Extraction of Nonionic Natural Surfactants (saponin) From Ginseng
Medical Plant
b , A. Bahramian a , S. Golafshan *,a , B. Sohrabi M. Rashidia
a Department of Chemistry, Surface Chemistry Research Laboratory, Iran University of Science and
Technology, P.O. Box 16846-13114, Tehran, Iran.
b Institute of Petroleum Engineering, School of Chemical Engineering, College of Engineering, University of
Tehran, Karegar Street, Tehran, Iran
Abstract:
In this study, nonionic surfactants were extracted from ginseng. The extraction of these
surfactants from the plant was done by soxhlet. After the extraction, we used FT-IR
spectroscopy for characterization of extracted saponin. Rates of change of water surface tension
in terms of these surfactants concentration were obtained at 25℃. It shows that saponin as a
surfactant decreased the surface tension of water. After that, the critical micelle concentration
of these surfactants was obtained by curve of change of water surface tension in terms of change
of these surfactants concentration.
Keywords: ginseng, nonionic surfactant, surface tension, critical micelle concentration
Introduction:
So far, many efforts to replace natural surfactants have been conducted in various processes.
However due to the low efficiency of some products, this products are not economically. So
replacing plant surfactants is further used due to having chemical surfactants and other natural
advantages and high production efficiency. Saponin is a kind of these natural surfactants.
Saponin is a kind of nonionic natural surfactant that can be found in many plant species.
Saponins are a major group of plant secondary metabolite. They are glycosides with high
molecular weight. Figure 1 shows two group of saponin chemical structure that include
triterpenoids and steroids [1-2].
1
Fig1. a) Structures of steroide saponin b) triterpenoide saponin
Saponins in addition to having the capability of chemical surfactants can also be selfdecomposable
[3].
There are more than 500 medicine plants in the world that they are having these nonionic
surfactants. Figure 2 shows the picture of one of the most common of this plants that is Asian
ginseng or Korean ginseng.
The main components of ginseng are triterpenoid saponins that they have been identified as an
agent with more versatile and useful effects including anti-inflammatory, antioxidant and
anticancer properties [4-5]. Figure 3 shows structure of these triterpenoid saponins.
Experimental:
Materials:
First, roots of Korean ginseng were purchased. Methanol as solvent and acetone as degreasing
were purchased from Merck Company and used as received.
Method of extraction:
First, certain amount of chopped roots of ginseng were put into the soxhlet in other to
degreasing by acetone for 4 hours. Then the residuum was placed into the oven at 40 ℃ for a
day. The degreased dry residuum was solved to mixture of methanol and water (3:2) at 70 ℃.
After that, the mixture was placed to the sonicator for 45 min. The obtained sample was spin
off and the residuum was placed into the soxhlet with mixture of methanol and water (3:2) as
solvent in other to complete extraction. The fluid obtained of centrifuges and soxhlet was
poured rotary evaporator in other to concentrate for 3 hours at 55 ℃. Finally, the crude saponin
were put to the fridge for future use [6]. Figure 4 shows the soxhlet system.
For characterization of extracted saponin, FT-IR shimadzu S8400 fourier transform infrared
spectrometer was used.
3
Surface tension measurement:
We measured the changes of surface tension of water with adding these saponins to the water.
For this work we used tensiometer sigma 700.
Result and discussion:
Figure 5 shows the FT-IR spectra of the gel and powder form of extracted saponin. The IR
spectra shows important absorption bands at 3354 cm-1
(attributed to OH stretching) , 2935
cm -1 (assigned to C−C overtone) and 1633-1662 cm -1 (assigned to C=C stretching).Those
peaks clearly shows that saponin have been extracted from ginseng.
Fig5. FT-IR spectra of extracted saponin
Figure 6 indicates changes in surface tension of deionized water by adding extracted saponins
at 25℃. By adding these kind of nonionic surfactants into the DI water, surface tension
decreased from 72.689