Antioxidative Effect of Amomum testaceum Ridl. Extract for Protecting against Vascular Dementia

Abstract

Vascular dementia is caused by decreased blood flow to the brain, which leads to neuronal damage and subsequent death. Therefore, development of alternative neuroprotective agents is critical. This study is aimed at investigating the effects of Amomum testaceum Ridl. extract or Siam cardamom extract (SCE) on oxidative markers in a rat model of vascular dementia. The phenolic content of SCE, represented as gallic acid equivalent (mg/100 GAE), was discovered to be $128.56\pm 0.58$  mg/100 GAE. The EC50 values for the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activities of SCE were $32.48\pm 0.39$  ug/mL. In addition, the reducing power of SCE, via a ferric reducing antioxidant power assay, was also determined, with an EC50 value of $142.55\pm 0.56$  ug/mL. SCE was administered orally to adult male Wistar rats weighing 250–300 g at doses of 100, 300, and 500 mg/kg over the course of 14 days; then, the rats underwent surgery of the right middle cerebral artery, producing an occlusion imitating vascular dementia in a controlled environment. All rats were euthanized to obtain brain tissue for biochemical testing and analysis. The results showed that malondialdehyde decreased and superoxide dismutase, catalase, and glutathione peroxidase increased at all doses (100, 300, and 500 mg/kg) of SCE ( $P<0.05$ ). In addition, SCE was shown to lower the expression level of S100B, a marker of neurologic injury ( $P<0.05$ ). The free radical scavenging and anti-inflammatory capabilities of SCE suggest that it has the potential to be used as a food supplement to protect against oxidative damage in vascular dementia. However, further clinical investigations are essential to elucidate this in clinical trials.