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 Method &
Choice of Solvent for Extraction,
Successive & Exhaustive Extraction.
Kaustav Dey
M. Pharm (Pharmacognosy)
1st 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
Purpose 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. Selection 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. Selection 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. Choice 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 :
a. Extraction time is long
b. Large amount of solvent is used
c. Agitation cannot be provided
d. Possibility of thermal decomposition of the target
compounds.

11. Recent Advances in Extraction
1. Ultrasound-assisted extraction (UAE)
2. Microwave-assisted extraction (MAE)
3. Supercritical fluid extraction (SFE)
4. Pulsed electric field extraction (PFE)
5. Enzyme-assisted extraction (EAE)
6. Pressurized liquid extraction (PLE)
7. Molecular distillation
8. Accelerated solvent Extraction (ASE)
9. Phytonics process
10. Headspace trapping techniques
○ Static headspace technique
○ Vacuum headspace technique
○ Dynamic headspace technique

12. Recent Advances in Extraction
11. Solid phase micro-extraction (SPME)
12. Supercritical fluid extraction (SFE)
13. Phytosol (phytol) extraction
14. Protoplast technique
15. Simultaneous distillation extraction (SDE)
16. Controlled instantaneous decomposition (CID)
17. Thermomicrodistillation
18. Microdistillation
19. Molecular spinning band distillation
20. Membrane extraction
21. Successive and Exhaustive Extraction (SEE)
22. Counter current extraction (CCE)
23. 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-
• Antioxidants, 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
• Increased 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

21. 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)

22. • 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 -
a) the cost of enzymes is relatively expensive for
processing large volumes of raw material
b) 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.

23. 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

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

25. 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

26. 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