Anti-acetylcholinesterase activity and antioxidant properties of extracts and fractions of Carpolobia lutea

Nwidu, Lucky Legbosi; Elmorsy, Ekramy; Thornton, Jack; Wijamunige, Buddhika; Wijesekara, Anusha; Tarbox, Rebecca; Warren, Averil; Carter, Wayne

Abstract

Context: There is an unmet need to discover new treatments for Alzheimer’s disease. This study determined the anti-acetylcholinesterase (AChE) activity, DPPH free radical scavenging and antioxidant properties of Carpolobia lutea G. Don (Polygalaceae).
Objective: To quantify C. lutea anti-AChE, DPPH free radical scavenging, and antioxidant activities, and cell cytotoxicity.
Materials and methods: Plant stem, leaves, and roots were subjected to sequential solvent extractions, and screened for anti-AChE activity across a concentration range of 0.02-200 μg//mL. Plant DPPH radical scavenging activity, reducing power, and total phenolic and flavonoid content were determined, and cytotoxicity evaluated using human hepatocytes.
Results: C. lutea exhibited concentration dependent anti-AChE activity. The most potent inhibitory activity for the stem was the crude ethanol extract and hexane stem fraction oil (IC₅₀ = 140 μg/mL); for the leaves the chloroform leaf fraction (IC₅₀ = 60 μg/mL/mL); and for roots, the methanol, ethyl acetate, and aqueous root fractions (IC₅₀ = 0.3-3 μg/mL). Dose-dependent free radical scavenging activity and reducing power were observed with increasing stem, leaf, or root concentration. Total phenolics were highest in the stem: ~632 mg gallic acid equivalents/g for a hexane stem fraction oil. Total flavonoid content was highest in the leaves: ~297 mg quercetin equivalents/g for a chloroform leaf fraction. At 1 μg/mL, only the crude ethanol extract oil was significantly cytotoxic to hepatocytes.
Discussion and conclusion: C. lutea possesses anti-AChE activity and beneficial antioxidant capacity indicative of its potential development as a treatment of Alzheimer’s and other diseases characterized by a cholinergic deficit.

Citation

Nwidu, L. L., Elmorsy, E., Thornton, J., Wijamunige, B., Wijesekara, A., Tarbox, R., Warren, A., & Carter, W. (2017). Anti-acetylcholinesterase activity and antioxidant properties of extracts and fractions of Carpolobia lutea. Pharmaceutical Biology, 55(1), https://doi.org/10.1080/13880209.2017.1339283

• Journal Article Type: Article
• Acceptance Date: Jun 3, 2017
• Publication Date: Jun 19, 2017
• Deposit Date: Jun 13, 2017
• Publicly Available Date: Jun 19, 2017
• Journal: Pharmaceutical Biology
• Print ISSN: 1388-0209
• Electronic ISSN: 1744-5116
• Publisher: Taylor and Francis
• Peer Reviewed: Peer Reviewed
• Volume: 55
• Issue: 1
• DOI: https://doi.org/10.1080/13880209.2017.1339283
• Keywords: Anti-acetylcholinesterase; Carpolobia lutea; Antioxidant; Alzheimer's disease
• Public URL: https://nottingham-repository.worktribe.com/output/866899
• Publisher URL: https://www.tandfonline.com/doi/full/10.1080/13880209.2017.1339283
• Contract Date: Jun 13, 2017