Effect of Cardamom oil on amyloid β expression in hippocampus tissue (400X). (a) Normal control: Hippocampus: showing normal neuronal cells without immunoreactivity (arrow){Immunostaining: Amyloid- β, 400X}, (b) AlCl3 group: Hippocampus: showing significantly mild enhanced expression of amyloid- β, exhibited by brown coloration (arrow){Immunostaining: Amyloid- β, 400X}, (c) AlCl3 + Donepezil hydrochloride (1 mg/kg): Hippocampus: showing normal histology, normal neuronal cells without immunoreactivity (arrow) {Immunostaining: Amyloid- β, 400X}, (d) AlCl3 + Cardamom oil (100 mg/kg): Hippocampus: showing significantly enhanced expression of amyloid- β, exhibited by brown coloration (arrow) {Immunostaining: Amyloid- β, 400X}, (e) AlCl3 + Cardamom oil (200 mg/kg): Hippocampus: showing normal histology, normal neuronal cells without immunoreactivity (arrow){Immunostaining: Amyloid- β, 400X}, (f) Histogram of IHC. Data are expressed as mean ± SEM (n = 6), ###p < 0.001 when compared with normal control, **p < 0.01, *p < 0.05 when compared with disease control group. The magnification was 400X. AlCl3, Aluminum chloride; SEM, Standard Error of Mean; IHC, Immunohistochemistry.