Potential antioxidant and anti-inflammatory effects of Erythroxylum cuneatum (Miq.) Kurz leaf extract against oxidised low-density lipoprotein in human aortic endothelial cell
Oxidative stress and inflammation are known to be associated with the pathogenesis of most chronic diseases such as atherosclerosis, cancer and diabetes. Medications like nonsteroidal anti-inflammatory drugs are commonly used to treat the diseases but are accompanied by adverse effects. Erythroxy...
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| Format: | Thesis |
| Language: | English |
| Published: |
2020
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/113793/1/113793.pdf http://psasir.upm.edu.my/id/eprint/113793/ |
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| Summary: | Oxidative stress and inflammation are known to be associated with the pathogenesis of
most chronic diseases such as atherosclerosis, cancer and diabetes. Medications like nonsteroidal
anti-inflammatory drugs are commonly used to treat the diseases but are
accompanied by adverse effects. Erythroxylum cuneatum (EC), also known locally as
“Chinta mula”, belongs to the Erythroxylaceae family. Scientific evidence for the
medicinal properties of the plant is still limited. Therefore, this study aims to determine
the antioxidant and anti-inflammatory properties of EC leaf extract for the prevention of
atherosclerosis in vitro. The study was divided into two phases. The first phase is
screening of EC leaf extract using four solvents, namely acetone, water, hexane and
ethanol. The four different types of EC leaf extracts were analysed for preliminary
phytochemical screening individually. The antioxidant activity was tested by total
phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydrogen peroxide
(H2O2)-scavenging activity. Based on Phase 1 results, acetone and ethanol extracts were
chosen to test the antioxidant and anti-inflammatory properties in vitro with oxidised
low-density lipoprotein (oxLDL)-induced human aortic endothelial cells (HAoEC). Cell
viability assay of EC leaf extract was conducted to determine the number of viable cells
by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay.
Antioxidant activity was determined by thiobarbituric acid reactive substances (TBARS)
assay, reactive oxygen species (ROS) assay and nitric oxide (NO) production assay. The
anti-inflammatory effects of EC leaf extract in HAoEC were determined by U937 cell
monocyte adhesion and migration assay. The expression of adhesion molecules, namely
human soluble intracellular adhesion molecule-1 (ICAM-1) and human soluble vascular
cell adhesion molecule-1 (VCAM-1) were quantified using ELISA kit. Phase 1 results
showed the presence of alkaloids, flavonoids and tannins in the acetone and ethanol
extract. Phenols were found only in acetone extract while saponins were detected only in
water extract. Additionally, acetone extracts exhibited the highest TPC and DPPH
scavenging activity, while ethanol extract showed the highest H2O2-scavenging activity.
Both extracts in Phase 2 inhibited lipid peroxidation and ROS production. They were
also able to increase NO production indicating their antioxidant activity. Acetone extract
was able to inhibit lipid peroxidation, ROS production and increase NO production better
than ethanol extract at 80 μg/ml. Both extracts showed anti-inflammatory activities by
reducing monocyte adhesion and migration and expression of ICAM-1 and VCAM-1.
Acetone extract was able to inhibit monocyte adhesion and expression of ICAM-1 better
than ethanol extract. While, ethanol extract showed significantly better inhibition of
monocyte migration and expression of VCAM-1 than acetone extract. This study showed
that EC acetone and ethanol extracts have high antioxidant activity among the four
extracts. Both extracts showed antioxidant and anti-inflammatory activity in HAoECinduced
with oxLDL. Generally, acetone extract at 80 μg/ml showed better antioxidant
and anti-inflammatory activities than ethanol extract. |
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