Effect of paraquat-induced toxicity and the therapeutic potentials of Moringa oleifera and Moringa stenopetala leaf alkaloid extracts

Paraquat (PQ) exposure is a risk factor for Parkinson's disease (PD), motivating treatment investigations. The efficacy of Ayurveda moringa leaf alkaloids in treating Paraquat toxicity was investigated in Drosophila models. The study included 10 fruit fly groups, four groups of which received moringa leaf alkaloid samples alone, one group was Paraquat-induced, and others received both. The experiment was terminated on day 3, after which fly heads and bodies were homogenized. Moringa oleifera and Moringa stenopetala alkaloid extracts were tested on Paraquat-induced flies' survival, biochemical, and genetic markers of PQ-toxicity. Alkaloid extracts significantly improved paraquat-induced fly survivability. Both Moringa species exhibited a stronger inhibition of monoamine oxidase and acetylcholinesterase at 50 mg/ml. Both Moringa species increased tyrosine hydroxylase activity, with PQ+MSL (50 mg/ml) displaying a more pronounced ameliorative effect. In comparison with the Paraquat-induced group, Moringa stenopetala significantly increased both catalase and total thiol levels. At the genetic level, catalase and tyrosine hydroxylase mRNA levels were downregulated in paraquat-induced flies. Moringa stenopetala exhibited a higher upregulation of tyrosine hydroxylase mRNA expression compared to Moringa oleifera, while Moringa oleifera upregulated catalase mRNA expression more than Moringa stenopetala. In conclusion, alkaloid extracts from moringa leaves demonstrated neuroprotective effects against paraquat-induced neurotoxicity in fruit flies. However, Moringa stenopetala exhibited superior medicinal properties compared to Moringa oleifera, as observed from this study. These findings support the antioxidant potential of Moringa extracts in counteracting environmental toxicant-induced stress. Future studies using non-lethal, neurodegeneration-focused Paraquat exposure models may further elucidate their neuroprotective potential.