Protective Effects of Cinnamic Acid Against Hyperglycemia Induced Oxidative Stress and Inflammation in HepG2 Cells

Abstract

Background: Cinnamic acid, a phenylpropanoid acid, has been investigated as a potential alternative therapy for diabetes and its complications in some studies.

Methods: In the first stage, the viability of HepG2 cells at different concentrations of glucose and CA was assessed by MTT assay. Oxidative stress markers) CAT, GPx, GSH, and MDA) were measured spectrophotometrically. After RNA extraction, the effect of different concentrations of CA on the expression of DPP4 and inflammatory factors (IL-6, NF- κB) in HepG2 cells was assessed using real-time PCR.

Results: In HepG2 cells, CA increased catalase and glutathione peroxidase activity and GSH production in a dose-dependent manner in the presence of high glucose concentrations, with the greatest effect seen at a concentration of 75 mg/ml. Also, it reduced the amount of MDA in high-glucose HepG2 cells. Furthermore, CA decreased the expression of DPP4, NF- κB, and IL-6 genes in HepG2 cells in the presence of high glucose levels.

Conclusions: The results of our study indicated that CA reduced hyperglycemia-induced complications in HepG2 cells by decreasing inflammatory gene expression, including IL-6 and NF- κB and inhibiting the expression of DPP4, and limiting oxidative stress.

Keywords: Cinnamic acid; Diabetes; HepG2 cells; Hyperglycemia ss; Oxidative stre.

Fig. 1

Impact of glucose on the viability of HepG2 cells after 24- and 48-hours treatment and at different concentrations. The findings are presented as a percentage relative to control and are calculated as the mean (standard deviation) of three separate measurements.

Fig. 2

Impact of different concentrations of cinnamic acid on the viability of HepG2 cells after 48 hours treatment in the presence or absence of 60 mM of glucose. The findings are presented as a percentage relative to control and are calculated as the mean (standard deviation) of three separate measurements.

Fig. 3

Impact of different concentrations of cinnamic acid on the CAT activity in HepG2 cells after 48 hours treatment in the presence or absence of 60 mM of glucose. The findings are presented as U/mg protein and are calculated as the mean (standard deviation) of three separate measurements. Different letters in each column indicate a significant difference between groups.

Fig. 4

Impact of different concentrations of cinnamic acid on the GPX activity in HepG2 cells after 48 hours treatment in the presence or absence of 60 mM of glucose. The findings are presented as U/mg protein and are calculated as the mean (standard deviation) of three separate measurements. Different letters in each column indicate a significant difference between groups.

Fig. 5

Impact of different concentrations of cinnamic acid on the GSH protein in HepG2 cells after 48 hours treatment in the presence or absence of 60 mM of glucose. The findings are presented as µM/mg protein and are calculated as the mean (standard deviation) of three separate measurements. Different letters in each column indicate a significant difference between groups.

Fig. 6

Impact of different concentrations of cinnamic acid on the MDA protein in HepG2 cells after 48 hours treatment in the presence or absence of 60 mM of glucose. The findings are presented as µM/mg protein and are calculated as the mean (standard deviation) of three separate measurements. Different letters in each column indicate a significant difference between groups.

Fig. 7

Impact of different concentrations of cinnamic acid on the DPP4 gene expression in HepG2 cells after 48 hours treatment in the presence or absence of 60 mM of glucose. The findings are presented as Fold change 2-ΔΔCt compared to the control group. Different letters in each column indicate a significant difference between groups.

Fig. 8

Impact of different concentrations of cinnamic acid on the NF- κB gene expression in HepG2 cells after 48 hours treatment in the presence or absence of 60 mM of glucose. The findings are presented as Fold change 2-ΔΔCt compared to the control group. Different letters in each column indicate a significant difference between groups.

Fig. 9

Impact of different concentrations of cinnamic acid on the IL-6 gene expression in HepG2 cells after 48 hours treatment in the presence or absence of 60 mM of glucose. The findings are presented as Fold change 2-ΔΔCt compared to the control group. Different letters in each column indicate a significant difference between groups.