Microwave-assisted extraction of solanesol from tobacco leaves

Extraction of polyphenols and essential oils from herbs with green extraction methods - An insightful review

The demand for polyphenols and essential oils (EOs) on the food market is high and grows every year. Its partially the result of the fact that these compounds can be used in formulation of clean label foods, a fast growing food sector. A significant share of polyphenols and EOs are extracted from herbs. The quality of the extracts is determined mainly by the extraction method. Conventional extraction techniques of phytochemicals are time-consuming, operate at high temperatures, and require usage of organic solvents and energy in large quantities. According to the United Nations Sustainability Development Plan, chemical processes should be replaced by green alternatives that would reduce the use of solvents and energy. Ultrasound-Assisted Extraction (UAE), Microwave-Assisted Extraction (MAE) and Cold Plasma-Assisted Extraction (CPAE) meets these criteria. The review shows that each of these techniques seems to be a great alternative for conventional extraction methods ensuring higher yields of bioactive compounds.

Phytochemical Compounds and Antioxidant Activity of Two Extracts of Wild and Domesticated Carob Leaves

<b>Background and Objective:</b> Carob tree (<i>Ceratonia siliqua</i> L.) is a perennial leguminous species and is known as a medicinal importance tree. This species exhibits a myriad of biological effects including antibacterial, antidiarrheal and antidiabetic. To this end, current study evaluates the difference between the phytochemical composition of the leaves of two accessions of "wild" and "domesticated" hermaphroditic carob trees. <b>Materials and Methods:</b> The comparison between two carob accessions "wild" and "domesticated" was done according to methanolic extraction by the Soxhlet and aqueous extraction by maceration. The polyphenols, flavonoids, tannins and their antioxidant activity were measured. The ANOVA test was used for the analysis of results. <b>Results:</b> The total polyphenols in aqueous extract are 6.19±0.25 mg equivalent gallic acid/g dry weight (EGA/g DW) and 4.23±0.2 mg EGA/g DW) in carob fresh leaves for wild and domesticated trees, respectively. The flavonoid content was higher in methanolic extract (3.17±0.64 mg quercetin equivalent/g DW) than in aqueous extract (1.06±0.19 mg EQ/g DW) for wild trees. Wild accession recorded the highest concentration of condensed tannins in the methanolic extract (6.4±0.3 mg catechin equivalents/g DW) while low levels were recorded in aqueous extract (0.51±0.27 mg EC/g DW). <b>Conclusion:</b> Such knowledge is expected to be the key to understanding the biochemical composition of two different leaves of <i>C. siliqua</i> accessions and its various commercial food products.

Rutin extraction from female Carica papaya Linn. using ultrasound and microwave-assisted extractive methods: Optimization and extraction efficiencies

Green extractive methods accompanied by resource conservation through process optimization are important in working towards sustainable processes. In the present paper, rutin was extracted from the leaf of female Carica papaya Linn using microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), sequential microwave ultrasound-assisted extraction (MUAE), and sequential ultrasound microwave-assisted extraction (UMAE) methods. Subsequently, the effect of extraction parameters on rutin yield were analyzed and compared. In addition, the extraction efficiency and energy consumption of the extraction processes were measured and discussed. In the present study, solid-liquid (S/L) ratio was determined to be the most significant extraction variable. Under optimized conditions, MUAE and UMAE were determined to yield the highest amount of rutin extracted at 18.46 ± 0.64 mg/g and 18.43 ± 0.81 mg/g, respectively. However, MUAE was determined to be the least resource efficient method as it consumed the highest amount of energy due to its relatively long extraction time. UAE was determined to be the most efficient in resource utilization as it required the least amount of energy for every mg/g of yield extracted, while the yield obtained was, nonetheless, comparatively high. The optimal condition obtained for UAE was 20 min of ultrasonic extraction time (TU), 20 % of ethanol mixture concentration (C), 710 μm of particle size (S), and 1:650 wt/wt of solid-liquid (S/L) ratio (R).

Green approach for the recovery of secondary metabolites from the roots of Nardostachys Jatamansi (D. Don) DC using microwave radiations: Process optimization and anti-alzheimer evaluation

Nardostachys jatamansi (D. Don) DC is a highly valued medicinal herb that has been used in traditional medicinal systems for its remedial effects. Owing to the over-exploitation and unethical trade of N. jatamansi, the accelerating global demand of herbal products from this plant cannot be satisfied by the conventional extraction approach. In view of the progressive demand and incredible biological potential of herb, the present research was designed to optimize various extraction parameters for microwave-assisted extraction (MAE). The extracts obtained from the traditional and green approach were also assessed for the recovery of secondary metabolites and anti-Alzheimer's potential. Various parameters like microwave power, temperature, and time of irradiation were optimized for MAE using Box Behkhen Design (BBD) The scanning electron microscopy of different plant samples was also done to observe the effect of microwave radiations. Further, the metabolite profiling of different extracts was also done by gas chromatography-mass spectrometry (GC-MS) analysis. Also the different behavioral and biochemical parameters along with acetylcholinesterase (AChE) inhibitory potential were assessed to evaluate the anti-Alzheimer's potential. Optimized parameters for MAE were found to be as microwave power 187.04 W, temperature 90°C, and irradiation time 20 min. The extract yield in MAE was significantly enhanced as compared to the conventional method. Also, the total phenolic content and total flavonoid content (TFC) were improved pointedly from 32.13 ± 0.55 to 72.83 ± 1.1 mg of GAE/g of extract and 21.7 ± 0.85 to 39.21 ± 0.7 mg of RUE/g of extract respectively. Later, the GC-MS analysis of various extracts confirmed the enhancement in the concentration of various sesquiterpenes like jatamansone, spirojatamol, valerenal, valeric acid, globulol, nootkatone and steroidal compounds such as sitosterol, ergosterol, stigmastanone, etc. in the optimized extract. A significant improvement in anti-Alzheimer's potential was also observed owing to the better concentration of secondary metabolites in the optimized microwave extract. From the current findings, it could be concluded that the MAE could be a successful and green alternative for the extraction and recovery of secondary metabolites from the selected medicinal herb.

Recent advances in medicinal and edible homologous polysaccharides: Extraction, purification, structure, modification, and biological activities

110 kinds of traditional Chinese medicines can be used for medicine and food from Chinese pharmacopoeia in 2021. With the deepening of research in recent years, medicinal and edible homologous (MEH) traditional Chinese medicines have great development and application prospects in many fields. Polysaccharides are one of the major and representative pharmacologically active macromolecules in traditional Chinese medicines with MEH. Moreover, traditional Chinese medicines with MEH have become the main source of natural polysaccharides with safety, high efficiency, and low side effects. Increasing researches have confirmed that MEH polysaccharides (MEHPs) have multiple biological activities both in vitro and in vivo methods, such as antioxidant, immunomodulatory, anti-tumor, anti-aging, anti-inflammatory, hypoglycemic, hypolipidemic activities, and regulating intestinal flora. Additionally, different raw materials, extraction, purification, and chemical modification methods result in differences in the structure and biological activities of MEHPs. The purpose of the present review is to provide comprehensively and systematically reorganized information in the extraction, purification, structure, modification, biological activities, and potential mechanism of MEHPs to support their therapeutic effects and health functions. New valuable insights and theoretical basis for the future researches and developments regarding MEHPs were proposed in the fields of medicine and food.

Evaluation of Different Extraction Methods on the Phenolic Profile and the Antioxidant Potential of Ceratonia siliqua L. Pods Extracts

The present work was designed to investigate the effects of different extraction processes, namely ultrasonic-assisted, supercritical fluid, microwave-assisted and Soxhlet applied to carob pods. The total phenolic quantification and the antioxidant activity were assessed by the means of rapid in vitro spectrophotometric assays; the phenolic profile was identified using ultra-high performance liquid chromatography coupled to mass spectrometry. The results revealed that the phenolic compounds and the antioxidant capacity varied significantly with the nature of the extraction process. The content of total phenolic compounds ranged from 11.55 to 34.38 mg GAE/g DW; the content of total flavonoids varied from 3.50 to 10.53 mg QE/g DW, and the content of condensed tannins fluctuated from 3.30 to 6.55 mg CE/ g DW. All extracts performed differently on antioxidant activity when determined by the DPPH assay producing a dose-dependent response, with IC₅₀ extended from 11.33 to 6.07 µg/mL. HPLC analysis enabled the identification of nine compounds. As a function of the studied extraction methods, the phenolic compound contents were positively correlated with antioxidant activity.

Extraction, purification, structure, modification, and biological activity of traditional Chinese medicine polysaccharides: A review

Traditional Chinese medicines (TCM), as the unique natural resource, are rich in polysaccharides, polyphenols, proteins, amino acid, fats, vitamins, and other components. Hence, TCM have high medical and nutritional values. Polysaccharides are one of the most important active components in TCM. Growing reports have indicated that TCM polysaccharides (TCMPs) have various biological activities, such as antioxidant, anti-aging, immunomodulatory, hypoglycemic, hypolipidemic, anti-tumor, anti-inflammatory, and other activities. Hence, the research progresses and future prospects of TCMPs must be systematically reviewed to promote their better understanding. The aim of this review is to provide comprehensive and systematic recombinant information on the extraction, purification, structure, chemical modification, biological activities, and potential mechanism of TCMPs to support their therapeutic effects and health functions. The findings provide new valuable insights and theoretical basis for future research and development of TCMPs.

Extraction of Antioxidant Compounds from Onion Bulb (Allium cepa L.) Using Individual and Simultaneous Microwave-Assisted Extraction Methods

Despite the excellent beneficial properties that anthocyanins and total phenolic compounds give to the red onion bulbs, few articles have investigated modern extraction techniques or experimental designs in this field. For this reason, the present study proposes the development and optimization of alternative methods for the extraction of these compounds based on microwave-assisted extraction and the Box-Behnken experiment design. The optimal values for the extraction of total anthocyanins have been established at 62% methanol composition as a solvent, pH 2, 56 °C temperature, and 0.2:13 g:mL sample-solvent ratio. Regarding the extraction of total phenolic compounds, the optimal conditions have been established at 100% pure methanol as a solvent with pH 2, 57 °C temperature, and 0.2:8.8 g:mL sample-solvent ratio. Short extraction times (min), good recoveries (mg of bioactive compound g⁻¹ of dry onion), and high repeatability and intermediate precision (coefficient of variation (%)) have been confirmed for both methods. Regarding total anthocyanins, the following results have been obtained: 2 min, 2.64 ± 0.093 mg of total anthocyanins g⁻¹ of dry onion, and 2.51% and 3.12% for precision. Regarding phenolic compounds, the following results have been obtained: 15 min, 7.95 ± 0.084 mg of total phenolic compound g⁻¹ of dry onion, and 3.62% and 4.56% for precision. Comparing these results with those of other authors and with those obtained in a previous study of ultrasound-assisted extraction, it can be confirmed that microwave-assisted extraction is a quantitative, repeatable, and very promising method for the extraction of phenolic compounds and anthocyanins, which offers similar and even superior results with little solvent expense, time, and costs.

Green extraction of bioactive compounds from wine lees and their bio-responses on immune modulation using in vitro sheep model

The objective of this study was to apply microwave-assisted extraction using green solvents starting from 3 different wine (white, rosé, and red) lees and to test their bio-response on sheep peripheral blood mononuclear cells proliferation, Bax/Bcl-2 ratio, and cytokines secretion. Wine lees (WL) of local organic farming from white wine, produced with Trebbiano cultivar, rosé and red wine, made with Nero di Troia cultivar, were collected. The WL were subjected to microwave-assisted extraction using 2 green solvents (water and ethanol) in 3 different combinations (water; water/ethanol 1:1 vol/vol; ethanol) with a dry matter-to-solvent ratio of 1:40 (wt/vol) at 4 temperature levels: 50, 100, 150, and 200°C. Sodium carbonate Na₂CO₃ (2 mmol/g of dry weight of lees) was used for increasing the polyphenol extraction yield. A total number of 6 extracts, 2 for each kind of WL investigated, according to their total phenolic content and in vitro antioxidant capacity, were selected to be tested on sheep peripheral blood mononuclear cells, as an animal model. All the WL extracts demonstrated a strong antiproliferative action. On the contrary, the cytokines' profile was mainly dependent on the different winemaking derived WL and the extraction solvent combination procedures. Red WL extract obtained by a combination of water/Na₂CO₃ and tested at 0.8 mg/mL, resulted in an increase of both IL-6 secretion and Bax/Bcl-2 ratio. Data from the present study demonstrated that WL extracts derived from different winemaking and solvent extraction could have a bimodal action on control of inflammatory mediated damage and highlighted the importance for further studies aimed at applying the biorefinery process on by-products to increase their economic value and exploit new derived bioactive compound.

Environmentally Friendly Techniques for the Recovery of Polyphenols from Food By-Products and Their Impact on Polyphenol Oxidase: A Critical Review

Even though food by-products have many negative financial and environmental impacts, they contain a considerable quantity of precious bioactive compounds such as polyphenols. The recovery of these compounds from food wastes could diminish their adverse effects in different aspects. For doing this, various nonthermal and conventional methods are used. Since conventional extraction methods may cause plenty of problems, due to their heat production and extreme need for energy and solvent, many novel technologies such as microwave, ultrasound, cold plasma, pulsed electric field, pressurized liquid, and ohmic heating technology have been regarded as alternatives assisting the extraction process. This paper highlights the competence of mild technologies in the recovery of polyphenols from food by-products, the effect of these technologies on polyphenol oxidase, and the application of the recovered polyphenols in the food industry.

Microwave-assisted extraction of phenolic compounds from coffee (Coffea robusta L. Linden) bee pollen

Introduction: Coffee bee pollen contains some precious bioactive compounds, especially phenolic compounds. This material is easily found in many regions in Vietnam and is quite useful for human health.

Objective: The main aim of this study was to determine the best extraction conditions for the total polyphenol content (TPC) and antioxidant capacity (AC) of coffee (Coffea robusta L. Linden) bee pollen with microwave-assisted extraction (MAE).

Methods: TPC and AC of extract of coffee (C. robusta) bee pollen were determined using Folin-Ciocalteu (FC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, respectively. In addition, micromorphology of sample was observed using scanning electron micrographs (SEM).

Results: The findings showed that all factors strongly affected the efficiency of the extraction process. The best extraction conditions obtained were ethanol concentration of 60% (v/v), solid to solvent ratio of 1/30 (w/v), extraction time of 7 min, and a microwave power of 314 W.

Conclusion: The highest TPC and AC obtained were 13.73 mg GAE/g DW and 10.08 µmol TE/g DW with aqueous ethanol as the solvent at the optimal extraction condition. In addition, the microstructures of the material changed insignificantly under microwave irradiation.

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.

Artichoke Biorefinery: From Food to Advanced Technological Applications

A sequential extraction process has been designed for valorizing globe artichoke plant residues and waste (heads, leaves, stalks, and roots left in the field) by means of green extraction techniques according to a biorefinery approach. We investigated two cascading extractions based on microwave-assisted extractions (MAE) and green solvents (water and ethanol) that have been optimized for varying temperature, solvent and extraction time. In the first step, phenols were extracted with yields that ranged between 6.94 mg g⁻¹ dw (in leaves) and 3.28 mg g⁻¹ dw (in roots), and a phenols productivity of 175.74 kg Ha⁻¹. In the second step, inulin was extracted with impressive yields (42% dw), higher than other conventional inulin sources, corresponding to an inulin productivity of 4883.58 kg Ha⁻¹. The remaining residues were found to be valuable feedstocks both for bioenergy production and green manure (back to the field), closing the loop according to the Circular Economy paradigm.

Efficient microwave-assisted extraction of salidroside from Rhodiola crenulata

A rapid microwave-assisted extraction (MAE) method was established to extract commercially important salidroside from dry plant materials of Rhodiola crenulata. Several parameters such as extraction time, solid/liquid ratio, extraction temperature and solvent concentration were investigated for efficient salidroside extraction. The estimated maximum salidroside extraction ratio based on parameter optimization using response surface methodology (RSM) reached 2.17% (w/w) in 20 min at optimum conditions of 90 °C, 60% aqueous ethanol and solid to liquid ratio of 2 g/100 mL, which was confirmed to the experimental data. Compared with ultrasonic assistant extraction method (UAE) and heat reflux extraction method (HRE), MAE was the most efficient and effective method in the extraction of salidroside from the dry plant materials. The mechanism on the extraction enhancement using MAE was elucidated further using fourier transform infrared spectroscopy (FTIR) and light microscope.

Extraction of Flavonoids From Natural Sources Using Modern Techniques

Flavonoids are one of the main groups of polyphenols found in natural products. Traditional flavonoid extraction techniques are being replaced by advanced techniques to reduce energy and solvent consumption, increase efficiency and selectivity, to meet increased market demand and environmental regulations. Advanced technologies, such as microwaves, ultrasound, pressurized liquids, supercritical fluids, and electric fields, are alternatives currently being used. These modern techniques are generally faster, more environmentally friendly, and with higher automation levels compared to conventional extraction techniques. This review will discuss the different methods available for flavonoid extraction from natural sources and the main parameters involved (temperature, solvent, sample quantity, extraction time, among others). Recent trends and their industrial importance are also discussed in detail, providing insight into their potential. Thus, this paper seeks to review the innovations of compound extraction techniques, presenting in each of them their advantages and disadvantages, trying to offer a broader scope in the understanding of flavonoid extraction from different plant matrices.

Potential Risk of Higenamine Misuse in Sports: Evaluation of Lotus Plumule Extract Products and a Human Study

Since 2017, higenamine has been added to the World Anti-Doping Agency (WADA) prohibited list as a β2-agonist prohibited at all times for sportspersons. According to WADA's report, positive cases of higenamine misuse have been increasing yearly. However, higenamine occurs naturally in the Chinese herb lotus plumule-the green embryo of lotus (Nelumbo nucifera Gaertn) seeds-commercially available as concentrated powder on the Asian market. This study evaluated the major phytochemical components of lotus plumule products using an appropriate extraction method, followed by a human study in which the products were orally administered in multiple doses to investigate the risk of doping violations. Comparing various extraction methods revealed that optimized microwave-assisted extraction exhibited the highest extraction efficiency (extraction time, 26 min; power, 1046 W; and temperature, 120 °C). Subsequently, the alkaloids in lotus plumule products were quantitatively confirmed and compared. Human study participants (n = 6) consumed 0.8 g of lotus plumule (equivalent to 679.6 μg of higenamine) three times daily for three consecutive days. All participants' urinary higenamine concentrations exceeded the WADA reporting cut-off of 10.0 ng/mL. Accordingly, lotus plumule consumption may engender adverse analytical findings regarding higenamine. Athletes should avoid consuming lotus plumule-containing products during in- and out-of-competition periods.

Recent Advances in Microwave Assisted Extraction of Bioactive Compounds from Complex Herbal Samples: A Review

Microwaves are utilized for extraction of Phytoconstituents from complex herbal sample as a result of incredible research. Conventional extraction strategies are tedious and need more solvents and are no more relevant for thermal sensitive plant components. This review emphasize on the working and significance of microwave extraction technology in herbal research and medical field. The extraction step must be more yielding; quick, particular, not more solvent consuming, ensuring stability of thermolabile components and these features are available with microwave extraction method. In this nonconventional technology heat is created utilizing microwave energy. The important parameters that influence extraction efficiency are solvent properties, volume, duration of exposure, microwave control, system attributes, temperature and application were discussed in this article. The microwave assisted extraction, as green technology is contrasted with other extraction technique. This review is intended to discuss this green extraction technique along with its critical parameters for extracting bioactive compounds from complex plant matrices.

A Facile Approach for On-Site Evaluation of Nicotine in Tobacco and Environmental Tobacco Smoke

Nicotine is highly addictive and harmful. It is one of the main active ingredients in tobacco and a major pollutant in environmental tobacco smoke. Thus, it is important to detect the nicotine content in tobacco and to monitor the nicotine content in environmental tobacco smoke. However, until present, there still has been no effective device for on-site determination of nicotine content in tobacco and environmental tobacco smoke. In this work, a portable device is fabricated for sensitive on-site evaluation of nicotine in tobacco and environmental tobacco smoke based on surface-enhanced Raman scattering (SERS). The weight of the entire device is less than 1 kg, and it uses a chargeable battery to drive both the pump and the Raman spectrometer. The total analysis time can be completed within 3-5 min. Thus, it has great potential for on-site analysis of nicotine in tobacco and environmental tobacco smoke.

Technology and Process Design for Phenols Recovery from Industrial Chicory (Chicorium intybus) Leftovers

Vegetal leftovers from the agro-food industry represent a huge source of primary and secondary metabolites, vitamin, mineral salts and soluble as well as insoluble fibers. Economic reports on the growth in the polyphenol market have driven us to focus our investigation on chicory (Chicorium intybus L.), which is one of the most popular horticultural plants in the world and a rich source of phenolic compounds. Ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE) and their simultaneous combination, using either ethanol/water or water alone (also sub-critical), have been investigated with the aim of designing a green and efficient extraction process. Higher total-polyphenol yields as well as dramatic reductions in extraction times and solvent consumption have been obtained under these conditions. ANOVA test for analyses of variance followed by the Tukey honestly significant difference (HSD) post-hoc test of multiple comparisons was used in the statistical analysis. MAE experiments performed with sub-critical water, and MW/US experiments with an ethanol solution have shown polyphenol recovery values of up to ~3 g of gallic acid equivalents (GAE) per kg of fresh material in only 15 min, while conventional extraction required 240 min to obtain the same result.

Optimization of Ultrasound-Assisted Extraction of Some Bioactive Compounds from Tobacco Waste

This is the first study on ultrasound-assisted extraction (UAE) of bioactive compounds from different types of tobacco industry wastes (scrap, dust, and midrib). The obtained results were compared with starting raw material (tobacco leaves) to see the changes in bioactive compounds during tobacco processing. Results suggested that tobacco waste extracts possess antioxidant activity and considerable amounts of targeted bioactive compounds (phenolics and solanesol). The content of chlorogenic acid varied between 3.64 and 804.2 μg/mL, caffeic acid between 2.34 and 10.8 μg/mL, rutin between 11.56 and 93.7 μg/mL, and solanesol between 294.9 and 598.9 μg/mL for waste and leaf extracts, respectively. There were noticeable differences between bioactive compounds content and antioxidant activity in extracts related to applied UAE conditions and the used type of tobacco waste. Results show that optimal UAE parameters obtained by response surface methodology (RSM) were different for each type of material, so process optimization proved to be necessary. Considering that tobacco waste is mostly discarded or not effectively utilized, the results clearly show that tobacco waste could be used as a potential source of some bioactive compounds.

A benign process for the recovery of solanesol from tomato leaf waste

Solanesol, the precursor for the synthesis of coenzyme Q10, is currently recovered from tobacco leaves by conventional extraction techniques that require multiple purification steps and a large amount of organic solvents. We recently identified tomato leaves as an alternative source of solanesol and hypothesized that a high-pressure CO2 extraction could be used as a clean extraction process. The effect of CO2 pressure and temperature on the extraction of solanesol was determined to achieve high yield and purity. It was found that solanesol could be extracted efficiently by subcritical CO2 at 25 °C from tomato leaves. The extract contained 40% solanesol and other active compounds such as vitamin K1. A higher level of purity of 93% was achieved using a secondary purification step. Different conventional methods for solanesol extraction was compared to determine the most efficient technique for production of solanesol from tomato leaf. The highest yield of solanesol was achieved at nearly 1% dry weight with using subcritical CO2, which was superior to conventional methods.

Deep Eutectic Solvent-Based Ultrahigh Pressure Extraction of Baicalin from Scutellaria baicalensis Georgi

Deep eutectic solvents (DESs), promising green solvents, and ultrahigh pressure extraction (UPE) as an effective auxiliary extraction method, have attracted wide attention. In this study, DES was coupled with UPE to efficiently extract baicalin from Scutellaria baicalensis Georgi. First, choline chloride: lactic acid (ChCl-LA, molar ratio 1:1) was selected as the most appropriate DES by comparing the extraction yield of different DESs. Second, the extraction protocol was optimized by response surface methodology (RSM) considering the impacts of ChCl-LA concentration, extraction pressure, extraction time and liquid-solid ratio on the extraction yield. Under the optimal condition (40 vol% water content, extraction pressure of 400 MPa, extraction time of 4 min and a liquid-solid ratio of 110 mL/g), a maximum yield of 116.8 mg/g was achieved, higher than that obtained by the traditional extraction method. The microstructure of the raw and extracted Scutellaria baicalensis Georgi samples according to scanning electron microscope (SEM) images revealed that the dissolution of chemical components was enhanced from the disrupted root tissues after DESs-UPE. DESs coupled with UPE could effectively extract the baicalin from Scutellaria baicalensis Georgi as a rapid and efficient extraction method.

Deep Eutectic Solvent-Based Microwave-Assisted Extraction of Baicalin from Scutellaria baicalensis Georgi

Deep eutectic solvents (DESs) have attracted significant attention as green media for the extraction and separation of natural compounds from Chinese medicine. In this study, a hydrophobic DESs-based microwave-assisted extraction (MAE) was successfully used to efficiently extract baicalin from Scutellaria baicalensis Georgi. Firstly, DecA: N4444-Cl (DES-1 , molar ratio 1 : 2) was screened and selected as the most appropriate DES by comparing the extraction yield in different hydrophobic DESs. Based on the extraction yield of baicalin, response surface methodology (RSM) was employed to model and optimize the parameters (extraction temperature, liquid-solid ratio, and extraction time). Furthermore, the maximum yield of 106.96 mg·g−1 was achieved under optimum conditions in DES-containing aqueous solutions (33 vol% water content), which reached a similar level that was conducted using the pharmacopoeia procedure (104.94 mg·g−1). These results indicated that the proposed method is an excellent alternative for the extraction of baicalin.

Intensification of marrubiin concentration by optimization of microwave-assisted (low CO2 yielding) extraction process for Marrubium vulgare using central composite design and antioxidant evaluation

CONTEXT

Marrubium vulgare Linn (Lamiaceae) was generally extracted by conventional methods with low yield of marrubiin; these processes were not considered environment friendly.

OBJECTIVE

This study extracts the whole plant of M. vulgare by microwave assisted extraction (MAE) and optimizes the effect of various extraction parameters on the marrubiin yield by using Central Composite Design (CCD).

MATERIALS AND METHODS

The selected medicinal plant was extracted using ethanol: water (1:1) as solvent by MAE. The plant material was also extracted using a Soxhlet and the various extracts were analyzed by HPTLC to quantify the marrubiin concentration.

RESULTS

The optimized conditions for the microwave-assisted extraction of selected medicinal plant was microwave power of 539 W, irradiation time of 373 s and solvent to drug ratio, 32 mL per g of the drug. The marrubiin concentration in MAE almost doubled relative to the traditional method (0.69 ± 0.08 to 1.35 ± 0.04%). The IC₅₀ for DPPH was reduced to 66.28 ± 0.6 μg/mL as compared to conventional extract (84.14 ± 0.7 μg/mL). The scanning electron micrographs of the treated and untreated drug samples further support the results.

DISCUSSION AND CONCLUSION

The CCD can be successfully applied to optimize the extraction parameters (MAE) for M. vulgare. Moreover, in terms of environmental impact, the MAE technique could be assumed as a 'Green approach' because the MAE approach for extraction of plant released only 92.3 g of CO₂ as compared to 3207.6 g CO₂ using the Soxhlet method of extraction.

Phytochemical analysis of Myrtus communis plant: Conventional versus microwave assisted-extraction procedures

Background

Myrtle (

Methods

Extraction yield/efficiency and antioxidant activity were measured using radical scavenging assay (DPPH

Results

The results show that the MAE was higher in terms of saving energy, extraction time (62 s) and extraction efficiency of bioactive compound compared to CME (2 h). Leaf presented the optimum content of total phenols (250 mg GAE.g

Conclusions

Principal component analysis (PCA) applied to the experimental data shows that the distribution of the myrtle phenolic compounds depended on their plant part localization as well as the extraction method.

Microwave-assisted extraction and ultrasound-assisted extraction for recovering carotenoids from Gac peel and their effects on antioxidant capacity of the extracts

The peel of Gac fruit (Momordica cochinchinensis Spreng.) contains high levels of bioactive compounds, especially carotenoids which possess significant antioxidant capacities. However, the peel of Gac is regarded as a waste from the production of carotenoid‐rich oil from Gac fruit. In this study, carotenoids of Gac peel were extracted by microwave‐assisted extraction (MAE) and ultrasound‐assisted extraction (UAE) using ethyl acetate as extraction solvent. The effect of extraction time and different levels of microwave and ultrasonic powers on the yield of total carotenoid and antioxidant capacity of the extracts were investigated. The results showed that an extraction at 120 W for 25 min and an extraction at 200 W for 80 min were the most effective for MAE and UAE of the Gac peel samples, respectively. The maximum carotenoid and antioxidant capacity yields of UAE were significantly higher than those of the MAE. The antioxidant capacity of extract obtained by the UAE was also significantly higher that of the conventional extraction using the same ratio of solvent to material. The results showed that both MAE and UAE could be used to reduce the extraction time significantly in comparison with conventional extraction of Gac peel while still obtained good extraction efficiencies. Thus, MAE and UAE are recommended for the improvement of carotenoid and antioxidant capacity extraction from Gac peel.

Influence of ultrasound-assisted extraction on the pyrolysis characteristics and kinetic parameters of eucalyptus

In this study, the influence of ultrasound-assisted extraction on eucalyptus samples with special focus on pyrolysis characteristics and kinetic parameters was explored. Ultrasound and Soxhlet extraction were used to pretreat samples respectively, then samples were assayed by component analysis, TG-FTIR, and kinetic analysis. Ultrasound-assisted extraction did change the physiochemical characteristics of eucalyptus samples, particularly in regards to the quantity of extractives obtained. In TG and DTG curves, ultrasound-extracted samples reflected lower residual weight ratio (17.77%) and higher maximum weight loss rate (-22.92%/min), and were accompanied by a slight shift in the weight loss rate peak to lower temperature (366°C). The volatiles produced during pyrolysis and the discrepancies of product distribution between experimental and controlled groups were explored based on TG-FTIR spectra. According to kinetic analysis results, ultrasound-treated samples showed higher activation energy at the primary portion of thermal degradation with an average of 206.09kJ/mol.

Extraction Methods for the Isolation of Isoflavonoids from Plant Material

The purpose of this review is to describe and compare selected traditional and modern extraction methods employed in the isolation of isoflavonoids from plants. Conventional methods such as maceration, percolation, or Soxhlet extraction are still frequently used in phytochemical analysis. Despite their flexibility, traditional extraction techniques have significant drawbacks, including the need for a significant investment of time, energy, and starting material, and a requirement for large amounts of potentially toxic solvents. Moreover, these techniques are difficult to automate, produce considerable amount of waste and pose a risk of degradation of thermolabile compounds. Modern extraction methods, such as: ultrasound-assisted extraction, microwave-assisted extraction, accelerated solvent extraction, supercritical fluid extraction, and negative pressure cavitation extraction, can be regarded as remedies for the aforementioned problems. This manuscript discusses the use of the most relevant extraction techniques in the process of isolation of isoflavonoids, secondary metabolites that have been found to have a plethora of biological and pharmacological activities.

Antioxidant Compounds from Vegetable Matrices: Biosynthesis, Occurrence, and Extraction Systems

Natural antioxidants such as vitamin C, tocopherols and tocotrienols, carotenoids, and phenolic compounds are largely distributed in plant products. Most of them are not synthesized by human and need to be introduced with diet according to the Recommended Daily Intake (RDI). This work was aimed to give a comprehensive overview on the occurrence of these antioxidants in plants, in particular in plant foods, on the mechanisms of biosynthesis, and on conventional (liquid-liquid or solid-liquid extraction, Soxhlet) and innovative (enzymatic-assisted, pressurized fluid, supercritical fluid, ultrasound-assisted, microwave-assisted, pulsed electric field) extraction systems.

Assessment of Various Pretreatment and Extraction Methods for the Extraction of Bioactive Compounds from Orthosiphon stamineus Leaf via Microstructures Analysis

The impacts of various methods such as mechanical grinding, ultrasonic-assisted extraction (UAE), microwave-assisted extraction (MAE), and also sample pretreatments using acid and alkali on the microstructure of plant sample were studied for the extraction of bioactive compounds from Orthosiphon stamineus leaf. From scanning electron microscopy (SEM) analysis of the extracted sample, UAE and MAE induced significant disruption on glandular trichomes structure, which is the main site for biosynthesis of plant secondary metabolites. This improves the diffusion of bioactive compound and resulted in approximately 86–95 % of the total extraction yield quantified by conventional Soxhlet extraction. Chemical pretreatments generally imparted weaker microstructures disruption thus slight improvement on the extraction yields was observed. In this case, acid reagent is more suitable for the pretreatment as the presence of alkali decomposes the bioactive compounds. In a nutshell, the performance of an extraction strongly depends on its degree of disruption on the plant sample microstructure.

Solanesol extraction from tobacco leaves by Flash chromatography based on molecularly imprinted polymers

A novel solanesol extraction method based on molecularly imprinted polymer (MIP) as the Flash chromatography stationary phase was established and evaluated. Spherical MIP particles in a size range of 250-350 μm (d (0.5)=320 μm) for solanesol were synthesized by suspension polymerization, with imprinting factor of 3.9. The MIP particles (5.5 g) were packed in common Teflon column as the stationary phase while the sample solution and elution solvent were confirmed as methanol and methanol/acetic acid solution (80/20, v/v), loading at 4 ml/min and eluting 8 ml/min, respectively. Under the optimal chromatographic conditions, the adsorption capacity of the MIP-Flash column was determined as 107.3 μmol/g, and in each process, 370.8 mg purified solanesol (98.4%) could be obtained from the extract (20 mM, 40 ml) of tobacco leaves (14.7 g), and the yield of solanesol was 2.5% of the dry weight of tobacco leaves. The results reported here confirm the feasibility to extract highly purified active ingredients directly from natural products on a large scale by MIP-Flash chromatography.

Infrared Irradiation: Toward Green Chemistry, a Review

This review provides a comprehensive overview of where infrared irradiation has been employed, mainly as regards activating green mode for natural products extractions, as well as to favor a reaction, highlighting its actual importance. It is also underlined that infrared irradiation heating has been around for a long time; however, only in the last eighteen years have many of its advantages been applied to satisfy a wide range of chemical processes, natural products extractions, and for the promotion of many kinds of reactions. In addition, it is brought to light that near infrared irradiation is more efficient than middle and far infrared irradiations, being easily controllable and with the quality of a fast responding heat source. Thus, the main objective of this review is to offer infrared irradiation as an alternative clean energy source to activate reactions, in addition to favor the selective extraction of natural products, all of which is within the Green Chemistry protocol. Some recent results from our laboratory are also included.

Lipidomics of tobacco leaf and cigarette smoke

Detailed lipidomics experiments were performed on the extracts of cured tobacco leaf and of cigarette smoke condensate (CSC) using high-resolution liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (LC-Q-TOF MS). Following automated solid-phase extraction (SPE) fractionation of the lipid extracts, over 350 lipids could be annotated. From a large-scale study on 22 different leaf samples, it was determined that differentiation based on curing type was possible for both the tobacco leaf and the CSC extracts. Lipids responsible for the classification were identified and the findings were correlated to proteomics data acquired from the same tobacco leaf samples. Prediction models were constructed based on the lipid profiles observed in the 22 leaf samples and successfully allowed for curing type classification of new tobacco leaves. A comparison of the leaf and CSC data provided insight into the lipidome changes that occur during the smoking process. It was determined that lipids which survive the smoking process retain the same curing type trends in both the tobacco leaf and CSC data.

Environmental and Genetic Factors Associated with Solanesol Accumulation in Potato Leaves

Solanesol is a high value 45-carbon, unsaturated, all-trans-nonaprenol isoprenoid. Recently solanesol has received particular attention because of its utility, both in its own right and as a precursor in the production of numerous compounds used in the treatment of disease states. Solanesol is found mainly in solanaceous crops such as potato, tomato, tobacco and pepper where it accumulates in the foliage. There is considerable potential to explore the extraction of solanesol from these sources as a valuable co-product. In this study we have characterized the genetic variation in leaf solanesol content in a biparental, segregating diploid potato population. We demonstrate that potato leaf solanesol content is genetically controlled and identify several quantitative trait loci associated with leaf solanesol content. Transient over-expression of genes from the methylerythritol 4-phosphate (MEP) and mevalonic acid (MVA) pathways, either singly or in combination, resulted in enhanced accumulation of solanesol in leaves of Nicotiana benthamiana, providing insights for genetically engineering the pathway. We also demonstrate that in potato, leaf solanesol content is enhanced by up to six-fold on exposure to moderately elevated temperature and show corresponding changes in expression patterns of MEP and MVA genes. Our combined approaches offer new insights into solanesol accumulation and strategies for developing a bio-refinery approach to potato production.

Optimization extraction, characterization and antioxidant activities of pectic polysaccharide from tangerine peels

Response surface methodology (RSM) was employed to optimize the microwave-assisted extraction (MAE) process of pectic polysaccharide (TPPs) from tangerines peel. The optimal extraction conditions were as follows: microwave power 704 W, extraction temperature 52.2 °C, and extraction time 41.8 min Under these conditions, the experimental yield was 19.9 ± 0.2%. The purified pectic polysaccharide TPPs-2-1 was successfully obtained by anion-exchange and gel filtration chromatography. TPPs-2-1, linked mainly by α-glycosidic bonds, consisted of galacturonic acid (GalA), arabinose (Ara), galactose (Gal), rhamnose (Rha), glucose (Glc) and mannose (Man) with the average molecular weight of 17.8 kDa, and had typical IR spectra characteristic of pectic polysaccharides. Antioxidant activities were investigated on the basis of ferric-reducing antioxidant power (FRAP), hydroxyl radical (OH), 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and superoxide radical (O2(-)) scavenging assay. TPPs-2-1 exhibited significant antioxidant activity in a concentration-dependent manner and might be exploited as effective natural antioxidant applied in functional food and medicine.

Optimization of microwave assisted extraction (MAE) and soxhlet extraction of phenolic compound from licorice root

In present study, response surface methodology was used to optimize extraction condition of phenolic compounds from licorice root by microwave application. Investigated factors were solvent (ethanol 80 %, methanol 80 % and water), liquid/solid ratio (10:1-25:1) and time (2-6 min). Experiments were designed according to the central composite rotatable design. The results showed that extraction conditions had significant effect on the extraction yield of phenolic compounds and antioxidant capacities. Optimal condition in microwave assisted method were ethanol 80 % as solvent, extraction time of 5-6 min and liquid/solid ratio of 12.7/1. Results were compared with those obtained by soxhlet extraction. In soxhlet extraction, Optimum conditions were extraction time of 6 h for ethanol 80 % as solvent. Value of phenolic compounds and extraction yield of licorice root in microwave assisted (MAE), and soxhlet were 47.47 mg/g and 16.38 %, 41.709 mg/g and 14.49 %, respectively. These results implied that MAE was more efficient extracting method than soxhlet.