The Effect of Rosmarinic Acid on Apoptosis and nNOS Immunoreactivity Following Intrahippocampal Kainic Acid Injections in Rats

Ferulic Acid Attenuates Kainate-induced Neurodegeneration in a Rat Poststatus Epilepticus Model

BACKGROUND AND AIMS

Increasing research evidence indicates that temporal lobe epilepsy (TLE) induced by kainic acid (KA) has high pathological similarities with human TLE. KA induces excitotoxicity (especially in the acute phase of the disease), which leads to neurodegeneration and epileptogenesis through oxidative stress and inflammation. Ferulic acid (FA) is one of the well-known phytochemical compounds that have shown potential antioxidant and anti-inflammatory properties and promise in treating several diseases. The current study set out to investigate the neuroprotective effects of FA in a rat model of TLE.

METHODS

Thirty-six male Wistar rats were divided into four groups. Pretreatment with FA (100 mg/kg/day p.o.) started one week before the intrahippocampal injection of KA (0.8 μg/μl, 5μl). Seizures were recorded and evaluated according to Racine's scale. Oxidative stress was assessed by measuring its indicators, including malondialdehyde (MDA), nitrite, and catalase. Histopathological evaluations including Nissl staining and immunohistochemical staining of cyclooxygenase-2 (COX-2), and neural nitric oxide synthases (nNOS) were performed for the CA3 region of the hippocampus.

RESULTS

Pretreatment with FA significantly attenuates the severity of the seizure and prevents neuronal loss in the CA3 region of the hippocampus in rats with KA-induced post-status epilepticus. Also, nitrite concentration and nNOS levels were markedly diminished in FA-pretreated animals compared to non-pretreated epileptic rats.

CONCLUSION

Our findings indicated that neuroprotective properties of FA, therefore, could be considered a valuable therapeutic supplement in treating TLE.

Biomedical features and therapeutic potential of rosmarinic acid

For decades, the use of secondary metabolites of various herbs has been an attractive strategy in combating human diseases. Rosmarinic acid (RA) is a bioactive phenolic compound commonly found in plants of Lamiaceae and Boraginaceae families. RA is biosynthesized using amino acids tyrosine and phenylalanine via enzyme-catalyzed reactions. However, the chemical synthesis of RA involves an esterification reaction between caffeic acid and 3,4-dihydroxy phenyl lactic acid contributing two phenolic rings to the structure of RA. Several studies have ascertained multiple therapeutic benefits of RA in various diseases, including cancer, diabetes, inflammatory disorders, neurodegenerative disorders, and liver diseases. Many previous scientific papers indicate that RA can be used as an anti-plasmodic, anti-viral and anti-bacterial drug. In addition, due to its high anti-oxidant capacity, this natural polyphenol has recently gained attention for its possible application as a nutraceutical compound in the food industry. Here we provide state-of-the-art, flexible therapeutic potential and biomedical features of RA, its implications and multiple uses. Along with various valuable applications in safeguarding human health, this review further summarizes the therapeutic advantages of RA in various human diseases, including cancer, diabetes, neurodegenerative diseases. Furthermore, the challenges associated with the clinical applicability of RA have also been discussed.

The protective effects of rosmarinic acid on ethanol-induced gastritis in male rats: antioxidant defense enhancement

Background and purpose:

Gastritis is one of the most current gastrointestinal disorders worldwide. Alcohol consumption is one of the major factors, which provides gastritis. Rosmarinic acid (RA) is found in many plants and has powerful antioxidant and anti-inflammatory effects. In this study, the protective effect of RA was evaluated on the histopathological indices, antioxidant ability, and prostaglandin E2 (PGE2) secretion in male rats.

Experimental approach:

Forty-two animals were divided into control, ethanol-induced gastritis, and RA groups, 6 each. The protective groups included RA administration before gastritis induction at 50 mg (R-G50), 100 mg (R-G100), 150 mg (R-G150), and 200 mg (R-G200) doses. Gastritis was induced by gavage of 1 mL pure ethanol in fasted animals. After 1 h of gastritis induction, the rats were sacrificed and stomach tissue was removed.

Findings/Results:

Histological evaluation revealed that RA significantly attenuated gastric ulcers, leucocyte infiltration, and hyperemia. It also increased mucosal layer thickness and restored gastric glands. Furthermore, RA decreased malondialdehyde level, increased superoxide dismutase, catalase, and glutathione in the stomach tissue, and raised gastric PGE2 level.

Conclusion and implications:

Our study demonstrated that rosmarinic acid has a notable effect on gastritis protection that could be due to increased antioxidant defense and PGE2 secretion, eventually maintenance of mucosal barrier integrity and gastric glands.

The potential neuroprotective roles of olive leaf extract in an epilepsy rat model induced by kainic acid

BACKGROUND AND PURPOSE

Epilepsy is recognized as a chronic neurologic disease. Increasing evidence has addressed the antioxidant and anti-inflammatory roles of olive leaf extract (OLE) in neurodegenerative diseases. So, the current study aimed to investigate the neuroprotective roles of OLE in epilepsy.

EXPERIMENTAL APPROACH

Forty rats were divided into 4 groups including a control group, sham group, kainic acid (KA) group, and KA + OLE group. KA (4 μg/rat) was injected intrahippocampal, and OLE (300 mg/kg) was orally administrated for 4 weeks. Animals were sacrificed, and their hippocampi were isolated. KA- induced seizure activity was recorded. Oxidative stress index was assessed by measuring its indicators including malondialdehyde (MDA), nitrite, nitrate, and glutathione (GSH) as well as the catalase (CAT) activity. The supernatant concentration of tumor necrosis factor-α (TNF-α) and the apoptosis rate in neurons were measured.

FINDINGS/RESULTS

Treatment with OLE significantly reduced the seizure score. OLE decreased oxidative stress index by reducing the concentration of MDA, nitrite, and nitrate as well as increasing the level of GSH. OLE had a significant anti-apoptotic effect on neurons. However, CAT activity and the level of TNF-α were not affected.

CONCLUSION AND IMPLICATIONS

Our findings indicated neuroprotective properties of OLE, which is mainly mediated by its antioxidant and anti-apoptotic effects, therefore, could be considered as a valuable therapeutic supplement for epilepsy.

Melissa officinalis L. hydro-alcoholic extract inhibits anxiety and depression through prevention of central oxidative stress and apoptosis

NEW FINDINGS

What is the central question of this study? How does an extract of Melissa officinalis L. ameliorate anxiety- and depressive-like behaviour of mice? What is the main finding and its importance? An extract of Melissa officinalis L. possessed anxiolytic and anti-depressant effects, which could mainly be mediated through its antioxidant and anti-apoptotic properties.

ABSTRACT

This study evaluated the effects of a hydro-alcoholic extract of Melissa officinalis (HAEMO) on anxiety- and depressive-like behaviours, oxidative stress and apoptosis markers in restraint stress-exposed mice. In order to induce a depression-like model, mice were subjected to restraint stress (3 h day-1 for 14 days) and received normal saline or HAEMO (50, 75 and 150 mg kg-1  day-1 ) for 14 days. The administered doses of HAEMO were designated based on the concentration of one of the main phenolic compounds present in the extract, rosmarinic acid (2.55 mg kg-1 at lowest dose); other phytochemical analyses including assays for antioxidant activity, total phenols and flavonoids were also carried out. The behavioural changes in an open field task, elevated plus maze, tail suspension and forced swimming tests were evaluated. Also, malondialdehyde (MDA) levels and enzyme activities of superoxide dismutase and glutathione peroxidase, and total antioxidant capacity were assessed in the prefrontal cortex and hippocampus. Moreover, levels of Bcl-2, Bax and caspase 3 in the brain as well as serum concentration of corticosterone were evaluated. HAEMO (75 and 150 mg kg-1 ) significantly reversed anxiety- and depressive-like behaviours. Also, HAEMO reduced MDA levels, enhanced enzymatic antioxidant activities and restored serum levels of corticosterone. An immunoblotting analysis also demonstrated that HAEMO decreased levels of pro-apoptotic markers and increased anti-apoptotic protein levels in the prefrontal cortex and hippocampus of restraint stress-exposed mice. Our findings suggested that HAEMO reduced inflammation and had anxiolytic and antidepressant effects in mice.