1. Physicochemical Properties and Antibacterial
Activity of Castor Oil and Its Derivatives
Muh. Iqbal Fitranda1, Sutrisno1*, Siti Marfuah1
1Chemistry Department, State University of Malang, Indonesia
*Corresponding author: sutrisno.kimia@um.ac.id
4. The classification of Triglyceride
Saturated triglyceride (fat)
1
i.e Unsaturated triglyceride (oil) i.e fish oil, vegetable oil
2
Vegetable oil can be classified as edible oil and non edible oil
One of the non edible oil and abundant oil is castor oil
5. Castor Oil 1. Castor oil can be obtained by pressing or extracting castor bean seeds.
2. Castor oil extract from seeds contains 40-55% oil, a very high potential compared to
most other commonly used oil plants
3. The content of fatty acids in castor oil is different from typical oils in general, namely
80-90% hydroxyl fatty acids, ricinoleic acid
Tree Leaf Seed Oil
Fruit
Structure of ricinoleic acid
6. Castor oil can be transformed to derivatives such as K-soap, free fatty acids and fatty acid methyl esters
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7. Current
research of
castor oil and
its derivatives
Evaluation of the Antimicrobial and Phytochemical Properties of
Oil from Castor Seeds (Ricinus communis Linn) (Momoh, 2012)
Synthesis and Bioactivity of (R)-Ricinoleic Acid Derivatives: A
Review (Kula, 2016)
Antioxidant activities of methyl ricinoleate and ricinoleic acid.
(Oloyede, 2012)
The current research has been done about it but is limited to single or pure compounds while for
K-soap, free fatty acids and fatty acid methyl esters of castor oil has never been reported.
The objective of research are transformation castor oil into k-soap, free fatty acids, methyl
esters and their antibacterial activity against gram-negative (E. coli) and gram-positive (S.
aureus) bacteria.
8. Castor Oil
Saponification
(KOH (aq))
K-soap Fatty acids Methyl esters
Transesterification
(CH3OH / KOH)
Acidification
(HCl)
Characteristics of K-soap, Fatty
acids, and Methyl esters
Diameter of the Inhibition Zone of
Castor Oil Derivatives
Tested antibacterial activity against
gram-negative (E. coli) and gram-
positive (S. aureus) bacteria
Research Method
Characterized of physico chemical
properties
IR analysis)
9. Characterization and Identification of Castor Oil and Its
Derivatives
Characterization
1. Physical Properties: state, color, boiling point (liquid), melting point (solid),
refractive index, viscosity, and density.
2. Chemical Properties: solubility, acid values, saponification value and ester
value.
Identification
1. Interpretation of IR spectrum
10. Physicochemical Properties of Castor Oil and Its Derivatives
No. Characteristics Castor Oil K-soap Fatty Acid Methyl Ester
1. State Liquid Solid Liquid Liquid
2. Color Yellow White Yellow Yellow
3. Boiling point (oC) 191 - 210 170
4. Melting point (oC) - 168-175 - -
5. Refractive index (25 oC) 1.477 - 1.462 1.461
6. Viscosity (cSt) 520.52 - 693.22 27.31
7. Density(g/cm3) 0.96 - 0.98 0.92
11. Continue...
No. Characteristics Castor Oil K-soap Fatty Acid Methyl Ester
8. Solubility
- Water
- Methanol
- Ethanol
- Chloroform
- n-Hexane
not soluble
not soluble
not soluble
soluble
not soluble
soluble
soluble
soluble
not soluble
not soluble
not soluble
soluble
soluble
soluble
not soluble
not soluble
soluble
soluble
soluble
soluble
9. Acid value (mg KOH/g
sample) 1.23 - 145.88 0.33
10. Saponification value
(mg KOH/g sample) 406.72 - 294.52 392.70
11. Ester value (mg KOH/g
sample) 405.49 - 148.64 392.37
12. IR Spectrum Interpretation of Castor Oil and Its Derivatives
Vibration
Wave number (cm-1)
Castor Oil K-soap Fatty Acid Methyl Ester
Stretch O-H 3360.00 -
3408.22
3388.93
3419.79
Stretch C=O 1745.58 - - 1741.72
C-H alkene 3007.02 3008.95 3010.88 3007.02
13. Antibacterial Activity Of Castor Oil’s Derivates
Type of Bacteria
Clear Zone Diameter (mm)
Negative
Control
K-soap Fatty Acid Methyl Ester
1 % 2 % 1 % 2 % 1 % 2 %
E. coli - 18.80 18.90 15.75 17.45 - 8.15
S. aureus - 14.65 16.90 13.25 16.35 - 8.75
14. Conclusion
1. Physicochemicals properties of castor oil are liquid, yellow, density 0.96 g.mL-1 ,
refraction index 1.477, viscosity 520.52 cSt, boiling point 191 oC, and the value of
acids, saponification, and esters are 1.23, 406.72, 405.49 .
2. Physicochemicals properties k-soap of castor oil (synthesized result) are solid, white,
melting point 168–175 oC)
3. Physicochemicals properties (free) fatty acids of castor oil (hydrolysis result) are
liquid, yellow, density 0.98 g.mL-1 , refraction index 1.462, viscosity 693.22 cSt, boiling
point 210 oC, and the value of acids, saponification, and esters are 145.88, 294.52,
148.64.
4. Physicochemicals properties fatty acids methyl esters of castor oil (transesterification
result) are liquid, yellow, density 0.98 g.mL-1, refraction index 1.461, viscosity 27.31 cSt,
boiling point 170 oC, and the value of acids, saponification and esters are 0.33, 392.7,
392.37.
5. K-soap, (free) fatty acids, and methyl esters from castor oil have antibacterial activity
against Escherichia coli and Staphylococcus aureus bacteria
16. Synthesis of K-soap
Slippery and foamy (K-soap)
20 g castor oil
- Put in a three neck flask
- Added 130 mL of 14.47% KOH solution
- Heated at ± 80 oC while stirring using a magnetic stirer. Heating
and stirring are stopped when no more foam is formed (± 3 hours).
- Let the temperature reach room temperature.
Mixture of k-soap
Top layer: k-soap
Bottom layer:
residual KOH and
unreacted oil.
- Separated using separating funnels
- Formed two layers above and below
- Organoleptic tested (caustic test
and saponification test)
17. K-soap (soft)
- 50 mL saturated NaCl solution was added.
- Stirring with a magnetic stirer until all the soap is deposited.
K-soap precipitate + saturated NaCl solution
- Washed with 20 mL of distilled water.
- Wash again with 10 mL of distilled water.
Residue
- Heated in the oven at 60 oC for 2 hours
- Mashed with mortar and pastle
K-soap (powder)
Filtrate
- Filtered with filter paper
K soap (solid)
18. Synthesis Free Fatty Acid
Emulsion
Residue: lumps Filtrate: HCl
residue
- 1 M HCl solution is added dropwise to form two layers and
the solution is acidic
- Filtered with filter paper
10 gram k-soap
- Added distilled water until all soap is emulsified (+ 10 mL)
Lumps + residual HCl
19. Continue..
Residue
Residue + water
- Wash with distilled water until the washing water is neutral
- Centrifuged at 3000 rpm for 20 minutes
- Separated with a dropper pipette
- Left at room temperature for 24 hours
Fluid + water
Centrate: water
Residue: Free Fatty Acid
20. Synthesis Fatty Acid Methyl Esters
Residual solvents,
reagents, and catalysts
- Put in a three neck round bottom flask.
- 0.2 g KOH added in 15 mL methanol p.a.
- Heated at 65 oC while stirring with a magnetic stirrer for 4 hours.
20 gram castor oil
Chocolate micture
- Separated with separating funnel.
Top layer Bottom layer
- Tested acidity.
- Tested solubility.
- Tested flash
Ester compound
- Tested acidity.
- Tested solubility.
- Tested flash
21. Continue
- Wash with warm water until the washing water is neutral.
Filtrate: water-free methyl
ester
- Added anhydrous MgSO4
Methyl esters + reagents and catalysts
Methyl esters
Residue: MgSO4
- Separated by filtration using fine filter paper.
Methyl esters + anhydrous MgSO4
22. 10 gram Nutrient Agar (NA) instant
- Dispersed in 250 mL of distilled water.
- Heated while continuing to stir until the
mixture is homogeneous.
- Pour into 10 ml petri dishes each.
- Sterilized by autoclaving at 115 oC for 15
minutes.
- The temperature and pressure are lowered
until it reaches the ambient condition.
- Leave it until the media becomes solid.
Nutrient Agar (NA) Solid Media
a. Media Making b. Making Suspension of S. aureus and E. coli
Bacteria
1 ose Bakteri S. aureus dan E. coli
- Put in 10 mL Nutrient Borth (NB) in a
different test tube.
- Divortex to homogeneous mixture.
Suspension of S. aureus and E. coli
bacteria.
Antibacterial Activity Test
23. 20 µL sample
- Inserted into a 6 mm diameter well that has been inoculated with gram-
positive (S. aureus) and gram-negative (E. coli) bacteria.
- Incubated at 37 oC for 24 hours.
- The diameter of the clear zone is measured with calipers.
Clear Zone Diameter (mm)
c. Inhibition Test
24. Interpretation of IR Castor Oil
3360 cm-1
(-OH)
3007,02 cm-1
(C-H alkena)
1745,58 cm-1
(C=O)
