Characterization and neuroprotective properties of alkaloid extract of Vernonia amygdalina Delile in experimental models of Alzheimer’s disease

Abstract

This study emphasized on the neuroprotective properties of bitter leaf alkaloid-rich extract (BLAE) using transgenic fruit fly (Drosophila melanogaster [D. melanogaster]) model and scopolamine-induced amnesia rats. In vitro antioxidant properties and modulatory effects on key neuronal enzymes were carried out. Thereafter, fruit flies expressing human amyloid precursor protein (hAPP) and BACE-1 genes were treated with BLAE for 7 d to determine survival rate, BACE-1, acetylthiocholine (AChE), glutathione-S-transferase (GST), and catalase activities. Also, the aftermath of the BLAE on the neuronal activities of AChE, butyrylcholine (BChE), monoamine oxidase (MAO), angiotensin-I converting enzyme (ACE), ATP diphosphohydrolase (ATPdase), and ADPdase, catalase, superoxide dismutase (SOD), plus TBARS, and nitric oxide (NO) content in rats treated with scopolamine (1 mg/kg. bwt. i.p.) was evaluated. In addition, the alkaloid characterization for constituent BLAE was determined. The outcomes proved that BLAE displayed antioxidant properties and inhibit activities of AChE, BChE, MAO, ACE, ATPdase, and ADPdase in vitro. Furthermore, transgenic flies treated with the BLAE exhibited significant levels of amelioration on survival rate and activities of BACE-1, AChE, GST, and catalase. In scopolamine-treated rats, AChE, BChE, MAO and NTPdases activities, and antioxidant status were upturned in rats pretreated with BLAE. This study disclosed the neuroprotective property of BLAE, which could be related to its alkaloid constituent, thereby making it a good candidate to explore as curative nutraceutical agent for cognitive impairments and affiliated diseases such as AD.

Keywords:

• Alkaloid
• nutraceuticals
• Drosophila
• scopolamine
• Alzheimer’s disease

Acknowledgments

The authors appreciate Dr. Daniel R. Marenda of the Department of Biology, University of Drexel, Philadelphia, PA, USA for the generous donations of the transgenic files used for this study. Authors also apricated Tertiary Educational Trust Fund (TETfund) for providing research grant (VCPU/TETFUND/155) to fund this project.

Disclosure statement

The authors declare that they have no conflicts of interest.

Additional information

Funding

This research was funded by Tertiary Educational Trust Fund (TETfund) Research Grant [VCPU/TETFUND/155].