Protein kinase C is involved in the neuroprotective effect of berberine against intrastriatal injection of quinolinic acid-induced biochemical alteration in mice

A critical appraisal on the involvement of plant-based extracts as neuroprotective agents (2012-2022): an effort to ease out decision-making process for researchers

The purpose of this review study is to provide a condensed compilation of 164 medicinal plants that have been investigated for their neuroprotective aspects by researchers between the years 2012 and 2022 which also includes a recent update of 2023-2024. After using certain keywords to retrieve the data from SCOPUS, it was manually sorted to eliminate any instances of duplication. The article is streamlined into three major segments. The first segment takes a dig into the current global trend and attempts to decrypt vital information related to plant names, families, plant parts used, and neurological disorders investigated. The second segment of the article makes an attempt to present a comprehensive insight into the various mechanistic pathways through which phytochemicals can intervene to exert neuroprotection. The final segment of the manuscript is a bibliometric appraisal of all researches conducted. The study is based on 256 handpicked articles based on decided inclusion criteria. Illustrative compilation of various pathways citing their activation and deactivation channels are also presented with possible hitting points of various phytochemicals. The present study employed Microsoft Excel 2019 and VOS viewer as data visualisation tools.

Berberine hydrochloride improves cognitive deficiency through hippocampal up-regulation of neurotrophins following inhalant self-administration of methamphetamine

Objectives

Chronic methamphetamine (METH) abuse is recognized as an important risk factor for cognitive impairment. A plant-based isoquinoline alkaloid, Berberine hydrochloride (BER), shows memory and cognition enhancement properties. Due to the aim of the present study which is to investigate the influence of BER administration on METH-induced cognitive deficits, we investigated neurotrophin signaling including brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) as a possible mechanism by which BER exerts its cognitive improvement influences.

Materials and Methods

In this experimental study, thirty-two male Wistar rats were randomly classified into four groups, including non-treated control, intubated control, METH-inhaled, and METH-inhaled + BER-intubated. Rats in the METH-inhaled group underwent METH inhalation for 14 days, and the BER-inhaled and BER-intubated rats were intubated (100mg/kg) for the following three weeks. A novel object recognition task (NORt) was carried out on days 36 and 37. Rats were sacrificed for histological preparations after the behavioral tests. Neurotrophic factors, including GDNF and BDNF, were evaluated by immunofluorescence staining in the hippocampus.

Results

This experiment indicated a dramatic improvement in cognitive deficits associated with chronic METH abuse (P<0.001). Furthermore, a significant decrease in the expression of both neurotrophins, GDNF (P<0.001) and BDNF (P<0.001), was observed in the METH-inhaled group compared with the METH-inhaled group treated with BER and non-treated control group.

Conclusion

Activation of neurotrophic factors after BER administration resulted in improvement of METH-induced cognitive deficits. Therefore, BER may be considered a promising treatment for METH users who experience cognition deficits.

Quinolinic Acid Impairs Redox Homeostasis, Bioenergetic, and Cell Signaling in Rat Striatum Slices: Prevention by Coenzyme Q10

Quinolinic acid (QUIN) is an important agonist of NMDA receptors that are found at high levels in cases of brain injury and neuroinflammation. Therefore, it is necessary to investigate neuroprotection strategies capable of neutralizing the effects of the QUIN on the brain. Coenzyme Q₁₀ (CoQ₁₀) is a provitamin that has an important antioxidant and anti-inflammatory action. This work aims to evaluate the possible neuroprotective effect of CoQ₁₀ against the toxicity caused by QUIN. Striatal slices from 30-day-old Wistar rats were preincubated with CoQ₁₀ 25-100 μM for 15 min; then, QUIN 100 μM was added to the incubation medium for 30 min. A dose-response curve was used to select the CoQ₁₀ concentration to be used in the study. Results showed that QUIN caused changes in the production of ROS, nitrite levels, activities of antioxidant enzymes, glutathione content, and damage to proteins and lipids. CoQ₁₀ was able to prevent the effects caused by QUIN, totally or partially, except for damage to proteins. QUIN also altered the activities of electron transport chain complexes and ATP levels, and CoQ₁₀ prevented totally and partially these effects, respectively. CoQ₁₀ prevented the increase in acetylcholinesterase activity, but not the decrease in the activity of Na⁺,K⁺-ATPase caused by QUIN. We also observed that QUIN caused changes in the total ERK and phospho-Akt content, and these effects were partially prevented by CoQ₁₀. These findings suggest that CoQ₁₀ may be a promising therapeutic alternative for neuroprotection against QUIN neurotoxicity.

Treatment of Parkinson's disease in Zebrafish model with a berberine derivative capable of crossing blood brain barrier, targeting mitochondria, and convenient for bioimaging experiments

Berberine is a famous alkaloid extracted from Berberis plants and has been widely used as medications and functional food additives. Recent studies reveal that berberine exhibits neuroprotective activity in animal models of Parkinson's disease (PD), the second most prevalent neurodegenerative disorders all over the world. However, the actual site of anti-PD action of berberine remains largely unknown. To this end, we employed a fluorescently labeled berberine derivative BBRP to investigate the subcellular localization and blood brain barrier (BBB) permeability in a cellular model of PD and zebrafish PD model. Biological investigations revealed that BBRP retained the neuroprotective activity of berberine against PD-like symptoms in PC12 cells and zebrafish, such as protecting 6-OHDA induced cell death, relieving MPTP induced PD-like behavior and increasing dopaminergic neuron loss in zebrafish. We also found that BBRP could readily penetrate BBB and function in the brain of zebrafish suffering from PD. Subcellular localization study indicated that BBRP could rapidly and specifically accumulate in mitochondria of PC12 cells when it exerted anti-PD effect. In addition, BBRP could suppress accumulation of Pink1 protein and inhibit the overexpression of LC3 protein in 6-OHDA damaged cells. All these results suggested that the potential site of action of berberine is mitochondria in the brain under the PD condition. Therefore, the findings described herein would be useful for further development of berberine as an anti-PD drug.

Berberine Administration in Treatment of Colitis: A Review

Berberine (Brb) is one of the well-known naturally occurring compounds exclusively found in Berberis vulgaris and other members of this family, such as Berberis aristata, Berberis aroatica, and Berberis aquifolium. This plant-derived natural compound has a variety of therapeutic impacts, including anti-oxidant, anti-inflammatory, anti-diabetic, and anti-tumor. Multiple studies have demonstrated that Brb has great anti-inflammatory activity and is capable of reducing the levels of proinflammatory cytokines, while it enhances the concentrations of anti-inflammatory cytokines, making it suitable for the treatment of inflammatory disorders. Colitis is an inflammatory bowel disease with chronic nature. Several factors are involved in the development of colitis and it appears that inflammation and oxidative stress are the most important ones. With respect to the anti-inflammatory and antioxidant effects of Brb, its administration seems to be beneficial in the treatment of colitis. In the present review, the protective effects of Brb in colitis treatment and its impact on molecular pathways are discussed.

Berberine Ameliorates Subarachnoid Hemorrhage Injury via Induction of Sirtuin 1 and Inhibiting HMGB1/Nf-κB Pathway

Excessive cerebral inflammation plays a key role in early brain injury (EBI) after subarachnoid hemorrhage (SAH). Berberine, an isoquinoline alkaloid isolated from Chinese herb Coptis chinensis, possesses anti-inflammatory, and neuroprotective effects. Here we evaluated the beneficial effects of berberine against SAH-induced inflammatory response and the subsequent brain injury. Our data showed that berberine treatment significantly inhibited microglia activation and proinflammatory cytokines release. Concomitant with suppressed cerebral inflammation, berberine mitigated the subsequent brain injury as demonstrated by improved neurological behavior, reduced brain edema, and decreased neural apoptosis. Moreover, berberine significantly inhibited high mobile group box 1 (HMGB1)/nuclear factor-κB (Nf-κB)-dependent pathway and enhanced sirtuin 1 (SIRT1) expression after SAH. Treatment with ex527, a selective SIRT1 inhibitor, reversed berberine-induced SIRT1 activation and inhibitory effects on HMGB1/Nf-κB activation. In addition, ex527 pretreatment abated the anti-inflammatory and neuroprotective effects of berberine on SAH. Taken together, these findings suggest that berberine provides beneficial effects against SAH-triggered cerebral inflammation by inhibiting HMGB1/Nf-κB pathway, which may be modulated by SIRT1 activation.

Protein kinase C is involved in the neuroprotective effect of berberine against intrastriatal injection of quinolinic acid-induced biochemical alteration in mice

Protein kinase C (PKC) shows a neuronal protection effect in neurodegenerative diseases. In this study, we test whether berberine has a positive effect on the activity of PKC in quinolinic acid (QA)‐induced neuronal cell death. We used intrastriatal injections of QA mice model to test the effect of berberine on motor and cognitive deficits, and the PKC signalling pathway. Treatment with 50 mg/kg b.w of berberine for 2 weeks significantly prevented QA‐induced motor and cognitive impairment and related pathologic changes in the brain. QA inhibited the phosphorylation of PKC and its downstream molecules, GSK‐3β, ERK and CREB, enhanced the glutamate level and release of neuroinflammatory cytokines; these effects were attenuated by berberine. We used in vivo infusion of Go6983, a PKC inhibitor to disturb PKC activity in mice brain, and found that the effect of berberine to reverse motor and cognitive deficits was significantly reduced. Moreover, inhibition of PKC also blocked the anti‐excitotoxicity effect of berberine, which is induced by glutamate in PC12 cells and BV2 cells, as well as anti‐neuroinflammatory effect in LPS‐stimulated BV2 cells. Above all, berberine showed neuroprotective effect against QA‐induced acute neurotoxicity by activating PKC and its downstream molecules.