Chlorogenic acid may improve memory function and decrease inflamation of frontal lobe in diabetic rat

Diabetes Mellitus (DM) is a chronic disease with many complications, one of which is diabetic encephalopathy which is characterised by memory dysfunction. Hyperglycaemia that occurs in DM will activate inflammatory pathways in neurons, including NF-κB pathway. Activation of this pathway produce proinflammatory agents such as MCP-1 and IL-6, which activate glial cells. Activation of glial cells is characterised by Glial Fibrillary Acid Protein (GFAP). Chlorogenic acid (CGA) has been reported to have anti-inflammatory effects and can improve memory function. This research aimed to determine the effect of CGA as anti-inflammation, its effect on memory function, mRNA expression of NF-κB, MCP-1, IL- 6, and GFAP of frontal lobe.

A total of 24 male rats were randomly divided into six groups: control, DM 1.5 month (DM1.5), DM 2 months (DM2) and the group with three different doses of CGA 12.5 (CGA1), 25 (CGA2), and 50 (CGA3) mg/KgBW. Frontal lobe tissue is taken for analysis of mRNA expression for NF-κB, MCP-1, IL-6, and GFAP using Reverse Transcriptase PCR (RT-PCR). Samples were also taken for histopathology preparation and stained by immunohistochemistry method using anti-GFAP antibodies to observe glial cell activation in frontal lobe tissue.

The group that was given CGA at all doses have statistically significant better memory function, i.e. DM2 versus CGA1 (p = 0.036), CGA2 (p = 0.040), and CGA3 (p = 0.021). The result of mRNA expression in NF-κB was lower in the group given CGA, i.e. DM2 compared to CGA2 (p = 0.007). mRNA expression of MCP-1 was significantly lower in all CGA treatment groups compared to the non-CGA group (p = 0.000). IL-6 mRNA expression was lower than the group not given CGA, DM compared to CGA2 (p = 0.028). GFAP mRNA expression was lower than the group given CGA in DM, DM2 group compared to CGA1 (p = 0.04) and CGA3 (p = 0.004).

Administration of CGA can improve memory function at all doses given, and can reduce brain inflammatory activity, especially in the CGA2 group.