Neuroprotective and Antioxidant Efficacy of Vigna spp. Against Rotenone-Induced Mitochondrial Dysfunction in Black Molly (Poecilia sphenops)

Abstract

Parkinson’s disease (PD) is a debilitating neurodegenerative disorder primarily driven by mitochondrial dysfunction and chronic oxidative stress. Rotenone, a potent Mitochondrial Complex I inhibitor, is frequently utilized to model PD-like pathology due to its ability to induce reactive oxygen species (ROS) and lipid peroxidation. This study investigated the neuroprotective potential of Vigna radiata (mung bean) water extract (MBWE) against rotenone-induced neurotoxicity in an aquatic model, Poecilia sphenops (Black Molly). Adult fish were subjected to a 30-day co-exposure paradigm consisting of five groups: Control, Rotenone (2 mg/L), and three treatment groups receiving MBWE (50, 100, and 150 mg/L). Neurobehavioral assessments via automated video-tracking revealed that rotenone exposure significantly impaired locomotor integrity, resulting in a 60% reduction in swimming distance and a profound increase in anxiety-like freezing behavior. These functional deficits were strongly correlated with a 2.6-fold elevation in brain malondialdehyde (MDA) levels (58.9 ± 4.2 nmol/mg protein), a definitive marker of lipid peroxidation. Conversely, co-administration of MBWE exhibited a dose-dependent ameliorative effect, with the high-dose group (150 mg/L) nearly normalizing behavioral parameters and effectively reducing MDA levels to 25.1 ± 1.8 nmol/mg protein. The results suggest that the bioactive C-glycosylflavonoids in V. radiata, such as vitexin and isovitexin, exert a potent neuroprotective shield by neutralizing ROS and stabilizing neuronal membranes. This study confirms that Vigna radiata is a promising natural nutraceutical candidate for mitigating oxidative stress-mediated neurodegeneration and provides a foundation for future research into plant-based therapeutic strategies in aquatic pharmacological models.

Introduction

This study examines the neuroprotective effects of a mung bean (Vigna radiata) aqueous extract (MBWE) against rotenone-induced Parkinson’s disease–like neurotoxicity in the black molly (Poecilia sphenops). Parkinson’s disease is associated with mitochondrial Complex I dysfunction, oxidative stress, and dopaminergic neuronal damage. Rotenone, a potent Complex I inhibitor, was used to induce mitochondrial impairment, oxidative damage, and behavioral deficits resembling Parkinsonian symptoms in an aquatic model.

Adult P. sphenops were exposed to rotenone (2 mg/L) for 30 days, with or without co-treatment of MBWE at different concentrations (50, 100, and 150 mg/L). Neurobehavioral parameters such as swimming speed, distance traveled, freezing behavior, and exploratory activity were assessed, along with biochemical analysis of lipid peroxidation using malondialdehyde (MDA) levels in brain tissue.

Rotenone exposure caused severe locomotor impairment, increased anxiety-like behavior, and a significant rise in brain MDA levels, indicating elevated oxidative stress and neuronal membrane damage. Co-treatment with MBWE produced dose-dependent neuroprotection. The highest MBWE dose substantially restored normal locomotor behavior, reduced freezing episodes, and markedly lowered MDA levels close to control values.

These results suggest that Vigna radiata extract effectively mitigates rotenone-induced mitochondrial dysfunction and oxidative damage, likely through its antioxidant phytochemicals. The findings highlight the potential of plant-derived dietary antioxidants as a protective strategy against environmental neurotoxicants and Parkinson’s-like neurodegeneration.

Conclusion

The present investigation provides compelling evidence that chronic exposure to the mitochondrial Complex I inhibitor, rotenone, induces profound neurobehavioral deficits and systemic oxidative stress in Poecilia sphenops (Black Molly). The substantial elevation in brain and liver malondialdehyde (MDA) levels confirms that rotenone-mediated mitochondrial dysfunction triggers an aggressive peroxidative cascade, compromising neuronal membrane integrity and mirroring the pathophysiological hallmarks of Parkinson’s disease. These biochemical alterations directly correlate with the observed decline in locomotor performance and increased anxiety-like freezing behavior, validating the sensitivity of the P. sphenops model for neurotoxicological screening. Conversely, the administration of Vigna radiata (mung bean) aqueous extract effectively counteracts these adverse effects. The dose-dependent reduction in lipid peroxidation suggests that the bioactive constituents of V. radiata—most notably its C-glycosylflavonoids, vitexin and isovitexin—exert a potent neuroprotective shield by neutralizing reactive oxygen species (ROS) and stabilizing cellular membranes. The restoration of normal exploratory swimming patterns and the significant mitigation of locomotor rigidity further underscore the functional benefits of V. radiata as a therapeutic intervention. Overall, these findings position Vigna radiata as a promising natural candidate for the development of nutraceutical strategies aimed at mitigating environmental neurotoxicant-induced brain damage. This study lays the groundwork for utilizing aqueous legume extracts in aquatic pharmacological models. Future research should focus on the immunohistochemical quantification of dopaminergic neurons in the teleost brain and the downstream signaling pathways associated with mitochondrial biogenesis to fully elucidate the molecular mechanisms underlying the neuroprotective efficacy of Vigna radiata.

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Copyright © 2025 Najnin Aslam Patel. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.