Ahlem Chira

Over the past decade, Urtica dioica L. (U. dioica) has gained prominence in biomedical research, particularly for its potential therapeutic applications in neurodegenerative diseases. This comprehensive review explores its botanical characteristics, toxicological considerations, and extensive traditional medicinal uses. Emphasizing the roles of phytochemical constituents such as flavonoids and overall polyphenolic compounds, this review examines their impact on mitigating critical pathways, such as neuroinflammation, oxidative stress, and mitochondrial dysfunction—all of which are implicated in Alzheimer’s Disease (AD), Parkinson’s Disease (PD), and Multiple Sclerosis (MS)—and, overall, in neurodegenerative processes in both humans and animal models. Notably, some phytochemicals are known to modulate crucial pathways for neuronal plasticity, learning, and memory, thereby enhancing cognitive functions. Hence, the potential of U. dioica-based therapies to improve cognitive function and pave the way for future therapeutic developments in neuroprotection is underscored.

This study examines the neuroprotective and antioxidant effects of Urtica dioica ethanolic extract (UDExt) and melatonin (Mel) in mitigating chlorpyrifos (CPF)-induced toxicity in rats, with melatonin serving as a standard antioxidant. Male Wistar rats were divided into six groups: (I) Control, (II) UDExt (200 mg/kg), (III) Mel (20 mg/kg), (IV) CPF (10 mg/kg), (V) UDExt + CPF, and (VI) Mel + CPF. UDExt and Mel were administered for 7 days prior to CPF exposure, followed by a treatment of 14 days. The findings revealed that CPF exposure significantly impaired hematological parameters (WBC, PLT, LYM), increased lipid peroxidation and protein oxidation, and decreased antioxidant enzyme activities (SOD, CAT, GPx) in brain and cerebellar tissues compared to control rats. Behavioral tests, including the open field test, showed that CPF reduced locomotor activity and increased anxiogenic symptoms. The Y-maze test revealed impaired recognition memory, and the tail suspension test indicated increased depressive symptoms. Histological analysis revealed neuronal damage in the brain and cerebellum tissues. Treatment with UDExt or melatonin, following CPF exposure, significantly improved hematological parameters, reduced lipid peroxidation and protein oxidation, normalized antioxidant enzyme activities, and alleviated neurobehavioral alterations. Histopathological analysis also showed that UDExt or melatonin combined with CPF notably reduced neuronal damage in the brain and cerebellum. UDExt and melatonin mitigated the CPF-induced neurobehavioral alterations associated oxidative injury.

Chlorpyrifos (CPF) is a widely used organophosphate insecticide, though its excessive use causes environmental contamination, raising concerns about its adverse effects on human health. In this regard, Urtica dioica stands out as a promising candidate for counteracting chemical ‘contaminant’ toxicity thanks to its therapeutic properties. Therefore, our study aimed to investigate the potential of an Urtica dioica ethanolic extract (UDE) to mitigate chlorpyrifos-induced toxicity. Eight compounds in the Urtica dioica ethanolic extract have been identified, most of which present significant potential as antioxidant, anti-inflammatory, and neuroprotective agents. Chlorpyrifos exposure altered hatching rates, increased the incidence of teratogenic effects, and upregulated the expression of brain-derived neurotrophic factor (Bdnf) in zebrafish larvae telencephalon. On the other hand, UDE demonstrated a preventive effect against CPF-induced teratogenicity, which is expressed by a lower morphological deformity rate. Moreover, the UDE showed a rather protective effect, maintaining the physiological condition of the telencephalon. Additionally, CPF altered the locomotor behavior of larvae, which was characterized by irregular swimming and increased activity. This defective behavioral pattern was slightly attenuated by the UDE. Our findings suggest that the UDE possesses significant protective properties against CPF-induced toxicity, probably conferred by its natural antioxidant and anti-inflammatory contents. Still, further research is needed to elucidate the recruited mechanisms and implicated pathways on UDE’s protective effects.

The present study aims to assess the antioxidant and antiviral effectiveness of leaf extracts obtained from Olea europaea L. var. sativa and Olea europaea L. var. sylvestris. The total antioxidant activity was determined via both an ammonium phosphomolybdate assay and a nitric oxide radical inhibition assay. Both extracts showed reducing abilities in an in vitro system and in human HeLa cells. Indeed, after oxidative stress induction, we found that exposition to olive leaf extracts protects human HeLa cells from lipid peroxidation and increases the concentration of enzyme antioxidants such as catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase. Additionally, OESA treatment affects viral DNA accumulation more than OESY, probably due to the exclusive oleuropein content. In fact, subtoxic concentrations of oleuropein inhibit HSV-1 replication, stimulating the phosphorylation of PKR, c-FOS, and c-JUN proteins. These results provide new knowledge about the potential health benefits and mechanisms of action of oleuropein and oleuropein-rich extracts.

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In our study, Allium subhirsutum L. (AS) was investigated to assess its phenolic profile and bioactive molecules including flavonoids and organosulfur compounds. The antioxidant potential of AS and wound healing activity were addressed using skin wound healing and oxidative stress and inflammation marker estimation in rat models. Phytochemical and antiradical activities of AS extract (ASE) and oil (ASO) were studied. The rats were randomly assigned to four groups: group I served as a control and was treated with simple ointment base, group II was treated with ASE ointment, group III was treated with ASO ointment and group IV (reference group; Ref) was treated with a reference drug “Cytolcentella^® cream”. Phytochemical screening showed that total phenols (215 ± 3.5 mg GAE/g) and flavonoids (172.4 ± 3.1 mg QE/g) were higher in the ASO than the ASE group. The results of the antioxidant properties showed that ASO exhibited the highest DPPH free radical scavenging potential (IC50 = 0.136 ± 0.07 mg/mL), FRAP test (IC50 = 0.013 ± 0.006 mg/mL), ABTS test (IC50 = 0.52 ± 0.03 mg/mL) and total antioxidant capacity (IC50 = 0.34 ± 0.06 mg/mL). In the wound healing study, topical application of ASO performed the fastest wound-repairing process estimated by a chromatic study, percentage wound closure, fibrinogen level and oxidative damage status, as compared to ASE, the Cytolcentella reference drug and the untreated rats. The use of AS extract and oil were also associated with the attenuation of oxidative stress damage in the wound-healing treated rats. Overall, the results provided that AS, particularly ASO, has a potential medicinal value to act as effective skin wound healing agent.