Razak, Nur Qistina Abdul
(2024)
Synthesis Of Choline Chloride-acetic
Acid Based Deep Eutectic Solvent (Des)
For The Extraction Of Bioactive
Polysaccharide From Garcinia
Atroviridis Fruit.
Masters thesis, Universiti Sains Malaysia.
Abstract
The fruit of Garcinia atroviridis was identified as a potential source of
bioactive polysaccharides. This study explored the ability of these polysaccharides
(referred to as GAP) to inhibit pancreatic lipase and angiotensin-converting enzyme
(ACE), both of which are important in managing obesity and hypertension. The
extraction of GAP was optimized using a microwave-assisted process involving deep
eutectic solvents (DES). The study was promoted to prepare deep eutectic solvents
(DES) from choline chloride and acetic acid in 1:2, 1:3, 1:4. The physicochemical
properties of the resulting DES were fully characterized. The interaction of the DES
components by hydrogen bonds was confirmed using Fourier-transform infrared
spectroscopy (FTIR) and changes in wavenumbers of their functional groups.
Moreover, these DES were shown to be hydrophilic and could dissolve in water with
high polarity while having compatibility with many of semi-polar solvents. the DES
demonstrates excellent potential for extraction applications due to its low pH and polar
nature. Therefore, DES is a promising medium for extracting GAP. The yield of GAP
was then extracted and the result concluded that the experimental yield of GAP
(24.33%) closely matched the predicted yield (24.88%), confirming the accuracy of
the extraction model. GAP was found to have a high molecular weight (28.15 ± 3.17
kDa) and viscosity (3.171 ± 1.23 Pa·s), along with a significant branching size (6.39 ± 0.030). These characteristics suggest that GAP can form complex structures that
effectively inhibit enzyme activity by physically blocking the enzymes from accessing
their substrates, thereby slowing down their function. In laboratory tests, GAP
demonstrated significant inhibitory effects, reducing pancreatic lipase activity by
79.41% and ACE activity by 81.23%. These results indicate that GAP has strong
potential for use in developing anti-obesity and antihypertensive treatments. Further
optimization of GAP's bioactivity led to even better results, with optimized GAP
inhibiting pancreatic lipase (GAP-L) by 87.93% and GAP that inhibits ACE (GAP-A)
by 95.91%. The experimental values closely aligned with the predicted values (86.57%
for pancreatic lipase inhibition and 95.64% for ACE inhibition), further validating the
model. Therefore, GAP shows great promise as a potential source for developing
effective agents to manage obesity and hypertension. The suitability of the DES
produced as well shown to have a polar nature, making it capable of interacting with
and dissolving a wide range of polar compounds, including polysaccharides and other
bioactive molecules.
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