Preparation method of mikania micrantha active extract based on high-temperature water extraction and application of mikania micrantha active extract in promoting growth of eucalyptus

Abstract

The invention discloses a preparation method of a mikania micrantha active extract based on high-temperature water extraction and application of the mikania micrantha active extract in promoting growth of eucalyptus, and belongs to the technical field of plant resource utilization and agriculture and forestry. The method comprises the following steps: crushing mikania micrantha which is naturally dried in the shade, adding a solvent according to a proper material-liquid ratio, performing reflux extraction at high temperature by adopting mikania micrantha extraction equipment, and filtering to obtain an active extract. After the extract is diluted, eucalyptus seedlings are irrigated, and the plant height and the ground diameter increase can be remarkably increased and are respectively increased by 13.5% and 16.4% compared with those of a normal-temperature extraction group. The method is easy and convenient to operate, high in extraction efficiency, environmentally friendly, free of organic solvents and pure water and suitable for popularization of basic forest farms and nursery gardens, and high-value utilization of mikania micrantha is achieved.

Description

Technical Field

[0001] This invention belongs to the fields of plant resource utilization and agricultural and forestry technology, specifically relating to a process for extracting active ingredients that promote eucalyptus growth from the invasive alien plant Mikania micrantha, and particularly to a preparation method that significantly enhances the bioactivity of the extract through specific high-temperature water extraction conditions, as well as the application of the extract in eucalyptus seedling cultivation and planting. Background Technology

[0002] Mikania micrantha, one of the first invasive alien species under key control in my country, originated in Central and South America. Due to its strong asexual reproduction ability and climbing growth characteristics, it has spread widely in South and Southwest my country. This species not only competes with native plants for sunlight, water, and nutrients, forming monoculture communities and leading to a decline in local biodiversity, but also inhibits the growth of surrounding plants by secreting allelochemicals, causing serious damage to forest ecosystems, farmland ecosystems, and landscapes, resulting in huge economic losses to my country's agricultural and forestry industries every year. According to statistics from the National Forestry and Grassland Administration in 2023, the affected area of ​​Mikania micrantha nationwide has reached 580,000 mu (approximately 38,000 hectares), mainly concentrated in eucalyptus plantation areas such as Guangdong, Guangxi, Yunnan, Guizhou, and Hainan, posing a serious threat to the growth of eucalyptus and other economic forests, and becoming one of the important factors restricting the sustainable development of local forestry.

[0003] With the increasing awareness of ecological and environmental protection, the management of invasive alien species has shifted from simple physical removal and chemical control to a comprehensive management model of "resource utilization." Mikania micrantha contains various bioactive components such as flavonoids, phenolic acids, and terpenes, possessing potential utilization values ​​in medicine, peticidal properties, and growth promotion. Its resource utilization can not only reduce the harm caused by invasion but also create economic value, realizing the transformation of "waste into treasure." In recent years, scholars at home and abroad have conducted extensive research on the resource utilization of Mikania micrantha, among which the application of its extracts to plant growth regulation has become one of the research hotspots.

[0004] Eucalyptus, an important fast-growing and high-yield economic tree species in southern my country, is widely used in papermaking, engineered wood products, and biomass energy. According to data released on the official websites of the National Forestry and Grassland Administration and the National Park Administration in 2025, the national eucalyptus planting area has exceeded 85 million mu (approximately 5 million hectares), playing a vital role in ensuring national timber security and promoting regional economic development. However, eucalyptus seedling cultivation often faces problems such as poor root development and uneven growth rates, affecting seedling quality and afforestation survival rates. Existing technologies have included research on using plant extracts to promote eucalyptus growth. For example, Chinese patent CN117814062A discloses a "method for promoting eucalyptus seedling rooting using Mikania micrantha aqueous extract." This method prepares Mikania micrantha aqueous extract by soaking at room temperature (25℃) for 24 hours, confirming its promoting effect on eucalyptus root growth.

[0005] However, existing technologies for the extraction and application of Mikania micrantha still have many shortcomings and deficiencies that urgently need to be addressed:

[0006] First, the extraction efficiency is low, making it difficult to meet the needs of large-scale applications. Current technologies generally employ room-temperature static immersion extraction, which takes up to 24 hours or even longer, resulting in long batch processing cycles and low equipment turnover efficiency. For scenarios requiring large quantities of extract, such as forest farms and nurseries, room-temperature extraction cannot achieve efficient preparation, severely limiting the technology's widespread application. For example, a 100L extraction tank can only process one batch of raw material per day using the room-temperature immersion method, while actual production often requires multiple batches of continuous preparation, highlighting the significant efficiency bottleneck of the existing process.

[0007] Secondly, the extract has limited vitality and insufficient effect on promoting the aboveground growth of eucalyptus. Current research focuses primarily on root growth regulation, with weaker effects on key aboveground growth indicators such as plant height and diameter at breast height. Experimental data shows that after treatment with the room-temperature extract described in CN117814062A, the eucalyptus plant height increased by only 230.30 cm and the diameter at breast height increased by only 31.67 mm, showing limited improvement compared to the control group and failing to meet the high-efficiency cultivation requirements of fast-growing eucalyptus. The core reason for this phenomenon is that the active ingredients in Mikania micrantha are not fully dissolved under room-temperature conditions, and some bound precursor substances fail to be converted into bioactive small molecule forms.

[0008] Third, the processes are costly, poorly adaptable, and not conducive to widespread adoption at the grassroots level. Some existing technologies suggest using pure water as the extraction solvent, requiring specialized pure water preparation equipment, which increases initial investment and operating costs. Furthermore, raw material processing often involves drying in 70℃ ovens, relying on electricity and potentially leading to the loss of volatile active ingredients or Maillard reactions. For grassroots units such as forest farms, nurseries, and township agricultural technology stations that lack advanced equipment and sufficient energy, the implementation threshold for existing processes is high, making widespread adoption difficult.

[0009] Fourth, temperature control lacks scientific design and contains misconceptions about the technology. Current technology generally assumes that most plant active ingredients are heat-sensitive, and that high temperatures will cause them to decompose and become ineffective. Therefore, low-temperature or room-temperature extraction strategies are blindly adopted without systematically investigating the impact of extraction temperature on the dissolution and transformation of active ingredients. In fact, the structure and stability of active ingredients vary among different plants. For components such as flavonoids and phenolic esters in Mikania micrantha, appropriately increasing the extraction temperature can actually promote their hydrolysis into aglycones or free phenolic acids that are more easily absorbed and utilized by plants. This technological potential has not been discovered or utilized in current technology.

[0010] Fifth, the process reproducibility is poor and the data reliability is insufficient. Existing extraction equipment lacks precise temperature control and solvent metering mechanisms. Steam flow regulation relies on manual operation, which is prone to temperature fluctuations (typically exceeding ±5℃) due to vibration and accidental touches. Solvent addition is done manually, with an error rate exceeding 10%, causing the material-to-liquid ratio to deviate from the preset value. These factors result in significant differences in the concentration of active ingredients in different batches of extract, leading to poor process reproducibility. This not only affects the reliability of research data but also makes it difficult to translate pilot-scale processes into large-scale production.

[0011] In summary, existing extraction processes for Mikania micrantha have significant shortcomings in terms of efficiency, activity, cost, compatibility, and reproducibility. There is an urgent need to develop an optimized process that is highly efficient, highly active, low-cost, and easy to promote, while also clarifying its application in promoting eucalyptus growth, so as to provide technical support for the high-value utilization of Mikania micrantha and the efficient cultivation of eucalyptus. Summary of the Invention

[0012] To address the shortcomings of existing Mikania micrantha extraction processes in terms of efficiency, activity, cost, compatibility, and reproducibility, this invention provides a method for preparing an active extract of Mikania micrantha based on high-temperature water extraction and its application in promoting eucalyptus growth. This method is simple to operate, has high extraction efficiency, low cost, and good process reproducibility. The prepared extract significantly promotes eucalyptus growth and is suitable for widespread application in forest farms, nurseries, and other grassroots units. Simultaneously, this invention achieves high-value utilization of the invasive alien plant Mikania micrantha, not only reducing its ecological harm but also providing a novel growth regulator for eucalyptus cultivation, thus possessing significant ecological, economic, and social benefits.

[0013] To achieve the above technical objectives, the present invention adopts the following technical solution:

[0014] A method for preparing active extracts of Mikania micrantha based on high-temperature water extraction includes the following steps:

[0015] (1) Raw material pretreatment: Fresh Mikania branches and leaves are collected, impurities are removed, and they are placed in a ventilated and dark place to air dry naturally until constant weight. After crushing, Mikania powder with a particle size of 1-10 mm is obtained.

[0016] (2) High temperature water extraction: Water extraction is carried out using Mikania micrantha extraction equipment. Solvent is added to the Mikania micrantha powder in step (1) at a material-to-liquid ratio of 1:30-1:70 (g / mL), and the mixture is heated and refluxed at 90-110℃ for 1-3 hours. During the extraction process, the liquid is kept circulating and mixed.

[0017] (3) Solid-liquid separation: After extraction, the extract is cooled to room temperature, filtered and the clear filtrate is collected to obtain the active extract of Mikania micrantha.

[0018] Further, the Mikania micrantha extraction equipment in step (2) includes a steam inlet pipe, an extraction tank, a concentration tank, a collection tank, and a condensation tank. The steam inlet pipe connects the extraction tank and the concentration tank. The extraction tank and the concentration tank are connected to the condensation tank through a steam outlet pipe. The steam inlet pipe is equipped with a locking control mechanism. The locking control mechanism is used to adjust the steam thermal balance state of the steam inlet pipe. The locking control mechanism includes a throttle valve body connected to the steam inlet pipe. The throttle valve body is equipped with a handle. A locking bolt for moving and locking the handle is provided on one side of the handle. A pressure gauge is provided at the bottom of the throttle valve body below the locking bolt. The extraction tank is equipped with a water inlet pipe. A liquid addition mechanism is connected to the top of the water inlet pipe of the extraction tank.

[0019] Furthermore, the locking control mechanism can control the extraction temperature fluctuation within ±2℃, and the solvent metering error of the liquid addition mechanism is ≤2%.

[0020] Furthermore, the extraction temperature in step (2) is 90-100℃, more preferably 100℃ at atmospheric pressure boiling.

[0021] Further, the material-liquid ratio in step (2) is 1:30-1:50 (g / mL), more preferably 1:40 (g / mL).

[0022] Furthermore, the particle size of the Mikania powder mentioned in step (1) is 2-5 mm.

[0023] Furthermore, the solvent mentioned in step (2) is municipal tap water, which does not require purification treatment.

[0024] Furthermore, the intensity of the drug solution circulation mixing in step (2) is a medium circulation flow rate, with a Reynolds number Re≈4000.

[0025] Furthermore, the extraction time in step (2) is 1.5-2.5 hours, more preferably 2 hours.

[0026] The present invention also provides the application of a micrantha active extract in promoting eucalyptus growth, wherein the extract is diluted to 5 g / L and directly watered into the roots of eucalyptus seedlings, with each seedling receiving 2000 mL of water, which can increase the growth rate of eucalyptus tree height and diameter at ground level.

[0027] Compared with existing technologies, this invention has achieved significant progress in terms of bioactivity, extraction efficiency, cost control, ease of operation, and potential for widespread application. Specific advantages are as follows:

[0028] 1. Significantly enhanced growth-promoting effect with highly statistically significant differences: Existing technologies using room-temperature soaking extraction, while promoting eucalyptus root growth, have limited effects on the above-ground parts (plant height and diameter at breast height) and lack statistically significant improvements. This invention, through a high-temperature water extraction process, significantly enhances the growth-promoting properties of the extract. Comparative experiments conducted from June to October 2025 showed that eucalyptus seedlings treated with the extract obtained from reflux extraction at 100℃ for 2 hours (diluted to 5 g / L) experienced an average plant height increase of 261.30 cm and a diameter at breast height increase of 36.87 mm; while the corresponding values ​​in the room-temperature extraction group were 230.30 cm and 31.67 mm, respectively, and the blank control group was only 208.50 cm and 30.36 mm. Compared with the normal temperature group, the plant height and diameter increase in the high-temperature group were 13.5% and 16.4% higher, respectively, and compared with the blank control group, they were 25.3% and 21.4% higher, respectively. Analysis of variance (ANOVA) confirmed that the differences were highly significant (p<0.01). The core advantage lies in the full dissolution and transformation of active ingredients under high-temperature conditions, enabling the extract to more effectively regulate the physiological metabolic processes of eucalyptus, promote cell division and elongation, and enhance the eucalyptus's ability to absorb and utilize nutrients and water, providing strong support for the rapid growth of eucalyptus. Furthermore, the extract of this invention not only promotes the growth of eucalyptus seedlings, but in multiple batches of repeated experiments, the extracts from different seasons and batches all showed stable growth-promoting effects, with plant height increases fluctuating only within the range of 258.2-275.3 cm, further confirming the stability and reliability of the growth-promoting effect.

[0029] 2. Enhanced Temperature Control Stability and Guaranteed Effective Component Dissolution Efficiency: This invention relies on a locking control mechanism to achieve precise and stable steam flow control. The core technology lies in the coordinated design of the throttle valve's scale and the mechanical locking function of the locking bolt. The throttle valve stem features 1-8 uniform scales, each precisely corresponding to the steam flow and extraction temperature. Operators can directly adjust to the target scale according to pre-set process requirements without repeated adjustments. The locking bolt, inserted into the corresponding groove on the handle, effectively resists external interference such as equipment vibration and accidental activation, ensuring a constant throttle valve opening and thus a continuously stable steam flow. Combined with real-time pressure feedback from the pressure gauge, a closed-loop control system of "precise scale adjustment - real-time pressure monitoring - mechanical locking of opening" is formed, strictly controlling the temperature fluctuation within the extraction tank to within ±2℃. Compared to the existing equipment's generally ±5℃ or higher fluctuation range, the control accuracy is significantly improved. This technology effectively avoids the decomposition of heat-sensitive components caused by excessively high temperatures, while also solving the problem of insufficient dissolution of active ingredients caused by excessively low temperatures. It not only ensures the dissolution efficiency and stability of the active ingredients of Mikania micrantha, providing stable and reliable temperature control support for related scientific research experiments, but also makes the quality of the produced products more uniform.

[0030] 3. Improve solvent metering accuracy and optimize precise control of the liquid-to-material ratio: The dispensing mechanism adopts a visually oriented metering tank with high-precision graduations. Combined with a pressure-balancing design using an exhaust vent on the top of the tank, this structurally solves the metering error problem that easily occurs when manually measuring solvents. The metering tank is made of transparent material, allowing operators to directly observe the liquid level inside. The minimum graduation value is ≤0.5L, which can accurately match the metering needs of small-volume solvents, reducing solvent metering error from over 10% in existing equipment to below 2%. The exhaust vent design on the top of the tank effectively avoids liquid level fluctuations caused by pressure buildup inside the tank during solvent dispensing, ensuring accurate graduation readings and reducing solvent evaporation losses. In addition, the metering tank integrates a dedicated feeding port, allowing solid raw materials and solvents to be pre-mixed in the metering tank before being simultaneously fed into the extraction tank. This simplifies the operation process, ensures uniform mixing of the liquid and material, and further achieves precise control of the liquid-to-material ratio. A stable and controllable feed-to-liquid ratio can improve mass transfer efficiency during the extraction process, reduce the loss and waste of effective components, reduce processing costs for subsequent concentration and purification processes, and ensure that the concentration of extracts from different batches remains consistent.

[0031] 4. Significantly Improved Extraction Efficiency and a 12-Fold Shortened Production Cycle: Low extraction efficiency is a key bottleneck restricting the large-scale application of existing Mikania micrantha extraction processes. Current technologies use a static soaking method at room temperature, with extraction times reaching up to 24 hours. A single unit can only process one batch of raw material per day, resulting in low equipment turnover efficiency and failing to meet the demands of large-scale production. The Mikania micrantha extraction equipment of this invention, through the synergistic effect of high-temperature reflux extraction and circulating mixing, shortens the extraction time from 24 hours to 2 hours, reducing the single-batch processing time by 91.7% and increasing extraction efficiency by 12 times. Taking a 50L extraction tank as an example, the existing process can only process one batch (1.0kg of raw material) per day, while the process of this invention can process 12 batches per day, with a daily raw material processing capacity of 12kg, greatly increasing production capacity. This advantage not only reduces equipment occupancy costs but also reduces energy consumption and labor input during the extraction process, laying the foundation for the large-scale promotion of the process. Simultaneously, shortening the extraction time also reduces the loss of active ingredients through oxidative decomposition during extraction, further ensuring the bioactivity of the extract. Experiments have shown that after extraction time exceeds 2.5 hours, the activity of the extract no longer increases significantly, but instead decreases slightly due to the oxidation of some components. Therefore, an extraction time of 2 hours achieves the best balance between efficiency and activity.

[0032] 5. Extremely low solvent cost, no need for pure water, suitable for grassroots applications: Existing technologies tend to use pure water as the extraction solvent to avoid interference from impurities, requiring pure water preparation equipment such as reverse osmosis or distillation, with initial equipment investment reaching tens of thousands of yuan. Furthermore, the operation consumes a large amount of electricity and water resources, increasing process costs. This invention breaks with this traditional understanding. Practice has proven that using municipal tap water directly as the extraction solvent can still yield highly active extracts under high-temperature conditions, and no negative impact of water quality on activity has been observed. The trace amounts of Ca in tap water... 2+ Mg 2+ Plasma can form stable complexes with phenolic acids, inhibiting their oxidative polymerization and thus contributing to improved extract stability. Furthermore, the sterilization effect during high-temperature extraction effectively kills microorganisms in tap water, preventing microbial contamination. This improvement eliminates the need for a pure water system, significantly reducing initial investment and operating costs, making it particularly suitable for widespread application in grassroots units lacking high-purity water resources, such as forest farms, nurseries, and township agricultural technology stations.

[0033] 6. More Practical Raw Material Processing, Avoiding Variables Introduced by Artificial Drying: Existing technologies mostly use 70℃ ovens to dry raw materials. While this allows for precise control of the drying degree, it relies on electricity, and high-temperature drying may trigger Maillard reactions or the loss of volatile components. For large quantities of Mikania micrantha raw materials collected in the wild, oven drying requires multiple steps such as handling, loading, drying, and unloading, which is cumbersome, labor-intensive, and unsuitable for on-site processing. This invention uses natural shade drying to dry Mikania micrantha raw materials. After removing impurities from fresh branches and leaves, they are placed in a well-ventilated, dark place to dry naturally to a constant weight. This method is simple to operate, requires no energy consumption, and can be processed on-site, reducing raw material transportation costs and labor intensity. Simultaneously, natural shade drying avoids the damage of high temperatures to active ingredients, preserving the original chemical composition of Mikania micrantha to the greatest extent, resulting in more stable raw material quality. Experimental comparisons show that after high-temperature extraction, the total flavonoid content of the extract from naturally shade-dried raw materials is 15.3% higher than that from oven-dried raw materials, and the activity-promoting properties are improved by 8.7%, fully demonstrating the superiority of natural shade drying. In addition, the raw materials that are naturally air-dried have a loose texture, making them easy to crush, and the crushed powder has a more uniform particle size distribution, which further ensures the uniformity of the extraction process.

[0034] 7. The overall technical system possesses synergistic effects and replicability, with excellent process reproducibility: This invention is not merely an adjustment of a single parameter, but rather the construction of a complete technical system of "naturally air-dried raw materials + tap water solvent + high-temperature short-time extraction + cyclic mixing." Each step works synergistically to achieve comprehensive optimization of activity, efficiency, and cost. Natural air-drying ensures the consistency of the raw materials, providing a stable starting material for subsequent extraction; tap water solvent lowers the implementation threshold while stabilizing the active ingredients; high-temperature extraction achieves efficient dissolution and conversion of the active ingredients; cyclic mixing enhances the mass transfer process and shortens the extraction time. Multiple batch replicate experiments (9 replicate groups, H1-H9) show that the within-group standard deviations of the final plant height and diameter at breast height were 3.37 cm and 0.79 mm, respectively, with coefficients of variation of only 1.29% and 2.14%, far lower than the coefficients of variation of existing technologies (usually exceeding 10%), indicating excellent process reproducibility. Furthermore, this invention clarified the optimal ranges for each key parameter through single-factor experiments, including powder particle size of 2-5 mm, material-liquid ratio of 1:30-1:50, extraction temperature of 90-100℃, extraction time of 1.5-2.5 hours, and moderate cycle intensity, providing a scientific basis for the standardized implementation of the process. Even under different operators and equipment conditions, as long as the process parameters of this invention are followed, stable extraction results can be obtained, facilitating the transformation of small-scale processes into large-scale production and demonstrating broad application prospects. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the structure of the Mikania micrantha extraction device of the present invention;

[0036] Figure 2This is a schematic diagram of the locking control structure in this invention;

[0037] Figure 3 This is a schematic diagram of the liquid addition mechanism in this invention.

[0038] In the diagram: 1-Steam inlet pipe; 2-Extraction tank; 3-Concentration tank; 4-Collection tank; 5-Steam outlet pipe; 6-Condensation tank; 7-Locking control mechanism; 71-Throttle valve body; 72-Handle; 73-Locking bolt; 74-Pressure gauge; 8-Liquid adding mechanism; 81-Quantitative tank; 82-Water adding pipe. Detailed Implementation

[0039] To make the technical solution of the present invention clearer and easier to understand, the following detailed description is provided in conjunction with specific embodiments. The embodiments are only used to explain the present invention and are not intended to limit the scope of protection of the present invention.

[0040] A method for preparing active extracts of Mikania micrantha based on high-temperature water extraction includes the following steps:

[0041] (1) Raw material pretreatment: Fresh Mikania branches and leaves are collected, impurities are removed, and they are placed in a ventilated and dark place to air dry naturally until constant weight. After crushing, Mikania powder with a particle size of 1-10 mm is obtained.

[0042] (2) High-temperature water extraction: Water extraction is carried out using a Mikania micrantha extraction device. The solvent is added to the Mikania micrantha powder in step (1) at a material-to-liquid ratio of 1:30-1:70 (g / mL). The mixture is heated and refluxed at 90-110℃ for 1-3 hours. During the extraction process, the liquid is kept circulating and mixed. The solvent is municipal tap water and does not require purification. The intensity of the liquid circulation is a medium circulation flow rate and the Reynolds number Re≈4000.

[0043] (3) Solid-liquid separation: After extraction, the extract is cooled to room temperature, filtered and the clear filtrate is collected to obtain the active extract of Mikania micrantha.

[0044] In step (2), a Mikania extracting device including a locking control mechanism and a liquid addition mechanism is used for extraction. The locking control mechanism can control the extraction temperature fluctuation within ±2℃, and the solvent metering error of the liquid addition mechanism is ≤2%.

[0045] Technical principle of the invention:

[0046] This invention, based on a systematic study of the extraction characteristics of active ingredients in Mikania micrantha and its plant growth regulation mechanism, breaks through the misconception of "low temperature and heat avoidance" in existing technologies. It constructs a complete technical system of "naturally air-dried raw materials + tap water solvent + high-temperature short-time reflux extraction + cyclic mixing enhancement," and its core technical principle is as follows:

[0047] 1. Dissolution and Transformation Mechanism of Active Ingredients Extracted by High-Temperature Water Extraction: The growth-promoting components in *Mikania micrantha* mainly include flavonoids, phenolic esters, and terpenoids. Flavonoids and phenolic esters are mostly present in bound form within the plant cell wall. Under high-temperature conditions of 90-100℃, the kinetic energy of water molecules is significantly enhanced, and the permeability and diffusion rate are greatly increased. This effectively disrupts the cellulose and hemicellulose structures of the plant cell wall, causing cell wall relaxation and increased porosity, thus promoting the release of bound active ingredients from the plant matrix into the solvent. Simultaneously, the high-temperature environment triggers ester bond hydrolysis, causing flavonoids to hydrolyze to generate aglycones and phenolic esters to hydrolyze to generate free phenolic acids. Compared to the bound precursors, aglycones and free phenolic acids have smaller molecular weights and stronger hydrophilicity, making them more easily absorbed by eucalyptus roots and exhibiting higher bioactivity, thereby significantly enhancing the growth-promoting effect of the extract on eucalyptus. Experiments have shown that under extraction conditions of 100℃, the total flavonoid aglycone content in Mikania micrantha extract increased by 28.7% and the free phenolic acid content increased by 32.4% compared with the group extracted at room temperature. This is the core material basis for the enhanced growth-promoting effect.

[0048] 2. Principle of Natural Shade-Drying as Raw Material Pretreatment: Raw material drying is a crucial pretreatment step in plant extraction. While existing oven drying (70℃) can achieve rapid drying, the high temperature can lead to the loss of some volatile active ingredients (such as monoterpenes and sesquiterpenes). It may also trigger Maillard reactions, causing sugars and amino acids to combine and form inactive melanoidins, reducing the bioactivity of the extract. This invention employs natural shade-drying, placing fresh Mikania micrantha in a well-ventilated, dark place to dry to constant weight. This avoids oxidation caused by direct sunlight and component changes caused by high-temperature drying, maximizing the preservation of the original chemical composition of Mikania micrantha. Furthermore, natural shade-drying simulates the natural state after field harvesting, is simple to operate, requires no energy consumption, and results in a loose texture of the dried raw material, facilitating subsequent crushing and extraction. This provides a stable and uniform starting material for subsequent high-temperature extraction, ensuring process reproducibility.

[0049] 3. Synergistic stabilizing effect of tap water solvent: Existing technology believes that pure water can avoid interference from impurities, but this invention has found that municipal tap water contains trace amounts of Ca... 2+ Mg 2+ Plasma is not a harmful impurity; on the contrary, it can form stable complexes with the phenolic acids in Mikania micrantha, inhibiting the oxidative polymerization of phenolic acids and improving the stability of the active ingredients. Furthermore, the high-temperature extraction process itself has a certain sterilization effect, effectively killing microorganisms in tap water and preventing microbial metabolism from damaging the active ingredients. At the same time, tap water does not require purification treatment and can be used directly, saving the investment and operating costs of pure water preparation equipment, lowering the barrier to entry for the process, and making it particularly suitable for grassroots applications.

[0050] 4. Mass Transfer Enhancement Principle of Circulating Mixing: The mass transfer efficiency during extraction directly affects the dissolution rate and amount of active ingredients. Existing room-temperature extraction methods often employ static soaking, resulting in insufficient contact between the raw material and solvent, easily forming local concentration gradients, leading to increased mass transfer resistance and slow dissolution of active ingredients. This invention introduces a circulating mixing mechanism during high-temperature extraction. A circulating pump circulates the liquid in the tank from bottom to top. The moderate circulation intensity (Reynolds number Re≈4000) ensures sufficient contact between the raw material and solvent, avoiding local accumulation and dead zones, thus enhancing the mass transfer process between the solid and liquid phases. Simultaneously, the shear force generated by the circulating flow further disrupts the plant cell wall structure, promoting the release of active ingredients and shortening the extraction time from 24 hours to 2 hours, significantly improving extraction efficiency.

[0051] 5. Synergistic Effect Principle of Each Process Step: This invention does not involve isolated adjustment of a single parameter, but rather achieves synergistic effects through a process design of "naturally air-dried raw materials → crushing → quantitative addition of tap water → high-temperature reflux extraction → circulating mixing → solid-liquid separation." Natural air-drying ensures the integrity of the raw material components, providing high-quality raw materials for high-temperature extraction; tap water solvent reduces costs and stabilizes active ingredients; high-temperature extraction achieves efficient dissolution and conversion of active ingredients; circulating mixing enhances the mass transfer process and shortens the extraction time. Multiple batches of repeated experiments show that under this technical system, the within-group standard deviations of eucalyptus tree height and diameter at breast height were 3.37 cm and 0.79 mm, respectively, with small coefficients of variation and good process reproducibility, fully demonstrating the stability and reliability of the synergistic effect of each step.

[0052] To make the present invention more fully disclosed, more specific embodiments are described below.

[0053] I. Raw Materials and Equipment

[0054] 1. Raw material of Mikania micrantha: Collect fresh Mikania micrantha branches and leaves, remove weeds, dead branches and other impurities, place them in a ventilated and dark place to air dry naturally until constant weight (moisture content ≤10%), put them into a universal pulverizer to pulverize and obtain powder with a particle size range of 1-30mm, of which 2-5mm particles account for ≥70%, which can be directly used for extraction.

[0055] 2. Extraction solvent: Nanning municipal tap water, without any purification treatment.

[0056] 3. Extraction equipment: such as Figure 1-3As shown, a Mikania micrantha extraction device includes a steam inlet pipe 1, an extraction tank 2, a concentration tank 3, a collection tank 4, and a condenser tank 6. The steam inlet pipe 1 connects the extraction tank 2 and the concentration tank 3, providing steam for extraction and concentration. The extraction tank 2 and the concentration tank 3 are connected to the condenser tank 6 via a steam outlet pipe 5, which guides the steam generated in the extraction tank 2 and the concentration tank 3 into the condenser tank 6 for condensation and recovery. The steam inlet pipe 1 is equipped with a locking control mechanism 7, used to adjust the steam thermal balance state of the steam inlet pipe 1 and achieve steam flow rate control. Precise control and stable locking; the locking control mechanism 7 includes a throttle valve body 71 connected to the steam inlet pipe 1, a handle 72 on the throttle valve body 71, a locking bolt 73 on one side of the handle 72 for moving and locking the handle 72, and a pressure gauge 74 at the bottom of the throttle valve body 71 below the locking bolt 73, which monitors the steam pressure in real time and provides feedback on the steam flow status; the extraction tank 2 is provided with a water inlet pipe, and a liquid adding mechanism 8 is connected to the top of the water inlet pipe of the extraction tank 2 for quantitative addition of solvent.

[0057] The liquid addition mechanism 8 is used to quantitatively add solvent or liquid to the extraction tank 2 to ensure precise control of the liquid-to-solid ratio. The liquid addition mechanism 8 includes a quantitative tank 81 connected to the top of the water inlet pipe of the extraction tank 2. The top of the quantitative tank 81 is provided with a water addition pipe 82. The water addition pipe 82 is provided with a valve body for controlling the opening and closing of the water addition pipe 82, which facilitates the water addition operation of the quantitative tank 81.

[0058] The steam inlet pipe 1 is a three-way pipe. The two-way pipe and the three-way pipe of the steam inlet pipe 1 are connected to the extraction tank 2 and the concentration tank 3 respectively. The two-way pipe and the three-way pipe of the steam inlet pipe 1 are equipped with valves for adjusting the flow rate, which can control the steam flow rate entering the extraction tank 2 and the concentration tank 3 respectively, so as to realize the independent operation or coordinated operation of the two tanks.

[0059] The throttle valve body 71 is connected to a through pipe of the steam inlet pipe 1. The handle 72 is an adjustment handle adapted to the throttle valve body 71. The valve stem of the throttle valve body 71 is engraved with 1-8 uniform scales on its outer circumference. The valve stem is 80mm long and has 8 uniformly engraved annular scale lines along the axial direction, with each scale interval of 5mm, which facilitates the operator to accurately adjust the steam flow. The locking bolt 73 is threaded through the bracket on the throttle valve body 71, and its end can be movably inserted into the groove on the side wall of the handle 72. The handle 72 has multiple sets of grooves, which are evenly distributed on the side wall of the handle 72. By inserting the locking bolt 73 into different grooves, the position of the handle 72 is fixed, thereby locking the opening of the throttle valve body 71 and preventing the steam flow from changing due to external factors.

[0060] The metering container 81 is a metering container with volume graduations. The metering container 81 is made of a visible transparent material (such as borosilicate glass), which makes it easy for operators to observe the liquid level in the container and accurately read the volume value. The metering container 81 has a vent at the top to balance the air pressure in the container and prevent liquid level fluctuations caused by air pressure obstruction when adding solvent, thus ensuring accurate scale readings. The end of the water inlet pipe 82 away from the metering container 81 is connected to a water source and can be directly connected to a tap water or purified water system, simplifying the water adding operation.

[0061] The extraction tank 2 is equipped with a valve on its inlet pipe to control the flow of solvent from the metering tank 81 to the extraction tank 2. The concentration tank 3 is equipped with a valve on its pipe connecting to the extraction tank 2. The steam outlet pipe 5 is a three-way pipe with three sets of valves on it for independent control. The connection status of the extraction tank 2, concentration tank 3 and condenser 6 can be flexibly controlled according to process requirements.

[0062] The pipe connecting the extraction tank 2 and the concentration tank 3 is equipped with a pump and a filter. The pump is used to facilitate the transport of the extract from the extraction tank 2 to the concentration tank 3, and the filter can filter out solid impurities in the extract to prevent impurities from entering the concentration tank 3 and affecting the concentration effect. The pipe connecting the concentration tank 3 and the collection tank 4 is equipped with a valve to control the transport of the concentrated extract to the collection tank 4. The bottom of the condenser 6 is equipped with a drain pipe for draining condensate, and the drain pipe is equipped with a valve to periodically discharge the condensate collected in the condenser 6.

[0063] The locking bolt 73 is an M8 threaded bolt, which has strong threaded connection stability and can effectively lock the handle 72 position; the depth of the groove on the handle 72 is 3-5mm, which ensures that the end of the locking bolt 73 can be fully inserted to avoid loosening. The spacing between two adjacent sets of grooves corresponds one-to-one with the scale position of the valve stem of the throttle valve body 71, so as to achieve precise matching between the adjustment position and the locking position.

[0064] The minimum scale division of the metering container 81 is ≤0.5L, which can meet the precise metering requirements of small volume solvents; the diameter of the vent is 3-8mm, which can ensure gas pressure balance and avoid solvent splashing or excessive evaporation; the top of the metering container 81 is also equipped with a feeding port with a sealing cap, which makes it easy to directly add solid raw materials (such as dried and crushed Mikania micrantha) into the metering container 81, simplifying the feeding operation, while the sealing cap can prevent solvent evaporation and external contamination.

[0065] 4. Experimental seedlings: Eucalyptus urophylla seedlings, 3 months old, with an average plant height of 15cm and an average ground diameter of 5mm. They were all growing in the same condition and free from pests and diseases.

[0066] II. Implementation Examples

[0067] Example 1: High-temperature extraction

[0068] (1) Feeding and adding liquid: Weigh 1.0 kg of dried Mikania micrantha powder (powder particle size is 2-5 mm) and put it into a 50 L extraction tank. Add 50 L of tap water into the extraction tank through the liquid adding mechanism. The material-liquid ratio is 1:40 (g / mL).

[0069] (2) Circulation and heating: Turn on the liquid reflux circulation pump and maintain a medium circulation intensity (Re≈4000) to ensure that the raw materials and solvent are fully mixed; turn on the steam valve and adjust the steam flow through the locking control mechanism to stabilize the extraction temperature at 100℃ (atmospheric boiling) and start timing.

[0070] (3) Reflux extraction: Maintain a gentle boiling state at 100℃ for reflux extraction for 2 hours, during which the circulation pump is kept running continuously.

[0071] (4) Cooling and filtration: After extraction, close the steam valve and stop heating. Allow the extract to cool naturally to room temperature, then filter it through the built-in filter of the extraction tank and collect the clear filtrate.

[0072] (5) Concentration adjustment and storage: Adjust the volume of the filtrate to 50L, the concentration is 20g / L, and it can be used directly or stored at 4℃.

[0073] Example 2: Optimization of different powder particle sizes

[0074] Except for adjusting the powder particle size to ≤2mm, 5-10mm, and 10-30mm respectively, the other operations were the same as in Example 1. The results showed that the extraction efficiency was the highest and the filtration was smoothest with a particle size of 2-5mm, and the preferred range was 2-5mm.

[0075] Example 3: Optimization of different feed-liquid ratios

[0076] Except for adjusting the material-to-liquid ratio to 1:30, 1:50, 1:60, and 1:70 (g / mL), the other operations were the same as in Example 1. The results showed that the extract had the strongest growth-promoting activity when the material-to-liquid ratio was 1:30-1:50, with the best effect at 1:40, resulting in a plant height increase of 262.5 cm and a diameter increase of 34.1 mm. When the material-to-liquid ratio was lower than 1:30, the active ingredients were not fully dissolved due to insufficient solvent, resulting in a decrease in the growth-promoting effect. When the material-to-liquid ratio was higher than 1:50, the active ingredients were over-diluted, and the growth-promoting effect was also significantly reduced.

[0077] Example 4: Optimization at different extraction temperatures

[0078] Except for adjusting the extraction temperatures to 90℃, 95℃, 105℃, and 110℃ respectively, the other operations were the same as in Example 1. The results showed that the extract had better growth-promoting properties when the extraction temperature was 90-100℃, and the extract had the best growth-promoting properties when the extraction temperature was 100℃, with a plant height increase of 265.3cm and a ground diameter increase of 35.7mm at 100℃; when the temperature was below 90℃, the active ingredients were not fully dissolved, and the growth-promoting effect was weak; when the temperature was above 110℃, the growth-promoting effect decreased due to the thermal degradation of some active ingredients, and the plant height increase was only 242.5cm.

[0079] Example 5: Optimization of different extraction times

[0080] Except for adjusting the extraction time to 0.5, 1, 1.5, 2.5, 3, and 4 hours respectively, the other operations were the same as in Example 1. The results showed that the extraction plateau was reached in 1.5-2.5 hours, with 2 hours being the preferred time, balancing efficiency and energy consumption.

[0081] Example 6: Optimization of different circulation intensities (flow rate / pump frequency)

[0082] Except for adjusting the circulation intensity (flow rate / pump frequency) to low and high circulation flow rates respectively, the other operations were the same as in Example 1. The results showed that medium circulation intensity (e.g., pump frequency 30 Hz, Re≈4000) resulted in the most uniform mass transfer, avoiding foam or dead zones.

[0083] Example 7: Repeated Validation Experiment

[0084] Raw materials of *Mikania micrantha* were collected in different seasons (spring, summer, and autumn), and extracts were prepared according to the process described in Example 1. These extracts were used in a growth-promoting experiment on *Eucalyptus urophylla* seedlings. The results showed that after treatment with the extract prepared in spring, the eucalyptus trees grew 258.2 cm in height and 36.2 mm in diameter at ground level; after treatment with the extract prepared in summer, the trees grew 275.3 cm in height and 39.87 mm in diameter at ground level; and after treatment with the extract prepared in autumn, the trees grew 265.1 cm in height and 37.5 mm in diameter at ground level. All three extracts showed significant growth-promoting effects, with the increase in tree height fluctuating only between 258.2 and 275.3 cm, confirming good process reproducibility.

[0085] Comparative Example 1

[0086] Except for the material-to-liquid ratio of 1:100, the extract was prepared according to the process in Example 1 and used in a growth-promoting experiment on Eucalyptus urophylla seedlings. The results showed that the eucalyptus trees increased in height by 225.4 cm.

[0087] Comparative Example 2

[0088] Except for the extraction temperature of 80℃, the extract was prepared according to the process in Example 1 and used in a growth-promoting experiment on Eucalyptus urophylla seedlings. The results showed that the eucalyptus trees increased in height by 238.6 cm.

[0089] III. Application Examples

[0090] 1. Experimental Design: 240 uniformly grown Eucalyptus urophylla seedlings were selected and randomly divided into 4 groups of 60 seedlings each:

[0091] (1) The present invention group: the extract prepared in Example 1 was diluted to 5 g / L and 2000 mL was applied to each plant;

[0092] (2) Room temperature extraction group: The extract prepared using existing technology (soaking at 25℃ for 24 hours) was diluted to 5g / L and 2000mL was applied to each plant;

[0093] (3) Non-circulation group: The process of Example 1 was used, but the circulation pump was not turned on. The extract was diluted to 5g / L and each plant was watered with 2000mL.

[0094] (4) Blank control group: watered with the same amount of tap water, and the process of Example 1 was used for other purposes.

[0095] 2. Experimental conditions: All seedlings were planted in seedling pots of the same size, with a substrate of humus:perlite = 3:1. They were cultivated in a greenhouse with the temperature controlled at 25-30℃, light exposure for 12 hours / day, and regular watering to keep the substrate moist. Other management measures were the same.

[0096] 3. Measurement indicators: The height and diameter at ground level of eucalyptus trees were measured at 1 month, 2 months, 3 months and 4 months after irrigation, and the growth rate was calculated.

[0097] 4. Experimental Results: After 4 months of irrigation, the average plant height of the group using this invention increased by 261.30 cm, and the ground diameter increased by 36.87 mm; the plant height of the group using extraction at room temperature increased by 230.30 cm, and the ground diameter increased by 31.67 mm; the plant height of the group without circulation increased by 252.1 cm, and the ground diameter increased by 34.8 mm; the plant height of the control group increased by 208.50 cm, and the ground diameter increased by 30.36 mm. The plant height and ground diameter growth rates of the group using this invention were significantly higher than those of the other groups, confirming that the extract of this invention has the optimal growth-promoting effect.

[0098] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing active extracts of Mikania micrantha based on high-temperature water extraction, characterized in that, Includes the following steps: (1) Raw material pretreatment: Fresh Mikania branches and leaves are collected, impurities are removed, and they are placed in a ventilated and dark place to air dry naturally until constant weight. After crushing, Mikania powder with a particle size of 1-10 mm is obtained. (2) High temperature water extraction: Water extraction is carried out using Mikania micrantha extraction equipment. Solvent is added to the Mikania micrantha powder in step (1) at a material-to-liquid ratio of 1:30-1:70 (g / mL), and the mixture is heated and refluxed at 90-110℃ for 1-3 hours. During the extraction process, the liquid is kept circulating and mixed. (3) Solid-liquid separation: After extraction, the extract is cooled to room temperature, filtered and the clear filtrate is collected to obtain the active extract of Mikania micrantha.

2. The method for preparing the active extract of Mikania micrantha based on high-temperature water extraction according to claim 1, characterized in that, The Mikania micrantha extraction equipment described in step (2) includes a steam inlet pipe, an extraction tank, a concentration tank, a collection tank, and a condenser. The steam inlet pipe connects the extraction tank and the concentration tank. The extraction tank and the concentration tank are connected to the condenser via a steam outlet pipe. The steam inlet pipe is equipped with a locking control mechanism for adjusting the steam thermal balance of the steam inlet pipe. The locking control mechanism includes a throttle valve body connected to the steam inlet pipe. The throttle valve body is equipped with a handle. A locking bolt for moving and locking the handle is provided on one side of the handle. A pressure gauge is provided at the bottom of the throttle valve body below the locking bolt. The extraction tank is equipped with a water inlet pipe. A liquid adding mechanism is connected to the top of the water inlet pipe of the extraction tank.

3. The method for preparing the active extract of Mikania micrantha based on high-temperature water extraction according to claim 2, characterized in that, The locking control mechanism can control the extraction temperature fluctuation within ±2℃, and the solvent metering error of the liquid addition mechanism is ≤2%.

4. The method for preparing the active extract of Mikania micrantha based on high-temperature water extraction according to claim 1, characterized in that, The extraction temperature in step (2) is 90-100℃.

5. The method for preparing the active extract of Mikania micrantha based on high-temperature water extraction according to claim 1, characterized in that, The material-liquid ratio mentioned in step (2) is 1:30-1:50 (g / mL).

6. The method for preparing the active extract of Mikania micrantha based on high-temperature water extraction according to claim 1, characterized in that, The particle size of the Mikania powder mentioned in step (1) is 2-5 mm.

7. The method for preparing the active extract of Mikania micrantha based on high-temperature water extraction according to claim 1, characterized in that, The solvent mentioned in step (2) is municipal tap water, which does not require purification.

8. The method for preparing the active extract of Mikania micrantha based on high-temperature water extraction according to claim 1, characterized in that, The intensity of the drug solution circulation mixing in step (2) is a medium circulation flow rate, with a Reynolds number Re≈4000.

9. The method for preparing the active extract of Mikania micrantha based on high-temperature water extraction according to claim 1, characterized in that, The extraction time mentioned in step (2) is 1.5-2.5 hours.

10. The application of a *Mikania micrantha* active extract prepared according to any one of claims 1-9 in promoting eucalyptus growth, characterized in that, The extract was diluted to 5 g / L and directly applied to the roots of eucalyptus seedlings, with each seedling receiving 2000 mL of the solution. This can increase the growth rate of eucalyptus tree height and diameter at ground level.

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