Analgesic effects of a hydro-ethanolic whole plant extract of Synedrella nodiflora (L.) Gaertn in paclitaxel-induced neuropathic pain in rats

Therapeutic Potential of Silymarin in Mitigating Paclitaxel-Induced Hepatotoxicity and Nephrotoxicity: Insights into Oxidative Stress, Inflammation, and Apoptosis in Rats

Background

Paclitaxel (PAX) is a widely used chemotherapy drug for various cancer types but often induces significant toxicity in multiple organ systems. Silymarin (SIL), a natural flavonoid, has shown therapeutic potential due to its multiple benefits.

Aims

To evaluate the therapeutic efficacy of SIL in mitigating liver and kidney damage induced by PAX in rats, focusing on oxidative stress, inflammation, and apoptosis pathways.

Study Design

Experimental animal model.

Methods

The study included 28 male Wistar rats aged 12-14 weeks weighing 270-300 g. The rats were divided into four groups: control, SIL, PAX, and PAX + SIL, with seven in each group. The rats received intraperitoneal (i.p.) injections at a dose of 2 mg per kilogram of body weight of PAX for 5 successive days, followed by oral gavage with 200 mg/kg body mass of SIL for 10 uninterrupted days. We examined the effect of SIL on specific serum biochemical parameters using an autoanalyzer and rat-specific kits. The spectrophotometric methods was used to investigate oxidative stress indicators in kidney and liver tissues. Aquaporin-2 (AQP-2), B-cell lymphoma-2 (Bcl-2), cysteine aspartate-specific protease-3 (caspase-3), interleukin-6 (IL-6), nuclear factor kappa B (NF-κB), and streptavidin-biotin staining were used to assess immunoreactivity in PAX-induced liver and kidney injury models.

Results

SIL treatment significantly reduced serum levels of alanine aminotransferase, aspartate aminotransferase, creatinine, urea, and C-reactive protein, indicating its effectiveness in treating PAX-induced liver and kidney injury. SIL treatment significantly reduced oxidative stress by increasing essential antioxidant parameters, such as superoxide dismutase, catalase, glutathione peroxidase, and glutathione. It also reduced malondialdehyde levels in liver and kidney tissues of SIL-PAX groups (p < 0.05). SIL administration reduced NF-κB, caspase-3, and IL-6 expression while increasing Bcl-2 and AQP2 levels in liver and kidney tissues of rats treated with SIL and PAX (p < 0.05).

Conclusion

Our findings indicate the potential of SIL to alleviate PAX-induced liver and kidney damage in rats by reducing oxidative stress, inflammation, and apoptotic processes.

Upregulation of neuronal progranulin mediates the antinociceptive effect of trimetazidine in paclitaxel-induced peripheral neuropathy: Role of ERK1/2 signaling

Neuronal progranulin (PGRN) overexpression is an endogenous adaptive pain defense following nerve injury. It allows the survival of injured neurons to block enhanced nociceptive responses. Trimetazidine (TMZ) is widely used by cardiac patients as an anti-anginal drug, reflecting its anti-ischemic property. TMZ promotes axonal regeneration of sciatic nerves after crush injury. This study explored the interplay between PGRN and extracellular signal-regulated kinases (ERK1/2) to address mechanisms underlying neuropathic pain alleviation following paclitaxel (PTX) administration. Rats were given four injections of PTX (2 mg/kg, i.p.) every other day. Two days after the last dose, rats received TMZ (25 mg/kg) with or without the ERK inhibitor, PD98059, daily for 21 days. TMZ preserved the integrity of myelinated nerve fibers, as evidenced by an obvious reduction in axonal damage biomarkers. Accordingly, it alleviated PTX-evoked thermal, cold, and mechanical hyperalgesia/allodynia. TMZ also promoted ERK1/2 phosphorylation with a profound upsurge in PGRN content. These effects were associated with a substantial increase in Notch1 receptor gene expression and a prominent anti-inflammatory effect with a marked increase in mRNA expression of secretory leukocyte protease inhibitor. Further, TMZ decreased oxidative stress and caspase-3 activity in the sciatic nerve. Conversely, co-administration of PD98059 completely abolished these beneficial effects. Thus, the robust antinociceptive effect of TMZ is largely attributed to upregulating PGRN and Notch1 receptors via ERK1/2 activation.

Effect of Cliothosa aurivilli on Paclitaxel-induced Peripheral Neuropathy in Experimental Animals

Chemotherapy-induced peripheral neuropathy (CIPN) is a serious complication leading to painful episodes of parasthesia and numbness in hands and feet. The present drugs that have been used for symptomatic treatment yield inconclusive results in trials and assorted side effects. Thus, there is a pressing demand for development of therapeutically efficacious strategy to combat CIPN. The present study investigates about the effect of a marine sponge; Cliothosa aurivilli (CA) on paclitaxel (PT)-induced peripheral neuropathy in mice. Peripheral neuropathy was induced by intoxication with chemotherapeutic drug PT (2 mg/kg; i.p.) for 5 days consequently. Subsequent treatment with aqueous extract of CA (100 and 200 mg/kg) and standard drug methylcobalamin (MCA) (5 mg/kg) was done and results compared statistically. Neuropathic pain sensations were assessed using various behavioural and locomotory models and evaluated on 0^th, 7^th and 14^th days. Kinovea software was used for video path-tracking of animals and total distance travelled calculated. The results indicated clear signs of improvement post 10 days of PT intoxication in CA-treated groups when compared PT challenged group. A significant reduction in pain behaviours in mechanical allodynia, cold chemical allodynia and thermal hyperalgesia models, improvement in sensory motor coordination, locomotor activity, and distance travelled in closed field model reveals that CA possesses potential ameliorating effect against PT-induced neuropathic pain symptoms. The extract notably improved the movement of the PT challenged animals which was shown by the video path-tracking software and total distance travelled by those animals.

Analgesic effects of medicinal plants and phytochemicals on chemotherapy-induced neuropathic pain through glial modulation

Chemotherapy-induced peripheral neuropathy (CIPN) frequently occurs in cancer patients. This side effect lowers the quality of life of patients and may cause the patients to abandon chemotherapy. Several medications (e.g., duloxetine and gabapentin) are recommended as remedies to treat CIPN; however, usage of these drugs is limited because of low efficacy or side effects such as dizziness, nausea, somnolence, and vomiting. From ancient East Asia, the decoction of medicinal herbal formulas or single herbs have been used to treat pain and could serve as alternative therapeutic option. Recently, the analgesic potency of medicinal plants and their phytochemicals on CIPN has been reported, and a majority of their effects have been shown to be mediated by glial modulation. In this review, we summarize the analgesic efficacy of medicinal plants and their phytochemicals, and discuss their possible mechanisms focusing on glial modulation in animal studies.

Medicinal plants and their isolated phytochemicals for the management of chemotherapy-induced neuropathy: therapeutic targets and clinical perspective

BACKGROUND

Chemotherapy, as one of the main approaches of cancer treatment, is accompanied with several adverse effects, including chemotherapy-induced peripheral neuropathy (CIPN). Since current methods to control the condition are not completely effective, new treatment options should be introduced. Medicinal plants can be suitable candidates to be assessed regarding their effects in CIPN. Current paper reviews the available preclinical and clinical studies on the efficacy of herbal medicines in CIPN.

METHODS

Electronic databases including PubMed, Scopus, and Cochrane library were searched with the keywords "neuropathy" in the title/abstract and "plant", "extract", or "herb" in the whole text. Data were collected from inception until April 2018.

RESULTS

Plants such as chamomile (Matricaria chamomilla L.), sage (Salvia officinalis L.), cinnamon (Cinnamomum cassia (L.) D. Don), and sweet flag (Acorus calamus L.) as well as phytochemicals like matrine, curcumin, and thioctic acid have demonstrated beneficial effects in animal models of CIPN via prevention of axonal degeneration, decrease in total calcium level, improvement of endogenous antioxidant defense mechanisms such as superoxide dismutase and reduced glutathione, and regulation of neural cell apoptosis, nuclear factor-ĸB, cyclooxygenase-2, and nitric oxide signaling. Also, five clinical trials have evaluated the effect of herbal products in patients with CIPN.

CONCLUSIONS

There are currently limited clinical evidence on medicinal plants for CIPN which shows the necessity of future mechanistic studies, as well as well-designed clinical trial for further confirmation of the safety and efficacy of herbal medicines in CIPN. Graphical abstract Schematic mechanisms of medicinal plants to prevent chemotherapy-induced neuropathy: NO: nitric oxide, TNF: tumor necrosis factor, PG: prostaglandin, NF-ĸB: nuclear factor kappa B, LPO: lipid peroxidation, ROS: reactive oxygen species, COX: cyclooxygenase, IL: interleukin, ERK: extracellular signal-related kinase, X: inhibition, ↓: induction.

An extract of Synedrella nodiflora (L) Gaertn exhibits antidepressant properties through monoaminergic mechanisms

Synedrella nodiflora (SNE) has been used traditionally for many neurological conditions and some of these neuroactive effects have been scientifically substantiated. The usefulness of SNE in depression has however not been investigated despite the availability of data in other disease models indicating it may be useful. The present study therefore examined the effect of SNE in acute murine models of depression and the possible mechanisms mediating its activities in these models. Preliminary qualitative phytochemical and high performance liquid chromatography (HPLC) screening were conducted on SNE. The behavioural effects of SNE (100, 300 and 1000 mg/kg) pre-treated mice were examined in the forced swimming (FST) and tail suspension (TST) tests. Behavioural events such as mobility (swimming, climbing, curling and climbing), and immobility, were scored. The possible involvement of monoamines in the effects of SNE was assessed in the TST by pre-treating mice with α-methyldopa, reserpine and para-chlorophenylalanine (pCPA) in separate experiments. Flavonoids, tannins, saponins, alkaloids, cardiac glycosides, coumarins, triterpenes, sterols, anthraquinones and phenolic compounds were present in SNE. HPLC analysis revealed the presence of two major constituents observed at retention times 42.56 and 46.51 min, with percentage composition of 45.72% and 36.88% respectively. SNE significantly reduced immobility scores in both FST and TST, suggesting antidepressant effects. The antidepressant properties of SNE were reversed by the pre-treatment of α-methyldopa, reserpine and pCPA, suggesting a possible involvement of monoamines (noradrenaline and serotonin) in its mechanism(s) of actions. SNE exhibits antidepressant effects, possibly mediated through an interplay of enhancement of noradrenergic and serotoninergic mechanisms.

Extract of Synedrella nodiflora (L) Gaertn exhibits antipsychotic properties in murine models of psychosis

BACKGROUND

The hydro-ethanolic whole plant extract of Synedrella nodiflora (SNE) has demonstrated anticonvulsant, sedative and analgesic effects. Preliminary studies conducted in animals, SNE significantly decreased stereotypic behaviours suggesting antipsychotic potential. Coupled with the central nervous system depressant effects of SNE, we hypothesized that it may have utility in the management of psychosis. The present study therefore investigated the antipsychotic potential of the SNE in several murine models of psychosis.

METHOD

The primary central nervous system activities of SNE (30-3000 mg/kg, p.o) were investigated using the Irwin's test. The novelty-induced rearing, locomotion and stereotypy counts provoked by SNE (100-1000 mg/kg, p.o) were conducted using the open-field paradigm. The antipsychotic test models used in the screening of SNE (100-1000 mg/kg, p.o) included apomorphine-induced stereotypy, rearing, locomotion and cage climbing activities. The combined effects of a low dose of SNE (100 mg/kg) with various doses of haloperidol and chlorpromazine were analysed using the apomorphine-induced cage climbing and stereotypy, respectively. The ability of SNE to cause catalepsy in naïve mice as well as its effect on haloperidol-induced catalepsy was assessed.

RESULTS

SNE showed acetylcholine-like and serotonin-like activities in the Irwin test, with sedation occurring at high doses. SNE significantly reduced the frequencies of novelty- and apomorphine-induced rearing and locomotion; stereotypy behaviour and the frequency and duration of apomorphine-induced cage climbing in mice. In all the tests performed, SNE was less potent than the reference drugs used (chlorpromazine and haloperidol). In addition, SNE potentiated the effects of haloperidol and chlorpromazine on apomorphine-induced cage climbing and stereotypy activities in mice.

CONCLUSION

SNE, while exhibiting antipsychotic properties itself, can also potentiate the antipsychotic effects of chlorpromazine and haloperidol.