Ameliorative effect of β‐pinene targeting mitochondrial dysfunction and oxidative stress in Alzheimer’s disease

Abstract Background Sporadic Alzheimer’s disease (sAD) is the most common type of dementia, characterized by the deposition of extracellular senile plaques, neurofibrillary tangles (NFTs), and neurodegeneration, leading to memory impairment and dementia. Intracerebroventricular (ICV) streptozotocin (STZ) mimics sporadic Alzheimer’s disease (sAD) characterized by neurodegeneration arising from oxidative stress, and mitochondrial dysfunction. β‐pinene is a monoterpene having antioxidant properties interlinked with mitochondrial functioning. To study the neuroprotective and cognitive enhancement properties of β‐pinene on mitochondrial dysfunction, oxidative stress, and histological changes in an animal model of Alzheimer’s disease induced by ICV‐STZ. Method To establish the sAD model, intracerebroventricular (ICV) streptozotocin (STZ) at a dose of 3 mg/kg was administered bilaterally in rats on a stereotaxic apparatus. Behavioral tests such as Morris water maze (MWM), novel object recognition (NOR) and Actophotometer were performed to evaluate spatial & recognition memory and locomotor functions. Three treatment doses (50mg/kg, 100 mg/kg and 200mg/kg) of Beta pinene (β‐pinene) and Galantamine (2 mg/kg) as a reference drug were given orally to ICV‐STZ induced rats for 21 days. Cortical and hippocampal tissues were dissected. Estimation of oxidative stress, mitochondrial dysfunction as complex I, II, III, IV activity and acetylcholinesterase activity were performed for cholinergic function. Moreover, histopathology was evaluated by hematoxylin and eosin (H&E) staining. Result β‐pinene treatment attenuated ICV‐STZ‐induced cognitive impairment in MWM and NOR. There is no significant effect revealed on locomotor activities. Moreover, in the cortex and hippocampal area of the brain, Mitochondrial enzyme complex I, II, III, and IV, and acetylcholinesterase (AchE) activities were normalized. Furthermore, reduced glutathione (GSH), catalase, superoxide dismutase (SOD), and (Lipid peroxidation) LPO were also reversed. β‐pinene prevents neurodegeneration as examined in histopathology. Conclusion In the ICV‐STZ rat model, β‐pinene was found to be neuroprotective by reducing oxidative stress and mitochondrial dysfunction, consequently enhancing cognitive functions indicated in the behavioral outcomes.