Curcumin reduces cisplatin-induced neurotoxicity in NGF-differentiated PC12 cells

Biflavonoid quercetin protects against cyclophosphamide-induced organ toxicities via modulation of inflammatory cytokines, brain neurotransmitters, and astrocyte immunoreactivity

BACKGROUND

Cyclophosphamide use has been associated with increased oxidative stress in cells and tissues. Quercetin's antioxidative properties make it of potential benefit in such conditions of oxidative stress.

OBJECTIVE

To assess quercetin's ability to mitigate cyclophosphamide-induced organ toxicities in rats.

METHODS

Sixty rats were assigned into six groups. Groups A and D served as normal and cyclophosphamide control and were fed standard rat chow, groups B and E were fed quercetin supplemented diet (100 mg/kg of feed), while those in groups C and F were fed quercetin at 200 mg/kg of feed. Groups A-C received intraperitoneal (ip) normal saline on days 1 and 2, while D-F received ip cyclophosphamide (150 mg/kg/day on days 1 and 2). On day 21, behavioural tests were carried out, animals were sacrificed and blood samples taken. Organs were processed for histological study.

RESULTS

Quercetin reversed cyclophosphamide-induced decrease in body weight, food intake and total antioxidant capacity, and increase in lipid peroxidation (p = 0.001), It also reversed derangement in levels of liver transaminase, urea, creatinine and proinflammatory cytokines (p = 0.001). Improvement in working-memory and anxiety-related behaviours were also observed. Finally, quercetin reversed alterations in levels of acetylcholine, dopamine and brain-derived neurotropic factor (p = 0.021); while reducing serotonin levels and astrocyte immunoreactivity.

CONCLUSION

Quercetin shows significant ability to protect against cyclophosphamide-induced changes in rats.

Recent Advances in Anticancer Activity of Novel Plant Extracts and Compounds from Curcuma longa in Hepatocellular Carcinoma

PURPOSE

Among all forms of cancers, hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide. There are several treatment options for HCC ranging from loco-regional therapy to surgical treatment. Yet, there is high morbidity and mortality. Recent research focus has shifted towards more effective and less toxic cancer treatment options. Curcumin, the active ingredient in the Curcuma longa plant, has gained widespread attention in recent years because of its multifunctional properties as an antioxidant, anti-inflammatory, antimicrobial, and anticancer agent.

METHODS

A systematic search of PubMed, Embase and Google Scholar was performed for studies reporting incidence of HCC, risk factors associated with cirrhosis and experimental use of curcumin as an anti-cancer agent.

RESULTS

This review exclusively encompasses the anti-cancer properties of curcumin in HCC globally and it's postulated molecular targets of curcumin when used against liver cancers.

CONCLUSIONS

This review is concluded by presenting the current challenges and future perspectives of novel plant extracts derived from C. longa and the treatment options against cancers.

Efficacy of Duloxetine on electrodiagnostic findings of Paclitaxel-induced peripheral neuropathy, does it have a prophylactic effect? A randomized clinical trial

This study aimed to evaluate the efficacy of Duloxetine on electrodiagnostic findings of Paclitaxel-induced peripheral neuropathy in patients with breast cancer. This randomized, double-blind clinical trial was conducted on 40 patients with breast cancer who received Paclitaxel as their first chemotherapy session. All the patients were randomly allocated into two groups, intervention (20 subjects) and placebo (20 subjects). The intervention group received 30 mg duloxetine/day in the first week, followed by 60 mg (twice daily) until 8 weeks. The patient neurotoxicity questionnaire (PNQ) was used to evaluate the severity of neuropathy. Nerve conduction study was also performed. The evaluations were performed at the baseline and 8 weeks after the treatment. Out of 20 subjects in the placebo group, 10 (50%) patients had neurotoxicity (two milds, three moderate, four severe, and one incapacitated), according to PNQ. However, in the duloxetine group, two patients had mild neurotoxicity ( P = 0.03). Significant differences between groups related to the mean of Median Sensory Latency ( P <0.001), Median Motor Latency ( P < 0.001), and Median Motor velocity ( P = 0.001) were reported. However, the relative risk of polyneuropathy between the two groups (relative risk: 1) was not significant. Regarding the results, duloxetine could be an effective treatment for preventing paclitaxel-induced peripheral neuropathy in patients with breast cancer, and an electrodiagnostic study confirmed this effect.

The Therapeutic Potential of Antioxidants in Chemotherapy-Induced Peripheral Neuropathy: Evidence from Preclinical and Clinical Studies

As cancer therapies advance and patient survival improves, there has been growing concern about the long-term adverse effects that patients may experience following treatment, and concerns have been raised about such persistent, progressive, and often irreversible adverse effects. Chemotherapy is a potentially life-extending treatment, and chemotherapy-induced peripheral neuropathy (CIPN) is one of its most common long-term toxicities. At present, strategies for the prevention and treatment of CIPN are still an open problem faced by medicine, and there has been a large amount of previous evidence that oxidative damage is involved in the process of CIPN. In this review, we focus on the lines of defense involving antioxidants that exert the effect of inhibiting CIPN. We also provide an update on the targets and clinical prospects of different antioxidants (melatonin, N-acetylcysteine, vitamins, α-lipoic acid, mineral elements, phytochemicals, nutritional antioxidants, cytoprotectants and synthetic compounds) in the treatment of CIPN with the help of preclinical and clinical studies, emphasizing the great potential of antioxidants as adjuvant strategies to mitigate CIPN.

Superparamagnetic Iron Oxide Nanoparticles and Curcumin Equally Promote Neuronal Branching Morphogenesis in the Absence of Nerve Growth Factor in PC12 Cells

Regeneration of the damaged neurons in neurological disorders and returning their activities are two of the main purposes of neuromedicine. Combination use of specific nanoformulations with a therapeutic compound could be a good candidate for neuroregeneration applications. Accordingly, this research aims to utilize the combination of curcumin, as a neurogenesis agent, with dextran-coated superparamagnetic iron oxide nanoparticles (SPIONs) to evaluate their effects on PC12 cellsʹ neuronal branching morphogenesis in the absence of nerve growth factor. Therefore, the effects of each component alone and in combination form on the cytotoxicity, neurogenesis, and neural branching morphogenesis were evaluated using MTT assay, immunofluorescence staining, and inverted microscopy, respectively. Results confirmed the effectiveness of the biocompatible iron oxide nanoparticles (with a size of about 100 nm) in improving the percentage of neural branching (p < 0.01) in PC12 cells. In addition, the combination use of these nanoparticles with curcumin could enhance the effect of curcumin on neurogenesis (p < 0.01). These results suggest that SPIONs in combination with curcumin could act as an inducing factor on PC12 neurogenesis in the absence of nerve growth factor and could offer a novel therapeutic approach to the treatment of neurodegenerative diseases.

Curcumin: A Novel Way to Improve Quality of Life for Colorectal Cancer Patients?

Colorectal cancer (CRC) is the third most common cancer in men and the second most common in women. Treatment of metastatic CRC consists of highly toxic chemotherapeutic drug combinations that often negatively affect patient quality of life (QoL). Moreover, chemotherapy-induced toxicity and chemotherapy resistance are among the most important factors limiting cancer treatment and can lead to the interruption or discontinuation of potentially effective therapy. Several preclinical studies have demonstrated that curcumin acts through multiple cellular pathways and possesses both anti-cancer properties against CRC and the capacity to mitigate chemotherapy-related side effects and overcome drug resistance. In this review article, we suggest that the addition of curcumin to the standard chemotherapeutic treatment for metastatic CRC could reduce associated side-effects and overcome chemotherapy resistance, thereby improving patient QoL.

Vitamin C (Ascorbic acid) protects from neuropathy caused by cisplatin, through enhanced heat shock protein-70 and reduced oxidant effect

OBJECTIVE:

We aimed to determine whether vitamin C has a protective effect on cisplatin-induced neuropathy in rats.

METHODS:

In total, 24 rats were included in the study of which 8 rats (no drug administered) were categorized as the control group. The remaining 16 rats were given a total dose of 20 mg/kg cisplatin to induce neuropathy. These drug-administered rats (16 rats) were randomly divided into two groups, namely, group-1 (n=8): cisplatin+saline and group-2 (n=8): cisplatin+vitamin C (500 mg/kg/day). All rats were tested for motor function and electromyographic activity 3 days after cisplatin. Motor performance was evaluated by an inclined-plane test. Compound muscle action potential was evaluated. Plasma malondialdehyde, glutathione, tumor necrosis factor-α, interleukin 6, and sciatic nerve HSP 70 levels were measured. Axon diameter and nerve growth factor expression levels were analyzed.

RESULTS:

Plasma malondialdehyde, tumor necrosis factor-α, and interleukin 6 levels were higher in the cisplatin+saline group than control group (p<0.001). But vitamin C significantly reduced malondialdehyde and inflammatory cytokine levels when compared with the cisplatin+saline group (p<0.001). Glutathione levels were lower in both cisplatin+saline and cisplatin+vitamin C groups than control group, but vitamin C significantly ameliorated the glutathione levels (p<0.05). Sciatic heat shock protein-70 levels were significantly higher in the cisplatin+vitamin C group than cisplatin+saline group. Compound muscle action potential amplitude and inclined plane test scores were significantly improved in the vitamin C group (p<0.05). Axon diameter and nerve growth factor expression ameliorated with vitamin C (p<0.05).

CONCLUSIONS:

We demonstrated the ameliorated effects of vitamin C on cisplatin-induced neuropathy through increased heat shock protein-70, nerve growth factor levels, and reduced inflammatory and oxidant effects. The results are promising to improve the neurotoxic effects of cisplatin in cancer patients.

A systematic review of nonclinical studies on the effect of curcumin in chemotherapy-induced cardiotoxicity

BACKGROUND

Various anticancer drugs are effective therapeutic agents for cancer treatment; however, they cause severe toxicity in body organs. Cardiotoxicity is one of the most critical side effects of these drugs. Based on various findings, turmeric extract has positive effects on cardiac cells.

OBJECTIVE

This study aims to evaluate how curcumin as the main component of turmeric may affect chemotherapy-induced cardiotoxicity.

METHOD

Database search was performed up to April 2021 using "curcumin OR turmeric OR Curcuma longa" and "chemotherapy-induced cardiac disease," including all their equivalents and similar terms. After screening the total articles obtained from the electronic databases, 25 relevant articles were included in this systematic review.

RESULTS

The studies demonstrate lower body weight and increased mortality rates due to doxorubicin administration. Besides, cancer therapeutic agents induced various morphological and biochemical abnormalities compared to the non-treated groups. Based on most of the obtained results, curcumin at nontoxic doses can protect the cardiac cells mainly through modulating antioxidant capacity, regulation of cell death, and anti-inflammatory effects. Nevertheless, according to a minority of findings, curcumin increases the susceptibility of the rat cardiomyoblast cell line (H9C2) to apoptosis triggered by doxorubicin.

CONCLUSION

According to most nonclinical studies, curcumin can have the potential of cardioprotective effects against cardiotoxicity induced by chemotherapy. However, based on limited, contradictory findings demonstrating the function of curcumin in potentiating doxorubicin-induced cardiotoxicity, well-designed studies are needed to evaluate the safety and effectiveness of treatment with new formulations of this compound during cancer therapy.

Biodegradable Nanoparticles Loaded with Levodopa and Curcumin for Treatment of Parkinson's Disease

Background: Parkinson’s disease (PD) is the second most common age-related neurodegenerative disorder. Levodopa (L-DOPA) remains the gold-standard drug available for treating PD. Curcumin has many pharmacological activities, including antioxidant, anti-inflammatory, antimicrobial, anti-amyloid, and antitumor properties. Copolymers composed of Poly (ethylene oxide) (PEO) and biodegradable polyesters such as Poly (ε-caprolactone) (PCL) can self-assemble into nanoparticles (NPs). This study describes the development of NH₂–PEO–PCL diblock copolymer positively charged and modified by adding glutathione (GSH) on the outer surface, resulting in a synergistic delivery of L-DOPA curcumin that would be able to pass the blood–brain barrier. Methods: The NH₂–PEO–PCL NPs suspensions were prepared by using a nanoprecipitation and solvent displacement method and coated with GSH. NPs were submitted to characterization assays. In order to ensure the bioavailability, Vero and PC12 cells were treated with various concentrations of the loaded and unloaded NPs to observe cytotoxicity. Results: NPs have successfully loaded L-DOPA and curcumin and were stable after freeze-drying, indicating advancing into in vitro toxicity testing. Vero and PC12 cells that were treated up to 72 h with various concentrations of L-DOPA and curcumin-loaded NP maintained high viability percentage, indicating that the NPs are biocompatible. Conclusions: NPs consisting of NH₂–PEO–PCL were characterized as potential formulations for brain delivery of L-DOPA and curcumin. The results also indicate that the developed biodegradable nanomicelles that were blood compatible presented low cytotoxicity.

Neuron Compatibility and Antioxidant Activity of Barium Titanate and Lithium Niobate Nanoparticles

The biocompatibility and the antioxidant activity of barium titanate (BaTiO₃) and lithium niobate (LiNbO₃) were investigated on a neuronal cell line, the PC12, to explore the possibility of using piezoelectric nanoparticles in the treatment of inner ear diseases, avoiding damage to neurons, the most delicate and sensitive human cells. The cytocompatibility of the compounds was verified by analysing cell viability, cell morphology, apoptotic markers, oxidative stress and neurite outgrowth. The results showed that BaTiO₃ and LiNbO₃ nanoparticles do not affect the viability, morphological features, cytochrome c distribution and production of reactive oxygen species (ROS) by PC12 cells, and stimulate neurite branching. These data suggest the biocompatibility of BaTiO₃ and LiNbO₃ nanoparticles, and that they could be suitable candidates to improve the efficiency of new implantable hearing devices without damaging the neuronal cells.

Curcumin and its derivatives in cancer therapy: Potentiating antitumor activity of cisplatin and reducing side effects

Curcumin is a phytochemical isolated from Curcuma longa with potent tumor-suppressor activity, which has shown significant efficacy in pre-clinical and clinical studies. Curcumin stimulates cell death, triggers cycle arrest, and suppresses oncogenic pathways, thereby suppressing cancer progression. Cisplatin (CP) stimulates DNA damage and apoptosis in cancer chemotherapy. However, CP has adverse effects on several organs of the body, and drug resistance is frequently observed. The purpose of the present review is to show the function of curcumin in decreasing CP's adverse impacts and improving its antitumor activity. Curcumin administration reduces ROS levels to prevent apoptosis in normal cells. Furthermore, curcumin can inhibit inflammation via down-regulation of NF-κB to maintain the normal function of organs. Curcumin and its nanoformulations can reduce the hepatoxicity, neurotoxicity, renal toxicity, ototoxicity, and cardiotoxicity caused by CP. Notably, curcumin potentiates CP cytotoxicity via mediating cell death and cycle arrest. Besides, curcumin suppresses the STAT3 and NF-ĸB as tumor-promoting pathways, to enhance CP sensitivity and prevent drug resistance. The targeted delivery of curcumin and CP to tumor cells can be mediated nanostructures. In addition, curcumin derivatives are also able to reduce CP-mediated side effects, and increase CP cytotoxicity against various cancer types.

Phytochemicals in Chemoprevention: A Cost-Effective Complementary Approach

Cancer is one of the leading causes of death across the world. Although conventional cancer treatments such as chemotherapy and radiotherapy have effectively decreased cancer progression, they come with many dose-limiting side-effects. Phytochemicals that naturally occur in spices, fruits, vegetables, grains, legumes, and other common foods are surprisingly effective complements to conventional cancer treatments. These biologically active compounds demonstrate anticancer effects via cell signaling pathway interference in cancerous cells. In addition, phytochemicals protect non-cancerous cells from chemotherapy-induced side-effects. This paper addresses the not only the potential of phytochemicals quercetin, isoflavones, curcumin, catechins, and hesperidin in terms of cancer treatment and protection against side-effects of chemotherapy, but also methods for increasing phytochemical bioavailability.

Neuroprotective Effects of Curcumin in Methamphetamine-Induced Toxicity

Curcumin (CUR), a natural polyphenol extracted from rhizome of the Curcuma longa L, has received great attention for its multiple potential health benefits as well as disease prevention. For instance, CUR protects against toxic agents acting on the human body, including the nervous system. In detail, CUR possesses, among others, strong effects as an autophagy activator. The present study indicates that CUR counteracts methamphetamine (METH) toxicity. Such a drug of abuse is toxic by disturbing the autophagy machinery. We profited from an unbiased, low variable cell context by using rat pheochromocytoma PC12 cell line. In such a system, a strong protection was exerted by CUR against METH toxicity. This was associated with increased autophagy flux, merging of autophagosomes with lysosomes and replenishment of autophagy vacuoles with LC3, which instead is moved out from the vacuoles by METH. This is expected to enable the autophagy machinery. In fact, while in METH-treated cells the autophagy substrates α-synuclein accumulates in the cytosol, CUR speeds up α-synuclein clearance. Under the effects of CUR LC3 penetrate in autophagy vacuoles to commit them to cell clearance and promotes the autophagy flux. The present data provide evidence that CUR counteracts the neurotoxic effects induced by METH by promoting autophagy.

PC12 and THP-1 Cell Lines as Neuronal and Microglia Model in Neurobiological Research

Models based on cell cultures have become a useful tool in modern scientific research. Since primary cell lines are difficult to obtain and handle, neoplasm-derived lines like PC12 and THP-1 offer a cheap and flexible solution for neurobiological studies but require prior differentiation to serve as a neuronal or microglia model. PC12 cells constitute a suitable research model only after differentiation by incubation with nerve growth factor (NGF) and THP-1 cells after administering a differentiation factor such as phorbol 12-myristate-13-acetate (PMA). Still, quite often, studies are performed on these cancer cells without differentiation. The study aimed to assess the impact of PC12 or THP-1 cell differentiation on sensitivity to harmful factors such as Aβ25-35 (0.001–5 µM) (considered as one of the major detrimental factors in the pathophysiology of Alzheimer’s disease) or lipopolysaccharide (1–100 µM) (LPS; a pro-inflammatory factor of bacterial origin). Results showed that in most of the tests performed, the response of PC12 and THP-1 cells induced to differentiation varied significantly from the effect in undifferentiated cells. In general, differentiated cells showed greater sensitivity to harmful factors in terms of metabolic activity and DNA damage, while in the case of the free radicals, the results were heterogeneous. Obtained data emphasize the importance of proper differentiation of cell lines of neoplastic origin in neurobiological research and standardization of cell culture handling protocols to ensure reliable results.

Effect of vitamin E on cisplatin-induced memory impairment in male rats

OBJECTIVE

Neurotoxicity is an adverse effect caused by cisplatin due to inflammation and oxidative stress in the central nervous system. The present study aimed to assess the effects of vitamin E injection on the learning and memory of rats with cisplatin-induced cognitive impairment.

METHODS

Male rats were administered with cisplatin (2 mg/kg/7 day; intraperitoneally [i i.p.]) and/or vitamin E (200 mg/kg/7 day; i.p.) for 1 week, and the control group received saline solution. Spatial memory was evaluated using Morris water maze (MWM). In addition, the hippocampal concentrations of malondialdehyde (MDA), thiol, and superoxide dismutase (SOD) were measured using biochemical methods.

RESULTS

According to the findings, cisplatin significantly increased the escape latency, while decreasing the time spent and travelled pathway in the target quadrant on the final trial day compared to the control group. Furthermore, pre-treatment with vitamin E significantly reversed all the results in the spatial memory test. The biochemical data indicated that vitamin E could decrease MDA activity and increase thiol and SOD activity compared to the control group.

CONCLUSION

According to the results, vitamin E could improve cisplatin-induced memory impairment possibly through affecting the hippocampal oxidative status.

Antioxidant Supplementation in the Treatment of Neurotoxicity Induced by Platinum-Based Chemotherapeutics-A Review

Cancer represents one of the most pernicious public health problems with a high mortality rate among patients worldwide. Chemotherapy is one of the major therapeutic approaches for the treatment of various malignancies. Platinum-based drugs (cisplatin, oxaliplatin, carboplatin, etc.) are highly effective chemotherapeutic drugs used for the treatment of several types of malignancies, but their application and dosage are limited by their toxic effects on various systems, including neurotoxicity. Simultaneously, researchers have tried to improve the survival rate and quality of life of cancer patients and decrease the toxicity of platinum-containing drugs by combining them with non-chemotherapy-based drugs, dietary supplements and/or antioxidants. Additionally, recent studies have shown that the root cause for the many side effects of platinum chemotherapeutics involves the production of reactive oxygen species (ROS) in naive cells. Therefore, suppression of ROS generation and their inactivation with antioxidants represents an appropriate approach for platinum drug-induced toxicities. The aim of this paper is to present an updated review of the protective effects of different antioxidant agents (vitamins, dietary antioxidants and supplements, medicaments, medicinal plants and their bioactive compounds) against the neurotoxicity induced by platinum-based chemotherapeutics. This review highlights the high potential of plant antioxidants as adjuvant strategies in chemotherapy with platinum drugs.

Key Developments in the Potential of Curcumin for the Treatment of Peripheral Neuropathies

Peripheral neuropathies (PN) can be triggered after metabolic diseases, traumatic peripheral nerve injury, genetic mutations, toxic substances, and/or inflammation. PN is a major clinical problem, affecting many patients and with few effective therapeutics. Recently, interest in natural dietary compounds, such as polyphenols, in human health has led to a great deal of research, especially in PN. Curcumin is a polyphenol extracted from the root of Curcuma longa. This molecule has long been used in Asian medicine for its anti-inflammatory, antibacterial, and antioxidant properties. However, like numerous polyphenols, curcumin has a very low bioavailability and a very fast metabolism. This review addresses multiple aspects of curcumin in PN, including bioavailability issues, new formulations, observations in animal behavioral tests, electrophysiological, histological, and molecular aspects, and clinical trials published to date. The, review covers in vitro and in vivo studies, with a special focus on the molecular mechanisms of curcumin (anti-inflammatory, antioxidant, anti-endoplasmic reticulum stress (anti-ER-stress), neuroprotection, and glial protection). This review provides for the first time an overview of curcumin in the treatment of PN. Finally, because PN are associated with numerous pathologies (e.g., cancers, diabetes, addiction, inflammatory disease...), this review is likely to interest a large audience.

Neurotoxicity of antineoplastic drugs: Mechanisms, susceptibility, and neuroprotective strategies

This review summarizes the adverse effects on the central and/or peripheral nervous systems that may occur in response to antineoplastic drugs. In particular, we describe the neurotoxic side effects of the most commonly used drugs, such as platinum compounds, doxorubicin, ifosfamide, 5-fluorouracil, vinca alkaloids, taxanes, methotrexate, bortezomib and thalidomide. Neurotoxicity may result from direct action of compounds on the nervous system or from metabolic alterations produced indirectly by these drugs, and either the central nervous system or the peripheral nervous system, or both, may be affected. The incidence and severity of neurotoxicity are principally related to the dose, to the duration of treatment, and to the dose intensity, though other factors, such as age, concurrent pathologies, and genetic predisposition may enhance the occurrence of side effects. To avoid or reduce the onset and severity of these neurotoxic effects, the use of neuroprotective compounds and/or strategies may be helpful, thereby enhancing the therapeutic effectiveness of antineoplastic drug.

The effect of some natural antioxidants against cisplatin-induced neurotoxicity in rats: behavioral testing

Background

Cisplatin (CP) is a common antineoplastic agent widely used to treat a broad spectrum of cancers. However, its usage for cancer treatment was restricted due to various side effects such as neurotoxicity, nephrotoxicity, hepatotoxicity and ototoxicity. Neurotoxicity in patients who have undergone a complete course of chemotherapy is clinically evident. CP administration caused problems in rats with memory and learning.

Methods

The effect of combination of CP with either thymoquinone (TQ) or geraniol (Ger) on cell viability of human breast cancer cells (MCF-7) was detected by MTT assay. Forty male Wistar albino rats, healthy and adult, were divided into four groups: normal control, CP-treated group, CP + TQ-treated group and CP + Ger-treated group.

Results

Our results demonstrated that prophylactic treatment with either TQ or Ger plus CP enhanced the anticancer effect of CP in MCF-7 cell line. In vivo study showed that CP-treated rats had higher depressives like behavior in open field and Morris water maze test while prophylactic treatment with either TQ or Ger and CP significantly enhanced the performance of depressive-like behavior. Also, histopathological evaluation of brain tissues proved the neurotoxic effect of CP and the possible protective activity of either TQ or Ger.

Conclusion

The findings of the present work revealed that TQ or Ger along with CP may enhance the antitumor effect of CP. Also, spontaneous administration of CP with either TQ or Ger as natural antioxidants may prevent CP-induced neurotoxicity in rats through diminishing the memory and learning impairment.

Curcumin as a preventive or therapeutic measure for chemotherapy and radiotherapy induced adverse reaction: A comprehensive review

Curcumin has attracted much attention for medicinal purposes in wide range of illnesses including cancer. In some studies, its efficacy is evaluated against chemotherapy and radiotherapy induced adverse reaction and also as adjuvant to cancer treatment. Here we have tried to present a comprehensive review on protective and therapeutic effect of curcumin against these side effects. METHOD: The data were collected by searching Scopus, PubMed, Medline, and Cochrane database systematic reviews, using key words "nephrotoxicity", "cardiotoxicity", "genotoxicity", "ototoxicity", "hepatotoxicity", "reproductive toxicity", "myelosuppression", "pulmonary toxicity", "radiotherapy induced side effect" with "turmeric" and "curcumin". Although curcumin has low bioavailability, it has shown brilliant profile on prevention and management of chemotherapy and radiotherapy induced adverse reactions, particularly based on in vitro and in vivo studies and limited number of human studies on radiotherapy adverse reactions. Antioxidant and anti-inflammatory properties of the curcumin are the main proposed mechanism of action for management and prevention of adverse reactions. One of the major points regarding the protective effect of curcumin is its wide tolerable therapeutic range of dose with minimal side effects. Furthermore, new nano-formulations help to improve the bioavailability, increase in efficacy and lower the adverse effects. In conclusion, based on the present knowledge, curcumin has significant supportive potential in patients receiving chemotherapy or radiotherapy and may be suggested as adjutant with cancer treatments. Further well-designed human studies are recommended.

Overview of cisplatin-induced neurotoxicity and ototoxicity, and the protective agents

Cisplatin has dramatically improved the survival rate of cancer patients, but it has also increased the prevalence of hearing and neurological deficits in this population. Cisplatin induces ototoxicity, peripheral (most prevalent) and central (rare) neurotoxicity. This review addresses the ototoxicity and the neurotoxicity associated with cisplatin-based chemotherapy, providing an integrated view of the potential protective agents that have been evaluated in vitro, in vivo and in clinical trials, their targets and mechanisms of protection and their effects on the antitumor activity of cisplatin. So far, the findings are insufficient to support the use of any oto- or neuroprotective agent before, during or after cisplatin chemotherapy. Despite their promising effects in vitro and in animal studies, many agents have not been evaluated in clinical trials. Additionally, the clinical trials have limitations concerning the sample size, controls, measurement, heterogeneous groups, several arms of treatment, short follow-up or no blinding. Besides that, for most agents, the effects on the antitumor activity of cisplatin have not been evaluated in tumor-bearing animals, which discourages clinical trials. Further well-designed randomized controlled clinical trials are necessary to definitely demonstrate the effectiveness of the oto- or neuroprotective agents proposed by animal and in vitro studies.

Combinations of the antioxidants sulforaphane or curcumin and the conventional antineoplastics cisplatin or doxorubicin as prospects for anticancer chemotherapy

Drugs used in clinical oncology have narrow therapeutic indices with adverse toxicity often involving oxidative damage. Chemoresistance to these conventional antineoplastics is usually mediated by oxidative stress-upregulated pathways such as those of nuclear factor-kappa B (NF-κB) and hypoxia-inducible factor-1 alpha (HIF-1α). Accordingly, the use of antioxidants in combinational approaches has begun to be considered for fighting cancer because of both the protective role against adverse effects and the ability to sensitize chemoresistant cancer cells. Nuclear factor erythroid 2-related factor 2 (Nrf2) has been identified as a mediator of the cytoprotection but it is not regularly associated with tumor chemosensitization. However, some Nrf2 inducers could be exerting cytoprotective and chemosensitizing roles through a simple integrated mechanism in which the cellular level of reactive oxygen species is controlled, thus inhibiting the oxidative damage in non-target tissues and the tumor chemoresistance mediated by NF-κB or HIF-1α. As examples to show the general idea of this antioxidant combination chemotherapy, this review explores the preclinical information available for four combinations, each composed by a paradigmatic oncological drug (cisplatin or doxorubicin) and a recognized antioxidant (sulforaphane or curcumin). The issues for translating these outcomes to clinical trials are briefly discussed.

Traditional oriental medicine for sensorineural hearing loss: Can ethnopharmacology contribute to potential drug discovery?

ETHNOPHARMACOLOGICAL RELEVANCE

In Traditional Oriental Medicine (TOM), the development of hearing pathologies is related to an inadequate nourishment of the ears by the kidney and other organs involved in regulation of bodily fluids and nutrients. Several herbal species have historically been prescribed for promoting the production of bodily fluids or as antiaging agents to treat deficiencies in hearing.

AIM OF REVIEW

The prevalence of hearing loss has been increasing in the last decade and is projected to grow considerably in the coming years. Recently, several herbal-derived products prescribed in TOM have demonstrated a therapeutic potential for acquired sensorineural hearing loss and tinnitus. Therefore, the aims of this review are to provide a comprehensive overview of the current known efficacy of the herbs used in TOM for preventing different forms of acquired sensorineural hearing loss and tinnitus, and associate the traditional principle with the demonstrated pharmacological mechanisms to establish a solid foundation for directing future research.

METHODS

The present review collected the literature related to herbs used in TOM or related compounds on hearing from Chinese, Korean, and Japanese herbal classics; library catalogs; and scientific databases (PubMed, Scopus, Google Scholar; and Science Direct).

RESULTS

This review shows that approximately 25 herbal species and 40 active compounds prescribed in TOM for hearing loss and tinnitus have shown in vitro or in vivo beneficial effects for acquired sensorineural hearing loss produced by noise, aging, ototoxic drugs or diabetes. The inner ear is highly vulnerable to ischemia and oxidative damage, where several TOM agents have revealed a direct effect on the auditory system by normalizing the blood supply to the cochlea and increasing the antioxidant defense in sensory hair cells. These strategies have shown a positive impact on maintaining the inner ear potential, sustaining the production of endolymph, reducing the accumulation of toxic and inflammatory substances, preventing sensory cell death and preserving sensory transmission. There are still several herbal species with demonstrated therapeutic efficacy whose mechanisms have not been deeply studied and others that have been traditionally used in hearing loss but have not been tested experimentally. In clinical studies, Ginkgo biloba, Panax ginseng, and Astragalus propinquus have demonstrated to improve hearing thresholds in patients with sensorineural hearing loss and alleviated the symptoms of tinnitus. However, some of these clinical studies have been limited by small sample sizes, lack of an adequate control group or contradictory results.

CONCLUSIONS

Current therapeutic strategies have proven that the goal of the traditional oriental medicine principle of increasing bodily fluids is a relevant approach for reducing the development of hearing loss by improving microcirculation in the blood-labyrinth barrier and increasing cochlear blood flow. The potential benefits of TOM agents expand to a multi-target approach on different auditory structures of the inner ear related to increased cochlear blood flow, antioxidant, anti-inflammatory, anti-apoptotic and neuroprotective activities. However, more research is required, given the evidence is very limited in terms of the mechanism of action at the preclinical in vivo level and the scarce number of clinical studies published.

Chinese Herbal Medicines Facilitate the Control of Chemotherapy-Induced Side Effects in Colorectal Cancer: Progress and Perspective

Side effects, including nausea, vomiting, mucositis, peripheral neuropathy, and diarrhea, have been frequently reported in colorectal cancer (CRC) patients undergoing chemotherapy. Chinese Herbal Medicines (CHMs) display distinct clinical outcomes, as a result, they have been increasingly used as an adjuvant therapy to manage chemotherapy-induced side effects. In this review, we aim to intensively explore the molecular mechanisms of CHMs, underline the significance of CHMs in mitigating the side effects induced by chemotherapy, and examine the necessary studies required to understand the role of CHMs in alleviating chemotherapy-induced side effects. Specifically, ginger, Astragali Radix, and Liujunzi Decoction have been verified to ameliorate nausea and vomiting. Banxia Xiexin Decoction and Huangqin Decoction have been confirmed to be beneficial to mucositis and delayed-onset of diarrhea. Moreover, Niuche Shenqi Wan, Guilong Tongluo Decoction, Huangqi Guizhi Wuwu Decoction, and tumeric have been found to display potential therapeutic effects for preventing the genesis and development of peripheral neurotoxicity. These findings have further emphasized the pivotal role of CHMs in improving the outcomes of chemotherapy-induced side effects in CRC. Nonetheless, more molecular evidence is required to comprehensively understand and more appropriately apply CHMs in routine clinical practice for CRC.

A review of complementary therapies with medicinal plants for chemotherapy-induced peripheral neuropathy

INTRODUCTION

Chemotherapy-induced peripheral neuropathy (CIPN) is a progressive, prolonged, and often irreversible side effect of many chemotherapeutic agents. The development of neuropathic pain is still poorly managed by clinically available drugs at present.

METHODS

In this mini-review, we summarized the current knowledge of pathobiology for CIPN, and selected evidence on the application of complementary therapies in experimental studies.

RESULTS

Medicinal plants are considered to be the most common complementary therapy modalities for CIPN. Therefore, we identified ten medicinal herbal extracts as well as their phytochemicals, and three herbal formulas. Multiple complementary therapies have been used and studied for decades, and their effects against CIPN are focus on anti-oxidative activity. However, there is still controversial due to the diverse manifestations of different antineoplastic agents and complex drug interactions.

CONCLUSIONS

Novel therapies or drugs that have proven to be effective in animals require further investigation, so confirmation of their efficacy and safety will require time.

Preventive Effect of Curcumin Against Chemotherapy-Induced Side-Effects

Cancer is still a severe threat to the health of people worldwide. Chemotherapy is one of main therapeutic approaches to combat cancer. However, chemotherapy only has a limited success with severe side effects, especially causing damage to normal tissues such as bone marrow, gastrointestine, heart, liver, renal, neuron, and auditory tissues, etc. The side-effects limit clinical outcome of chemotherapy and lower patients’ quality of life, and even make many patients discontinue the chemotherapy. Thus, there is a need to explore effective adjuvant strategies to prevent and reduce the chemotherapy-induced side effects. Naturally occurring products provide a rich source for exploring effective adjuvant agents to prevent and reduce the side effects in anticancer chemotherapy. Curcumin is an active compound from natural plant Curcuma longa L., which is widely used as a coloring and flavoring agent in food industry and a herbal medicine in Asian countries for thousands of years to treat vomiting, headache, diarrhea, etc. Modern pharmacological studies have revealed that curcumin has strong antioxidative, anti-microbial, anti-inflammatory and anticancer activities. Growing evidence shows that curcumin is able to prevent carcinogenesis, sensitize cancer cells to chemotherapy, and protect normal cells from chemotherapy-induced damages. In the present article, we review the preventive effect of curcumin against chemotherapy-induced myelosuppression, gastrointestinal toxicity, cardiotoxicity, hepatotoxicity, nephrotoxicity, neurotoxicity, ototoxicity, and genotoxicity, and discuss its action mechanisms.

Mitigation of cisplatin-induced peripheral neuropathy by canagliflozin in rats

Peripheral nervous system neurotoxicity is the most problematic complication of cisplatin treatment. In this study, we have addressed the possible neuroprotective effect of canagliflozin on cisplatin-induced peripheral neurotoxicity in rats. Rats were randomly allocated into the following: control (vehicle) group, received hydhroxypropyl methyl cellulose; cisplatin group, injected cisplatin 2 mg/kg intraperitoneal, twice a week for 5 consecutive weeks; canagliflozin-cisplatin of received canagliflozin, 10 mg/kg/day by gavage and cisplatin in the same schedule like cisplatin group. Thermal nociception and rotarod performance were assessed. Malondialdehyde (MDA), reduced glutathione (GSH), tumor necrosis factor-α (TNF-α), and caspase 3 were determined in serum. Hematoxylin and eosin (H&E) and immunohistochemical stained sciatic nerve sections were examined. Cisplatin induced thermal hypoalgesia and decreased rotarod performance as well as GSH serum level while increased MDA, TNF-α, and caspase-3 serum levels with atrophy and fragmentation of the nerve fibers with decreased expression of myelin basic protein. Canagliflozin prevented thermal hypoalgesia and improved rotarod performance with increment in GSH serum level while decreased MDA, TNF-α, and caspase-3 levels as well as prevented fragmentation of the nerve fibers and enhanced myelin basic protein expression in relation to cisplatin group. Canagliflozin attenuates the neurotoxic effect of cisplatin through anti-inflammatory and anti-oxidant actions as well as inhibition of apoptosis.

Anti-neuroinflammatory Potential of Natural Products in Attenuation of Alzheimer's Disease

Alzheimer's disease (AD) is a chronic progressive neurodegenerative disorder associated with dementia and cognitive impairment most common in elderly population. Various pathophysiological mechanisms have been proposed by numerous researcher, although, exact mechanism is not yet elucidated. Several studies have been indicated that neuroinflammation associated with deposition of amyloid- beta (Aβ) in brain is a major hallmark toward the pathology of neurodegenerative diseases. So, there is a need to unravel the link of inflammatory process in neurodegeneration. Increased microglial activation, expression of cytokines, reactive oxygen species (ROS), and nuclear factor kappa B (NF-κB) participate in inflammatory process of AD. This review mainly concentrates on involvement of neuroinflammation and the molecular mechanisms adapted by various natural compounds, phytochemicals and herbal formulations in various signaling pathways involved in neuroprotection. Currently, pharmacologically active natural products, having anti-neuroinflammatory potential are being focused which makes them potential candidate to cure AD. A number of preclinical and clinical trials have been done on nutritional and botanical agents. Analysis of anti-inflammatory and neuroprotective phytochemicals such as terpenoids, phenolic derivatives, alkaloids, glycosides, and steroidal saponins displays therapeutic potential toward amelioration and prevention of devastating neurodegeneration observed in AD.

Cisplatin and curcumin co-loaded nano-liposomes for the treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) continues to be a leading cause of cancer related death in the world. Conventional chemotherapeutic agents such as cisplatin (CDDP) have an unsatisfactory efficacy on HCC due to the poor response, severe toxicity and drug resistance. Curcumin (CUR) could improve the chemosensitivity of HCC to chemotherapy drugs by regulating a variety of signaling pathways. Herein, we describe a combination strategy using co-loaded liposomes to effectively deliver and release CDDP and curcumin (CUR) to HCC for overcoming the unsatisfactory clinical outcome of CDDP monotherapy. In the study, CDDP and CUR co-loaded liposomes (CDDP/CUR-Lip) were prepared by a reverse microemulsion and film dispersion method and their average particle size 294.6 ± 14.8 nm with uniform size distribution. In vitro study showed that the nano sized CDDP/CUR-Lip could synchronously release both CDDP and CUR to achieve the synergistic effect against HCC cells based on the optimal ratio (1:8) of both drugs. Compared with free drug or encapsulated mono-drug therapy, CDDP/CUR-Lip demonstrated the higher anti-tumor activity in vitro against HepG2 cells with the IC₅₀ of 0.62 μM. In addition, CDDP/CUR-Lip also increased intracellular ROS level during the HCC cells treatment. Furthermore, compared with single drug formulation, CDDP/CUR-Lip showed the elongated retention time (t_1/2 = 2.38 h) and improved antitumor effect in both mouse hepatoma H22 and human HCC HepG2 xenograft models with reduced side effects. In conclusion, CDDP/CUR-Lip provide an attractive and potential strategy to attain synergistic effect of CDDP and CUR for the treatment of HCC.

Curcumin suppresses inflammatory cytokines and heat shock protein 70 release and improves metabolic parameters during experimental sepsis

CONTEXT

Curcumin has been reported to have anti-inflammatory, antioxidant and hypoglycaemic properties, besides reducing mortality in sepsis.

OBJECTIVE

This study evaluates the biological activities of a curcumin dispersion formulated by spray-drying in experimental sepsis.

MATERIALS AND METHODS

Male Wistar rats were subjected to sepsis by caecal ligation and puncture (CLP), controls were sham operated. The animals were treated with curcumin dispersion (100 mg/kg, p.o.) or water for 7 days prior to CLP and at 2 h after surgery. One group was used to analyze curcumin absorption through HPLC; another had the survival rate assessed during 48 h; and from a third group, blood was collected by decapitation to analyze metabolic and inflammatory parameters.

RESULTS

The plasma curcumin levels reached 2.5 ng/mL at 4 h, dropped significantly (p < 0.001) at 6 h (1.2 ng/mL), and were undetectable at 24 h in both groups. Curcumin temporarily increased the survival rate of the septic rats by 20%. Moreover, it attenuated glycaemia (p < 0.05) and volemia (p < 0.05) alterations typically observed during sepsis, and decreased the levels of the proinflammatory cytokines IL-1β and IL-6 in plasma (p < 0.001) and peritoneal lavage fluid (p < 0.05) of septic rats. Serum HSP70 levels were decreased (p < 0.01) at 24 h after CLP.

DISCUSSION AND CONCLUSION

Our results show that the curcumin dispersion dose employed was not detrimental to the septic rats. In fact, it temporarily increased their survival rate, improved important metabolic parameters, reduced proinflammatory cytokines and HSP70 production.

Application of stem cell derived neuronal cells to evaluate neurotoxic chemotherapy

The generation of induced pluripotent stem cells (iPSCs) and differentiation to cells composing major organs has opened up the possibility for a new model system to study adverse toxicities associated with chemotherapy. Therefore, we used human iPSC-derived neurons to study peripheral neuropathy, one of the most common adverse effects of chemotherapy and cause for dose reduction. To determine the utility of these neurons in investigating the effects of neurotoxic chemotherapy, we measured morphological differences in neurite outgrowth, cell viability as determined by ATP levels and apoptosis through measures of caspase 3/7 activation following treatment with clinically relevant concentrations of platinating agents (cisplatin, oxaliplatin and carboplatin), taxanes (paclitaxel, docetaxel and nab-paclitaxel), a targeted proteasome inhibitor (bortezomib), an antiangiogenic compound (thalidomide), and 5-fluorouracil, a chemotherapeutic that does not cause neuropathy. We demonstrate differential sensitivity of neurons to mechanistically distinct classes of chemotherapeutics. We also show a dose-dependent reduction of electrical activity as measured by mean firing rate of the neurons following treatment with paclitaxel. We compared neurite outgrowth and cell viability of iPSC-derived cortical (iCell® Neurons) and peripheral (Peri.4U) neurons to cisplatin, paclitaxel and vincristine. Goshajinkigan, a Japanese herbal neuroprotectant medicine, was protective against paclitaxel-induced neurotoxicity but not oxaliplatin as measured by morphological phenotypes. Thus, we have demonstrated the utility of human iPSC-derived neurons as a useful model to distinguish drug class differences and for studies of a potential neuroprotectant for the prevention of chemotherapy-induced peripheral neuropathy.

Loading cisplatin onto 6-mercaptopurine covalently modified MSNS: a nanomedicine strategy to improve the outcome of cisplatin therapy

In the treatment of cancer patients, cisplatin (CDDP) exhibits serious cardiac and renal toxicities, while classical combinations related to CDDP are unable to solve these problems and may result in worse prognosis. Alternately, this study covalently conjugated 6-mercaptopurine (6MP) onto the surface of mercapto-modified mesoporous silica nanoparticles (MSNS) to form MSNS-6MP and loaded CDDP into the holes on the surface of MSNS-6MP to form MSNS-6MP/CDDP, a tumor-targeting nano-releasing regime for CDDP and 6MP specifically. In the S180 mouse model, the anti-tumor activity and overall survival of MSNS-6MP/CDDP (50 mg·kg⁻¹·day⁻¹, corresponding to 1 mg·kg⁻¹·day⁻¹ of 6MP and 5 mg·kg⁻¹·day⁻¹ of CDDP) were significantly higher than those of CDDP alone (5 mg·kg⁻¹·day⁻¹) or CDDP (5 mg·kg⁻¹·day⁻¹) plus 6MP (1 mg·kg⁻¹·day⁻¹). The assays of serum alanine aminotransferase, aspartate aminotransferase and creatinine, as well as the images of myocardium and kidney histology, support that MSNS-6MP/CDDP is able to completely eliminate liver, kidney and heart toxicities induced by CDDP alone or CDDP plus 6MP.

Therapeutic role of sirtuins in neurodegenerative disease and their modulation by polyphenols

Searching for effective therapeutic agents‏‎ to ‎‏prevent‏ ‏neurodegeneration ‎is a challenging task due ‎to ‎the growing list of neurodegenerative disorders associated with a multitude of inter-related pathways.‎ The induction and inhibition of several different signaling pathways has been shown to slow down and/or attenuate ‎neurodegeneration and decline in cognition and locomotor function. Among these signaling pathways, a new class of enzymes known as sirtuins or silent information regulators of gene transcription has been shown to play important regulatory roles in the ageing process. SIRT1, a nuclear sirtuin, has received ‎particular interest due to its role as a deacetylase for several metabolic and signaling proteins involved in stress response, apoptosis, mitochondrial function, self-renewal, and ‎neuroprotection. ‎A new strategy to treat ‎neurodegenerative diseases is targeted therapy. In ‎this ‎paper, we‎ ‎ reviewed up-to-date findings regarding the targeting of ‎SIRT1 by polyphenolic ‎compounds,‎ ‎as a ‎new ‎‏approach in the search for novel, safe and effective treatments for ‎ ‎neurodegenerative ‎diseases. ‎.

Protective Effect of Selenium Against Cisplatin-Induced Ototoxicity in an Experimental Design

Cisplatin is an effective chemotherapeutic agent in the treatment of several types of malignant solid tumors but its clinical use is associated with ototoxicity. In the present study, we investigated the effect of selenium administration on lipid peroxidation (malondialdehyde [MDA]) and cisplatin-induced ototoxicity in rats. Healthy wistar albino rats (n = 21) were randomly divided into 3 groups: control (C), cisplatin (Cis), cisplatin and selenium (Cis+Se). Cisplatin was administered for 3 days to Cis and Cis+Se groups. Cis+Se group received selenium 5 days before cisplatin injection and continued for 11 consecutive days. Hearing thresholds and lipid peroxidation (MDA) levels of the rats were recorded before injections and at the end of experimental protocol. The cochleas of animals were harvested for histologic and immunuhistochemical examinations. In biochemichal analyses, pretreatment with selenium prevented the elevation of MDA levels in Cis+Se group rats. Moreover, animals in Cis+Se group had better hearing threshold levels than animals in cis group. Samples obtained from the animals in Cis group revealed extensive loss of the normal microarchitecture of the organ of Corti. On the other hand, animals in Cis+Se group exhibited a preservation of the morphology of the organ of Corti and outer hair cells. In the immunohistochemical examinations of cochlear tissues stained with anti-caspase-3, a higher degree of immunopositivity was found in the Cis group. When Cis+Se group and Cis group were compared, significantly less immunopositivity occurred in the Cis+Se group (P < 0.05). Thus, it appears that pretreatment with selenium may reduce cisplatin-induced ototoxicity in rats.

Edaravone alleviates cisplatin-induced neurobehavioral deficits via modulation of oxidative stress and inflammatory mediators in the rat hippocampus

Cisplatin is a chemotherapeutic agent used in the treatment of malignant tumors. A major clinical limitation of cisplatin is its potential toxic effects, including neurotoxicity. Edaravone, a potent free radical scavenger, has been reported to have the neuroprotective effect against neurological deficits. The aim of the present study was to determine the neuroprotective effect of edaravone against cisplatin-induced behavioral and biochemical anomalies in male Wistar rats. Our results showed that cisplatin (5mg/kg/week, i.p.) administration for seven weeks caused marked cognitive deficits and motor incoordination in rats. This was accompanied by oxido-nitrosative stress, neuroinflammation, NF-κB activation and down-regulation of Nrf2/HO-1 gene expression level in the hippocampus. Edaravone (10mg/kg/week, i.p.) treatment for seven weeks inhibited the aforementioned neurobehavioral and neurochemical deficits. Furthermore, edaravone was found to up-regulate the gene expression level of Nrf2/HO-1 and prevented the cisplatin-induced NF-κB activation. These findings demonstrated that oxido-nitrosative stress and inflammatory signaling mediators play a key role in the development of cisplatin-induced neurobehavioral deficits which were prevented by edaravone treatment.

Modulation of neurotrophic signaling pathways by polyphenols

Polyphenols are an important class of phytochemicals, and several lines of evidence have demonstrated their beneficial effects in the context of a number of pathologies including neurodegenerative disorders such as Alzheimer’s and Parkinson’s disease. In this report, we review the studies on the effects of polyphenols on neuronal survival, growth, proliferation and differentiation, and the signaling pathways involved in these neurotrophic actions. Several polyphenols including flavonoids such as baicalein, daidzein, luteolin, and nobiletin as well as nonflavonoid polyphenols such as auraptene, carnosic acid, curcuminoids, and hydroxycinnamic acid derivatives including caffeic acid phentyl ester enhance neuronal survival and promote neurite outgrowth in vitro, a hallmark of neuronal differentiation. Assessment of underlying mechanisms, especially in PC12 neuronal-like cells, reveals that direct agonistic effect on tropomyosin receptor kinase (Trk) receptors, the main receptors of neurotrophic factors including nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) explains the action of few polyphenols such as 7,8-dihydroxyflavone. However, several other polyphenolic compounds activate extracellular signal-regulated kinase (ERK) and phosphoinositide 3-kinase (PI3K)/Akt pathways. Increased expression of neurotrophic factors in vitro and in vivo is the mechanism of neurotrophic action of flavonoids such as scutellarin, daidzein, genistein, and fisetin, while compounds like apigenin and ferulic acid increase cyclic adenosine monophosphate response element-binding protein (CREB) phosphorylation. Finally, the antioxidant activity of polyphenols reflected in the activation of Nrf2 pathway and the consequent upregulation of detoxification enzymes such as heme oxygenase-1 as well as the contribution of these effects to the neurotrophic activity have also been discussed. In conclusion, a better understanding of the neurotrophic effects of polyphenols and the concomitant modulations of signaling pathways is useful for designing more effective agents for management of neurodegenerative diseases.

Chemotherapy-induced peripheral neuropathy: Current status and progress

As there are increasing numbers of cancer survivors, more attention is being paid to the long term unwanted effects patients may experience as a result of their treatment and the impact these side effects can have on their quality of life. Chemotherapy-induced peripheral neuropathy (CIPN) is one of the most common long-term toxicities from chemotherapy. In this review we will briefly review the clinical presentation, evaluation and management of chemotherapy-induced peripheral neuropathy, with a focus on CIPN related to platinum and taxane agents. We will then discuss current clinical models of peripheral neuropathy and ongoing research to better understand CIPN and develop potential treatment options.

Chemotherapy-induced peripheral neurotoxicity and complementary and alternative medicines: progress and perspective

Chemotherapy-induced peripheral neurotoxicity (CIPN) is a severe and dose-limiting side effect of antineoplastic drugs. It can cause sensory, motor and autonomic system dysfunction, and ultimately force patients to discontinue chemotherapy. Until now, little is understood about CIPN and no consistent caring standard is available. Since CIPN is a multifactorial disease, the clinical efficacy of single pharmacological drugs is disappointing, prompting patients to seek alternative treatment options. Complementary and alternative medicines (CAMs), especially herbal medicines, are well known for their multifaceted implications and widely used in human health care. Up to date, several phytochemicals, plant extractions, and herbal formulas have been evaluated for their potential therapeutic benefit of preventing the onset and progression of CIPN in experimental models. Clinical acupuncture has also been shown to improve CIPN symptoms. In this review, we will give an outline of our current knowledge regrading the advanced research of CIPN, the role of CAMs in alleviating CIPN and possible lacunae in research that needs to be addressed.

Neuroprotection by Cocktails of Dietary Antioxidants under Conditions of Nerve Growth Factor Deprivation

Dietary antioxidants may be useful in counteracting the chronic inflammatory status in neurodegenerative diseases by reducing oxidative stress due to accumulation of reactive oxygen species (ROS). In this study, we newly described the efficacy of a number of dietary antioxidants (polyphenols, carotenoids, thiolic compounds, and oligoelements) on viability of neuronal PC12 cells following Nerve Growth Factor (NGF) deprivation, a model of age-related decrease of neurotrophic support that triggers neuronal loss. Neuroprotection by antioxidants during NGF deprivation for 24 h was largely dependent on their concentrations: all dietary antioxidants were able to efficiently support cell viability by reducing ROS levels and restoring mitochondrial function, while preserving the neuronal morphology. Moreover, ROS reduction and neuroprotection during NGF withdrawal were also achieved with defined cocktails of 3-6 different antioxidants at concentrations 5-60 times lower than those used in single treatments, suggesting that their antioxidant activity was preserved also at very low concentrations. Overall, these data indicate the beneficial effects of antioxidants against oxidative stress induced by decreased NGF availability and suggest that defined cocktails of dietary factors at low concentrations might be a suitable strategy to reduce oxidative damage in neurodegenerative diseases, while limiting possible side effects.

The beneficial role of curcumin on inflammation, diabetes and neurodegenerative disease: A recent update

The concept of using phytochemicals has ushered in a new revolution in pharmaceuticals. Naturally occurring polyphenols (like curcumin, morin, resveratrol, etc.) have gained importance because of their minimal side effects, low cost and abundance. Curcumin (diferuloylmethane) is a component of turmeric isolated from the rhizome of Curcuma longa. Research for more than two decades has revealed the pleiotropic nature of the biological effects of this molecule. More than 7000 published articles have shed light on the various aspects of curcumin including its antioxidant, hypoglycemic, anti-inflammatory and anti-cancer activities. Apart from these well-known activities, this natural polyphenolic compound also exerts its beneficial effects by modulating different signalling molecules including transcription factors, chemokines, cytokines, tumour suppressor genes, adhesion molecules, microRNAs, etc. Oxidative stress and inflammation play a pivotal role in various diseases like diabetes, cancer, arthritis, Alzheimer's disease and cardiovascular diseases. Curcumin, therefore, could be a therapeutic option for the treatment of these diseases, provided limitations in its oral bioavailability can be overcome. The current review provides an updated overview of the metabolism and mechanism of action of curcumin in various organ pathophysiologies. The review also discusses the potential for multifunctional therapeutic application of curcumin and its recent progress in clinical biology.

Curcumin alleviates cisplatin-induced learning and memory impairments

The present study has been designed to investigate the role of curcumin on cisplatin-inducedcognitive impairment and to reveal mechanisms of cisplatin's detrimental actions on cognition in rats. Animals were treated with cisplatin (5mg/kg/week) and/or curcumin (300mg/kg/day) for 5weeks. Morris water maze test was used to assess spatial learning and memory. Enzymatic activities of acetylcholinesterase (AChE) and superoxide dismutase (SOD) were evaluated from hippocampus and plasma samples, and malondialdehyde (MDA), which is the end-product of lipid peroxidation, was determined by a colorimetric method. Our results showed that cisplatin (5mg/kg/week, 5weeks) caused learning and memory deficits, elevated MDA content, decreased SOD activity in the hippocampus and plasma, and AChE activity in the hippocampus. Curcumin improved learning and memory in rats with administration of cisplatin. In addition, curcumin significantly reduced the level of MDA and increased the activities of SOD and AChE. Taken together, our findings indicate that curcumin ameliorates cisplatin-induced spatial learning and memory impairment, possibly through restored cholinergic function and enhanced oxidative status.

Phytochemicals that regulate neurodegenerative disease by targeting neurotrophins: a comprehensive review

Alzheimer's disease (AD), characterized by progressive dementia and deterioration of cognitive function, is an unsolved social and medical problem. Age, nutrition, and toxins are the most common causes of AD. However, currently no credible treatment is available for AD. Traditional herbs and phytochemicals may delay its onset and slow its progression and also allow recovery by targeting multiple pathological causes by antioxidative, anti-inflammatory, and antiamyloidogenic properties. They also regulate mitochondrial stress, apoptotic factors, free radical scavenging system, and neurotrophic factors. Neurotrophins such as BDNF, NGF, NT3, and NT4/5 play a vital role in neuronal and nonneuronal responses to AD. Neurotrophins depletion accelerates the progression of AD and therefore, replacing such neurotrophins may be a potential treatment for neurodegenerative disease. Here, we review the phytochemicals that mediate the signaling pathways involved in neuroprotection specifically neurotrophin-mediated activation of Trk receptors and members of p75(NTR) superfamily. We focus on representative phenolic derivatives, iridoid glycosides, terpenoids, alkaloids, and steroidal saponins as regulators of neurotrophin-mediated neuroprotection. Although these phytochemicals have attracted attention owing to their in vitro neurotrophin potentiating activity, their in vivo and clinical efficacy trials has yet to be established. Therefore, further research is necessary to prove the neuroprotective effects in preclinical models and in humans.

Curcumin Ameliorates Functional and Structural Abnormalities in Cisplatin-induced Neuropathy

Peripheral neuropathy is one of the major side effects of cisplatin; however, effective treatments are lacking. Curcumin is a polyphenol found in the root of Curcuma longa and has been shown neuroprotective against several neurological diseases. Nevertheless, its effects on cisplatin neuropathy remain unclear. This study aimed to clarify this issue by inducing neuropathy in the rats with intraperitoneal injection of cisplatin 2 mg/kg twice a week for 5 consecutive weeks. Curcumin 200 mg/kg/day was given by gavage to a group of cisplatin-treated rats during these five weeks. The results showed that cisplatin induced thermal hypoalgesia in the 5^th week which could be prevented by curcumin. In the 5^th and 8^th weeks, sciatic motor nerve conduction velocity was reduced in the cisplatin compared with the control groups. Curcumin significantly attenuated this deficit. Morphometric analysis of L4 dorsal root ganglia from the cisplatin group revealed nuclear and nucleolar atrophy including loss of neurons in the 8^th week. These alterations were significantly blocked by curcumin. Moreover, curcumin also ameliorated the reduced myelin thickness in the sciatic nerve of cisplatin-treated rats. Taken together, our findings suggest the favorable effects of curcumin on both functional and structural abnormalities in cisplatin neuropathy. Future studies are needed to clarify the exact underlying mechanisms.