EFFICACY OF NIGELLA SATIVA, OLIVE LEAF EXTRACTS, CINNAMALDEHYDE, AND ITS NANO-EMULSION ON ALLEVIATION OF DEPRESSION IN MNCL2-INDUCED PARKINSON'S DISEASE RAT MODEL

Parkinson's disease (PD) is a complex disorder that may have been causally associated with various environmental exposures and genetic factors. A lot of research focuses on the main motor manifestations of PD and ignores its severe non-motor behavioral disorders. Persistent and chronic industrial contact with manganese is considered a potential cause of PD. Olive leaf extract, nigella sativa seeds extracts, and cinnamaldehyde possess a neuroprotective power against neuronal damage. The study was performed over sixteen weeks, with ninety rats assigned into seven groups: Control negative group (C-ve); Parkinson's disease model group (PD): rats injected daily in the intraperitoneal cavity by MnCl₂·4H₂O at a 10 mg/kg body weight dose for eight weeks (1-8weeks). Following the induction of PD, rats in the PD model group were subdivided into five groups for treatment and recovery over eight weeks (9-16 weeks) as follows: Parkinson's model withdrawal group (PDW), Olive leaf extract-treated group (PD+OLT), nigella sativa seeds extract-treated group (PD+NST), cinnamaldehyde-treated group (PD+CNT), and cinnamaldehyde loaded niosomes-treated group (PD+CLNT). At the beginning of the 8th week and the 16th week, depressive-like behavioral tests were performed, followed by decapitation, and brain samples were removed for biochemical measures and histopathological examination. The PD group showed depression, reduced dopamine, and severe neurodegeneration, and treatments alleviated all disturbances. In conclusion, the CLNT, OLT, NST, and CNT treatments alleviated the biochemical alterations and neurodegeneration, as they have a neuroprotective effect.