Optimization of ionic liquid-based microwave-assisted extraction technique for curcuminoids from Curcuma longa L

Valorization of pawpaw (Carica papaya L.) leaves as a source of polyphenols by ionic liquid-based microwave-assisted extraction: Comparison with other extraction methods and bioactivity evaluation

This study aimed to valorize pawpaw (Carica papaya L.) leaves as a rich source of polyphenols through the application of ionic liquid-based microwave-assisted extraction (ILMAE). Initially, the ILMAE process was optimized using response surface methodology (RSM), resulting in a total polyphenols yield of 27.84 ± 0.33 mg GAE/g DW under the optimal conditions: [BMIM]Br concentration of 0.57 mol/L, extraction time of 14 min, microwave power of 460 W, extraction temperature of 77 °C, solvent-to-material ratio of 30 mL/g, and three extraction cycles. Compared to conventional methods such as maceration extraction (ME), heat reflux extraction (HRE), and microwave-assisted extraction (MAE), the ILMAE method exhibited a significantly higher PLTP yield. Furthermore, the PLTP extracts demonstrated strong antioxidant activity against DPPH• and ABTS+• radicals, as well as a significant inhibitory effect on α-glucosidase activity. This work demonstrates that ILMAE is a green and efficient strategy for the valorization of pawpaw leaves.

Energy Applications of Ionic Liquids: Recent Developments and Future Prospects

Ionic liquids (ILs) consisting entirely of ions exhibit many fascinating and tunable properties, making them promising functional materials for a large number of energy-related applications. For example, ILs have been employed as electrolytes for electrochemical energy storage and conversion, as heat transfer fluids and phase-change materials for thermal energy transfer and storage, as solvents and/or catalysts for CO2 capture, CO2 conversion, biomass treatment and biofuel extraction, and as high-energy propellants for aerospace applications. This paper provides an extensive overview on the various energy applications of ILs and offers some thinking and viewpoints on the current challenges and emerging opportunities in each area. The basic fundamentals (structures and properties) of ILs are first introduced. Then, motivations and successful applications of ILs in the energy field are concisely outlined. Later, a detailed review of recent representative works in each area is provided. For each application, the role of ILs and their associated benefits are elaborated. Research trends and insights into the selection of ILs to achieve improved performance are analyzed as well. Challenges and future opportunities are pointed out before the paper is concluded.

Various Extraction Techniques of Curcumin-A Comprehensive Review

Curcumin, the active component of the rhizome of Curcuma longa, is a safe substance whose applications are extensively used in medicinal, biological, pharmacological activities, and food cosmetic additives. In the field of medicine, curcuminoids have a greater impact; they have been associated with the suppression of neuropathic pain, depression, angiogenesis, tumorigenesis, diabetes, and diseases of the liver, skin, and pulmonary systems, as well as cardiovascular and nervous systems. These are in high demand and have high market potential and inflated costs. For the aforementioned uses, as well as for basic research, it is crucial to get pure curcumin from plant sources. There is a need for effective extraction and purification techniques that adhere to standards for process efficiency, environmental friendliness, and safety. Scope: This account offers an accurate and thorough explanation of the many techniques used to extract and purify curcumin from plant sources, as well as a look at its various roles in the pharmaceutical, cosmetic, medical, and other industries. Curcumin's prospective and commercial roles are also discussed. Key findings: Curcuminoids have been extracted and purified by using a broad range of techniques that are utilized extensively across the world. Extraction of curcuminoids includes both traditional and contemporary approaches, of which a handful include Soxhlet extraction, maceration, solvent extraction, ultrasound-assisted extraction, microwave-assisted extraction, enzyme-assisted extraction, and supercritical liquid extraction. The other process called purification can be performed alone or in combination with techniques. The use of column chromatography and semipreparative high-performance liquid chromatography are examples of traditional purification procedures, and other innovative methods include high-speed counter-current chromatography and supercritical fluid chromatography.

Deep Eutectic Solvent-Based Microwave-Assisted Extraction for the Extraction of Seven Main Flavonoids from Ribes mandshuricum (Maxim.) Kom. Leaves

Flavonoids exhibit many biological properties, so it is very important to find an efficient and green method to extract them from plant materials. In this paper, DES-MAE (deep eutectic solvent-based microwave-assisted extraction) technique was developed to extract the seven major active flavonoids from Ribes mandshuricum leaves, namely, trifolin, isoquercetin, rutin, astragalin, quercetin, hyperoside, and kaempferol. After the completion of the extraction process, macroporous adsorption resin was used for the purification of seven flavonoids. The BBD (Box–Behnken design) method combined with RSM (response surface methodology) was applied to acquire the optimal operating conditions of DES-MAE. The optimal parameters were: temperature: 54 °C, time: 10 min, extraction solvent: choline chloride/lactic acid with a 1:2 mass ratio, water content: 25%, and liquid/solid ratio: 27 mL/g. The yields of the seven target flavonoids were 4.78, 2.57, 1.25, 1.15, 0.34, 0.32, and 0.093 mg/g DW (dry weight), respectively. The direct purification of trifolin, isoquercetin, rutin, astragalin, quercetin, hyperoside, and kaempferol in DES-MAE solution was achieved by using macroporous resin X-5. The recoveries were 87.02%, 81.37%, 79.64%, 87.13%, 97.36%, 88.08%, and 99.39%, respectively. The results showed that DES-MAE followed by MRCC (macroporous resin column chromatography) represents a promising approach to extracting and separating active components from plants.

Therapeutic Applications of Curcumin in Diabetes: A Review and Perspective

Diabetes is a metabolic disease with multifactorial causes which requires lifelong drug therapy as well as lifestyle changes. There is now growing scientific evidence to support the effectiveness of the use of herbal supplements in the prevention and control of diabetes. Curcumin is one of the most studied bioactive components of traditional medicine, but its physicochemical characteristics are represented by low solubility, poor absorption, and low efficacy. Nanotechnology-based pharmaceutical formulations can help overcome the problems of reduced bioavailability of curcumin and increase its antidiabetic effects. The objectives of this review were to review the effects of nanocurcumin on DM and to search for databases such as PubMed/MEDLINE and ScienceDirect. The results showed that the antidiabetic activity of nanocurcumin is due to complex pharmacological mechanisms by reducing the characteristic hyperglycemia of DM. In light of these results, nanocurcumin may be considered as potential agent in the pharmacotherapeutic management of patients with diabetes.

Curcumin: Biological Activities and Modern Pharmaceutical Forms

Curcumin (1,7-bis-(4-hydroxy-3-methoxyphenyl)-hepta-1,6-diene-3,5-dione) is a natural lipophilic polyphenol that exhibits significant pharmacological effects in vitro and in vivo through various mechanisms of action. Numerous studies have identified and characterised the pharmacokinetic, pharmacodynamic, and clinical properties of curcumin. Curcumin has an anti-inflammatory, antioxidative, antinociceptive, antiparasitic, antimalarial effect, and it is used as a wound-healing agent. However, poor curcumin absorption in the small intestine, fast metabolism, and fast systemic elimination cause poor bioavailability of curcumin in human beings. In order to overcome these problems, a number of curcumin formulations have been developed. The aim of this paper is to provide an overview of recent research in biological and pharmaceutical aspects of curcumin, methods of sample preparation for its isolation (Soxhlet extraction, ultrasound extraction, pressurised fluid extraction, microwave extraction, enzyme-assisted aided extraction), analytical methods (FTIR, NIR, FT-Raman, UV-VIS, NMR, XRD, DSC, TLC, HPLC, HPTLC, LC-MS, UPLC/Q-TOF-MS) for identification and quantification of curcumin in different matrices, and different techniques for developing formulations. The optimal sample preparation and use of an appropriate analytical method will significantly improve the evaluation of formulations and the biological activity of curcumin.

Microwave-Assisted Extraction of Curcuma longa L. Oil: Optimization, Chemical Structure and Composition, Antioxidant Activity and Comparison with Conventional Soxhlet Extraction

Curcuma root (Curcuma longa L.) is a very important plant in gastronomy and medicine for its unique antiseptic, anti-inflammatory, antimicrobial and antioxidant properties. Conventional methods for the extraction of curcuma oil require long extraction times and high temperatures that can degrade the active substances. Therefore, the objectives of the present study were: (i) first, to optimize the extraction yield of curcuma oil by applying a Box-Behnken experimental design using surface response methodology to the microwave-assisted extraction (MAE) technique (the independent variables studied were reaction time (10–30 min), microwave power (150–200 W) and curcuma powder/ethanol ratio (1:5–1:20; w/v); and, (ii) second, to assess the total phenolic content (TPC) and their antioxidant activity of the oil (at the optimum conditions point) and compare with the conventional Soxhlet technique. The optimum conditions for the MAE were found to be 29.99 min, 160 W and 1:20 w/v to obtain an optimum yield of 10.32%. Interestingly, the oil extracted by microwave-assisted extraction showed higher TPC and better antioxidant properties than the oil extracted with conventional Soxhlet technique. Thus, it was demonstrated that the method applied for extraction influences the final properties of the extracted Curcuma longa L. oil.

Enhanced Water Solubility and Oral Bioavailability of Paclitaxel Crystal Powders through an Innovative Antisolvent Precipitation Process: Antisolvent Crystallization Using Ionic Liquids as Solvent

Paclitaxel (PTX) is a poor water-soluble antineoplastic drug with significant antitumor activity. However, its low bioavailability is a major obstacle for its biomedical applications. Thus, this experiment is designed to prepare PTX crystal powders through an antisolvent precipitation process using 1-hexyl-3-methylimidazolium bromide (HMImBr) as solvent and water as an antisolvent. The factors influencing saturation solubility of PTX crystal powders in water in water were optimized using a single-factor design. The optimum conditions for the antisolvent precipitation process were as follows: 50 mg/mL concentration of the PTX solution, 25 °C temperature, and 1:7 solvent-to-antisolvent ratio. The PTX crystal powders were characterized via scanning electron microscopy, Fourier transform infrared spectroscopy, high-performance liquid chromatography–mass spectrometry, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, Raman spectroscopy, solid-state nuclear magnetic resonance, and dissolution and oral bioavailability studies. Results showed that the chemical structure of PTX crystal powders were unchanged; however, precipitation of the crystalline structure changed. The dissolution test showed that the dissolution rate and solubility of PTX crystal powders were nearly 3.21-folds higher compared to raw PTX in water, and 1.27 times higher in artificial gastric juice. Meanwhile, the bioavailability of PTX crystal increased 10.88 times than raw PTX. These results suggested that PTX crystal powders might have potential value to become a new oral PTX formulation with high bioavailability.

Evaluation of Structurally Different Ionic Liquid-Based Surfactants in a Green Microwave-Assisted Extraction for the Flavonoids Profile Determination of Mangifera sp. and Passiflora sp. Leaves from Canary Islands

Aqueous solutions of ionic liquids (ILs) with surface active properties were used as extraction solvents, taking advantage of their impressive solvation properties, in a green microwave-assisted solid-liquid extraction method (IL-MA-SLE) for the extraction of flavonoids from passion fruit and mango leaves. The extraction method was combined with high-performance liquid chromatography and photodiode-array detection (HPLC-PDA) and optimized by response surface methodology using the Box-Behnken experimental design. Under optimum conditions, the extraction efficiency of six structurally different IL-based surfactants was evaluated. Thus, imidazolium-, guanidinium- and pyridinium-type ILs with different tailorable characteristics, such as side chain length and multicationic core, were assessed. The decylguanidinium chloride ([C10Gu+][Cl-]) IL-based surfactant was selected as key material given its superior performance and its low cytotoxicity, for the determination of flavonoids of several samples of Passiflora sp. and Mangifera sp. leaves from the Canary Islands, and using as target analytes: rutin, quercetin and apigenin. The analysis of 50 mg of plant material only required 525 µL of the low cytotoxic IL-based surfactant solution at 930 mM, 10.5 min of microwave irradiation at 30 °C and 50 W, which involves a simpler, faster, more efficient and greener method in comparison with other strategies reported in the literature for obtaining bioactive compounds profiles from plants.

Separation of the main flavonoids and essential oil from seabuckthorn leaves by ultrasonic/microwave-assisted simultaneous distillation extraction

Volatile essential oils (EOs), non-volatile rutin (RU), quercetin (QU), kaempferol (KA) and isorhamnetin (IS) were effectively extracted and isolated from seabuckthorn (Hippophae rhamnoides L.) leaves by ionic liquid-based ultrasound/microwave-assisted simultaneous distillation extraction (ILUMASDE). After optimization by response surface methodology, EOs, RU, QU, KA and IS were separated under the following optimum conditions: an ionic liquid of 1.0 M 1-butyl-3-methyl imidazole bromine salt ([C4mim]), liquid/solid ratio of 12 ml g^-1, extraction time of 34 min, microwave power of 540 W and a fixed ultrasonic power of 50 W. Under the optimized conditions of ILUMASDE, the extraction yields of RU, QU, KA, IS and EOs were 9.18 ± 0.35, 5.52 ± 0.23, 3.03 ± 0.11, 5.64 ± 0.24 mg g^-1 and 0.095 ± 0.004%, respectively. The yield of EOs obtained using ILUMASDE was 1.07-fold higher than that obtained by conventional hydrodistillation extraction (HDE). In addition, the components of the EOs obtained using ILUMASDE and HDE were similar. The extraction yields of RU, QU, KA, IS obtained by ILUMASDE were 1.03-1.35-fold higher than that obtained by the ethanol ultrasonic-assisted extraction (EUAE), ionic liquid-based ultrasonic-assisted extraction (ILUAE) and ionic liquid-based microwave-assisted extraction (ILMAE). And the extraction time used by ILUMASDE was 34 min, which is 14.17%, 56.67%, 56.67% and 85.00% less than those used by HDE, EUAE, ILUAE and ILMAE, respectively. Therefore, ILUMASDE can be considered a rapid and efficient method for extracting flavonoids and EO from seabuckthorn (Hippophae rhamnoids L.) leaves.