MODERN EXTRACTION TECHNOLOGIES notes.ppt

Preparation of medicinal plants for experimental purposes is an initial step and key in achieving quality research outcome. It involves extraction and determination of quality and quantity of bioactive constituents before proceeding with the intended biological testing. The primary objective of this study was to evaluate various methods used in the preparation and screening of medicinal plants in our daily research. Although the extracts, bioactive fractions, or compounds obtained from medicinal plants are used for different purposes, the techniques involved in producing them are generally the same irrespective of the intended biological testing. The major stages included in acquiring quality bioactive molecule are the selection of an appropriate solvent, extraction methods, phytochemical screening procedures, fractionation methods, and identification techniques. The nitty-gritty of these methods and the exact road map followed solely depends on the research design. Solvents commonly used in extraction of medicinal plants are polar solvent (e.g., water, alcohols), intermediate polar (e.g., acetone, dichloromethane), and nonpolar (e.g., n-hexane, ether, chloroform). In general, extraction procedures include maceration, digestion, decoction, infusion, percolation, Soxhlet extraction, superficial extraction, ultrasound-assisted, and microwave-assisted extractions. Fractionation and purification of phytochemical substances are achieved through application of various chromatographic techniques such as paper chromatography, thin-layer chromatography, gas chromatography, and high-performance liquid chromatography. Finally, compounds obtained are characterized using diverse identification techniques such as mass spectroscopy, infrared spectroscopy, ultraviolet spectroscopy, and nuclear magnetic resonance spectroscopy. Subsequently, different methods described above can be grouped and discussed according to the intended biological testing to guide young researchers and make them more focused.

Keywords: Chromatography, extraction, fractionation, isolation, medicinal plants
Go to:
Introduction
Medicinal plants are extracted and processed for direct consumption as herbal or traditional medicine or prepared for experimental purposes. The concept of preparation of medicinal plant for experimental purposes involves the proper and timely collection of the plant, authentication by an expert, adequate drying, and grinding. This is followed by extraction, fractionation, and isolation of the bioactive compound where applicable. In addition, it comprises determination of quantity and quality of bioactive compounds.[1,2,3,4,5] Recently, plant as a source of medicine is gaining international popularity because of its natural origin, availability in local communities, cheaper to purchase, ease of administration, and perhaps less troublesome. Also, herbal medicine may be useful alternative treatment in case of numerous side effects and drug resistance.[1,2,3,4,5] Extrac

1. EXTRACTION: The first stop in the “plant to drug
pathway” which needs serious attention
Theaimsofmedicinalplant
researchcanbesummarizedas
follows
qualitativeandquantitative
analysisoftheconstituentsof
medicinalplants;
isolationofplant-originated,
biologicallyactive,purified
fractionsandmoleculeswithnew
structures;
optimizationoftheamountand/or
ratioofmedicinalplant
compounds responsiblefor
therapeuticeffects.
Theentireobjectiveof
medicinalplantresearch
canbejeopardizedifthe
sample preparation
methodiscompromised
1

2. Classical Techniques
Maceration
Soxhlet
Reflux
Percolation
Distillation
2
•organic solvent
consumption
•SampleDegradation
•specificity
•additionalsample
clean-up and
concentrationsteps
before
chromatographic
analysis
•extractionefficiency,
selectivity,and/or
Kineticsandeaseof
automation

3. Soxhletmodifications
3

4. 4

5. Green Extraction is based on the discovery and design of
extraction processes which will reduce energy consumption,
allows use of alternative solvents and renewable natural
products, and ensure a safe and high quality extract/product.
Principlesofgreenextraction
Principle1:Innovationbyselectionofvarietiesanduseof
renewableplantresources
Principle2:Useofalternativesolventsandprincipally
wateroragro-solvents
Principle3:Reduceenergyconsumptionbyenergy
recoveryandusinginnovativetechnologies
Principle4:Reduceunitoperationsandfavoursafe,robust
andcontrolledprocesses
5

6. Principle 1: Innovation by the Selection of Varieties
and the Use of Renewable Plant Resources
Theincreasingdemandofnaturalproductsandextractsis
leadingtotheover-exploitationofnaturalplantresources.
Historyreportsseveralexamplesofplantextinctionbecauseof
overutilization;thepreservationofbiodiversityistherefore
mandatoryintherespectoffuturegenerations.Ingreen
extraction,fullyrenewableresourceshavetobefavouredeither
withintensivecultivationorinvitrogrowthofplantcellsor
organisms.
6

7. Theanti-cancerpaclitaxel(Taxol®)extractedfromthebarkof
thewesternyew(Taxusbrevifolia)isthebestknownexample.
Duringthe1970snotlessthan30tonnesofbarkwere
collectedforclinicaltrials:10kgofdrybarkproduceonly1
goftaxolafterextractionandpurification.Alargenumber
ofresearchprojectshavethereforebeenaimedatfinding
alternativestofellingtreesofthisthreatenedspecies.Since
1980paclitaxelanddocetaxol(Taxotere®)arepreparedby
semisynthesisfromthenaturalprecursor,10-deacetylbaccatine
III,extractedfromneedlesandbranches(renewableresource)
ofdifferentyewtreespecies.
7

8. Principle 2: Use of Alternative Solvents and
Principally Water or Agro-Solvents Issued from
Agricultural Resources
Currentregulationshaveaprogressivedirectimpactindiminishingthe
consumptionofpetrochemicalsolventsandVolatileOrganicCompounds
(VOCs).Manufacturersthatuseorganicsolventshavetoshowtheabsence
ofriskduringextractionandtodemonstratethesafetyofingredientsas
regardstosolventtraces.
Mostorganicsolventsareflammable,volatile,andoftentoxicandare
responsibleforenvironmentalpollutionandthegreenhouseeffect.
Safety,environmentalandeconomicalaspectsareforcingindustrytoturnto
greenersolvents.Amonggreensolvents,theagro-orbio-solventsplayan
importantroleforthereplacementofpetrochemicalsolvents.
Theyarearenewableresourceproducedfrombiomassessuchaswood,
starch,vegetableoilsorfruits.Thesebio-solventshaveahighsolvent
power,arebiodegradable,non-toxicandnon-flammable.
8

9. 9Alternative solvents for green extraction

10. Principle 3: Reduce Energy Consumption by Energy
Recovery and Using Innovative Technologies
Hydrodistillationisanancienttechniqueforextractionof
essentialoils.Itisusedworldwideforitssimplicitybut
requireshighenergyconsumptionforheatingandcooling.
Whentheprocessiscarriedoutundermoderatepressure,
distillationtimeisreducedbyafactorof2or3,withareduced
consumptionofsteamandhencereducedenergyconsumption.
Somearomaticplantssuchassandalwood,cloves,orthe
rhizomesofgingerandiris,needmorethan24hourswith
atmosphericdistillationbutlessthan3hourswithpressure
steam-distillationat0.5MPa.
10

11. Principle 4: Reduce Unit Operations through
Technical Innovation and Favour Safe, Robust and
Controlled Processes
Tobecompetitiveindustriesinvolvedinextractionofnatural
products(perfume,cosmetic,pharmaceutical,food,andbio-fuel)
havetocombineprocessintensificationwithcleanerandsafer
extractionprotocols.Processintensificationcoversalldevelopments
ofthenewequipment,techniques,orproceduresthatbring
significantprogressincomparisonwiththecurrentproduction
methods.Developmentofintensifiedprocesseswillleadtocompact
productionunitsandareducednumberofunitoperations,energy
andrawmaterialsavings,processsafetycontrol,reductioninwaste
andecologicalfootprint.
Extractioninvolvesmultiplesteps
Portabilityofextractionset-up
11

12. Steps of extraction
Theextractionandrecoveryoftheanalytefromthesamplematrixcanbe
expressedinfewsteps.Initially,tobeabletoremovetheanalytefromthe
extractionvessel,
Thecompoundisfirstdesorbedfromitssiteinthesamplematrix,
Thenitisdiffusedthroughtheorganicpartofthematrixtobeableto
reachthematrix–fluidinterface.Atthisstagetheanalyteisdistributed
intotheextractionphase,
Thenitdiffusesthroughtheextractionphase,thereafteritreachesthe
partoftheextractionphasethatisaffectedbyconvection
Thefinalstageoftheextractionprocessiscollectionoftheextracted
analyte
12

13. 13

14. Inenvironmentalapplications,
desorptionstepisusuallytherate-limitingstep,since
solute–matrixinteractionsaredifficulttoovercome,for
exampleinnaturalsediments,soilsandsludge.
Inplantmaterials,
therate-limitingstepismorecommonlythesolubilization
orthediffusionsteps
14

15. Microwave assisted extraction: Basic set-up and
principle
15

16. Microwavesaremadeoftwooscillatingperpendicular
fields–electricfiledandmagneticfield
Theprincipleofheatingisbasedontwoprinciples
whichusuallyoccurssimultaneously
Ionicconduction
Dipolerotation
16

17. 17

18. My expereinces with Microwave assisted extraction
18
Plant material
Microwave
irradiation
HPTLC/HPLC
quantification
Extraction
conditions
optimised
Process
reproducibility
check
Comparison with
conventional
techniques
Optimization
parameters
•Extraction time
•Microwave
power
•Preleaching
•Solvent nature
•Matrix
characteristics
•Loading ratio
•Extraction cycle

19. 19
Normal sample Heat refluxed sample

20. 20
Microwave treated sample

21. 21

22. 22
Extraction method Extraction time Solvent volume R.S.D (%) Response
MAE 4 min 40 ml 3.5 (n=5) 5.55
Maceration 24 hrs 40 ml 14.5 (n=5) 1.20
Soxhlet 24 hrs 300 ml 8.4 (n=5) 4.37
Stirring extraction24 hrs 40 ml 12.1 (n=5) 1.56100
21.62
78.73
28.1
0 25 50 75 100
'MAE
Maceration
Soxhlet
Stirring extraction'
Extraction methods
Extraction rate
Extraction rate
MAE results of curcumin

23. Environmental impact
Theenergyrequiredtoperformthetwoextractionswas1.8kWh
forheatrefluxextractionand667×10
−4
kWhforMAE.The
powerconsumptionwasmeasuredwithawattmeteratthe
microwavegeneratorentranceandtheelectricalheaterpower
supply.Withregardtoenvironmentalimpact,thequantityof
carbondioxidereleasedtotheatmospherewas1440gCO
2g
−1
extractforheatrefluxextraction(calculatedonthebasisthat
obtaining1kWhenergyfromcoalorfuelwillrelease800g
CO
2totheatmosphereduringcombustionoffossilfuel).This
isalarminglymorethanthe53.336gCO
2g
−1
extractforMAE.
23

24. Ultrasound assisted extraction
Theenhancementofextractionefficiencyoforganic
compoundsbyultrasoundisattributedtothepheomenonof
acousticcavitation.Theyinvolveexpansionandcompression
cyclesduringtravelinthemedium.Expansionpullsmolecules
apartandcompressionpushesthemtogether.Theexpansion
cancreatebubblesinaliquidandproducenegativepressure.
Thebubblesform,growandfinallycollapse.Closetoasolid
boundary,cavitycollapseisasymmetricandproduceshigh-
speedjetsofliquid.Theliquidjetshavestrongimpactonthe
solidsurfacecalledacousticcavitation.
24

25. 25
Types of sonication

26. 26
Commonly used ultrasonic systems

27. My expereinces
with UAE
Hencethefinalrobust
optimumextractionconditions
forUAEwasconcludedtobe
as:70minextractiontime,
ethanol(80%v/v)asthe
extractingsolvent,particles
screenedthroughsieve20and
solventvolume20ml.
Extraction
method
Extraction
time
Solvent
volume
R.S.D (%) Response
Maceration 24 hrs 50 ml 14.5 (n=5) 1.20
Soxhlet 4 hrs 100 ml 8.4 (n=5) 2.64
Stirring
extraction
UAE
24 hrs
70 min
50 ml
20 ml
12.1 (n=5)
4.9 (n=5)
1.56
3.96
27
Comparison

28. Solid phase extraction
28

29. Contributions towards developing PharmaExcellence
by the Pharmacognosyand PytotherapyReseach
Group
Journal Pharmaceutical and Biomedical Analysis (Elsevier, Netherlands),46(2): 322-327,
2008 [Impact Factor: 2.9].
Planta Medica, 74(09): SL46, DOI: 10.1055/s-0028-1083926, 2008. [Impact Factor 2.15].
Cited in Pubmed, Science Citation Index (SCI), JCR, Scopus
Natural Product Communications (USA),4(8): 1047-1052, 2009 [Impact Factor: 1.2],
Cited in Pubmed, Science Citation Index Expanded, JCR, Scopus.
Biochemical Engineering Journal (Elsevier),50: 63-70, 2010 [Impact factor 2.6]
Phytochemical Analysis (John Willey & Sons),DOI 10.1002/pca.2403 [Impact Factor 2.6].
Phytochemical Analysis (John Willey & Sons),20(6): 491-497, 2009 [Impact Factor 2.6].
Cited in Pubmed, ScienceCitation Index (SCI), JCR, Scopus.
Patents: 02
Books: 01
29

30. Updates
International Conference and Exhibition on Pharmacognosy,
Phytochemistry & Natural Products
Accelerating plant based drug discovery for safer drug development
Dates: October 21-23, 2013,
Venue: Hyderabad
Plant Biotechnology and Tissue Culture
Evaluation and Identification of Phytoconstituents
Analytical Techniques in Phytochemistry
Herbal Drugs and Formulations
Drugs from Natural Sources
Toxicology Studies of Plant Products
Ethnopharmacology
Phytochemistry and Phytoconstituents
Industrial Pharmacognosy
Natural products of medicinal interest
Crude Drugs and Plant Poducts
Ayurvedic System of Medicine
30

31. Registration fees (INR)
Upto January 24, Upto May 2, On October 21, 2013
1 Students 1500 ` 2000 ` 2500
2 Research Scholars 2000 ` 2500 ` 3000
3 Faculty Members4000 ` 5000 ` 6000
4 Industry Professionals 6000 ` 7000 ` 8000
31

32. Job dates
FacultyopeninginBITSPilani
FacultyopeninginDoonUniversity
FacultyopeninginCentralUniversityofPunjab
StaffandscientistopeningatRajibGandhicenterfor
Biotechnology,Kerala
FacultyopeningatIECGroupofInstitutions,greater
Noida
SCIENTIFIC GROUP LEADER (FACULTY)
RECRUITMENT at CENTRE FOR DNA
FINGERPRINTING ANDDIAGNOSTICS,Hyderabad
32

33. 33
Thank you