying 192 h21.024.40
S655.88 ± 1.0316.85 ± 0.308.08 ± 0.02Sun drying 48 h53.604.19
S744.68 ± 1.3514.52 ± 0.088.09 ± 0.06Sun drying 72 h41.957.58
S857.50 ± 0.7217.84 ± 0.048.67 ± 0.07Sun drying 120 h22.913.92
S956.02 ± 1.3414.57 ± 0.109.21 ± 0.11Sun drying 144 h13.884.02
S1044.12 ± 1.2714.58 ± 0.048.85 ± 0.04Oven drying (60 °C) 4 h70.175.52
S1146.38 ± 1.2417.46 ± 0.048.45 ± 0.03Oven drying (60 °C) 8 h49.795.79
S1255.07 ± 1.5818.57 ± 0.038.64 ± 0.02Oven drying (60 °C) 12 h33.745.11
S1356.52 ± 1.1017.17 ± 0.087.81 ± 0.32Oven drying (60 °C) 16 h18.014.35
S1458.61 ± 1.9218.19 ± 0.058.49 ± 0.05Shade drying 720 h45.643.60
S1544.40 ± 1.5917.28 ± 0.039.52 ± 0.16Sun drying 480 h51.423.44
S1644.88 ± 1.4718.43 ± 0.088.46 ± 0.24Oven drying (60 °C) 48 h57.425.52
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Zhang, L.; Zhang, X.; Begum, N.; Xia, P.; Liu, J.; Liang, Z. Effects of Different Processing Methods Based on Different Drying Conditions on the Active Ingredients of Salvia miltiorrhiza Bunge. Molecules 2022, 27, 4860. https://doi.org/10.3390/molecules27154860

AMA Style

Zhang L, Zhang X, Begum N, Xia P, Liu J, Liang Z. Effects of Different Processing Methods Based on Different Drying Conditions on the Active Ingredients of Salvia miltiorrhiza Bunge. Molecules. 2022; 27(15):4860. https://doi.org/10.3390/molecules27154860

Chicago/Turabian Style

Zhang, Liuwei, Xuemei Zhang, Naheeda Begum, Pengguo Xia, Jingling Liu, and Zongsuo Liang. 2022. "Effects of Different Processing Methods Based on Different Drying Conditions on the Active Ingredients of Salvia miltiorrhiza Bunge" Molecules 27, no. 15: 4860. https://doi.org/10.3390/molecules27154860

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