Abstract

Parkinson’s disease (PD) is a progressive neurodegenerative disorder marked by the loss of dopaminergic neurons, impaired neurotransmission, oxidative stress, neuroinflammation, and the disruption of cellular signalling pathways. This research examined the neuroprotective efficacy of extracts from Moringa oleifera Lam. (MO), Mucuna pruriens (L.) DC. (MP), and Silybum marianum (L.) Gaertn. (SM) in a rotenone-induced PD mice model. Male Balb/c mice received daily intraperitoneal injections of rotenone (2.5 mg/kg) to induce PD, alongside oral administration of individual aqueous plant extracts (5%) for three weeks, noting that Levodopa (the usual positive control) was not included since our plant extracts were primarily tested during PD induction to explore their protective and preventive effects. Neurotransmitters (dopamine, serotonin, and norepinephrine) and inflammatory cytokines interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α) were quantified using Enzyme-Linked Immunosorbent Assay. Reverse transcription polymerase chain reaction was used to measure dopa-decarboxylase (DDC) levels, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), nuclear factor erythroid 2-related factor 2 (Nrf2), Phosphatidylinositol 3-Kinase (PI3K), activates protein kinase B (AKT), mammalian target of rapamycin (mTOR), and caspase-3. Protein levels of tyrosine hydroxylase (TH) were assessed using Western blot analysis. All three extracts significantly enhanced the expression of TH and DDC while reducing the concentrations of IL-6, TNF-α, NF-κB, and caspase-3. MO and SM extracts stimulated Nrf2 activation. The PI3K/AKT/mTOR pathway was augmented, facilitating neuronal survival. MO, MP, and SM extracts exhibit neuroprotective advantages via modulating dopaminergic signalling, diminishing inflammation and apoptosis, and enhancing antioxidant pathways in PD. A primary limitation of the current study is the lack of phytochemical standardization and quantification of the administered extracts (e.g., L-dihydroxyphenylalanine in MP, silymarin in SM, and principal flavonoids in MO) by high-performance liquid chromatography or Liquid chromatography–mass spectrometry; this limitation constrains dose-response interpretation and reproducibility. Future work will include analytical standardization of extracts and quantitative correlation of active constituents with biological effects.

Key words: Parkinson's disease, Moringa oleifera Lam, Mucuna pruriens (L.) DC., Silybum marianum (L.) Gaertn., PI3K/AKT/mTOR.