Processing and drying method of fresh salvia miltiorrhiza

Abstract

The present application relates to a kind of processing and drying method of fresh salvia miltiorrhiza, the method, steps are as follows:1) using microwave to irradiate fresh salvia miltiorrhiza and control the water loss rate of fresh salvia miltiorrhiza is 22-28%;2) continue drying using natural drying method.

Description

Technical fields:

[0001] This invention relates to a method for processing traditional Chinese medicine, and particularly to a method for drying fresh medicinal materials, specifically a method for processing and drying fresh Salvia miltiorrhiza. Background technology:

[0002] Danshen is the dried root and rhizome of *Salvia miltiorrhiza* Bge. Its main active components are water-soluble phenolic acids and fat-soluble diterpenoid quinones, possessing the effects of removing blood stasis and relieving pain, promoting blood circulation and regulating menstruation, and clearing the heart and relieving irritability. As a blood-activating and stasis-removing herb, Danshen is clinically used to treat coronary atherosclerotic heart disease (CHD) and angina pectoris. Danshen preparations have significant effects on cerebral thrombosis, hepatitis, and cirrhosis. Its use is extremely widespread. Its effective components are mainly water-soluble components, primarily salvianolic acid B, and fat-soluble components, primarily tanshinone IIA. The Chinese Pharmacopoeia (2015 edition) uses tanshinone IIa (≥0.25%) and salvianolic acid B (≥3%) as the quality control indicators for Danshen medicinal materials. Zhou Tongshui et al. (The main active ingredient of Salvia miltiorrhiza, salvianolic acid B, is a product induced by postharvest drying stress [J], Modern Chinese Materia Medica, 2013, 15(3): 211-218) found that the content of salvianolic acid B in fresh medicinal materials is very small and is formed in large quantities during the drying process. That is, salvianolic acid B is actually a product induced by postharvest drying stress, rather than an original accumulated component during the cultivation period.

[0003] Current research on the processing of fresh Salvia miltiorrhiza mainly focuses on natural sun-drying and oven-drying. Some literature reports on the drying of fresh Salvia miltiorrhiza using natural sun-drying, oven-drying, and microwave drying (Zhang Wei, Zou Zhaozhong, Liu Huizhen, et al. HPLC determination of the content of tanshinone I and tanshinone IIA in microwave-dried Salvia miltiorrhiza [J], Modern Scientific Instruments, 2010, 5: 96-98; Huang Song, Fan Kai, Huang Jing, et al. Experimental study on microwave drying of fresh Salvia miltiorrhiza [J], Modern Chinese Medicine Research and Practice, 2012, 26(5): 48-50). The evaluation indicators are appearance, moisture drying efficiency, and the influence of tanshinone substances. It is believed that microwave drying has a better effect, but the influence of the content of salvianolic acid B in Salvia miltiorrhiza has not been studied.

[0004] Chinese patent application CN102784199A discloses a microwave drying technology for fresh Salvia miltiorrhiza: fresh Salvia miltiorrhiza is taken and dried using microwaves to obtain dried Salvia miltiorrhiza. The microwave drying conditions are: temperature 35-90℃, drying time 5-360 min, and atmospheric or reduced pressure. However, this patent does not disclose whether the microwave conditions affect the content of salvianolic acid B.

[0005] Guo Yongxue et al. (Microwave Drying of Salvia miltiorrhiza Slices and Dissolution Characteristics of Tanshinone B [J], Journal of Process Engineering, 2010.6: 603-607) disclosed a microwave drying method for Salvia miltiorrhiza slices. Fresh Salvia miltiorrhiza slices of uniform thickness were selected, and after removing the rootlets, impurities, washing, and drying the surface moisture, they were cut into slices approximately 5 mm thick. One portion was sun-dried for 20 days at room temperature, under ventilation and natural light, while the other four portions were microwave-dried. Preliminary experiments were conducted, and microwave drying powers of 650, 700, and 750 W were selected. No special temperature control was performed during the heating process. The results showed that at powers of 750, 700, and 650 W, the drying times to achieve a moisture content of 0.05 were 11, 15, and 24 min, respectively. At this point, the dry basis moisture content of the Salvia miltiorrhiza slices was 7.0%, which meets the requirement in the Pharmacopoeia of the People's Republic of China (2010 edition) that the moisture content of Salvia miltiorrhiza should not exceed 13%. However, at drying power of 700 and 750W, some individual slices showed localized scorching. Ultimately, drying at 650W microwave power for 30 minutes resulted in a tanshinone B content of 4.9% in the slices, approximately 1.2 times that of sun-dried slices, exceeding the requirement of at least 3% tanshinone B content in the Pharmacopoeia of the People's Republic of China (2010 edition).

[0006] However, current regulations require that Salvia miltiorrhiza be dried before being prepared into slices, rather than being prepared as fresh slices and then dried. Therefore, the Salvia miltiorrhiza slices obtained by this processing method do not meet the requirements of the regulations. In addition, the fresh Salvia miltiorrhiza needs to be washed and dried, then sliced ​​thinly and arranged in a single layer, and then microwaved until the moisture content of the Salvia miltiorrhiza slices reaches the pharmacopoeia requirements. From the operation process, it is difficult to industrialize, consumes a lot of energy, and at high power, the Salvia miltiorrhiza slices will partially carbonize, thus affecting the quality of the Salvia miltiorrhiza slices. Summary of the Invention:

[0007] To overcome the aforementioned problems and find a suitable drying process for fresh Salvia miltiorrhiza for large-scale industrial production, maximizing the content of salvianolic acid B while meeting regulatory requirements, and improving the processing efficiency and quality of fresh Salvia miltiorrhiza, this application investigated different heating and drying methods and performed different sample pretreatments on fresh and dried medicinal materials before determining the content. The results were compared and analyzed, and a better processing method for fresh medicinal materials was preliminarily identified. This method was then scaled up and applied to large-scale industrial production, resulting in a significant increase in the content of salvianolic acid B. This is of great significance for the preliminary processing of fresh Salvia miltiorrhiza and the improvement of the quality of Salvia miltiorrhiza medicinal materials.

[0008] This invention provides a method for processing and drying fresh Salvia miltiorrhiza, the method comprising the following steps:

[0009] 1) Microwave irradiation pretreatment was used to treat fresh Salvia miltiorrhiza, and the water loss rate of fresh Salvia miltiorrhiza was controlled to be 22-28%;

[0010] 2) Continue drying using natural drying method.

[0011] In step 1), the microwave irradiation is carried out using a tunnel microwave drying device.

[0012] The tunnel-type microwave drying equipment is a key model for continuous production in enterprises. The drying chamber can be divided into multiple groups, each equipped with a microwave generator, allowing for adjustable microwave power. Materials pass through the conveyor belt within the microwave drying chamber, entering from the feed end and exiting from the discharge end, operating continuously. The conveyor belt speed can also be adjusted to control the microwave irradiation time of the materials.

[0013] The microwave power range of this application can be set to 2.4KW to 7.2KW, and the drying time is 5 to 20 minutes.

[0014] Preferably, the drying time is 10-15 minutes.

[0015] However, it is important to note that the ultimate goal of this application is to control the water loss rate of fresh Salvia miltiorrhiza to 22-28%. To achieve this, a higher power, such as 7.2KW, can be selected, which will correspondingly shorten the drying time; alternatively, a lower power, such as 2.4KW, can be selected, which will allow for a more extended drying time. Regardless of the power and time used, it is crucial to ensure that the water loss rate of the fresh Salvia miltiorrhiza is controlled within 22-28% to maximize the final content of salvianolic acid B.

[0016] In step 2), the natural drying process is selected from: sun drying, air drying, blow drying, and low-temperature drying.

[0017] Low temperature refers to temperatures below 60°C.

[0018] The preferred method for processing and drying fresh Salvia miltiorrhiza according to this application includes the following steps:

[0019] Freshly harvested Salvia miltiorrhiza → trimming the rhizome at the field → tunnel microwave drying → rinsing off soil and sand with water → natural drying → Salvia miltiorrhiza medicinal material → inspection → warehousing.

[0020] or,

[0021] Freshly harvested Salvia miltiorrhiza → trimming the rhizome at the field → tunnel microwave drying → rinsing off soil and sand with water → fresh cutting → natural drying → Salvia miltiorrhiza slices → inspection → warehousing.

[0022] The Danshen medicinal material obtained by the method of the present invention has a content of more than 50% higher than that of the prior art in terms of effective ingredients, especially the Danshen medicinal material can reach a content of 15% of salvianolic acid B.

[0023] The method described in this invention was obtained through screening and a large number of comparative experiments before the final conclusion was reached.

[0024] It should be noted that the screening tests in this application were small-scale trials conducted in the laboratory. The conclusions drawn from these small-scale trials are equally applicable when scaled up to the production process. However, for large-scale production, suitable equipment—such as tunnel microwave drying equipment—must be used to handle the drying of kilogram-level fresh Salvia miltiorrhiza. Therefore, the microwave power must also be correspondingly adapted to the power of the tunnel microwave drying equipment.

[0025] Specifically, the screening experiment process is as follows:

[0026] I. Experimental Instruments and Materials

[0027] 1. Fresh Salvia miltiorrhiza was supplied by Shaanxi Tasly Herbal Medicine Co., Ltd., with production areas in Shangluo, Weinan and Tongchuan respectively;

[0028] 2. Test instruments

[0029] Microwave Oven: Guangdong Midea Kitchen Appliance Manufacturing Co., Ltd.; Model: M1-L201B; Rated Voltage / Frequency: 220V 50Hz;

[0030] Microwave output power: 800W; Microwave operating frequency: 2450MHz.

[0031] Electric heating drying oven: Shanghai Yiheng Scientific Instruments Co., Ltd.; DHG-9070A; Power: 1250W;

[0032] Ultrasonic cleaner: AS20500B ultrasonic cleaner manufactured by Tianjin Autos Instrument Co., Ltd.

[0033] Centrifuge: Shanghai Anting Scientific Instrument Factory; Model: TDL-40B; Rotation speed: 0-4000 rpm;

[0034] HPLC instrument: Waters e2695-2998 liquid chromatograph

[0035] 3. Reagents

[0036] Purified water is produced by the company itself;

[0037] Methanol, analytical grade, produced by Tianjin Fengfan Technology Co., Ltd.

[0038] II. Experimental Methods and Results

[0039] 2.1 Experimental Methods

[0040] 2.1.1 Determination of Tanshinone B Content (The determination of Tanshinone B content shall be performed according to the high performance liquid chromatography method (General Chapter 0512, Part IV, Chinese Pharmacopoeia 2015 Edition).

[0041] (1) Chromatographic method 1:

[0042] The chromatographic column was a Waters C18 (250 mm × 4.6 mm, 5 μm). The mobile phase was acetonitrile-0.05% phosphoric acid aqueous solution (22:78), with isocratic elution. The column temperature was 25 °C, the detection wavelength was 288 nm, and the flow rate was 0.7 mL / min. 10 μL of each solution was injected.

[0043] (2) Chromatographic method 2:

[0044] 1) Chromatographic conditions and system suitability test: Octadecylsilane-bonded silica gel was used as the packing material; acetonitrile-0.1% phosphoric acid solution (22:78) was used as the mobile phase; the column temperature was 20℃; the flow rate was 1.2 ml per minute; and the detection wavelength was 286 nm. The theoretical plate number, calculated based on the B peak of salvianolic acid, should not be less than 6000.

[0045] 2) Assay Method: Accurately pipette 10 μl each of the reference solution and the test solution into the liquid chromatograph and determine the result. 2.2 Different Treatment Methods and Determination Results of Fresh Salvia miltiorrhiza

[0046] 2.2.1 Effects of different treatments on the content of salvianolic acid B in fresh salvia miltiorrhiza

[0047] 2.2.1.1 Preparation method of reference solution

[0048] Preparation of salvianolic acid B reference solution: Weigh 10 mg of salvianolic acid B reference standard accurately, place it in a 50 ml volumetric flask, add methanol to dissolve and dilute to the mark, and shake well.

[0049] 2.2.1.2 Preparation method of test solution

[0050] Take 3 portions of fresh Salvia miltiorrhiza (10g each).

[0051] One slice was placed in a beaker, 100 ml of water was added, and the slice was weighed. The slice was then crushed, boiled for 30 minutes, cooled to room temperature, weighed again, water was added to bring the weight back up, the slice was stirred, centrifuged, and the supernatant was used as the test solution for the determination of the content of salvianolic acid B.

[0052] One slice is placed in a beaker containing 100ml of boiling water, weighed, boiled again for 30 minutes, cooled to room temperature, weighed, water is added to the original weight, stirred well, centrifuged, and the supernatant is used as the test solution for the determination of the content of salvianolic acid B.

[0053] One slice is placed in a beaker containing 100 ml of methanol, weighed, crushed, sonicated for 30 minutes, cooled to room temperature, weighed, methanol is added to the original weight, stirred well, centrifuged, and the supernatant is used as the test solution for the determination of the content of salvianolic acid B.

[0054] 2.2.1.3 Experiment and Conclusion

[0055] The content of salvianolic acid B in fresh salvia miltiorrhiza was calculated, and the variation pattern of salvianolic acid B content was investigated.

[0056] Fresh Salvia miltiorrhiza slices were separately crushed with purified water, and then crushed with boiling water and methanol. The first two were boiled on an electric stove for half an hour; the latter was ultrasonicated for 30 minutes in an ultrasonic cleaner. The slices were centrifuged separately, and the supernatant was used to separate and determine salvianolic acid B under the given chromatographic conditions. The results are shown in Table 1 and [Table data missing]. Figure 1 The results showed significant differences in the content of salvianolic acid B among different treatment methods.

[0057] Table 1. Effects of different treatment methods on the content of salvianolic acid B in fresh salvia miltiorrhiza from different origins (control concentration: 0.2 mg / ml)

[0058]

[0059] 2.2.2 Effect of Oven Drying of Fresh Salvia miltiorrhiza on the Content of Salvia miltiorrhiza B

[0060] Fresh Salvia miltiorrhiza (tanshinone) was baked in a 100℃ oven for 10, 20, 30, 40, and 60 minutes, sliced, and placed in beakers. 100 ml of water was added, and the slices were weighed. The slices were then crushed, sonicated for 30 minutes, removed, and allowed to cool to room temperature. The slices were weighed again, water was added to the original weight, and the mixture was stirred. The supernatant was centrifuged, and the supernatant was used as the test solution for the determination of salvianolic acid B content. The results are shown in Table 2. Figure 2 .

[0061] Table 2. Effect of different drying times at 100℃ on the content of salvianolic acid B in fresh salvia miltiorrhiza (reference concentration: 0.2 mg / ml)

[0062]

[0063] To find a suitable processing method for fresh Salvia miltiorrhiza, the effect of different heating times on the content of salvianolic acid B in fresh Salvia miltiorrhiza was investigated at 100℃. The results showed that salvianolic acid B was detectable after 40 minutes in a drying oven, and significantly detectable after 60 minutes, but the content was much lower than that after microwave treatment (see Experiment 2.2.3). The experimental results are shown in Table 2 and... Figure 2Clearly, oven drying of fresh Salvia miltiorrhiza is not a good processing method. The reason is likely that heat needs time to gradually transfer from the skin to the tissues of the fresh Salvia miltiorrhiza. Heating the water-rich tissues gradually results in a slow temperature rise within a short period. Furthermore, high-temperature drying is an inefficient method and unsuitable for the initial processing of fresh Salvia miltiorrhiza.

[0064] 2.2.3 Effect of different microwave drying times on the content of salvianolic acid B in fresh salvia miltiorrhiza under the same microwave conditions.

[0065] 2.2.3.1 Preparation method of test solution

[0066] Take 10g of fresh Salvia miltiorrhiza that has been microwaved (10 minutes, 15 minutes, 20 minutes and 30 minutes), slice it, put it into a beaker, add 100ml of water, weigh it, crush it, sonicate it for 30 minutes, let it cool to room temperature, weigh it, add water to the original weight, stir it, centrifuge it, and take the supernatant as the test solution.

[0067] 2.2.3.2 Experiment and Conclusion

[0068] The content of salvianolic acid B in the test solution was determined according to the method described in "2.1.1 Determination of salvianolic acid B Content". The changes in moisture content and salvianolic acid B content in fresh Salvia miltiorrhiza were calculated, and the variation pattern of salvianolic acid B content was investigated. The results are shown in Tables 3 and 4. Figure 3 (1) Effect of microwave treatment time on the weight loss of fresh Salvia miltiorrhiza

[0069] Table 3. Effects of microwave treatment time on the weight change of fresh Salvia miltiorrhiza.

[0070]

[0071]

[0072] (2) Effect of different microwave treatment times on the content of salvianolic acid B

[0073] Table 4. Effect of different microwave treatment times on the content of salvianolic acid B in fresh salvia miltiorrhiza (reference concentration: 0.2 mg / ml)

[0074]

[0075] To investigate the effect of different treatment times under microwave conditions on the content of salvianolic acid B in fresh Salvia miltiorrhiza, fresh Salvia miltiorrhiza from Tongchuan, Weinan, and Shangluo were treated for different times under the same microwave conditions. The results are shown in Table 4 and 5. Figure 3It can be seen that under the same microwave conditions, the same amount of fresh Salvia miltiorrhiza and different treatment times have a significant effect on the salvianolic acid B content in the fresh Salvia miltiorrhiza. Microwave treatment for 10 minutes has the best effect, and it has been preliminarily confirmed that the water loss rate of fresh Salvia miltiorrhiza is 22-28% (see Table 3), and the content of salvianolic acid B in fresh Salvia miltiorrhiza is the highest.

[0076] Microwave intensity and duration are essentially the amount of energy supplied to fresh Salvia miltiorrhiza. While heating for 10 minutes under microwave regulation appears to be a key point, the actual key factor should be the weight loss rate of the fresh Salvia miltiorrhiza after microwave treatment. It is believed that confirming a water loss rate of 22-28% for fresh Salvia miltiorrhiza under microwave treatment conditions is the optimal control parameter for microwave treatment, thereby ensuring that the content of salvianolic acid B in the dried Salvia miltiorrhiza after treatment is much higher than that of Salvia miltiorrhiza treated in other ways.

[0077] 2.2.4 Effect of different amounts of fresh Salvia miltiorrhiza dried under the same microwave conditions and for the same time on the content of salvianolic acid B.

[0078] Two samples of fresh Salvia miltiorrhiza from the same batch, 423.60g and 577.77g respectively, were microwaved for 10 minutes each, weighed, and the water loss rate was calculated. The microwave-treated herbs were then naturally dried in the sun to obtain dried Salvia miltiorrhiza. The weight loss rate of the dried herbs was calculated according to the quality standards for Salvia miltiorrhiza in the Pharmacopoeia. The content of salvianolic acid B in the dried Salvia miltiorrhiza was also determined according to the Pharmacopoeia testing methods. The results are shown in Table 5.

[0079] Table 5. Effects of microwave treatment followed by natural drying on the content of salvianolic acid B in different amounts of fresh Salvia miltiorrhiza.

[0080]

[0081] Different quantities of the same batch of fresh Salvia miltiorrhiza were microwaved for the same duration (10 minutes) and then naturally dried. The content of salvianolic acid B was then determined. It was found that the salvianolic acid B content was lower in samples with larger quantities of fresh Salvia miltiorrhiza compared to samples with smaller quantities. The former had a water loss rate of 20.3%, while the latter had a water loss rate of 26.21%. However, the salvianolic acid B content in the dried Salvia miltiorrhiza samples was 6.4% and 8.7%, respectively, showing a significant difference. Analysis suggests that under the same microwave energy, the energy received per unit mass of fresh Salvia miltiorrhiza varies, resulting in different internal heating times and durations, leading to different water loss rates. This difference in salvianolic acid content in the dried Salvia miltiorrhiza is directly reflected in the different water loss rates of the microwave-treated fresh Salvia miltiorrhiza (see Table 5). Overall, the microwave treatment of fresh Salvia miltiorrhiza with a water loss rate of 22-28% resulted in a higher salvianolic acid B content in the dried Salvia miltiorrhiza samples. Therefore, controlling the water loss rate of fresh Salvia miltiorrhiza during microwave treatment is a crucial process parameter.

[0082] 2.2.5 Comparison of the effects of fresh tanshinone and microwave-dried tanshinone on the content of tanshinone B.

[0083] Take three portions of fresh Salvia miltiorrhiza, each equivalent to 10g, and prepare the test solution according to "2.2.1.2 Test Solution Preparation Method". Take another portion of fresh Salvia miltiorrhiza from the same origin, microwave it for 10 minutes, and then take 10g of the equivalent fresh Salvia miltiorrhiza to prepare the test solution according to "2.2.3.1 Test Solution Preparation Method". Determine the content of salvianolic acid B in the test solutions according to "2.1.1 Determination Method for Salvia miltiorrhiza B Content" to investigate the variation pattern of salvianolic acid B content.

[0084] After processing fresh Salvia miltiorrhiza with microwave equipment for 10 minutes, a sample equivalent to 10g of fresh Salvia miltiorrhiza was taken based on the weight change before and after. Purified water was added, the mixture was crushed, sonicated for 30 minutes, and then centrifuged. The supernatant was taken for determination of the content of salvianolic acid B. The results are shown in Table 6.

[0085] Table 6. Effects of different treatment methods on the content of salvianolic acid B in fresh Salvia miltiorrhiza from different origins.

[0086]

[0087]

[0088] The data in the table above shows that when fresh herbs are directly sliced, crushed, and then decocted, the content of salvianolic acid B is very low. Slices added directly to boiling water and decocted result in higher content, as does slices added to methanol, crushed, and then ultrasonically treated. However, the content varies slightly between boiling water and methanol / ultrasonic treatment, suggesting that the content of salvianolic acid B in fresh salvia miltiorrhiza obtained by these two methods is relatively high and comparable. After microwave irradiation of a certain amount of fresh salvia miltiorrhiza for 10 minutes and measuring the weight loss, the salvianolic acid B content was measured on a 10g sample, revealing the highest content. Therefore, it is concluded that microwave-treated fresh salvia miltiorrhiza has a significantly higher salvianolic acid B content than boil-water-treated fresh salvia miltiorrhiza, while the salvianolic acid B content in boil-water-treated fresh salvia miltiorrhiza is comparable to that in methanol-treated fresh salvia miltiorrhiza, both higher than that in purified water-treated fresh salvia miltiorrhiza. It is believed that the need for slicing and exposure to air during boiling and methanol treatment allows for rapid degradation of some salvianolic acid B, while in water-treated salvia miltiorrhiza, most of the salvianolic acid B is already degraded before boiling.

[0089] 2.2.6 Comparison of salvianolic acid B content in fresh salvia miltiorrhiza after natural drying and microwave drying.

[0090] Take naturally dried medicinal materials and medicinal materials that have been microwaved and then naturally dried, pulverize them, pass them through a No. 3 sieve, mix them well, take 0.15g of each powder, weigh them accurately, add purified water and methanol respectively, and weigh them; place them in a 35℃ water bath for 60 minutes, then sonicate them for 30 minutes, wipe them dry, weigh them and add the amount of solvent lost, then centrifuge them, take the supernatant, and determine the content according to the "2.1.1 Determination Method of Tanshinone B Content", calculate the content of Tanshinone B in the medicinal materials and the changes in the chromatographic pattern.

[0091] The results are shown in Table 7 and Figure 5 The results showed that the content of salvianolic acid B in pulverized danshen after natural drying was below the detection limit, while the content was very high in danshen that was microwaved for 10 minutes and then naturally dried in the same way. The content of salvianolic acid B was consistently high in danshen treated with methanol, regardless of whether purified water or methanol was used for microwave treatment.

[0092] Additionally, from Table 7 and Figure 5 The results showed that the content of tanshinone B in microwave-treated tanshinone was significantly higher than that in naturally dried tanshinone, with the former containing over 8.2% and the latter only 5.6%, demonstrating a significant difference. This also suggests that during the extraction of tanshinone, boiling water should be added directly for extraction to reduce the degradation of the tanshinone B component.

[0093] Table 7. Effects of different pretreatment methods after natural drying and microwave drying on the content of salvianolic acid B in Salvia miltiorrhiza.

[0094]

[0095] 2.2.7 Determination of Tanshinone B Content in Dried Salvia miltiorrhiza after Different Drying Methods

[0096] 2.2.7.1 Preparation of the test solution

[0097] Take Salvia miltiorrhiza that has been naturally dried, microwave-dried, and then naturally dried again (under the same microwave conditions and with the same amount of fresh Salvia miltiorrhiza, but with different microwave heating times before natural drying), pulverize it, and pass it through a No. 3 sieve. Take about 0.15g and put it into a stoppered conical flask. Accurately add 50ml of methanol:water (8:2) mixed solution, seal tightly, weigh, and sonicate (power 140W, frequency 42KHz) for 30 minutes. Let it cool, weigh it again, and then replenish the lost weight with methanol:water (8:2) mixed solution. Shake well, filter, and accurately measure 5ml of the filtrate into a 10ml volumetric flask. Dilute to the mark with methanol:water (8:2) mixed solution, shake well, filter, and take the filtrate as the test solution.

[0098] The content of salvianolic acid B was determined according to the method for determining salvianolic acid B (2.1.1 method for determining salvianolic acid B content), and the results are shown in Table 8.

[0099] Table 8. Effects of different treatments followed by natural drying on the content of salvianolic acid B in Salvia miltiorrhiza.

[0100]

[0101] The results in Table 8 show that the content of salvianolic acid B in microwave-treated Salvia miltiorrhiza was higher than that in naturally dried Salvia miltiorrhiza. Specifically, the highest content of salvianolic acid B was found in Salvia miltiorrhiza obtained by microwave treatment for ten minutes followed by natural drying. Generally, microwave treatment for 10 to 20 minutes resulted in a higher content of salvianolic acid B than natural drying. However, excessive microwave treatment caused the internal temperature of fresh Salvia miltiorrhiza to rise too quickly, and the presence of the epidermis and tissues prevented rapid heat dissipation, leading to excessively high internal temperatures. Salvia miltiorrhiza B is unstable at high temperatures, causing it to degrade at high temperatures, thus decreasing the content of salvianolic acid B and even causing carbonization (obvious carbonization was observed after microwave heating for 30 and 40 minutes). Therefore, appropriate microwave energy treatment (microwave power and time) for fresh Salvia miltiorrhiza is crucial. While 10 minutes of microwave heating appears optimal, the amount of fresh Salvia miltiorrhiza treated should be considered. Overall, maintaining the water loss of fresh Salvia miltiorrhiza within the range of 22-28% during microwave heating is beneficial for maintaining the optimal content of salvianolic acid B.

[0102] In addition, the fresh Salvia miltiorrhiza provided by Shangluo, when naturally dried, had a salvianolic acid B content of 2.0%, which did not meet the quality standard requirements for Salvia miltiorrhiza (≥3.0%). However, after microwave treatment, the content of salvianolic acid B in the Salvia miltiorrhiza reached 3.3%, which met the quality standard requirements for Salvia miltiorrhiza. This further indicates that microwave treatment of fresh Salvia miltiorrhiza in its initial processing is beneficial to improving the quality of the Salvia miltiorrhiza. It can be preliminarily determined that microwave drying has significant technical advantages for the initial processing of fresh Salvia miltiorrhiza.

[0103] In summary, the content of salvianolic acid B in fresh Salvia miltiorrhiza is highly dependent on its place of origin. Salvia miltiorrhiza from Tongchuan has a higher content of salvianolic acid B than that from Weinan, which in turn has a higher content than that from Shangluo. The content of salvianolic acid B in fresh Salvia miltiorrhiza determines the content of salvianolic acid B in the dried herb. However, regardless of the content of salvianolic acid B in fresh Salvia miltiorrhiza, after microwave treatment, the content of salvianolic acid B in the dried herbs from three batches of fresh Salvia miltiorrhiza (from different origins) was more than 50% higher than that obtained by traditional processing, with the highest content reaching 15%. Attached image description:

[0104] Figure 1 Effects of different solvent pretreatment methods on the content of salvianolic acid B in fresh medicinal materials (water, boiling water, and methanol) (A. Sample images from Tongchuan area B. Sample images from Weinan area C. Sample images from Shangluo area)

[0105] Figure 2 Chromatograms showing the effect of different baking times in a 100℃ oven on the content of salvianolic acid B (reference standard chromatogram, a set of 6 chromatograms of fresh Salvia miltiorrhiza from Tongchuan at 10, 20, 30, 40 and 60 minutes).

[0106] Figure 3Chromatograms showing the effect of microwave treatment on the content of salvianolic acid B in fresh salvia miltiorrhiza from three different origins (vertical axis represents chromatographic intensity, horizontal axis represents retention time; A. Tongchuan; B. Weinan; C. Shangluo are combined separately, with each combination consisting of 4 microwave-treated samples).

[0107] Figure 4 Chromatographic studies of the effects of different pretreatment methods on the content of salvianolic acid B in fresh Salvia miltiorrhiza (A. Tongchuan; B. Weinan; C. Shangluo)

[0108] Figure 5 The effect of different solvent treatment methods on the change of salvianolic acid B content

[0109] Figure 6 The process flow of the fresh calamine drying method of the present invention Figure 1 .

[0110] Figure 7 The process flow of the fresh calamine drying method of the present invention Figure 2 . Detailed implementation method:

[0111] The present invention will be further illustrated by the following examples.

[0112] Example 1

[0113] Freshly harvested Salvia miltiorrhiza from Tongchuan was collected. The rhizome was removed, and 6 kg of fresh Salvia miltiorrhiza was weighed and spread evenly in three rectangular trays (90cm x 50cm). Each tray was weighed separately. The trays were then placed on the tracks of a GWM-70B tunnel-type microwave drying equipment (10 microwave irradiation groups, each with three power levels: 2.4KW, 4.8KW, and 7.2KW). The equipment was started according to the microwave drying process operating procedures, with the exhaust device turned on. All 10 groups were maintained at a microwave power of 4.8KW (each group measuring 120cm x 60cm), with a track speed set to 1 meter / minute. The time from entering to exiting the microwave irradiation track was 12 minutes. The trays were then removed, weighed, and the water loss rate of the Salvia miltiorrhiza was determined. The herbs were then rinsed with water to remove soil and sand, cut, and sun-dried in a polycarbonate room to obtain Salvia miltiorrhiza slices. The content of Salvia miltiorrhiza was tested according to the methods for determining the content of the medicinal material in the Pharmacopoeia. The test results are as follows:

[0114] Water loss rate of fresh Salvia miltiorrhiza after microwave irradiation: 23.53%

[0115] The content of salvianolic acid B in Danshen (Salvia miltiorrhiza) is 12.52%.

[0116] Tanshinone content in Salvia miltiorrhiza: 0.50%

[0117] Example 2

[0118] Freshly harvested Salvia miltiorrhiza from Tongchuan was collected. The rhizome was removed, and 6 kg of fresh Salvia miltiorrhiza was weighed and spread evenly in three rectangular trays (90cm x 50cm). Each tray was weighed separately. The trays were then placed on the tracks of a GWM-70B tunnel-type microwave drying equipment (10 microwave irradiation groups, each with three power settings: 2.4KW, 4.8KW, and 7.2KW). The equipment was started according to the microwave drying process operating procedures, with the exhaust device turned on. All 10 groups were maintained at a microwave power of 4.8KW (each group measuring 120cm x 60cm), with a track speed set to 0.8 m / min. The time from entering to exiting the microwave irradiation track was 15 minutes. The trays were then removed, weighed, and the water loss rate of the Salvia miltiorrhiza was determined. The herbs were then rinsed with water to remove soil and sand, cut, and sun-dried in a polycarbonate room to obtain Salvia miltiorrhiza slices. The content of Salvia miltiorrhiza was tested according to the methods for determining the content of the medicinal material in the Pharmacopoeia. The test results are as follows:

[0119] Water loss rate of fresh Salvia miltiorrhiza after microwave irradiation: 27.33%

[0120] The content of salvianolic acid B in danshen (Salvia miltiorrhiza) is 14.52%.

[0121] Tanshinone content in Salvia miltiorrhiza: 0.53%

[0122] Example 3

[0123] Freshly harvested Salvia miltiorrhiza from Tongchuan was collected. The rhizome was removed, and 6 kg of fresh Salvia miltiorrhiza was weighed and spread evenly in three rectangular trays (90cm x 50cm). Each tray was weighed separately. The trays were then placed on the tracks of a GWM-70B tunnel-type microwave drying equipment (10 microwave irradiation groups, each with three power levels: 2.4KW, 4.8KW, and 7.2KW). The equipment was started according to the microwave drying process operating procedures, with the exhaust device turned on. All 10 groups were maintained at a microwave power of 7.2KW (each group measuring 120cm x 60cm), with a track speed set to 1.2 m / min. The time from entering to exiting the microwave irradiation track was 10 minutes. The trays were then removed, weighed, and the water loss rate of the Salvia miltiorrhiza was determined. The herbs were then rinsed with water to remove soil and sand, cut, and sun-dried in a polycarbonate room to obtain Salvia miltiorrhiza slices. The content of Salvia miltiorrhiza was tested according to the Pharmacopoeia's method for determining the content of the medicinal material. The test results are as follows:

[0124] Water loss rate of fresh Salvia miltiorrhiza after microwave irradiation: 28.05%

[0125] The content of salvianolic acid B in danshen (Salvia miltiorrhiza) is 11.52%.

[0126] Tanshinone content in Salvia miltiorrhiza: 0.52%

[0127] Example 4

[0128] Freshly harvested Salvia miltiorrhiza from Tongchuan was collected. The rhizome was removed, and 7 kg of fresh Salvia miltiorrhiza was weighed and spread evenly in three rectangular trays (90cm x 50cm). Each tray was weighed separately. The trays were then placed on the tracks of a GWM-70B tunnel-type microwave drying equipment (10 microwave irradiation groups, each with three power levels: 2.4KW, 4.8KW, and 7.2KW). The equipment was started according to the microwave drying process operating procedures, with the exhaust device turned on. All 10 groups were maintained at a microwave power of 7.2KW (each group measuring 120cm x 60cm), with a track speed set to 1.2 m / min. The time from entering to exiting the microwave irradiation track was 10 minutes. The trays were then removed, weighed, and the water loss rate of the Salvia miltiorrhiza was determined. The herbs were then rinsed with water to remove soil and sand, cut, and sun-dried in a polycarbonate room to obtain Salvia miltiorrhiza slices. The content of Salvia miltiorrhiza was tested according to the methods for determining the content of the medicinal material in the Pharmacopoeia. The test results are as follows:

[0129] Water loss rate of fresh Salvia miltiorrhiza after microwave irradiation: 26.55%

[0130] The content of salvianolic acid B in danshen (Salvia miltiorrhiza) is 14.52%.

[0131] Tanshinone content in Salvia miltiorrhiza: 0.53%

[0132] Example 5

[0133] Freshly harvested Salvia miltiorrhiza from Weinan was collected. The rhizome was removed, and 6 kg of fresh Salvia miltiorrhiza was weighed and spread evenly in three rectangular trays (90cm x 50cm). Each tray was weighed separately. The trays were then placed on the tracks of a GWM-70B tunnel-type microwave drying equipment (10 microwave irradiation groups, each with three power levels: 2.4KW, 4.8KW, and 7.2KW). The equipment was started according to the microwave drying process operating procedures, with the exhaust device turned on. All 10 groups were maintained at a microwave power of 4.8KW (each group measuring 120cm x 60cm), with a track speed set to 1 meter / minute. The time from entering to exiting the microwave irradiation track was 12 minutes. The trays were then removed, weighed, and the water loss rate of the Salvia miltiorrhiza was determined. The herbs were then rinsed with water to remove soil and sand, cut, and sun-dried in a polycarbonate room to obtain Salvia miltiorrhiza slices. The content of Salvia miltiorrhiza was tested according to the Pharmacopoeia's method for determining the content of the medicinal material. The test results are as follows:

[0134] Water loss rate of fresh Salvia miltiorrhiza after microwave irradiation: 22.15%

[0135] The content of salvianolic acid B in danshen (Salvia miltiorrhiza) is 10.52%.

[0136] Tanshinone content in Salvia miltiorrhiza: 0.58%

[0137] Example 6

[0138] Freshly harvested Salvia miltiorrhiza from Weinan was collected. The rhizome was removed, and 6 kg of fresh Salvia miltiorrhiza was weighed and spread evenly in three rectangular trays (90cm x 50cm). Each tray was weighed separately. The trays were then placed on the tracks of a GWM-70B tunnel-type microwave drying equipment (10 microwave irradiation groups, each with three power levels: 2.4KW, 4.8KW, and 7.2KW). The equipment was started according to the microwave drying process operating procedures, with the exhaust device turned on. All 10 groups were maintained at a microwave power of 4.8KW (each group measuring 120cm x 60cm), with a track speed set to 0.8 m / min. The time from entering to exiting the microwave irradiation track was 15 minutes. The trays were then removed, weighed, and the water loss rate of the Salvia miltiorrhiza was determined. The herbs were then rinsed with water to remove soil and sand, cut, and sun-dried in a polycarbonate room to obtain Salvia miltiorrhiza slices. The content of Salvia miltiorrhiza was tested according to the Pharmacopoeia's method for determining the content of the medicinal material. The test results are as follows:

[0139] Water loss rate of fresh Salvia miltiorrhiza after microwave irradiation: 27.58%

[0140] The content of salvianolic acid B in danshen (Salvia miltiorrhiza) is 10.52%.

[0141] Tanshinone content in Salvia miltiorrhiza: 0.58%

[0142] Example 7

[0143] Freshly harvested Salvia miltiorrhiza from Weinan was collected. The rhizome was removed, and 7 kg of fresh Salvia miltiorrhiza was weighed and spread evenly in three rectangular trays (90cm x 50cm). Each tray was weighed separately. The trays were then placed on the tracks of a GWM-70B tunnel-type microwave drying equipment (10 microwave irradiation groups, each with three power levels: 2.4KW, 4.8KW, and 7.2KW). The equipment was started according to the microwave drying process operating procedures, with the exhaust device turned on. All 10 groups were maintained at a microwave power of 7.2KW (each group measuring 120cm x 60cm), with a track speed set to 1.2 m / min. The time from entering to exiting the microwave irradiation track was 10 minutes. The trays were then removed, weighed, and the water loss rate of the Salvia miltiorrhiza was determined. The herbs were then rinsed with water to remove soil and sand, cut, and sun-dried in a polycarbonate room to obtain Salvia miltiorrhiza slices. The content of Salvia miltiorrhiza was tested according to the Pharmacopoeia's method for determining the content of the medicinal material. The test results are as follows:

[0144] Water loss rate of fresh Salvia miltiorrhiza after microwave irradiation: 27.55%

[0145] The content of salvianolic acid B in danshen (Salvia miltiorrhiza) is 11.02%.

[0146] Tanshinone content in Salvia miltiorrhiza: 0.57%

[0147] Example 8

[0148] Freshly harvested Salvia miltiorrhiza from Shangluo was collected. The rhizome was removed, and 6 kg of fresh Salvia miltiorrhiza was weighed and spread evenly in three rectangular trays (90cm x 50cm). Each tray was weighed separately. The trays were then placed on the tracks of a GWM-70B tunnel-type microwave drying equipment (10 microwave irradiation groups, each with three power levels: 2.4KW, 4.8KW, and 7.2KW). The equipment was started according to the microwave drying process operating procedures, with the exhaust device turned on. All 10 groups were maintained at a microwave power of 4.8KW (each group measuring 120cm x 60cm), with a track speed set to 1 meter / minute. The time from entering to exiting the microwave irradiation track was 12 minutes. The trays were then removed, weighed, and the water loss rate of the Salvia miltiorrhiza was determined. The herbs were then rinsed with water to remove soil and sand, cut, and sun-dried in a polycarbonate room to obtain Salvia miltiorrhiza slices. The content of Salvia miltiorrhiza was tested according to the methods for determining the content of the medicinal material in the Pharmacopoeia. The test results are as follows:

[0149] Water loss rate of fresh Salvia miltiorrhiza after microwave irradiation: 22.55%

[0150] The content of salvianolic acid B in danshen (Salvia miltiorrhiza) is 8.32%.

[0151] Tanshinone content in Salvia miltiorrhiza: 0.59%

[0152] Example 9

[0153] Freshly harvested Salvia miltiorrhiza from Shangluo was collected. The rhizome was removed, and 6 kg of fresh Salvia miltiorrhiza was weighed and spread evenly in three rectangular trays (90cm x 50cm). Each tray was weighed separately. The trays were then placed on the tracks of a GWM-70B tunnel-type microwave drying equipment (10 microwave irradiation groups, each with three power settings: 2.4KW, 4.8KW, and 7.2KW). The equipment was started according to the microwave drying process operating procedures, with the exhaust device turned on. All 10 groups were maintained at a microwave power of 4.8KW (each group measuring 120cm x 60cm), with a track speed set to 0.8 m / min. The time from entering to exiting the microwave irradiation track was 15 minutes. The trays were then removed, weighed, and the water loss rate of the Salvia miltiorrhiza was determined. The herbs were then rinsed with water to remove soil and sand, cut, and sun-dried in a polycarbonate room to obtain Salvia miltiorrhiza slices. The content of Salvia miltiorrhiza was tested according to the methods for determining the content of the medicinal material in the Pharmacopoeia. The test results are as follows:

[0154] Water loss rate of fresh Salvia miltiorrhiza after microwave irradiation: 27.80%

[0155] The content of salvianolic acid B in danshen (Salvia miltiorrhiza) is 8.52%.

[0156] Tanshinone content in Salvia miltiorrhiza: 0.58%

[0157] Example 10

[0158] Freshly harvested Salvia miltiorrhiza from Shangluo was collected. The rhizome was removed, and 7 kg of fresh Salvia miltiorrhiza was weighed and spread evenly in three rectangular trays (90cm x 50cm). Each tray was weighed separately. The trays were then placed on the tracks of a GWM-70B tunnel-type microwave drying equipment (10 microwave irradiation groups, each with three power levels: 2.4KW, 4.8KW, and 7.2KW). The equipment was started according to the microwave drying process operating procedures, with the exhaust device turned on. All 10 groups were maintained at a microwave power of 7.2KW (each group measuring 120cm x 60cm), with a track speed set to 1.2 m / min. The time from entering to exiting the microwave irradiation track was 10 minutes. The trays were then removed, weighed, and the water loss rate of the Salvia miltiorrhiza was determined. The herbs were then rinsed with water to remove soil and sand, cut, and sun-dried in a polycarbonate room to obtain Salvia miltiorrhiza slices. The content of Salvia miltiorrhiza was tested according to the methods for determining the content of the medicinal material in the Pharmacopoeia. The test results are as follows:

[0159] Water loss rate of fresh Salvia miltiorrhiza after microwave irradiation: 27.55%

[0160] The content of salvianolic acid B in danshen (Salvia miltiorrhiza) is 8.25%.

[0161] Tanshinone content in Salvia miltiorrhiza: 0.58%

Claims

1. A method for processing and drying fresh Salvia miltiorrhiza suitable for large-scale industrial production, the method comprising the following steps: Step 1) Use a tunnel microwave drying device to irradiate fresh Salvia miltiorrhiza to control the water loss rate of fresh Salvia miltiorrhiza to 22-28%; Step 2) Continue drying using natural air drying method; in, The microwave irradiation in step 1) uses a microwave power of 2.4KW to 7.2KW and an irradiation time of 5-20 minutes; the natural drying in step 2) is selected from: air drying and low-temperature drying.

2. The method according to claim 1, characterized in that, in, The low-temperature drying described in step 2) is drying at a temperature below 60°C.

3. The method according to claim 1, characterized in that, in, The fresh Salvia miltiorrhiza was selected from Tongchuan, Weinan, and Shangluo.

4. The method according to claim 1, characterized in that, The fresh Salvia miltiorrhiza mentioned refers to fresh Salvia miltiorrhiza with the root tip removed.

5. The method according to claim 1, characterized in that, The steps are as follows: Freshly harvested Salvia miltiorrhiza → trimming the rhizome at the field → tunnel microwave drying → rinsing off soil and sand with water → natural drying → Salvia miltiorrhiza medicinal material → inspection → warehousing.

6. The method according to claim 1, characterized in that, The steps are as follows: Freshly harvested Salvia miltiorrhiza → trimming the rhizome at the field → tunnel microwave drying → rinsing off soil and sand with water → fresh cutting → natural drying → Salvia miltiorrhiza slices → inspection → warehousing.

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