Recent Advances in Extraction

Extraction of Phytochemicals
recent advances in extraction
Choice of solvent
Selection of method
Successive and exhaustive extraction

1. Recent Advances in Extraction with Emphasis on Selection of M ethod & Choice of S olvent for Extraction, Successive & E xhaustive E xtraction. Kaustav Dey M. Pharm (Pharmacognosy) 1 st Sem UIPS, Panjab University

2. Contents What is Extraction ? Purpose & Benefits Selection of Method Choice of Solvent Traditional Method of Extraction Conventional Soxhlet Extraction Recent Advances in Extraction Ultrasound assisted extraction Microwave assisted extraction Supercritical fluid extraction Enzyme assisted extraction Successive & Exhaustive Extraction References

3. What is Extraction ? It is the separation of medicinally active portions of plant (and animal) tissues using selective solvents through standard procedures . The products so obtained from plants are relatively complex mixtures of metabolites, in liquid or semisolid state or in dry powder form (after removing the solvent), & are intended for oral or external use.

4. Purpose & Benefits P urpose of extraction of crude drugs :- To attain the therapeutically desired portions To eliminate unwanted material by treatment with a selective solvent known as “menstruum” The extract thus obtained, after standardization, may be used as medicinal agent as such in the form of tinctures fluid extracts further processed to be incorporated in any dosage form such as tablets and capsules

5. S election of Method Parameters for Selecting an Appropriate Extraction Method Authentication of plant material by botanist. Use the right plant part + the age of plant + the time, season & place of collection. The nature of its chemical constituents. Grinding methods & powdering techniques. Nature of constituents (polar/nonpolar). The quality of water / menstruum. The design & material of fabrication of the extractor. Analytical parameters of the final extract, (TLC/HPLC).

6. S election of Method Variation in extraction methods usually depends upon: Length of the extraction period Solvent used pH of the solvent Temperature Particle size of the plant tissues The solvent-to-sample ratio Scale

7. C hoice of Solvent Successful determination of biologically active compounds depends on the type of solvent used in the extraction procedure. The choice of solvent is influenced by what is intended with the extract. Properties of a good solvent in plant extractions :- low toxicity ease of evaporation at low heat promotion of rapid physiologic absorption of the extract preservative action inability to cause the extract to complex or dissociate.

8. The factors affecting the choice of solvent are: Quantity of phytochemical to be extracted Rate of extraction Diversity of different compounds extracted Diversity of inhibitory compounds extracted Ease of subsequent handling of the extracts Toxicity of the solvent in the bioassay process Potential health hazard of the extractants

9. Traditional Method of Extraction Maceration Percolation Decoction Digestion Infusion Hot continuous extraction (Soxhlet)

10. Conventional Soxhlet Extraction Form of continuous extraction Evaporation & condensation mechanism is followed Standard technique / used as a reference for evaluation of other techniques LIMITATIONS : Extraction time is long Large amount of solvent is used Agitation cannot be provided Possibility of thermal decomposition of the target compounds.

11. Recent Advances in Extraction Ultrasound-assisted extraction (UAE) Microwave-assisted extraction (MAE) Supercritical fluid extraction (SFE) Pulsed electric field extraction (PFE) Enzyme-assisted extraction (EAE) Pressurized liquid extraction (PLE) Molecular distillation Accelerated solvent Extraction (ASE) Phytonics process Headspace trapping techniques Static headspace technique Vacuum headspace technique Dynamic headspace technique

12. Recent Advances in Extraction Solid phase micro-extraction (SPME) Supercritical fluid extraction (SFE) Phytosol (phytol) extraction Protoplast technique Simultaneous distillation extraction (SDE) Controlled instantaneous decomposition (CID) Thermomicrodistillation Microdistillation Molecular spinning band distillation Membrane extraction Successive and Exhaustive Extraction (SEE) Counter current extraction (CCE) Hydrodistillation

13. Ultrasound-assisted Extraction Frequency ranges from 20 kHz to 100 MHz Waves passes through the medium causing compression and expansion giving rise to cavity which further leads in production, growth, and collapse of bubbles. It gives rise to temp. of 5000° C & 50 MPa due to the conversion of kinetic energy of motion Extraction mechanism- Diffusion across the cell wall Rinsing the contents of cell after breaking the walls

14. Contd... APPLICATION - A ntioxidants, pigments, lipids, phytochemicals and aromas extraction from fruits & vegetables intended for direct or indirect applications in food, pharmaceutical and cosmetic industries. BENEFITS – Inexpensive, simple and efficient I ncreased extraction rate and yield. Better reduction in particle size Reduce the operating temperature allowing the extraction of thermolabile compounds. Can be used as a hybrid form by clubbing with other extraction method e.g., Sono-Soxhlet, UAE+MAE Fig. 2. Effect of power ultrasound on spinach leaves. ( A : Comparison of chlorophyll extraction kinetics for UAE & for maceration

15. Microwave-assisted Extraction Microwaves are electromagnetic radiations with a frequency from 0.3 to 300 GHz. These are transmitted as waves, which can penetrate biomaterials and interact with polar molecules such as water to create heat and causing dehydration of cellulose present inside. This leads to reduction of its mechanical strength

16. Types of MAE Closed extraction vessels- performs extraction under controlled pressure & temperature Focused microwave ovens - only a part of the extraction vessel containing the sample is irradiated with microwave

17.   ADVANTAGES DISADVANTAGES CLOSED VESSEL SYSTEM Decreased extraction time High pressure poses safety risks No loss of volatile system Addition of reagent is impossible Less solvent required Vessel must be cooled down before opened No hazardous fumes       OPEN VESSEL SYSTEM Increased safety Less precise than the former Addition of reagent is possible Time consuming Ability to process large samples System cannot process samples simultaneously Suitable for thermolabile equipment Low cost equipment   No requirement for cooling down or depressurization  

18. Supercritical Fluid Extraction At a certain temp. and pressure condition, liquid & vapor phases of a substance become indistinguishable. This is known as Critical Point. Substances above critical point- Supercritical Fluid It is the process of separating one component from another (the matrix) using supercritical fluids as the extracting solvent . PROPERTIES OF SCF :- • Physical and thermal properties of SCFs are in between pure liquid and gas, hence can also be known as ‘ Compressible liquids ’ or ‘ dense gases ’ Changes in properties are for a SCF are as follows: – – Liquid like densities (100-1000 times greater than gases) – Diffusivities higher than liquids (10-3 and 10-4cm2/s) – Good solvating power

19. – Reduction in surface tension – Low viscosity (10-100 times less than liquid) – Gas like compressibility properties Therefore they posses high penetrating power Solvent of choice for SFE – CO2 Temperature - 304 K and 7.3 Mpa , non-flammable & non-toxic Used for extraction of non-polar compounds such as hydrocarbons To extract polar compounds , some polar supercritical fluids such as Freon-22, nitrous oxide and hexane have been considered. Use of co-solvent like methanol is seen to increase solubility of polar compound

20. Enzyme-assisted Extraction Some phytochemicals are retained in polysaccharide-lignin network by hydrogen bonding or hydrophobic interactions, rather than cytoplasm These are not accessible with a solvent in a routine extraction process. So, enzymatic pre-treatment has been considered as a novel and an effective way to release bounded compounds and also to increase overall yield. Enzyme used - cellulase, α- amylase, pectinase Types of Extraction process - 1. Enzyme-assisted aqueous extraction (EAAE) 2. Enzyme-assisted cold pressing (EACP)

21. EAAE methods have been developed mainly for the extraction of oils from various seeds In EACP technique, enzymes is used to hydrolyze the seed cell wall BENEFITS - Decreased solvent use during extraction is particularly important for both regulatory and environmental reasons, providing a ‘greener’ option than traditional non-enzymatic extraction. LIMITATIONS - the cost of enzymes is relatively expensive for processing large volumes of raw material enzyme-assisted extraction can be difficult to scale up to industrial scale because enzymes behave differently as environmental conditions such as the percentage of dissolved oxygen, temperature and nutrient availability vary.

22. Successive & Exhaustive Extraction It is another common method of extraction which involves successive extraction with solvents of increasing polarity from a non-polar (hexane) to a more polar solvent (methanol) to ensure that a wide polarity range of compound could be extracted. Some researchers employ Soxhlet extraction of dried plant material using organic solvent. This method cannot be used for thermolabile compounds as prolonged heating may lead to degradation of compounds

23. Figure- Venn diagram elucidate the overlapping of compounds belonging to different identified chemical groups between different extraction solvents.

24. Difference between Traditional & Successive & Exhaustive Extraction TRADITIONAL SUCCESSIVE & EXHAUSTIVE Single solvent Multi solvent Aqueous solvent Organic solvent Single polarity Variable polarity Less extraction efficiency More extraction efficiency Less hazardous More hazardous Simple but time Consuming Complex but faster Easy to operate Laborious operation Selective phytoconstituents gets extracted from one plant Maximum phytoconstituents gets extracted from one plant

25. References Recent advances in extraction of nutraceuticals from plants - Lijun Wang*and Curtis L. Weller - Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE 68583-0726, USA Recent advances in extraction of antioxidants from plant by-products processing industries - M. Selvamuthukumaran* and John Shi**-*Department of Food Science and Post Harvest Technology, Institute of Technology, Haramaya University, PO Box 138, Dire Dawa, Ethiopia and **Guelph Research and Development Center, Agriculture and Agri-Food Canada, 93 Stone Road West, Guelph, Ontario N1G 5C9, Canada Altemimi A, Lakhssassi N, Baharlouei A, Watson DG, Lightfoot DA. Phytochemicals: Extraction, Isolation, and Identification of Bioactive Compounds from Plant Extracts.  Plants . 2017 Sandra Pimentel-Moral, María de la Luz Cádiz-Gurrea, Celia Rodríguez-Pérez, Antonio Segura-Carretero,-Recent advances in extraction technologies of phytochemicals applied for the revaluation of agri-food by-products

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