Green Extraction Of Natural Products Research Articles

Towards green extraction of bioactive natural compounds

The increasing interest in natural bioactive compounds is pushing the development of new extraction processes that may allow their recovery from a variety of different natural matrices and biomasses. These processes are clearly sought to be more environmentally friendly than the conventional alternatives that have traditionally been used and are closely related to the 6 principles of green extraction of natural products. In this trend article, the most critical aspects regarding the current state of this topic are described, showing the different lines followed to make extraction processes greener, illustrated by relevant examples. These include the implementation of new extraction technologies, the research on new bio-based solvents, and the development of new sequential process and biorefinery approaches to produce a full valorization of the natural sources. Moreover, the future outlook in the field is presented, in which the main areas of evolution are identified and discussed.Graphical abstract

High-Value Bioconversion of Ginseng Extracts in Betaine-Based Deep Eutectic Solvents for the Preparation of Deglycosylated Ginsenosides.

Deep eutectic solvents (DES), as a green alternative to traditional organic solvents in biocatalysis, not only activate proteins but even increase the efficiency of enzymatic reactions. Here, DES were used in a combinatorial enzyme-catalyzed system containing β-glucosidase BGLAt and β-galactosidase BGALAo to produce deglycosylated ginsenosides (De-g) from ginseng extracts (GE). The results showed that DES prepared with betaine and ethylene glycol (molar ratio, 1:2) could significantly stimulate the activity of the combinatorial enzymes as well as improve the acid resistance and temperature stability. The DES-based combinatorial enzyme-catalyzed system could convert 5 g of GE into 1.24 g of De-g (F1, F2, 20 (S)-PPT, and CK) at 24 h, which was 1.1 times that of the buffer sample. As confirmed by the spectral data, the changes in the conformations of the combinatorial enzymes were more favorable for the binding reaction with the substrates. Moreover, the constructed DES-based aqueous two-phase system enabled the recovery of substantial amounts of DES and De-g from the top phase. These results demonstrated that DES shows great application as a reaction solvent for the scale-up production of De-g and provide insights for the green extraction of natural products.

Subcritical Water Extraction of Natural Products.

Subcritical water refers to high-temperature and high-pressure water. A unique and useful characteristic of subcritical water is that its polarity can be dramatically decreased with increasing temperature. Therefore, subcritical water can behave similar to methanol or ethanol. This makes subcritical water a green extraction fluid used for a variety of organic species. This review focuses on the subcritical water extraction (SBWE) of natural products. The extracted materials include medicinal and seasoning herbs, vegetables, fruits, food by-products, algae, shrubs, tea leaves, grains, and seeds. A wide range of natural products such as alkaloids, carbohydrates, essential oil, flavonoids, glycosides, lignans, organic acids, polyphenolics, quinones, steroids, and terpenes have been extracted using subcritical water. Various SBWE systems and their advantages and drawbacks have also been discussed in this review. In addition, we have reviewed co-solvents including ethanol, methanol, salts, and ionic liquids used to assist SBWE. Other extraction techniques such as microwave and sonication combined with SBWE are also covered in this review. It is very clear that temperature has the most significant effect on SBWE efficiency, and thus, it can be optimized. The optimal temperature ranges from 130 to 240 °C for extracting the natural products mentioned above. This review can help readers learn more about the SBWE technology, especially for readers with an interest in the field of green extraction of natural products. The major advantage of SBWE of natural products is that water is nontoxic, and therefore, it is more suitable for the extraction of herbs, vegetables, and fruits. Another advantage is that no liquid waste disposal is required after SBWE. Compared with organic solvents, subcritical water not only has advantages in ecology, economy, and safety, but also its density, ion product, and dielectric constant can be adjusted by temperature. These tunable properties allow subcritical water to carry out class selective extractions such as extracting polar compounds at lower temperatures and less polar ingredients at higher temperatures. SBWE can mimic the traditional herbal decoction for preparing herbal medication and with higher extraction efficiency. Since SBWE employs high-temperature and high-pressure, great caution is needed for safe operation. Another challenge for application of SBWE is potential organic degradation under high temperature conditions. We highly recommend conducting analyte stability checks when carrying out SBWE. For analytes with poor SBWE efficiency, a small number of organic modifiers such as ethanol, surfactants, or ionic liquids may be added.

Synthesis and characteristic of 1-amino-2-propanol-based ionic liquids and effective extraction of antioxidants from Mugwort

Green extraction of natural products from plants is of high importance to the pharmaceuticals and fine chemicals industry. Novel bio-renewable ionic liquids, a class of safe and powerful medium, has aroused broad attention from the field of extraction and separation. In the present study, the 1-amino-2-propanol-based ionic liquids (PA-ILs) were used to selectively extract the antioxidants from Mugwort (Artemisia argyi Lévl. et Vant.). As revealed from the results, among ten PA-ILs carrying different counter anions, the PA/mandelic acid, PA/EDTA and PA/lactic acid exhibited the best extraction efficiency to polyphenols (120.34 mg/g), flavones (128.87 mg/g) and polysaccharides (43.62 mg/g), respectively. Furthermore, the time-dependent DPPH radical scavenging shown that flavones are the major antioxidants and PA-ILs extractants were higher than those of conventional solvents. According to the reversed-phase HPLC profiles, more polar substances (e.g. glycosides) existed in ILs extract compared with alcohols solvent. The Fermi resonance in the FT-IR spectrum indicated the complex H-bonding framework in ILs, which may act as a crucial factor to assess extraction performance. Moreover, the in vitro studies reported that the cytotoxicity of PA-ILs for HaCaT and Caco-2 cell lines was less than that of pure PA. It was, therefore, demonstrated that PA-ILs are a secure medium that can help alternate organic solutions.

Editorial “High-Performance Green Extraction of Natural Products”

There has been, to-date, a large number of studies pertaining to the exploitation of plant resources (herbs, botanicals, processing by-products) for the production of extracts enriched with bioactive substances [...]

2-Methyloxolane (2-MeOx) as Sustainable Lipophilic Solvent to Substitute Hexane for Green Extraction of Natural Products. Properties, Applications, and Perspectives.

This review presents a complete picture of current knowledge on 2-methyloxolane (2-MeOx), a bio-based solvent for the extraction of natural products and food ingredients. It provides the necessary background about the properties of 2-MeOx, not only its solvent power and extraction efficiency, but its detailed toxicological profile and environmental impacts are discussed. We compared 2-MeOx with hexane which is the most used petroleum-based solvent for extraction of lipophilic natural products. The final part focuses on successful industrial transfer, including technologic, economic, and safety impacts. The replacement of petroleum-based solvents is a hot research topic, which affects several fields of modern plant-based chemistry. All the reported applications have shown that 2-MeOx is an environmentally and economically viable alternative to conventional petroleum-based solvents for extraction of lipophilic foodstuff and natural products.

STUDIES ON REDUCTION OF EXTRACTION TIME OF SUPERCRITICAL CO2 TO SAVE ENERGY

The present research work was conducted to examine the effect of changing geometric pattern of the extractor bed on the performance of supercritical co2 extraction (scco2e) of clove buds. The results of this study indicate that this modification of extractor bed geometry helps to complete this extraction process with higher yield in lesser time than conventional type of extractor bed. Since operating cost of extraction by supercritical fluid is higher than other methods, reduction of extraction time with better quality product in larger quantity significantly saves energy. Scco2e is already established as a promising novel technology for green extraction of natural products. Lot of research works are going on worldwide to reduce its energy consumption, thus cost of extraction to meet the challenges of the modern industrial development. This article explores a new research angle in the field of developing supercritical fluid extraction as an efficient, energy-saving, eco-friendly, sustainable technology for extraction of natural products from different plant materials.

Green extraction of natural products: theory and practice

Green extraction of natural products: theory and practice

Direct green extraction of volatile aroma compounds using vegetable oils as solvents: Theoretical and experimental solubility study

The current study aimed at evaluation of the dissolving power of various vegetable oils in both theoretical and experimental way for the extraction of volatile aroma compounds (VACs) from basil. The solubility of six main VACs from basil in ten vegetable oils was firstly investigated through a theoretical modeling of their Hansen solubility parameters (HSP), followed by real experimental extractions using vegetable oils as solvents instead of petroleum-based solvents such as dichloromethane. Furthermore, multivariate statistical analyses were performed to partition vegetable oils into clusters referring to their dissolving power of VACs, which could be quantified by gas chromatography–mass spectroscopy (GC–MS) coupling to the headspace solid phase micro-extraction (HS-SPME). The results indicated that the solubility of VACs in enriched vegetable oils was significantly different (p < 0.05). Vegetable oils has theoretically and experimentally proved their potential to be alternative solvents for further application in green extraction of natural products, in which sunflower oil gave the best performance.

Green extraction processes of natural products as tools for biorefinery

AbstractThis review introduces a new and innovative area in the frontiers of chemistry, biology and processing: green extraction with special emphasis on natural products processing. Green extraction is a part of the sustainable development and industrial strategy; its history, concept, principles, and fundamentals are described. We pay special attention to the strategies and the tools available to make biorefinery greener. This review presents the innovative research in this area in the past five years in terms of innovative techniques (microwave, ultrasound, instantaneous pressure drop, supercritical fluid extraction, pressing) applied to green extraction of natural products with special examples applied to biorefinery concept.

Green Extraction of Natural Products: Concept and Principles

The design of green and sustainable extraction methods of natural products is currently a hot research topic in the multidisciplinary area of applied chemistry, biology and technology. Herein we aimed to introduce the six principles of green-extraction, describing a multifaceted strategy to apply this concept at research and industrial level. The mainstay of this working protocol are new and innovative technologies, process intensification, agro-solvents and energy saving. The concept, principles and examples of green extraction here discussed, offer an updated glimpse of the huge technological effort that is being made and the diverse applications that are being developed.