African Jointfir (Gnetum africanum) and Editan (Lasianthera africana) leaf alkaloid extracts exert antioxidant and anticholinesterase activities in fruit fly (Drosophila melanogaster)

Abstract

African Jointfir (Gnetum africanum) and Editan (Lasianthera africana) leaves are two leafy green veggies with several nutritional and medicinal properties. Alzheimer's disease (AD) is a form of neurodegeneration that is believed to cause dementia in affected individuals. The quest for alternative treatments has necessitated the exploitation of plants' secondary metabolites. Plant alkaloids have recently demonstrated relevance in the management of a variety of neurodegenerative disorders; although there is limited information on the neuroprotective properties of alkaloids from various tropical green leafy vegetables with neuroprotective potentials. As a result, this study examined the cholinesterase inhibitory activity and antioxidant potential of alkaloid extracts from the leaves of African Jointfir (G. africanum) and Editan (L. africana). Standard solvent extraction techniques were used to prepare alkaloid extracts. After that, these extracts were characterized using high-performance liquid chromatography. In vitro acetylcholinesterase inhibition assay for the extracts was also carried out. Subsequently, the alkaloid extracts were included in the diets of these flies (2 and 10 μg/g) for 7 days. Thereafter, treated fly homogenates were assayed for cholinesterase, monoamine oxidase, and antioxidant enzymes (specifically, glutathione-S-transferase catalase, and superoxide dismutase) activities, in addition, thiobarbituric acid reactive substance, reactive oxygen species, and total thiol contents. The extracts showed considerable anticholinesterase, antioxidant, and antimonoamine oxidase capabilities, according to the study's findings. Also, HPLC characterization revealed that desulphosinigrin (597,000 ng/100 g) and atropine (44,200 ng/100 g) are the predominating phytochemicals in Editan and African Jointfir respectively. These extracts could serve as potential sources of nutraceuticals with neuroprotective properties which can be used in the treatment/management of Alzheimer's disease.