What is extraction and cultivation

Adsorptive macroporous resins are polymer adsorbents with macroporous structures but without ion exchange groups that can selectively adsorb almost any type of natural products. They have been widely used either as a standalone system, or as part of a pretreatment process for removing impurities or enriching target compounds due to their advantages, which include high adsorptive capacity, relatively low cost, easy regeneration and easy scale-up.

The adsorptive mechanisms of adsorptive macroporous resins include electrostatic forces, hydrogen bonding, complex formation and size-sieving actions between the resins and the natural products in solution. Surface area, pore diameter and polarity are the key factors affecting the capacity of the resins [ 54 ].

Recently, Meng et al. Some researchers assumed that the principal adsorptive mechanism between macroporous resins and polyphenols was associated with the hydrogen bonding formation between the oxygen atom of the ether bond of the resin and the hydrogen atom of phenolic hydroxyl group of the phenol. The hydrogen bonding interaction force was significantly affected by the pH value of the solution [ 57 , 58 ].

Silver nitrate is another useful solid support in the separation of natural products. The greater the number of double bonds or aromaticity of the natural product, the stronger the complexation forms. Silver nitrate is typically impregnated on silica gel SNIS or alumina for separation. Several research groups reported the separation of fatty acids on SNIS [ 59 — 61 ].

Wang et al. A pair of isomers, brasiliensic acid 83 , Fig. Some research groups also applied silver nitrate in the two-phase system in high-speed counter-current chromatography HSCCC to improve the separation. Partition chromatography PC follows the liquid—liquid extraction principle based on the relative solubility in two different immiscible liquids. In the early stage, one liquid phase was coated to a solid matrix silica gel, carbon, cellulose, etc.

The disadvantage of an easily removed stationary phase and unrepeatable results has led to this kind of PC being rarely used today. The bonded-phase, in which the liquid stationary phase is chemically bound to the inert support, which is used as the stationary phase overcomes those drawbacks. Commercially available alkyl such as C8 and C18, aryl, cyano and amino substituted silanes are often used as bonded phases, which are widely used to separate a variety of natural products, especially in the final purification step.

A novel polyacrylamide-based silica stationary phase was synthesized by Cai et al. Counter-current chromatography CCC is kind of PC that holds the liquid stationary phase by gravity or centrifugal force. CCC has rarely been used in early stages due to its poor stationary retention, long separation time and labor intensive process.

The hydrodynamic CCC systems such as HSCCC have a planetary rotation movement around two rotating axes with no rotating seals, which offers a low pressure drop process. Hydrostatic CCC, e. The high system pressure in CPC prevents the improvement of the resolution by increasing the length of the column.

Compared to the conventional column separation method using a solid stationary phase, both hydrostatic and hydrodynamic CCC systems offer some advantages including the elimination of irreversible adsorption and peak tailing, high loading capacity, high sample recovery, minimal risk of sample denaturation and low solvent consumption.

The limitation of CCC is that it only separates the compounds in a relatively narrow polarity window. Tang et al. Li et al. Few reports could be obtained due to commercial confidentiality.

It is difficult to judge whether hydrostatic or hydrodynamic CCC is better for industrial applications. Users might select different types of CCC instrument for different purposes. When the stationary phase is poorly retained in hydrodynamic CCC due to high viscosity and small density differences between the mobile and stationary phases, the hydrostatic CCC is more practical than hydrodynamic CCC because the retention of the stationary phase of hydrostatic CCC is less sensitive to the physical properties of liquid systems and will have a higher retention of the stationary phase.

When the stationary phase is well retained in hydrodynamic CCC, higher separation efficiency will be obtained from hydrodynamic CCC than from hydrostatic CCC with the same liquid system and similar column volumes because hydrostatic CCC has relatively low partition efficiency due to a limited degree of mixing, and the hydrodynamic system provides efficient mixing to yield a high partition efficiency.

The separation of natural products by membrane filtration MF or gel filtration chromatography GFC is based on their molecular sizes. In MF, the semipermeable membrane allows smaller molecules to pass through and retains the larger molecules.

MF of natural products could be characterized as microfiltration, ultrafiltration, and nanofiltration based on the pore size of the membrane applied. Membrane filtration has been a powerful tool for the concentration, clarification and removal of impurities in the lab, as well as in the food and pharmaceutical industries.

Coupling membrane filtration is applied when a single membrane filtration step is not satisfactory. A sequence of microfiltration, ultrafiltration and nanofiltration was applied in the isolation of bioactive components from olive leaf extract. Microfiltration followed by ultrafiltration removed the impurities larger than 5 kDa. Nanofiltration recovered the antioxidative and antibacterial polyphenols and flavonoids, and the content of the major component, oleuropein , in the nanofiltration retentate was concentrated approximately ten times [ 74 ].

Gel filtration chromatography is also known as gel permeation chromatography or size exclusion chromatography. The small molecules have a longer retention time in GFC than large molecules. Sephadex is formed by cross-linking dextran, and the G-types of Sephadex were used for the separation of hydrophilic compounds such as peptides [ 75 ], oligosaccharides and polysaccharides [ 76 ]. Sephadex LH20, a hydroxypropylated derivative of Sephadex G25, has both hydrophobic and hydrophilic natures.

An adsorption mechanism was also involved in separation using Sephadex LH Sephadex LH can be used for the separation of a wide variety of natural products in either an aqueous or non-aqueous solvent system.

Three new pyrimidine diterpenes, axistatins 1—3 — , Fig. Polyacrylamide bio-gel P [ 79 ] and cross-linked agarose [ 80 ] were also used in the separation of natural products. Ion-exchange chromatography IEC separates molecules based on the differences in their net surface charge.

Some natural products, such as alkaloids and organic acids possessing a functional group capable of ionization, might be separated by IEC. The charged molecules could be caught and released by ion-exchange resin by changing the ionic strength of the mobile phase e.

Cation ion-exchange resins were used for the separation of alkaloids, while the anion ion-exchange resins were used for the separation of natural organic acids and phenols. The positively charged anthocyanins were separated from the neutral polyphenolic compounds in the XAD-7 treated Actinidia melanandra fruit kiwifruit extract using Dowex 50WX8 cation ion-exchange resin [ 81 ].

Molecular distillation separates the molecular by distillation under vacuum at a temperature far below its boiling point. It is a suitable distillation method for separating thermosensitive and high-molecular-weight compounds. Borgarello et al. The obtained fraction had antioxidant properties and could stabilize the sunflower oil [ 84 ]. Gas chromatography GC with high separation efficiency and fast separation and analysis makes it potentially the ideal preparative method for the separation of volatile compounds.

The injection port, column, split device and trap device of GC equipment must be modified for preparative separation due to a lack of commercial Prep-GC [ 86 ].

Five volatile compounds, namely, curzerene 98 6. Prep-GC was also applied for the separation of natural isomers. Prep-GC has become an important separation method for natural volatile compounds; however, a heavier sample load and the large-diameter preparative column employed decreased the efficiency [ 89 ].

Meanwhile, the disadvantages of Prep-GC, including the lack of commercial Prep-GC equipment, consumption of a large volume of carrier gas, the decomposition of thermolabile compounds under high operation temperature, the difficulties of fraction collection, and low production, still restrict the usage of Prep-GC.

SFC uses supercritical fluid as the mobile phase. SFC integrates the advantages of both GC and liquid chromatography LC as the supercritical fluids possess properties of high dissolving capability, high diffusivity and low viscosity, which allows rapid and efficient separation.

Thus, SFC can use a longer column and smaller particles of the stationary phase than HPLC, which provides greater numbers of theoretical plates and better separation. SFC can be used for the separation of non-volatile or thermally labile compounds to which GC is not applicable. The polarity of the widely used mobile phase, S-CO 2 , in SFC is close to the polarity of hexane, with the result that SFC was used for the separation of non-polar natural products such as fatty acids, terpenes and essential oils for many years.

Eluent modifiers such methanol and acetonitrile enhance the elution strength, which is increasing the interest in separating polar natural products by SFC [ 90 — 92 ]. Zhao et al. Yang et al. The non-aqueous mobile phase used in SFC prevented the tautomerization of the separated spiro oxindole alkaloids [ 94 ]. SFC is also applied in the separation of natural enantiomers.

The chiral separation of R and S goitrins was successfully achieved by prep-SFC on a Chiralpak IC column using acetonitrile as the organic modifier [ 95 ]. Molecular imprinted technology has been an attractive separation method in the last decade due to its unique features, which include high selectivity, low cost and easy preparation.

Many complementary cavities with the memory of size, shape, and functional groups of the template molecules are generated when the template molecules are removed from the molecular imprinted polymer MIP. Thus, the template molecule and its analogs will have the specific recognition and selective adsorption for the MIP. MIPs have been widely used in the separation of natural products or as solid-phase extraction sorbents for sample preparation of herbal materials to enrich the minor compounds.

Ji et al. Ma et al. The MIP was prepared with methyl methacrylate as the monomer, solanesol as the template molecule and ethylene glycol dimethacrylate as the crosslinker by a suspension polymerization method. A total of You et al. The designed thermo-responsive magnetic MIP showed good imprinting factor for curcuminoids in a range between 2. Simulated moving bed SMB chromatography uses multiple columns with stationary phases bed. The countercurrent movement of the bed is simulated through rotary valves, which periodically switch the inlet feed and eluent and outlet extract and raffinate.

The SMB process is a continuous separation method and a powerful tool for the large-scale separation of natural products with the advantage of lower solvent consumption over a shorter period of time. Two cyclopeptides, cyclolinopeptides C and E — , Fig. Kang et al. Supercritical fluids can also be used as the desorbent in SMB chromatography. Liang et al. The components in the extract subjected to separation were complex, and generally, no pure compound will be separated in one column chromatography.

Multi-dimensional separation based on the solid phase extraction and coupling of multiple columns with different stationary phases greatly improves the separation efficiency. With more commercial multiple dimensional separation equipment entering the market, the separation of natural products is becoming more rapid, efficient and automated. Usually, the target compound was enriched by first dimensional separation and purified by last dimensional separation. A novel volatile compound, 2 E ,6 E methyl 4-methylcyclohexenylidene heptenal , was purified by a three-dimensional prep-GC from wampee essential oil [ ].

Five antioxidant compounds, including two alkaloids [glusodichotomine AK and glusodichotomine B ] and three flavonoids [tricin , homoeriodictyol Fig. Sciarrone et al. Patchouli alcohol , Fig. They found that the first dimensional separation using LC reduced the sample complexity and increased the productivity of low-concentration components [ ].

Natural products have contributed to drug development over the past few decades and continue to do so. The lab-intensive and time-consuming of extraction and isolation processes, however, have hindered the application of natural products in drug development. As technology continues to develop, more and more new automatic and rapid techniques have been created to extract and separate natural products, which might reach the requirement of high-throughput screening.

Regarding extraction, reflux extraction is the most commonly employed technique for preparative separation. The modern extraction methods, also regarded as green extraction methods, including UAE, MAE, SFE and PLE, have also been the subject of increased attention in recent years due to their high extraction yields, selectivity, stability of the target extracts and process safety merits. Some of those green methods have become routine sample preparation methods for analytical purposes.

Regarding isolation, the development of novel packing material could enhance the efficiency of isolation, which should be researched further. The hyphenation of chromatographic and spectroscopic or spectrometric techniques with the aim of elucidating structures without the need for isolation, such as LC-NMR and LC—MS, is a useful dereplication tool for searching for novel natural products.

Although the isolation of pure natural products from complex mixtures remains challenging and we are far from one-step isolation procedures, the application of more selective methods from extraction to fractionation and purification will speed up the time from collecting biological material to isolating the final purified compound.

In conclusion, there is a clear and increasing interest in the extraction and isolation of natural products and their advantageous applications. These specific applications are also conditioning the employed extraction methods and novel stationary phases and mobile phases to be used by these techniques.

It is thus expected that these trends will be maintained in the near future as they are mostly motivated by emerging consumer demands and by safety, environmental and regulatory issues.

QWZ designed the study, conducted the literature search, extracted and analyzed data, drafted the manuscript, and is the corresponding author. LGL contributed to the critical revisions of the manuscript. WCY co-designed the study and co-developed the full text of the review, and is the co-corresponding author. All authors read and approved the final manuscript. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Li-Gen Lin, Email: om. National Center for Biotechnology Information , U. Journal List Chin Med v. Chin Med. Published online Apr Author information Article notes Copyright and License information Disclaimer. Corresponding author. Received Jan 7; Accepted Apr 4. This article has been cited by other articles in PMC. Associated Data Data Availability Statement All data used in this systematic review are fully available in the public domain. Abstract Natural medicines were the only option for the prevention and treatment of human diseases for thousands of years.

Background Natural medicines, such as traditional Chinese medicine TCM and Ayurveda, were formed and developed in the daily life of ancient people and in the process of their fight against diseases over thousands of years, and they have produced a positive impact on the progress of human civilization. Extraction Extraction is the first step to separate the desired natural products from the raw materials.

Table 1 A brief summary of various extraction methods for natural products. Open in a separate window. Maceration This is a very simple extraction method with the disadvantage of long extraction time and low extraction efficiency. Structures of compounds 1 — 3. Percolation Percolation is more efficient than maceration because it is a continuous process in which the saturated solvent is constantly being replaced by fresh solvent. Structures of compounds 4 — 6. Decoction The extract from decoction contains a large amount of water-soluble impurities.

Reflux extraction Reflux extraction is more efficient than percolation or maceration and requires less extraction time and solvent. Structures of compounds 50 — Soxhlet extraction The Soxhlet extraction method integrates the advantages of the reflux extraction and percolation, which utilizes the principle of reflux and siphoning to continuously extract the herb with fresh solvent. Pressurized liquid extraction PLE Pressurized liquid extraction PLE has also been described as accelerated solvent extraction, enhanced solvent extraction, pressurized fluid extraction, accelerated fluid extraction, and high pressure solvent extraction by different research groups.

Ultrasound assisted extraction UAE Ultrasonic-assisted extraction UAE , also called ultrasonic extraction or sonication, uses ultrasonic wave energy in the extraction. Structures of compounds 54 — Microwave assisted extraction MAE Microwaves generate heat by interacting with polar compounds such as water and some organic components in the plant matrix following the ionic conduction and dipole rotation mechanisms.

Structures of compounds 60 — Pulsed electric field PEF extraction Pulsed electric field extraction significantly increases the extraction yield and decreased the extraction time because it can increase mass transfer during extraction by destroying membrane structures. Enzyme assisted extraction EAE The structure of the cell membrane and cell wall, micelles formed by macromolecules such polysaccharides and protein, and the coagulation and denaturation of proteins at high temperatures during extraction are the main barriers to the extraction of natural products.

Structures of compounds 66 — Hydro distillation and steam distillation Hydro distillation HD and steam distillation SD are commonly used methods for the extraction of volatile oil. Separation methods The components in the extract from above methods are complex and contain a variety of natural products that require further separation and purification to obtain the active fraction or pure natural products.

Separation based on adsorption properties Adsorption column chromatography is widely used for the separation of natural products, especially in the initial separation stage, due to its simplicity, high capacity and low cost of adsorbents such as silica gel and macroporous resins.

Structures of compounds 68 — Separation based on partition coefficient Partition chromatography PC follows the liquid—liquid extraction principle based on the relative solubility in two different immiscible liquids. Structures of compounds 89 — Separation based on the molecular size The separation of natural products by membrane filtration MF or gel filtration chromatography GFC is based on their molecular sizes.

Membrane filtration MF In MF, the semipermeable membrane allows smaller molecules to pass through and retains the larger molecules. Structures of compounds — Gel filtration chromatography GFC Gel filtration chromatography is also known as gel permeation chromatography or size exclusion chromatography.

Separation based on ionic strength Ion-exchange chromatography IEC separates molecules based on the differences in their net surface charge. Structures of compounds —1 Other modern separation techniques Molecular distillation MD Molecular distillation separates the molecular by distillation under vacuum at a temperature far below its boiling point. Preparative gas chromatography Prep-GC Gas chromatography GC with high separation efficiency and fast separation and analysis makes it potentially the ideal preparative method for the separation of volatile compounds.

Molecular imprinted technology Molecular imprinted technology has been an attractive separation method in the last decade due to its unique features, which include high selectivity, low cost and easy preparation. Simulated moving bed chromatography Simulated moving bed SMB chromatography uses multiple columns with stationary phases bed.

Multi-dimensional chromatographic separation The components in the extract subjected to separation were complex, and generally, no pure compound will be separated in one column chromatography. Summary Natural products have contributed to drug development over the past few decades and continue to do so. Acknowledgements Not applicable. Competing interests The authors declare that they have no competing interests. Availability of data and materials All data used in this systematic review are fully available in the public domain.

Consent for publication Not applicable. Ethics approval and consent to participate Not applicable. References 1. WHO traditional medicine strategy: —; Accessed 29 Dec Natural products as sources of new drugs from to J Nat Prod. Natural products as sources of new drugs over the 30 years from to Discovery and resupply of pharmacologically active plant-derived natural products: a review.

Biotechnol Adv. Natural products: a continuing source of novel drug leads. Biochim Biophys Acta Gen Subj. Optimizing ultra performance liquid chromatographic analysis of 10 diterpenoid compounds in Salvia miltiorrhiza using central composite design.

J Agric Food Chem. Simultaneous determination of eight flavonoids and pogostone in Pogostemon cablin by high performance liquid chromatography. J Liq Chromatogr Relat Technol. Food Chem. Quality evaluation of semen oroxyli through simultaneous quantification of 13 components by high performance liquid chromatography.

Curr Pharm Anal. Rapid simultaneous determination of isoflavones in Radix puerariae using high-performance liquid chromatography-triple quadrupole mass spectrometry with novel shell-type column. J Sep Sci. Optimization of polyphenols extraction from dried chokeberry using maceration as traditional technique. Catechin-based extract optimization obtained from Arbutus unedo L. Ind Crops Prod. Optimization of the extraction process of polyphenols from Thymus serpyllum L. Sep Purif Technol.

Microwave-assisted extraction of flavonoids from Cajanus cajan leaves. Study on comparison of extracting fucoxanthin from Undaria pinnatifida with percolation extraction and refluxing methods. Zhongguo Shipin Tianjiaji. Optimization of the technology of ethanol extraction for Goupi patch by orthogonal design test.

Zhongguo Yaoshi Wuhan, China ; 11 1 — Study on optimizing the technological condition of ethanol percolating extraction for Goupi patch. Zhongguo Yaoshi. J Pharm Biomed Anal. Hydrolysis of glycosidic flavonoids during the preparation of Danggui Buxue Tang: an outcome of moderate boiling of chinese herbal mixture.

Evid Based Complement Altern Med. Biomed Chromatogr. Kongkiatpaiboon S, Gritsanapan W. Optimized extraction for high yield of insecticidal didehydrostemofoline alkaloid in Stemona collinsiae root extracts. Zhang L. Comparison of extraction effect of active ingredients in traditional Chinese medicine compound preparation with two different method. Heilongjiang Xumu Shouyi. The study on optimization of Soxhlet extraction process for ursolic acid from Cynomorium. Shipin Yanjiu Yu Kaifa. Tea polyphenols and alkaloids content using soxhlet and direct extraction methods.

World J Agric Sci. Pressurized liquid extraction and GC—MS analysis for simultaneous determination of seven components in Cinnamomum cassia and the effect of sample preparation.

Fast determination of five components of coumarin, alkaloids and bibenzyls in Dendrobium spp. A novel strategy for rapid quantification of 20 S -protopanaxatriol and 20 S -protopanaxadiol saponins in Panax notoginseng , P. Nat Prod Res. Effect of pressurized hot water extraction on antioxidants from grape pomace before and after enological fermentation. Pressurized acidified water extraction of black carrot [ Daucus carota ssp. Eur Food Res Technol. CO2-supercritical extraction, hydrodistillation and steam distillation of essential oil of rosemary Rosmarinus officinalis J Food Eng.

Supercritical fluid extraction of vinblastine from Catharanthus roseus. J Supercrit Fluids. Green alternative methods for the extraction of antioxidant bioactive compounds from winery wastes and by-products: a review. Trends Food Sci Technol. Ultrasound assisted extraction of food and natural products.

Mechanisms, techniques, combinations, protocols and applications. A review. Ultrason Sonochem. Simultaneous determination of six saponins in Panacis Japonici Rhizoma using quantitative analysis of multi-components with single-marker method.

Comparative study on extraction of febrifugine from traditional Chinese medicine Dichroa febrifuga by reflux method and ultrasonic method. Shizhen Guoyi Guoyao. Chemat F, Cravotto G. Microwave-assisted extraction for bioactive compounds. Boston: Springer; Ultrasonically assisted extraction UAE and microwave assisted extraction MAE of functional compounds from plant materials.

Chen H. Optimization of microwave-assisted extraction of resveratrol from Polygonum cuspidatum sieb et Zucc by orthogonal experiment. Nat Prod Indian J. Enhanced solvent-free microwave extraction of Foeniculum vulgare Mill. Arabian J Chem Optimization of microwave-assisted extraction of bioactive alkaloids from lotus plumule using response surface methodology.

J Pharm Anal. A method of extracting ginsenosides from Panax ginseng by pulsed electric field. The cannabis industry has been chasing the shiny object of legalization for so long that we never stopped to think about what to do with it once we achieved it.

How do we prepare for the time when normal economic forces take over and production costs and product offerings become a concern? While most of the industry will keep rushing, I will stop and think. I will stop and think about the fundamentals, about how to achieve expertise and excellence, and most importantly, how to leverage what we learned in order to produce the right products in this new market. And I hope that many of you will join me, because the green-hued crumbles and black oils of the present will not secure success in a legal market for long.

Markus Roggen is the vice president of extraction at OutCo. He has a Ph. More information can be found at outco. Home Opinion Now is the time to stop and think about extraction, cultivation methods.

October 30, Share on Pinterest Share. Share on Facebook Share. Share on Twitter Tweet. Share on LinkedIn Share. Send email Mail. Markus Roggen, Ph. You may also like. Living the Dream: Danielle Rosellison October 27, Success as a cannabis retailer October 13, Living the Dream: Danielle Rosellison October 7, Living the Dream: Courtney Bailey October 3, Living the Dream: Greta Brandt September 26, Living the Dream: Graham Farrar September 19, Cannabis 2.

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