Effect of Andrographis paniculata and Phyllanthus amarus leaf extracts on selected biochemical indices in Drosophila melanogaster model of neurotoxicity.

Aluminum (Al)-induced toxicity in fruit fly (Drosophila melanogaster) is one of the established models for studying neurotoxicity and neurodegenerative diseases. Alkaloid phytochemicals have been reported to exhibit neuroprotective effects. Therefore, the aim of this study is to determine the effect of alkaloid extracts of Andrographis paniculata and Phyllanthus amarus leaves on Al-induced toxicity in wild type Drosophila melanogaster. The flies were exposed to diets containing 40 mM AlCl₃, and the alkaloid extracts (0.1 and 1 mg/ml). Thereafter, the flies were assessed for learning and memory, as well as locomotor performance 14 days post-treatment. This was followed by homogenizing the flies and the homogenates were assayed for acetylcholinesterase, monoamine oxidase and catalase activities, as well as the malondialdehyde content. The results showed that the alkaloid extracts of both leaves could ameliorate the aluminum-induced behavioral and biochemical impairments in the flies. The HPLC analysis of the alkaloid contents revealed that there is an abundance of Amaryllidaceae alkaloids, caffeine and carpaine. Thus, alkaloid extracts from these leaves could serve as promising therapeutic candidates for the management of neurodegenerative disease.