Use of a green (bio) solvent – limonene – as extractant and immiscible diluent for large volume injection in the RPLC‐tandem MS assay of statins and related metabolites in human plasma

Limonene, considered a green solvent, was successfully used to extract simvastatin, lovastatin, and their hydroxy‐acid metabolites from human plasma samples. The extraction process was followed by the direct injection of a large volume aliquot (100 μL) from the limonene layer into a Zorbax SB‐C₁₈ Rapid Resolution chromatographic column (50 mm length × 4.6 mm i.d. × 1.8 µm d.p.), operated under gradient elution reversed‐phase separation mechanism. Tandem mass spectrometry operated under the multiple reaction monitoring mode was used for detection, providing low quantitation limits in the 0.25–0.5 ng/mL concentration interval. This method was validated and used for quantitation of simvastatin and its hydroxy acid metabolite in incurred plasma samples obtained from two volunteers participating in a bioequivalence study, using lovastatin and its hydroxy analog as internal standards. The results were statistically compared with those produced by means of an alternative RPLC‐tandem MS using protein precipitation with acetonitrile. The quality attributes of the two methods are comparatively discussed. The agreement between the quality characteristics of the two methods and the experimental results obtained on real samples may be considered as a consistent basis for the simultaneous use of limonene as extraction medium and injection diluent for hydrophobic compounds in bioanalytical approaches. Copyright © 2012 John Wiley & Sons, Ltd.     

Optimization of Extraction of Bioactive Compounds from Baphicacanthus cusia Leaves by Hydrophobic Deep Eutectic Solvents

Deep eutectic solvents (DESs) are considered as efficient and green solvents for the extraction of bioactive compounds from medicinal plants. In this work, a novel method of DES-based ultrasound-assisted extraction of bioactive compounds from Baphicacanthus cusia leaves (BCL) was established. Systematic screening and the morphology of the original and treated BCL were observed with scanning electron microscopy to determine the extraction efficiency of different solvents. The extraction conditions were optimized by Box–Behnken design (BBD) tests and the optimal extraction conditions were as follows: lactic acid/L-menthol ratio of 5: 2 (mol/mol), solid–liquid ratio of 80.0 mL/g and temperature of 60.5 °C. The extraction yields of tryptanthrin, indigo and indirubin reached 0.356, 1.744 and 0.562 mg/g, respectively. The results of a 2,2-diphenyl-1-picrylhydrazy (DPPH) radical scavenging activity test indicated the feasibility of DESs in the extraction of bioactive compounds. This study indicated that L-menthol/lactic acid was a green and efficient solvent for the extraction of bioactive compounds from BCL, and DES-based ultrasound-assisted extraction could be used as an effective application strategy for the extraction of bioactive compounds from medicinal plants.     

Determination of metabolites in Uncaria sinensis by HPLC and GC-MS after green solvent microwave-assisted extraction

Uncaria sinensis (Oliv.) Havil (Rubiaceae) has been used as an important Traditional Chinese Medicine (TCM) herb for the treatment of fevers and various nervous disorders. The major bioactive secondary metabolites from different classes of chemical compounds, i.e. organic acid, flavonoid and alkaloid, present in this TCM herb, namely catechin, caffeic acid, epicatechin and rhynchophylline, were extracted by microwave-assisted extraction (MAE) method with ultra-pure water as the extraction solvent. The optimal extraction conditions for this green solvent MAE method were found to be 100 °C for 20 min. The recoveries of the compounds were found to be comparable to that of heating under reflux using ultra-pure water for 60 min. The method precision (RSD, n = 6) was found to vary from 0.19% to 5.60% for the proposed method on different days for the secondary metabolites. Simultaneously, the key primary metabolites such as sucrose and phenylalanine for the biosynthesis of bioactive secondary metabolites were successfully characterized by GC-MS. Furthermore, an approach using the combination of primary and secondary metabolite profiling based on their chemical fingerprints with Principal Component Analysis (PCA) was successfully developed to evaluate the quality of U. sinensis obtained from different sources. This approach was shown to be feasible in discriminating U. sinensis from different origins and thus a potential application for the quality control of other medicinal herbs.     

Optimization of MAE for the Separation of Nicotine and Phenolics from Tobacco Waste by Using the Response Surface Methodology Approach

This study intends to valorize by-products of the industrial processing of tobacco to obtain nicotine and phenolics as value-added compounds. Three influential parameters of the microwave-assisted extraction-MAE (temperature, treatment time, and solvent/solid ratio) were studied for the optimization of the extraction protocol for tobacco leaves and three types of waste—scrap, dust, and midrib, respectively. Nicotine was the dominant bioactive compound in all extracts, ranging from 1.512 to 5.480% in leaves, 1.886 to 3.709% in scrap, 2.628 to 4.840% dust, and 0.867 to 1.783% in midrib extracts. Five phenolic compounds were identified and quantified, predominated by chlorogenic acid and rutin. Additionally, total phenol content and antioxidant activity were determined using spectrophotometric assays. Optimization was performed in two aspects: to obtain a maximum extraction yield with minimum nicotine content and to obtain a maximum extraction yield with maximum nicotine content. These findings demonstrate that tobacco waste is a valuable source of bioactive compounds and MAE can be a promising alternative technique to obtain extracts rich in targeted bioactive compounds, especially nicotine.     

Rapid extraction of bioactive compounds from gardenia fruit using new and recyclable deep eutectic solvents

The utilization of deep eutectic solvent as an alternative and environmentally friendly option has gained significant attention. This study first proposed a series of benzylammonium chloride based-deep eutectic systems for the extraction of bioactive compounds from Gardenia jasminoides Ellis. Through the implementation of response surface methodology, the optimal solvent was determined to be dodecyldimethylbenzylammonium chloride–levulinic acid (1:3, mol/mol) with 35% (v/v) water, specifically tailored to extract geniposide, genipin-1-β-d -gentiobioside, crocin-1, and crocin-2 from gardenia fruits with the ratio of solid to liquid of 1:20 at 86°C for 16 min. Their total extraction yields could reach 70.6 mg/g, outperforming those obtained by other solvents and corresponding techniques. Furthermore, the eutectic system was retrieved after first-cycle extraction, and then applied in the subsequent extraction progress, yielding a consistent extraction efficiency of 97.1%. As compared to previous traditional methods, a quick, high-yielding, and green extraction procedure was achieved through simple heating settings that did not constrain the instrument. Therefore, dodecyldimethylbenzylammonium chloride–levulinic acid could serve as a sustainable and reusable solvent for efficient extraction of natural bioactive compounds from plant-based raw materials. The application of deep eutectic solvents has demonstrated their potential as designable solvents with stronger extraction capabilities than traditional organic solvents.     

Extraction and determination of bioactive flavonoids from Abelmoschus manihot (Linn.) Medicus flowers using deep eutectic solvents coupled with high‐performance liquid chromatography

A highly efficient and ecofriendly extraction method using deep eutectic solvents was developed to extract bioactive flavonoids from Abelmoschus manihot (Linn.) Medicus flowers. First, a series of deep eutectic solvents using choline chloride as hydrogen bond acceptor with different hydrogen bond donors was successfully synthesized. Then, the types of deep eutectic solvents and the extraction conditions for bioactive flavonoids (hyperoside, isoquercitrin, and myricetin) were optimized based on the flavonoids extraction efficiencies. The optimized deep eutectic solvent for hyperoside and isoquercitrin extraction was composed of choline chloride and acetic acid with a molar ratio of 1:2. The optimized deep eutectic solvent for myricetin extraction was composed of one mole of choline chloride and two moles of methacrylic acid. The optimal extraction conditions were set as: solid to solvent ratio, 35:1 (mg/mL); extraction time, 30 min; extraction temperature, 30°C. Qualitative and quantitative analysis were performed using ultra high performance liquid chromatography with tandem mass spectrometry and high‐performance liquid chromatography. And the extraction efficiencies of hyperoside, isoquercitrin, and myricetin under optimal extraction conditions were calculated as 11.57, 5.64, and 1.11 mg/g, much higher than those extracted by traditional extraction solvents. Therefore, the prepared deep eutectic solvents can be selected as alternative solvent to extract bioactive flavonoids.     

Bioactive Phenolic Compounds from Primula veris L.: Influence of the Extraction Conditions and Purification

Our experiments may help to answer the question of whether cowslip (Primula veris L.) is a rich source of bioactive substances that can be obtained by efficient extraction with potential use as a food additive. A hypothesis assumed that the type of solvent used for plant extraction and the individual morphological parts of Primula veris L. used for the preparation of herbal extracts will have key impacts on the efficiency of the extraction of bioactive compounds, and thus, the health-promoting quality of plant concentrates produced. Most analysis of such polyphenolic compound contents in extracts from Primula veris L. has been performed by using chromatography methods such as ultra-performance reverse-phase liquid chromatography (UPLC−PDA−MS/MS). Experiments demonstrated that the most effective extraction agent for fresh study material was water at 100 °C, whereas for dried material it was 70% ethanol. The richest sources of polyphenolic compounds were found in cowslip primrose flowers and leaves. The aqueous and ethanol extracts from Primula veris L. were characterized by a quantitatively rich profile of polyphenolic substances, and a high antioxidative potential. Selective extraction with the use of mild conditions and neutral solvents is the first step to obtaining preparations from cowslip primrose with a high content of bioactive substances.     

Microwave-Assisted Extraction/Dispersive Liquid–Liquid Microextraction Coupled with DSI-GC-IT/MS for Analysis of Essential Oil from Three Species of Cardamom

A novel method of microwave-assisted extraction coupled with polyethylene Pasteur-pipette-based dispersive liquid–liquid microextraction applying low-density organic solvent (MAE-LDS-DLLME) was successfully developed for extraction and preconcentration of essential oil from three species of cardamom (Semen Alpiniae Katsumadai, Fructus Amomi Rotundus, and Semen Myristicae). The essential oil was analyzed by gas chromatography-ion trap/mass spectrometry (GC-IT/MS) using a ChromatoProbe direct sample introduction (DSI) device. The effects of various parameters affecting the extraction process, such as the type of extraction solvent and dispersive solvent, ionic strength, microwave power, and irradiation time, were investigated thoroughly and optimized. The optimal conditions were extraction solvent of toluene, dispersive solvent of methanol, microwave power of 80 W, irradiation time of 4.0 min, plant material amount of 0.1 g, and no addition of salt. Compared with hydrodistillation, MAE-DLLME-DSI-GC–MS is a simple, rapid, low-cost, efficient, and environmentally friendly method, and the essential oil contains higher amounts of oxygenated compounds, which play an important and valuable role in terms of their contribution to the fragrance of the essential oil. In this work, we also studied the main components of the three varieties of cardamom. Qualitative and quantitative differences in the components of the three essential oils were found to be present. Based on comparison of the main bioactive compounds of essential oil, a significant difference was found between Semen Alpiniae Katsumadai or Fructus Amomi Rotundus and Semen Myristicae. This study also provides a new approach for quality assessment of traditional Chinese medicines.     

Effective Extraction of Limonene and Hibaene from Hinoki (Chamaecyparis obtusa) Using Ionic Liquid and Deep Eutectic Solvent

The essential oils of hinoki (Chamaecyparis obtusa) leaves have anti-bacterial, anti-fungal, and relaxation properties that are likely associated with the major components such as sabinene, α-terpinyl acetate, limonene, elemol, myrcene, and hibaene. The present study describes the use of a cellulose-dissolving ionic liquid (IL) [C₂mim][(MeO)(H)PO₂] and low-toxicity solvents called betaine-based deep eutectic solvents (DESs) for the efficient extraction of hinoki essential oils. As a control method, organic solvent extraction was performed using either hexane, ethyl acetate (EtOAc), or acetone at 30 °C for 1 h. Both the experimental and control methods were conducted under the same conditions, which relied on partial dissolution of the leaves using the IL and DESs before partitioning the hinoki oils into the organic solvent for analysis. Quantitative analysis was performed using gas chromatography–mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode. The results indicated that extraction using the [C₂mim][(MeO)(H)PO₂]/acetone bilayer system improved the yields of limonene and hibaene, 1.5- and 1.9-fold, respectively, when compared with the control method. In addition, extraction using betaine/l-lactic acid (molar ratio 1:1) gave the greatest yields for both limonene and hibaene, 1.3-fold and 1.5-fold greater, respectively, than when using an organic solvent. These results demonstrate the effective extraction of essential oils from plant leaves under conditions milder than those needed for the conventional method. The less toxic and environmentally begin DESs for the extraction are also applicable to the food and cosmetic industries.     

Polyphenolic Compounds Extracted and Purified from Buddleja Globosa Hope (Buddlejaceae) Leaves Using Natural Deep Eutectic Solvents and Centrifugal Partition Chromatography

Chemical profiling of Buddleja globosa was performed by high-performance liquid chromatography coupled to electrospray ionization (HPLC-DAD-ESI-IT/MS) and quadrupole time-of-flight high-resolution mass spectrometry (HPLC-ESI-QTOF/MS). The identification of 17 main phenolic compounds in B. globosa leaf extracts was achieved. Along with caffeoyl glucoside isomers, caffeoylshikimic acid and several verbascoside derivatives (β-hydroxyverbascoside and β-hydroxyisoverbascoside) were identified. Among flavonoid compounds, the presence of 6-hydroxyluteolin-7-O-glucoside, quercetin-3-O-glucoside, luteolin 7-O-glucoside, apigenin 7-O-glucoside was confirmed. Campneoside I, forsythoside B, lipedoside A and forsythoside A were identified along with verbascoside, isoverbascoside, eukovoside and martynoside. The isolation of two bioactive phenolic compounds verbascoside and forsythoside B from Buddleja globosa (Buddlejaceae) was successfully achieved by centrifugal partition chromatography (CPC). Both compounds were obtained in one-step using optimized CPC methodology with the two-phase solvent system comprising ethyl acetate-n-butanol-ethanol-water (0.25:0.75:0.1:1, v/v). Additionally, eight Natural Deep Eutectic Solvents (NADESs) were tested for the extraction of polyphenols and compared with 80% methanol. The contents of verbascoside and luteolin 7-O-glucoside after extraction with 80% methanol were 26.165 and 3.206 mg/g, respectively. Among the NADESs tested in this study, proline- citric acid (1:1) and choline chloride-1, 2- propanediol (1:2) were the most promising solvents. With these NADES, extraction yields for verbascoside and luteolin 7-O-glucoside were 51.045 and 4.387 mg/g, respectively. Taken together, the results of this study confirm that CPC enabled the fast isolation of bioactive polyphenols from B. globosa. NADESs displayed higher extraction efficiency of phenolic and therefore could be used as an ecofriendly alternative to classic organic solvents.     

Determination of limonene oxidation products using SPME and GC-MS

Limonene is a common component found in consumer goods ranging from beverages to cleaning compounds. Limonene oxidation products, however, have a less desirable flavor and fragrance. Early detection of limonene oxide formation would aid quality control. A method is developed to determine the concentration of limonene oxide in essential oils and beverages using solid-phase microextraction (SPME). A headspace sampling technique is used to reduce or eliminate the presence of less volatile components. Several different SPME fibers are tested, varying in polymer thickness, polymer cross-linking and bonding, and polarity of the polymer. For each fiber tested, the sampling time is optimized for reproducible results. The 7-microm-thick bonded poly(dimethylsiloxane) fiber provides the best results. External standards are used for quantitation.     

Effect of Extraction Solvent and Temperature on Polyphenol Profiles,Antioxidant and Anti-Inflammatory Effects of Red Grape Skin By-Product

A fully-detailed LC-MS qualitative profiling of red grape skin, extracted with a mixture of ethanol and water (70:30 v:v) has permitted the identification of 65 compounds which can be classified into the following chemical classes: organic and phenolic acids (14 compounds), stilbenoids (1 compound), flavanols (21 compounds), flavonols (15 compounds) and anthocyanins (14 compounds). The extraction yield obtained with water at different temperatures (100 °C, 70 °C, room temperature) was then evaluated and the overall polyphenol content indicates that EtOH:H₂O solvent is the most efficient and selective for polyphenol extraction. However, by analyzing the recovery yield of each single polyphenol, we found that water extraction under heating conditions is effective (extraction yield similar or even better in respect to the binary solvent) for some polyphenolic classes, such as hydrophilic procyanidins, phenolic acids, flavonol glucosides and stilbenoids. However, according to their lipophilic character, a poor yield was found for the most lipophilic components, such as flavonol aglycones, and in general for anthocyanins. The radical scavenging activity was in accordance with the polyphenol content, and hence, much higher for the extract obtained with the binary solvent in respect to water extraction. All the tested extracts were found to have an anti-inflammatory activity in the R3/1 cell line with NF-kb reporter challenged with 0.01 µg/mL of IL-1α, in a 1 to 250 µg/mL concentration range. An intriguing result was that the EtOH:H₂O extract was found to be superimposable with that obtained using water at 100 °C despite the lower polyphenol content. Taken together, the results show the bioactive potentialities of grape skin extracts and the possibility to exploit this rich industrial waste. Water extraction carried out by heating is an easy, low-cost and environmentally friendly extraction method for some polyphenol classes and may have great potential for extracts with anti-inflammatory activities.     

柠檬烯和柠檬烯氧化物与硫酸的非均相反应动力学

主要对天然挥发性有机物柠檬烯和柠檬烯氧化物在30%-80% (w)硫酸表面的非均相吸收反应进行了研究, 借以评估天然挥发性有机物与大气环境中的酸性气溶胶的反应活性. 采用自行搭建的配以单光子激光电离飞行时间质谱的湿壁流动反应管的设备对柠檬烯及其氧化物在硫酸表面的非均相吸收动力学进行了测定,计算了稳态摄取系数(γ). 实验结果表明, 柠檬烯氧化物在硫酸表面比只含有双键的柠檬烯的反应活性高, 室温下柠檬烯氧化物在30%-50% (w)硫酸上对应的稳态摄取系数是(7.100±0.023)×10^-5-(8.150±0.162)×10^-3. 此外, 还利用气相色谱-质谱(GC-MS)联用和电喷雾电离质谱(ESI-MS)对柠檬烯氧化物与硫酸的体相反应产物进行了研究, 产物包括单萜烯、松油醇、水合萜二醇和水合萜二醇二硫酸酯. 其中, 水合萜二醇二硫酸酯作为有机硫酸酯的一种, 能够改变气溶胶的吸湿性, 增强云凝结核的活性, 对于大气中灰霾的形成可能有明显的促进作用.     

Metabolic fate of dietary volatile compounds in Pieris brassicae

In this work, the evolution of the qualitative and quantitative profile of the volatile fraction of Pieris brassicae after feeding on Brassica oleracea var. acephala (kale) was monitored through time. HS-SPME/GC-MS was applied to both the host plant and the living insect and its excrements. A total of seventy seven compounds (lipoxygenase pathway by-products, nitrogen compounds, norisoprenoids, sulphur compounds, terpenes, among others) were identified. Thirty eight compounds were identified in insect after 2 h of starvation and forty eight compounds in excrements. Qualitative and quantitative changes were detected along time. Dimethyldisulfide, dimethyltrisulfide, limonene and eugenol were major compounds for all analysed times in both matrices, being limonene an important compound in insect after starvation. The accumulation by P. brassicae of some compounds, such as limonene, was verified, suggesting a mechanism by which the insect can take benefit from bioactive constituents from the diet. Along with accumulation, complete excretion of some compounds, including nitrogen bearing compounds, by-products of glucosinolates was detected. These results reflect one of the strategies used to overcome plant barriers, namely detoxification of toxic compounds. The findings contribute to the knowledge of the metabolization of the volatile compounds in insects and contribute to the body of knowledge of this ecologic system.     

An efficient microwave assisted extraction of phenolic compounds and antioxidant potential of Ginkgo biloba

Flavonoid glycosides are a significant group of compounds found in Ginkgo biloba leaves, but the long extraction procedures in existing methods are a challenging problem. In this work, a microwave-assisted extraction (MAE) method has been developed for extracting bioactive compounds from G. biloba. Several variables were optimized, such as extracting solvent, microwave power, and extraction time that can potentially affect the extraction yield. The total phenolic content, antioxidant activity (using DPPH, ABTS and FRAP assays) and flavonoid glycosides of different extracts using RP-HPLC were assessed. The antioxidant capacity was found to be highest with MAE using 60% aq. ethanol as extracting solvent and microwave power of 120W for 20 min.     

Influence of solvents and novel extraction methods on bioactive compounds and antioxidant capacity of <Emphasis Type="Italic">Phyllanthus amarus</Emphasis>

Phyllanthus amarus (P. amarus) is a herbal plant used in the treatment of various diseases such as hepatitis, diabetes, and cancer. Efficiency of its bioactive compounds extraction and therefore the biological activity of the extracts are significantly influenced by both solvent character and extraction method. This study is aimed at the determination of the influence of six various solvents (water, acetonitrile, ethanol, methanol, ethyl acetate, and dichloromethane) and nine different extraction methods (conventional, ultrasound-assisted, microwave-assisted, and six novel methods) on the extraction efficiency and antioxidant capacity of P. amarus. The results indicated that water extracted the maximal amount of phenolics from P. amarus and had the highest antioxidant capacity, while microwave-assisted extraction provided the highest yields of phenolics and saponins, and the highest antioxidant capacity with the lowest energy consumption when compared to the other extraction methods. These findings implied that water and microwave-assisted extraction are recommended as the most effective solvent and method for the extraction of bioactive compounds from P. amarus for potential application in the pharmaceutical and nutraceutical industries.     

Enhanced Antioxidant,Hyaluronidase, and Collagenase Inhibitory Activities of Glutinous Rice Husk Extract by Aqueous Enzymatic Extraction

In this research, we aimed to compare the biological activities related to cosmeceutical applications of glutinous rice husk extracted by aqueous enzymatic extraction (AEE) and conventional solvent extraction. Cellulase enzymes were used to assist the extraction process. The vanillic and ferulic acid contents of each extract were investigated by high-performance liquid chromatography, and their antioxidant and anti-aging activities were investigated by spectrophotometric methods. The irritation effects of each extract were investigated by the hen’s egg test on chorioallantoic membrane. The rice husk extract from AEE using 0.5% w/w of cellulase (CE0.5) contained the significantly highest content of vanillic and ferulic acid (p < 0.05), which were responsible for its biological activities. CE0.5 was the most potent antioxidant via radical scavenging activities, and possessed the most potent anti-skin wrinkle effect via collagenase inhibition. Aside from the superior biological activities, the rice husk extracts from AEE were safer than those from solvent extraction, even when 95% v/v ethanol was used. Therefore, AEE is suggested as a green extraction method that can be used instead of the traditional solvent extraction technique given its higher yield and high quality of bioactive compounds. Additionally, CE0.5 is proposed as a potential source of natural antioxidants and anti-aging properties for further development of anti-wrinkle products.     

Study of Ozone-Initiated Limonene Reaction Products by Low Temperature Plasma Ionization Mass Spectrometry

Limonene and its ozone-initiated reaction products were investigated in situ by low temperature plasma (LTP) ionization quadrupole time-of-flight (QTOF) mass spectrometry. Helium was used as discharge gas and the protruding plasma generated ~850 ppb ozone in front of the glass tube by reaction with the ambient oxygen. Limonene applied to filter paper was placed in front of the LTP afterglow and the MS inlet. Instantly, a wide range of reaction products appeared, ranging from m/z 139 to ca. 1000 in the positive mode and m/z 115 to ca. 600 in the negative mode. Key monomeric oxidation products including levulinic acid, 4-acetyl-1-methylcyclohexene, limonene oxide, 3-isopropenyl-6-oxo-heptanal, and the secondary ozonide of limonene could be identified by collision-induced dissociation. Oligomeric products ranged from the nonoxidized dimer of limonene (C₂₀H₃₀) and up to the hexamer with 10 oxygen atoms (C₆₀H₉₀O₁₀). The use of LTP for in situ ozonolysis and ionization represents a new and versatile approach for the assessment of ozone-initiated terpene chemistry.

Pressurized hot water extraction of bioactive or marker compounds in botanicals and medicinal plant materials

To reduce the use of organic solvent, pressurized hot water extraction (PHWE) has been shown to be a feasible option for the extraction of bioactive and marker compounds in botanicals and medicinal plants. The parameters that may affect the extraction efficiencies in PHWE include temperature, extraction time and addition of small percentage of organic solvent or surfactants. Currently, applications of PHWE for the extraction of thermally labile compounds in botanicals are still rather limited. PHWE with and without the additional of a small percentage of organic solvent such as ethanol is highly suited for the chemical standardization and quality control of medicinal plants. At the same time, it can be applied at the pilot scale as a manufacturing process for medicinal plants. Surfactant assisted PHWE was found to enhance the extraction of thermally labile and more hydrophobic species in medicinal plants at a lower temperature. The addition of small amount of surfactants in PHWE is highly suited for the determination of bioactive or marker compounds in medicinal plants. With proper optimization, PHWE was observed to have good extraction efficiency and precision when compared to other reference methods of extraction.