Comparative effects of berberine and piperine on the neuroprotective potential of neostigmine

Abstract

Objectives: This study examined effect of berberine and piperine on neuroprotective potential of neostigmine in the management of neurological disorders.

Methods: Berberine and neostigmine were weighed (30 g), dissolved in distilled water (30 mL) separately, while, 30 mg piperine was dissolved in ethanol (0.45 mL), made up to 30 mL with distilled water. Antioxidant activities in 2, 2-diphenyl-1-picrylhydrazyl radical (DPPH), 2, 2-azinobis (3-ethylbenzothiazoline-6-sulfonate) radical (ABTS), Fe-chelation, ferric reducing properties (FRAP), nitric oxide (NO) and hydroxyl (OH) radical scavenging abilities and Fe²⁺, cisplatin and sodium nitroprusside (SNP) induced lipid peroxidation (LPO), and acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and monoamine oxidase (MAO) activities were assessed in vitro.

Results: The result revealed that tested compounds inhibited enzymes activities dose-dependently. However, berberine (IC₅₀=0.17 mg/mL) had slight higher AChE inhibitory effect than piperine and neostigmine (p<0.05). Also, berberine had the highest BChE inhibitory effect (IC₅₀=0.16 mg/mL) while piperine exhibited the highest MAO inhibitory effect (IC₅₀=0.21 mg/mL). Berberine, piperine and neostigmine exhibited high antioxidant properties and inhibited Fe²⁺, cisplatin and SNP induced LPO.

Conclusions: Both alkaloids demonstrated antiradical scavenging ability comparable to neostigmine action against Alzheimer's disease (AD). The modulatory and antioxidant berberine and piperine properties on these enzymes (AChE, BChE and MAO) could be possible underlying mechanisms in employing these compounds as a complementary therapy in neurodegenerative diseases (NDDs) management.

Keywords: acetylcholinesterase; antioxidant; berberine; butyrylcholinesterase; monoamine oxidase; neostigmine; neuromodulation; piperine.