This study investigated the ameliorative effects of beta-carotene (BC) on diabetes-associated vascular dementia and its action against biomolecule oxidation. The diabetic vascular dementia (VaD) was induced by administration of nicotinamide (NA; 50 mg/kg; i.p.) and streptozotocin (STZ; 50 mg/kg; i.p.). The test compound, BC (50 and 100 mg/kg; p.o.), and the reference compound, donepezil (DP) (1 mg/kg; p.o.), were administered for 15 consecutive days. Changes in learning and memory were assessed by escape latency time (ELT) and times spent in target quadrant (TSTQ) in the Morris water maze (MWM) test. The changes in neurotransmitter, i.e., acetylcholinesterase (AChE) and oxidative stress markers, i.e., thiobarbituric acid reactive substance (TBARS) and reduced glutathione (GSH), were estimated in hippocampal tissue of the rat brain. The administration of STZ caused significant deterioration of cognitive function (decreased ELT and raised the TSTQ) as compared to the normal group. Treatment with BC and DP diminished the increased AChE activity, TBARS level and decreased GSH level caused by STZ. Thus, BC ameliorates the diabetic vascular complications in VaD due to its potential anticholinergic, antioxidative and free radical scavenging actions.

Vascular dementia (VaD) is a serious global health issue and type 2 diabetes mellitus (T2DM) patients are at higher risk. Palm oil tocotrienol-rich fraction (TRF) exhibits neuroprotective properties; however, its effect on VaD is not reported. Hence, we evaluated TRF effectiveness in T2DM-induced VaD rats. Rats were given a single dose of streptozotocin (STZ) and nicotinamide (NA) to develop T2DM. Seven days later, diabetic rats were given TRF doses of 30, 60, and 120 mg/kg orally for 21 days. The Morris water maze (MWM) test was performed for memory assessment. Biochemical parameters such as blood glucose, plasma homocysteine (HCY) level, acetylcholinesterase (AChE) activity, reduced glutathione (GSH), superoxide dismutase (SOD) level, and histopathological changes in brain hippocampus and immunohistochemistry for platelet-derived growth factor-C (PDGF-C) expression were evaluated. VaD rats had significantly reduced memory, higher plasma HCY, increased AChE activity, and decreased GSH and SOD levels. However, treatment with TRF significantly attenuated the biochemical parameters and prevented memory loss. Moreover, histopathological changes were attenuated and there was increased PDGF-C expression in the hippocampus of VaD rats treated with TRF, indicating neuroprotective action. In conclusion, this research paves the way for future studies and benefits in understanding the potential effects of TRF in VaD rats.

Vascular dementia (VaD) is a major factor for the progress of stroke and other memory disorders. It is the second leading cause of death. The burden of VaD is higher in the aged population (>65 years). The progression of VaD occurs with lifestyle modifications i.e., fast food, smoking, and alcohol. The medicines for the treatment of VaD are limited. The palm oil is one of the rich sources of beta-carotene (BC). The present research designed to investigate the potential role of palm oil mill effluent derived BC in experimental model of diabetic VaD. The diabetic VaD was induced by administration of nicotinamide (NA, 50 mg/kg; i.p.) followed by streptozotocin (STZ, 50 mg/kg; i.p.). The test compound i.e., BC (50 and 100 mg/kg) and reference compound donepezil (1 mg/kg) were administered orally for 15 consecutive days. The changes of cognitive patterns i.e., escape latency time (ELT) and time spent in target quadrant (TSTQ) was assessed by Morris water maze (MWM) test. Besides the changes of neurotransmitter i.e., acetylcholinesterase (AChE) was estimated in brain (hippocampus, cerebellum, entorhinal cortex, amygdala and septum) samples. The administration of STZ caused the significant changes of cognitive functions (increased ELT and decreased TSTQ) as indicated in the development of VaD when compared to normal group. The treatment of BC was ameliorated the cognitive dysfunctions against the STZ associated cholinergic neurotransmitter (elevated AChE) changes. The effects were similar to donepezil treatment group. Hence, it proved that BC possesses the potential therapeutic effects in the management of diabetic VaD due to its potential anti-cholinergic effects.