Pharmacology of natural radioprotectors

Food Polyphenols in Radiation-Related Diseases: The Roles and Possible Mechanisms

PURPOSE OF REVIEW

As science and technology continue to evolve, the potential harm of radiation to the human body cannot be overlooked. Radiation has the capacity to inflict cellular and body-wide damage. Polyphenols are a group of naturally occurring compounds that are found in an array of plant foods. Scientific studies have demonstrated that these compounds possess noteworthy anti-radiation efficacy. Furthermore, they have been observed to be less toxic at higher doses. In the present review, we discussed the mechanisms of ionizing radiation damage and the progress in the research on the radiation resistance mechanism of polyphenol compounds, to provide guidance for the prevention and treatment of radiation related diseases.

RECENT FINDINGS

Food polyphenols can reduce the oxidative damage caused by ionizing radiation, clear free radicals, reduce DNA damage, regulate NF-KB, MAPK, JAK/STAT, Wnt and other signaling pathways, improve immune function, and have significant protective effects on radiation-induced inflammation, fibrosis, cancer and other aspects. In addition, it also has significant dual effects on radiation sensitization and radiation protection. Food polyphenols come from a wide range of sources, are abundant in daily food, and have no toxic side effects, demonstrating that food polyphenols have great advantages in preventing and treating radiation-related diseases.

Impact of dietary ingredients on radioprotection and radiosensitization: a comprehensive review

Radiation exposure poses significant health risks, particularly in radiotherapy and nuclear accidents. Certain dietary ingredients offer potential radioprotection and radiosensitization. In this review, we explore the impact of dietary ingredients, including vitamins, minerals, antioxidants, and other bioactive compounds, on radiation sensitivity and their potential for radioprotection. Radiosensitizers reoxygenate hypoxic tumor cells, increase the radiolysis of water molecules, and regulate various molecular mechanisms to induce cytotoxicity and inhibit DNA repair in irradiated tumor cells. Several dietary ingredients, such as vitamins C, E, selenium, and phytochemicals, show promise in protecting against radiation by reducing radiation-induced oxidative stress, inflammation, and DNA damage. Radioprotectors, such as ascorbic acid, curcumin, resveratrol, and genistein, activate and modulate various signaling pathways, including Keap1-Nrf2, NF-κB, PI3K/Akt/mammalian target of rapamycin (mTOR), STAT3, and mitogen-activated protein kinase (MAPK), in response to radiation-induced oxidative stress, regulating inflammatory cytokine expression, and promoting DNA damage repair and cell survival. Conversely, natural dietary radiosensitizers impede these pathways by enhancing DNA damage and inducing apoptosis in irradiated tumor cells. Understanding the molecular basis of these effects may aid in the development of effective strategies for radioprotection and radiosensitization in cancer treatment. Dietary interventions have the potential to enhance the efficacy of radiation therapy and minimize the side effects associated with radiation exposure.

Modulatory effect of the fruit rind extract of Garcinia indica Choisy against gamma radiation induced damage in human peripheral blood lymphocytes: a preliminary study

PURPOSE

Nowadays people are exposed to radiation due to various reasons, including natural, diagnostic, occupational or accidental exposure. High level of exposure to ionizing radiation can be fatal to human body. Synthetic drugs used to prevent radiation-induced damage are toxic in nature. Recently, Herbal drugs are being screened as an alternative due to their mechanism of action. Garcinia indica (G. indica) is one of the traditional medicinal plant which contains phytochemicals having several medicinal properties.

MATERIALS AND METHODS

In this study, G. indica extract was observed for its modulatory effect against 3 Gray (Gy) gamma radiation-induced damages in human peripheral blood lymphocytes. Various concentrations of G. indica extract ranging from 1 to 25 µg/mL was added to the blood post irradiation at 0 hr. Chromosomal aberration (CA) and Cytochalasin B blocked Micronuclei Cytome (CBMN) Assay were performed as per standard procedure.

RESULTS

Radiomodulatory effect of Garcinia indica fruit rind extract (GIFRE) on CA and MN formation was observed in this study. Treatment of GIFRE did not affect the mitotic index. Positive inhibition percentages for dicentrics, total chromosomal aberrations and micronuclei were observed except for one instance.

CONCLUSION

Owing to the various properties of Garcinia extracts, it makes it a potential candidate to be tested for its radiomodulatory effect. Based on the results observed in this preliminary study, it could act as a radiomodulatory agent. Radiomodulatory effect of GIFRE could possibly serve it as a potential herbal medicinal alternative to current drugs. However, results of this study need to be validated on larger sample size.

Insights into the radioprotective efficacy of Pterocarpus santalinus L. aqueous extract

In the present study, we have attempted a comprehensive assessment of the possible radioprotective efficacy of Pterocarpus santalinus aqueous extract (PSAE). All the studied models were gamma-irradiated with prior treatment with PSAE. First, the content of total phenols (4.061 μg/mg gallic acid equivalents), flavonoids (6.616 μg/mg quercetin equivalents), and tannins (0.008 mg/L of PSAE) were determined spectrophotometrically. Second, UHPLC-HRMS analysis was performed to identify the possible radioprotectors. Of those, santalins A & B are known for their usage as natural color in foods and alcoholic beverages identified in PSAE. Treatment was well tolerated with no side effects from PSAE. Later, it was shown that radiation-induced lethality significantly amended in PSAE-treated spleen lymphocytes as evidenced by reduced elevated levels of ROS and lipid peroxidation, restored total thiols and GSH: GSSG, inhibited DNA DSBs and cell death. Furthermore, an immunomodulation study was carried out because radiation exposure induces an inflammatory response. Our study shows that PSAE suppressed concanavalin A-induced T-cell proliferation as evidenced by CFSE dye dilution and CD69 antibody staining methods. Taken together, the current study explored the protective efficacy of PSAE from gamma radiation-inflicted injuries and hence we recommend PSAE as a potent radioprotective formulation.

Review of the evidence of radioprotective potential of creatine and arginine as dietary supplements

PURPOSE

Creatine (Cr) and l-arginine are naturally occurring guanidino compounds, commonly used as ergogenic dietary supplements. Creatine and l-arginine exhibit also a number of non-energy-related features, such as antioxidant, anti-apoptotic, and anti-inflammatory properties, which contribute to their protective action against oxidative stress (OS). In this regard, there are a number of studies emphasizing the protective effect of Cr against OS, which develops in the process of aging, increased physical loads as part of athletes' workouts, as well as a number of neurological diseases and toxic effects associated with xenobiotics and UV irradiation. Against this backdrop, and since ionizing radiation causes OS in cells, leading to radiotoxicity, there is an increasing interest to understand whether Cr has the full potential to serve as an effective radioprotective agent. The extensive literature search did not provide any data on this issue. In this narrative review, we have summarized some of our own experimental data published over the last years addressing the respective radioprotective effects of Cr. Next, we have additionally reviewed the existing data on the radiomodifying effects of l-arginine presented earlier by other research groups.

CONCLUSIONS

Creatine possesses significant radioprotective potential including: (1) radioprotective effect on the survival rate of rats subjected to acute whole-body X-ray irradiation in a LD70/30 dose of 6.5 Gy, (2) radioprotective effect on the population composition of peripheral blood cells, (3) radioprotective effect on the DNA damage of peripheral blood mononuclear cells, (4) radioprotective effect on the hepatocyte nucleus-nucleolar apparatus, and (5) radioprotective effect on the brain and liver Cr-Cr kinase systems of the respective animals. Taking into account these cytoprotective, gene-protective, hepatoprotective and energy-stimulating features of Cr, as well as its significant radioprotective effect on the survival rate of rats, it can be considered as a potentially promising radioprotector for further preclinical and clinical studies. The review of the currently available data on radiomodifying effects of l-arginine has indicated its significant potential as a radioprotector, radiomitigator, and radiosensitizer. However, to prove the effectiveness of arginine (Arg) as a radioprotective agent, it appears necessary to expand and deepen the relevant preclinical studies, and, most importantly, increase the number of proof-of-concept clinical trials, which are evidently lacking as of now.

Fraxin (7-hydroxy-6-methoxycoumarin 8-glucoside) confers protection against ionizing radiation-induced intestinal epithelial injury in vitro and in vivo

The small intestine exhibits remarkable sensitivity to ionizing radiation (IR), which significantly hampers the effectiveness of radiotherapy in the treatment of abdominal and pelvic tumors. Unfortunately, no effective medications are available to treat radiation-induced intestinal damage (RIID). Fraxin (7-hydroxy-6-methoxycoumarin 8-glucoside), is a coumarin derivative extracted from the Chinese herb Cortex Fraxini. Several studies have underscored the anti-inflammatory, antibacterial, antioxidant, and immunomodulatory properties of fraxin. However, the efficacy of fraxin at preventing or mitigating RIID remains unclear. Thus, the present study aimed to investigate the protective effects of fraxin against RIID in vitro and in vivo and to elucidate the underlying mechanisms. The study findings revealed that fraxin markedly ameliorated intestinal injuries induced by 13 Gy whole abdominal irradiation (WAI), which was accompanied by a significant increase in the population of Lgr5+ intestinal stem cells (ISCs) and Ki67+ progeny. Furthermore, fraxin mitigated WAI-induced intestinal barrier damage, and reduced oxidative stress and intestinal inflammation in mice. Transcriptome sequencing of fraxin-treated mice revealed upregulation of IL-22, a pleiotropic cytokine involved in regulating the function of intestinal epithelial cells. Moreover, in both human intestinal epithelial cells and ex vivo cultured mouse intestinal organoids, fraxin effectively ameliorated IR-induced damage by promoting the expression of IL-22. The radioprotective effects of fraxin were partially negated in the presence of an IL-22-neutralizing antibody. In summary, fraxin is demonstrated to possess the ability to alleviate RIID and maintain intestinal homeostasis, suggesting that fraxin might serve as a strategy for mitigating accidental radiation exposure- or radiotherapy-induced RIID.

The scheme, and regulative mechanism of pyroptosis, ferroptosis, and necroptosis in radiation injury

Radiotherapy (RT) stands as the primary treatment for tumors, but it inevitably causes damage to normal cells. Consequently, radiation injury is a crucial consideration for radiation oncologists during therapy planning. Cell death including apoptosis, autophagy, pyroptosis, ferroptosis, and necroptosis play significant roles in tumor treatment. While previous studies elucidated the induction of apoptosis and autophagy by ionizing radiation (IR), recent attention has shifted to pyroptosis, ferroptosis, and necroptosis, revealing their effects induced by IR. This review aims to summarize the strategies employed by IR, either alone or in combination therapy, to induce pyroptosis, ferroptosis, and necroptosis in radiation injury. Furthermore, we explore their effects and molecular pathways, shedding light on their roles in radiation injury. Finally, we summarize the regulative agents for these three types of cell death and their mechanisms. In summary, optimizing radiation dose, dose rate, and combined treatment plans to minimize radiation damage and enhance the killing effect of RT is a key focus.

Optimization of radioprotective dose of Juglans nigra leaf extract using response surface methodology

J. nigra leaf contains mixture of various pharmacologically active compounds and it is assumed that they may have the potential radioprotective effect. The purpose of this work was to predict radioprotective doses by correlating changes in organ distribution of radiopharmaceuticals with extract dose levels and rat body weight using response surface methodology (RSM) based on a second-order polynomial equation. The extract was administered daily by oral gavage to rats at dose of 6.9, 10.3, or 13.7 mg kg-1 body weight (bw) day-1 for 10 days. On the eleventh day, 0.1 ml of the one radiopharmaceutical (Na99mTcO4, 99mTc-dimercaptosuccinic acid and 99mTc-tin colloid) was injected into the tail vein. The statistical parameters: the coefficient of determination (0.81-0.95), the coefficient of variation (3.05-11.1), the adequate precision (8.82-19.12) and the mean relative percentage deviation (± 2.3-8.2) were indicated the precision and reliability of RSM. Using RSM, the predicted daily dose of leaf extract ranging from 11.19 to 11.99 mg kg-1 bw may be considered as an optimal daily radiopotective dose for protection of organs from radiation in cases of planned radiation exposures.

Effect of adenosine treatment on ionizing radiation toxicity in zebrafish early life stages

The danger of ionizing radiation exposure to human health is a concern. Since its wide use in medicine and industry, the development of radioprotectors has been very significant. Adenosine exerts anti-inflammatory actions and promotes tissue protection and repair, by activating the P1 receptors (A1, A2A, A2B, and A3). Zebrafish (Danio rerio) is an appropriate tool in the fields of toxicology and pharmacology, including the evaluation of radiobiological outcomes and in the search for radioprotector agents. This study aims to evaluate the effect of adenosine in the toxicity induced by radiation in zebrafish. Embryos were treated with 1, 10, or 100 µM adenosine, 30 min before the exposure to 15 Gy of gamma radiation. Adenosine potentiated the effects of radiation in heart rate, body length, and pericardial edema. We evaluated oxidative stress, tissue remodeling and inflammatory. It was seen that 100 µM adenosine reversed the inflammation induced by radiation, and that A2A2 and A2B receptors are involved in these anti-inflammatory effects. Our results indicate that P1R activation could be a promising pharmacological strategy for radioprotection.

Radioprotective Potency of Nanoceria

Cancer presents a significant medical challenge that requires effective management. Current cancer treatment options, such as chemotherapy, targeted therapy, radiotherapy, and immunotherapy, have limitations in terms of their efficacy and the potential harm they can cause to normal tissues. In response, researchers have been focusing on developing adjuvants that can enhance tumor responses while minimizing damage to healthy tissues. Among the promising options, nanoceria (NC), a type of nanoparticle composed of cerium oxide, has garnered attention for its potential to improve various cancer treatment regimens. Nanoceria has demonstrated its ability to exhibit toxicity towards cancer cells, inhibit invasion, and sensitize cancer cells to both radiation therapy and chemotherapy. The remarkable aspect is that nanoceria show minimal toxicity to normal tissues while protecting against various forms of reactive oxygen species generation. Its capability to enhance the sensitivity of cancer cells to chemotherapy and radiotherapy has also been observed. This paper thoroughly reviews the current literature on nanoceria's applications within different cancer treatment modalities, with a specific focus on radiotherapy. The emphasis is on nanoceria's unique role in enhancing tumor radiosensitization and safeguarding normal tissues from radiation damage.

Protective Effects of Alpha-lipoic Acid, Resveratrol, and Apigenin Against Oxidative Damages, Histopathological Changes, and Mortality Induced by Lung Irradiation in Rats

AIM

This study investigated the protective effects of three antioxidants on radiationinduced lung injury.

BACKGROUND

Oxidative stress is one of the key outcomes of radiotherapy in normal tissues. It can induce severe injuries in lung tissue, which may lead to pneumonitis and fibrosis. Recently, interest in natural chemicals as possible radioprotectors has increased due to their reduced toxicity, cheaper price, and other advantages.

OBJECTIVE

The present study was undertaken to evaluate the radioprotective effect of Alpha-lipoic Acid (LA), Resveratrol (RVT), and Apigenin (APG) against histopathological changes and oxidative damage and survival induced by ionizing radiation (IR) in the lung tissues of rats.

METHODS

First, the lung tissue of 50 mature male Wistar rats underwent an 18 Gy gamma irradiation. Next, the rats were sacrificed and transverse sections were obtained from the lung tissues and stained with hematoxylin and eosin (H and E) and Mason trichrome (MTC) for histopathological evaluation. Then, the activity of Glutathione peroxidase (GPx), Superoxide Dismutase (SOD), and Malondialdehyde (MDA) was measured by an ELISA reader at 340, 405, and 550 nm.

RESULTS

Based on the results of this study, IR led to a remarkable increase in morphological changes in the lung. However, APG, RVT, and LA could ameliorate the deleterious effects of IR in lung tissue. IR causes an increase in GPX level, and APG+IR administration causes a decrease in the level of GPX compared to the control group. Also, the results of this study showed that RVT has significant effects in reducing MDA levels in the short term. In addition, compared to the control group, IR and RVT+IR decrease the activity of SOD in the long term in the lung tissues of rats. Also, the analysis of results showed that weight changes in IR, LA+IR, APG+IR, and control groups were statistically significant.

CONCLUSION

APG and RVT could prevent tissue damage induced by radiation effects in rat lung tissues. Hence, APG, LA, and RVT could provide a novel preventive action with their potential antioxidant anti-inflammatory properties, as well as their great safety characteristic.

Bis(1-methylimidazol-2-yl) diselenide and its evaluation as a chemical radio-protector: role of kinetic rate constants for ROS scavenging and glutathione peroxidase like activity

Bis(1-methylimidazol-2-yl) diselenide (MeImSe), a derivative of selenoneine, has been examined for bimolecular rate constants for scavenging of various radiolytically and non-radiolytically generated reactive oxygen species (ROS). Further, its potential to show glutathione peroxidase (GPx)-like activity and to protect in vitro models of DNA and lipid against radiation induced strand breakage and lipid peroxidation, respectively were studied. The results confirmed that MeImSe scavenged all major short-lived (hydroxyl radical) and long-lived (peroxyl radical, carbonate radical, nitrogen dioxide radical, hypochlorite and hydrogen peroxide) oxidants involved in the radiation toxicity either directly or through GPx-like catalytic mechanism. The rate constants of MeImSe for these oxidants were found to be comparable to analogous sulfur and selenium-based compounds. The enzyme kinetics study established that MeImSe took part in the GPx cycle through the reductive pathway. Further, MeImSe inhibited the radiation induced DNA strand cleavage and lipid peroxidation with half maximal inhibitory concentration (IC50) of ∼ 60 μM and ∼100 μM, respectively. Interestingly, MeImSe treatment in the above concentration range (>100 μM) did not show any significant toxicity in normal human lung fibroblast (WI26) cells. The balance between efficacy and toxicity of MeImSe as a chemical radioprotector was attributed to the formation of less reactive intermediates during its oxidation/reduction reactions as evidenced from NMR studies.HighlightsMeImSe, a derivative of selenoneine protects DNA and lipid from radiation damageMeImSe scavenges all major short- and long-lived oxidants involved in radiation toxicityRate constants of MeImSe for ROS scavenging determined by pulse radiolysis techniqueFirst organoselenium compound reported to scavenge nitrogen dioxide radicalMeImSe exhibits GPx-like activity through reductive pathway.

Crosstalk between Oxidative Stress and Inflammation Induced by Ionizing Radiation in Healthy and Cancerous Cells

Radiotherapy (RT) is a unique modality in cancer treatment with no replacement in many cases and uses a tumoricidal dose of various ionizing radiation (IR) types to kill cancer cells. It causes oxidative stress through reactive oxygen species (ROS) production or the destruction of antioxidant systems. On the other hand, RT stimulates the immune system both directly and indirectly by releasing danger signals from stress-exposed and dying cells. Oxidative stress and inflammation are two reciprocal and closely related mechanisms, one induced and involved by the other. ROS regulates the intracellular signal transduction pathways, which participate in the activation and expression of pro-inflammatory genes. Reciprocally, inflammatory cells release ROS and immune system mediators during the inflammation process, which drive the induction of oxidative stress. Oxidative stress or inflammation-induced damages can result in cell death (CD) or survival mechanisms that may be destructive for normal cells or beneficial for cancerous cells. The present study has focused on the radioprotection of those agents with binary effects of antioxidant and anti-inflammatory mechanisms IR-induced CD.

Chinese herbal injections in combination with radiotherapy for advanced pancreatic cancer: A systematic review and network meta-analysis

Background

Advanced pancreatic cancer (APC) is a fatal disease with limited treatment options. This study aims to evaluate the effectiveness and safety of different Chinese herbal injections (CHIs) as adjuvants for radiotherapy (RT) in APC and compare their treatment potentials using network meta-analysis.

Methods

We systematically searched three English and four Chinese databases for randomized controlled trials (RCTs) from inception to July 25, 2023. The primary outcome was the objective response rate (ORR). Secondary outcomes included Karnofsky performance status (KPS) score, overall survival (OS), and adverse events (AEs). The treatment potentials of different CHIs were ranked using the surface under the cumulative ranking curve (SUCRA). The Cochrane RoB 2 tool and CINeMA were used for quality assessment and evidence grading.

Results

Eighteen RCTs involving 1199 patients were included. Five CHIs were evaluated. Compound Kushen injection (CKI) combined with RT significantly improved ORR compared to RT alone (RR 1.49, 95 % CrI 1.21-1.86). Kanglaite (KLT) plus RT (RR 1.58, 95 % CrI 1.20-2.16) and CKI plus RT (RR 1.49, 95 % CrI 1.16-1.95) were associated with improved KPS score compared to radiation monotherapy, with KLT+RT being the highest rank (SUCRA 72.28 %). Regarding AEs, CKI plus RT was the most favorable in reducing the incidence of leukopenia (SUCRA 90.37 %) and nausea/vomiting (SUCRA 85.79 %).

Conclusions

CKI may be the optimal choice of CHIs to combine with RT for APC as it may improve clinical response, quality of life, and reduce AEs. High-quality trials are necessary to establish a robust body of evidence.

Protocol registration

PROSPERO, CRD42023396828.

Evaluation of deep space exploration risks and mitigations against radiation and microgravity

Ionizing radiation and microgravity are two considerable health risks encountered during deep space exploration. Both have deleterious effects on the human body. On one hand, weightlessness is known to induce a weakening of the immune system, delayed wound healing and musculoskeletal, cardiovascular, and sensorimotor deconditioning. On the other hand, radiation exposure can lead to long-term health effects such as cancer and cataracts as well as have an adverse effect on the central nervous and cardiovascular systems. Ionizing radiation originates from three main sources in space: galactic cosmic radiation, solar particle events and solar winds. Furthermore, inside the spacecraft and inside certain space habitats on Lunar and Martian surfaces, the crew is exposed to intravehicular radiation, which arises from nuclear reactions between space radiation and matter. Besides the approaches already in use, such as radiation shielding materials (such as aluminium, water or polyethylene), alternative shielding materials (including boron nanotubes, complex hybrids, composite hybrid materials, and regolith) and active shielding (using fields to deflect radiation particles) are being investigated for their abilities to mitigate the effects of ionizing radiation. From a biological point of view, it can be predicted that exposure to ionizing radiation during missions beyond Low Earth Orbit (LEO) will affect the human body in undesirable ways, e.g., increasing the risks of cataracts, cardiovascular and central nervous system diseases, carcinogenesis, as well as accelerated ageing. Therefore, it is necessary to assess the risks related to deep space exploration and to develop mitigation strategies to reduce these risks to a tolerable level. By using biomarkers for radiation sensitivity, space agencies are developing extensive personalised medical examination programmes to determine an astronaut's vulnerability to radiation. Moreover, researchers are developing pharmacological solutions (e.g., radioprotectors and radiomitigators) to proactively or reactively protect astronauts during deep space exploration. Finally, research is necessary to develop more effective countermeasures for use in future human space missions, which can also lead to improvements to medical care on Earth. This review will discuss the risks space travel beyond LEO poses to astronauts, methods to monitor astronauts' health, and possible approaches to mitigate these risks.

Dual anticancer activity of Aspergillus nidulans pigment and Ionizing γ-Radiation on human larynx carcinoma cell line

BACKGROUND

Fungi are a readily available source of naturally generated colored compounds. These compounds might be used as radiosensitizers for treating cancer cells.

METHODS

Aspergillus nidulans was examined for its color-producing ability in Potato dextrose agar (PDA) broth medium. The pigment was characterized by Ultraviolet (UV) spectrophotometer and Gas Chromatography Mass Spectrometry (GC/MS). Pigment extracts from A. nidulans were studied for their cytotoxic effects on the growth of human larynx carcinoma cell line (HEp-2) with or without exposure to γ-radiation at three different doses (5, 10, and 15 Gy). A. nidulans pigment cytotoxic activity was tested against normal Vero cells. Cell apoptosis was studied using flow cytometry. Gene expression of P53, Caspase 3 and Bcl-2 were quantified.

RESULTS

Ultraviolet spectrum and GC/MS revealed the ability of Aspergillus nidulans to produce Rhodopin pigment. HEp-2 cells treated with A. nidulans pigment only give IC50 about 208 µg/ml. In contrast, when treated with the pigment +10 Gy γ-radiation, it give about 115 µg/ml. However, for normal cells, lower cytotoxic activity was detected. Treatment with pigment (208 g/mL) caused about 50% ± 1.0 total apoptosis level and gene expression of P53: 2.3 fold and Caspase 3: 1.84 fold in respect to untreated HEp-2), while Bcl-2 was decreased (Bcl-2: 0.63 fold in respect to untreated HEp-2). Furthermore, treated with pigment (115 µg/mL) + 10Gy caused about 47.41% ± 1.7 total apoptosis level and P53: 2.53 fold and Caspase 3: 2.0 fold in respect to untreated HEp-2, while Bcl-2 was downregulated (Bcl-2: 0.61 fold in respect to untreated HEp-2).

CONCLUSION

This study concluded that the anti-cancer activity of Aspergillus nidulans pigment was enhanced by ionizing radiation at 10 Gy, as well as its low cytotoxic activity against normal Vero cells.

Connection between Radiation-Regulating Functions of Natural Products and miRNAs Targeting Radiomodulation and Exosome Biogenesis

Exosomes are cell-derived membranous structures primarily involved in the delivery of the payload to the recipient cells, and they play central roles in carcinogenesis and metastasis. Radiotherapy is a common cancer treatment that occasionally generates exosomal miRNA-associated modulation to regulate the therapeutic anticancer function and side effects. Combining radiotherapy and natural products may modulate the radioprotective and radiosensitizing responses of non-cancer and cancer cells, but there is a knowledge gap regarding the connection of this combined treatment with exosomal miRNAs and their downstream targets for radiation and exosome biogenesis. This review focuses on radioprotective natural products in terms of their impacts on exosomal miRNAs to target radiation-modulating and exosome biogenesis (secretion and assembly) genes. Several natural products have individually demonstrated radioprotective and miRNA-modulating effects. However, the impact of natural-product-modulated miRNAs on radiation response and exosome biogenesis remains unclear. In this review, by searching through PubMed/Google Scholar, available reports on potential functions that show radioprotection for non-cancer tissues and radiosensitization for cancer among these natural-product-modulated miRNAs were assessed. Next, by accessing the miRNA database (miRDB), the predicted targets of the radiation- and exosome biogenesis-modulating genes from the Gene Ontology database (MGI) were retrieved bioinformatically based on these miRNAs. Moreover, the target-centric analysis showed that several natural products share the same miRNAs and targets to regulate radiation response and exosome biogenesis. As a result, the miRNA-radiomodulation (radioprotection and radiosensitization)-exosome biogenesis axis in regard to natural-product-mediated radiotherapeutic effects is well organized. This review focuses on natural products and their regulating effects on miRNAs to assess the potential impacts of radiomodulation and exosome biogenesis for both the radiosensitization of cancer cells and the radioprotection of non-cancer cells.

Exploring Natural Products as Radioprotective Agents for Cancer Therapy: Mechanisms, Challenges, and Opportunities

Radiotherapy is an important cancer treatment. However, in addition to killing tumor cells, radiotherapy causes damage to the surrounding cells and is toxic to normal tissues. Therefore, an effective radioprotective agent that prevents the deleterious effects of ionizing radiation is required. Numerous synthetic substances have been shown to have clear radioprotective effects. However, most of these have not been translated for use in clinical applications due to their high toxicity and side effects. Many medicinal plants have been shown to exhibit various biological activities, including antioxidant, anti-inflammatory, and anticancer activities. In recent years, new agents obtained from natural products have been investigated by radioprotection researchers, due to their abundance of sources, high efficiency, and low toxicity. In this review, we summarize the mechanisms underlying the radioprotective effects of natural products, including ROS scavenging, promotion of DNA damage repair, anti-inflammatory effects, and the inhibition of cell death signaling pathways. In addition, we systematically review natural products with radioprotective properties, including polyphenols, polysaccharides, alkaloids, and saponins. Specifically, we discuss the polyphenols apigenin, genistein, epigallocatechin gallate, quercetin, resveratrol, and curcumin; the polysaccharides astragalus, schisandra, and Hohenbuehelia serotina; the saponins ginsenosides and acanthopanax senticosus; and the alkaloids matrine, ligustrazine, and β-carboline. However, further optimization through structural modification, improved extraction and purification methods, and clinical trials are needed before clinical translation. With a deeper understanding of the radioprotective mechanisms involved and the development of high-throughput screening methods, natural products could become promising novel radioprotective agents.

Liposome Formulations for the Strategic Delivery of PARP1 Inhibitors: Development and Optimization

The development of a lipid nano-delivery system was attempted for three specific poly (ADP-ribose) polymerase 1 (PARP1) inhibitors: Veliparib, Rucaparib, and Niraparib. Simple lipid and dual lipid formulations with 1,2-dipalmitoyl-sn-glycero-3-phospho-rac-(1'-glycerol) sodium salt (DPPG) and 1,2-dipalmitoyl-sn-glycero-3-phosphocoline (DPPC) were developed and tested following the thin-film method. DPPG-encapsulating inhibitors presented the best fit in terms of encapsulation efficiency (>40%, translates into concentrations as high as 100 µM), zeta potential values (below -30 mV), and population distribution (single population profile). The particle size of the main population of interest was ~130 nm in diameter. Kinetic release studies showed that DPPG-encapsulating PARP1 inhibitors present slower drug release rates than liposome control samples, and complex drug release mechanisms were identified. DPPG + Veliparib/Niraparib presented a combination of diffusion-controlled and non-Fickian diffusion, while anomalous and super case II transport was verified for DPPG + Rucaparib. Spectroscopic analysis revealed that PARP1 inhibitors interact with the DPPG lipid membrane, promoting membrane water displacement from hydration centers. A preferential membrane interaction with lipid carbonyl groups was observed through hydrogen bonding, where the inhibitors' protonated amine groups may be the major players in the PARP1 inhibitor encapsulation mode.

In-vivo and in vitro assessments of the radioprotective potential natural and chemical compounds: a review

PURPOSE

The study of the radioactive role of natural and chemical substances on human and animal studies has been the subject of research by some researchers. Therefore, the review of some of the past and current studies conducted in this field, can provide helpful information to elucidate of the importance of radioprotective components in reducing radiation exposure side effects.

METHODS

The authors search for keywords including In vitro, In vivo, Radioprotective, Ionizing radiation, and Vitamin in ScienceDirect, Scopus, Pubmed, and Google Scholar databases to access previously published articles and search for more reference articles on the role of radioprotective materials from natural and chemical compounds.

RESULTS

Radiation exposure can produce reactive oxygen species (ROS) in the body, however most of which are eliminated by the body's natural mechanisms, but when the body's antioxidant systems do not have enough ability to neutralize free radicals, oxidative stress occurs, which causes damage to DNA and body tissues. Therefore, it is necessary use of alternative substances that reduce and inhibit free radicals.

CONCLUSION

In general, recommended that antioxidant component(s) can be protect tissue damages in humans or animals, due to the their ability to scavenge free radicals generated by ionizing radiation.

Review of compounds that exhibit radioprotective and/or mitigatory effects after application of diagnostic or therapeutic ionizing radiation

PURPOSE

Exposure to ionizing radiation can be accidental or for medical purposes. Analyzes of the frequency of radiation damage in the general population, it has been determined that by far the most common are those that occur as a result of diagnostic or therapeutic procedures. Damage caused by radiation, either accidentally or for therapeutic purposes, can be reduced by the use of radioprotectors, mitigators or other therapeutic agents. A detailed research of the available literature shows that there is little systematized data of potentially radioprotective and/or mitigating effects of drugs from the personal therapy of patients during the application of therapeutic ionizing radiation. The aim of this paper is to present review of compounds, especially personal therapy drugs, that exhibit radioprotective and/or mitigating effects after the application of diagnostic or therapeutic ionizing radiation.

CONCLUSIONS

Given the widespread use of ionizing radiation for diagnostic and therapeutic purposes, there is a clear need to create a strategy and recommendations of relevant institutions for the use of radioprotectors and mitigators in everyday clinical practice, with individual evaluation of the patient's condition and selection of the compounds that will show the greatest benefit in terms of radioprotection.

Recent Progress in the Hesperetin Delivery Regimes: Significance of Pleiotropic Actions and Synergistic Anticancer Efficacy

BACKGROUND

In the plant kingdom, flavonoids are widely distributed with multifunctional immunomodulatory actions. Hesperetin (HST) remains one of the well-studied compounds in this domain, initially perceived in citrus plants as an aglycone derivative of hesperidin (HDN).

OBSERVATIONS

Natural origin, low in vivo toxicity, and pleiotropic functional essence are the foremost fascinations for HST use as an anticancer drug. However, low aqueous solubility accompanied with a prompt degradation by intestinal and hepatocellular enzymes impairs HST physiological absorption.

MOTIVATION

Remedies attempted herein comprise the synthesis of derivatives and nanocarrier (NC)-mediated delivery. As the derivative synthesis aggravates the structural complexity, NC-driven HST delivery has emerged as a sustainable approach for its sustained release. Recent interest in HST has been due to its significant anticancer potential, characterized via inhibited cell division (proliferation), new blood vessel formation (angiogenesis), forceful occupation of neighboring cell's space (invasion), migration to erstwhile physiological locations (metastasis) and apoptotic induction. The sensitization of chemotherapeutic drugs (CDs) by HST is driven via stoichiometrically regulated synergistic actions. Purpose and Conclusion: This article sheds light on HST structure-function correlation and pleiotropic anticancer mechanisms, in unaided and NC-administered delivery in singular and with CDs synergy. The discussion could streamline the HST usefulness and long-term anticancer efficacy.

Differential Radiomodulating Action of Olea europaea L. cv. Caiazzana Leaf Extract on Human Normal and Cancer Cells: A Joint Chemical and Radiobiological Approach

The identification of a natural compound with selectively differential radiomodulating activity would arguably represent a valuable asset in the striving quest for widening the therapeutic window in cancer radiotherapy (RT). To this end, we fully characterized the chemical profile of olive tree leaf polyphenols from the Caiazzana cultivar (OLC), autochthonous to the Campania region (Italy), by ultra-high-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HR-MS). Oleacein was the most abundant molecule in the OLC. Two normal and two cancer cells lines were X-ray-irradiated following 24-h treatment with the same concentration of the obtained crude extract and were assessed for their radioresponse in terms of micronucleus (MN) induction and, for one of the normal cell lines, of premature senescence (PS). Irradiation of pre-treated normal cells in the presence of the OLC reduced the frequency of radiation-induced MN and the onset of PS. Conversely, the genotoxic action of ionising radiation was exacerbated in cancer cells under the same experimental conditions. To our knowledge, this is the first report on the dual action of a polyphenol-rich olive leaf extract on radiation-induced damage. If further confirmed, these findings may be pre-clinically relevant and point to a substance that may potentially counteract cancer radioresistance while reducing RT-associated normal tissue toxicity.

Design, synthesis and biological evaluation of 2-pyrrolone derivatives as radioprotectors

It is known that p53 is an important transcription factor and plays a central role in ionizing radiation (IR)-induced DNA damage responses such as cell cycle arrest, DNA repair and apoptosis. We previously reported that regulating p53 protein is an effective strategy for modulating cell fate by reducing the acute side effects of radiation therapy. Herein, we report on the discovery of STK160830 as a new radioprotector from a chemical library at The University of Tokyo and the design, synthesis and biological evaluation of its derivatives. The radioprotective activity of STK160830 itself and its derivatives that were synthesized in this work was evaluated using a leukemia cell line, MOLT-4 cells as a model of normal cells that express the p53 protein in a structure-activity relationships (SAR) study. The experimental results suggest that a direct relationship exists between the inhibitory effect of these STK160830 derivatives on the expression level of p53 and their radioprotective activity and that the suppression of p53 by STK160830 derivatives contribute to protecting MOLT-4 cells from apoptosis that is induced by exposure to radiation.

Lactobacillus reuteri Releasing IL-22 (LR-IL-22) Facilitates Intestinal Radioprotection for Whole-Abdomen Irradiation (WAI) of Ovarian Cancer

Oral administration (gavage) of a second-generation probiotic, Lactobacillus reuteri (L. reuteri), that releases interleukin-22 (LR-IL-22) at 24 h after total-body irradiation (TBI) mitigates damage to the intestine. We determined that LR-IL-22 also mitigates partial-body irradiation (PBI) and whole-abdomen irradiation (WAI). Irradiation can be an effective treatment for ovarian cancer, but its use is limited by intestinal toxicity. Strategies to mitigate toxicity are important and can revitalize this modality to treat ovarian cancer. In the present studies, we evaluated whether LR-IL-22 facilitates fractionated WAI in female C57BL/6 mice with disseminated ovarian cancer given a single fraction of either 15.75 Gy or 19.75 Gy or 4 daily fractions of 6 Gy or 6.5 Gy. Mice receiving single or multiple administrations of LR-IL-22 during WAI showed improved intestinal barrier integrity (P = 0.0167), reduced levels of radiation-induced intestinal cytokines including KC/CXCL1 (P = 0.002) and IFN-γ (P = 0.0024), and reduced levels of plasma, Eotaxin/CCL11 (P = 0.0088). LR-IL-22 significantly preserved the numbers of Lgr5+GFP+ intestinal stem cells (P = 0.0010) and improved survival (P < 0.0343). Female C57BL/6MUC-1 mice with widespread abdominal syngeneic 2F8cis ovarian cancer that received LR-IL-22 during 6.5 Gy WAI in 4 fractions had reduced tumor burden, less intestinal toxicity, and improved 30-day survival. Furthermore, LR-IL-22 facilitated WAI when added to Paclitaxel and Carboplatin chemotherapy and further increased survival. Oral administration (gavage) of LR-IL-22 is a potentially valuable intestinal radioprotector, which can facilitate therapeutic WAI for widespread intra-abdominal ovarian cancer.

Histopathological Evaluation of Protective Effect of Telmisartan against Radiation-Induced Bone Marrow Injury

BACKGROUND

Radiation-induced hematopoietic suppression and myelotoxicity can occur due to the nuclear accidents, occupational irradiation and therapeutic interventions. Bone marrow dysfunction has always been one of the most important causes of morbidity and mortality after ionizing irradiation.

OBJECTIVE

This study aims to investigate the protective effect of telmisartan against radiation-induced bone marrow injuries in a Balb/c mouse model.

MATERIAL AND METHODS

In this experimental study, male Balb/c mice were divided into four groups as follow: group 1: mice received phosphate buffered saline (PBS) without irradiation, group 2: mice received a solution of telmisartan in PBS without irradiation, group 3: mice received PBS with irradiation, and group 4: mice received a solution of telmisartan in PBS with irradiation. A solution of telmisartan was prepared and administered orally at 12 mg/kg body weight for seven consecutive days prior to whole body exposing to a single sub-lethal dose of 5 Gy X-rays. Protection of bone marrow against radiation induced damage was investigated by Hematoxylin-Eosin (HE) staining assay at 3, 9, 15 and 30 days after irradiation.

RESULTS

Histopathological analysis indicated that administration of telmisartan reduced X-radiation-induced damage and improved bone marrow histology. The number of different cell types in bone marrow, including polymorphonuclear /mononuclear cells and megakaryocytes significantly increased in telmisartan treated group compared to the only irradiated group at all-time points.

CONCLUSION

The results of the present study demonstrated an efficient radioprotective effect of telmisartan in mouse bone marrow against sub-lethal X-irradiation.

Nuclear and Radiological Emergencies: Biological Effects, Countermeasures and Biodosimetry

Atomic and radiological crises can be caused by accidents, military activities, terrorist assaults involving atomic installations, the explosion of nuclear devices, or the utilization of concealed radiation exposure devices. Direct damage is caused when radiation interacts directly with cellular components. Indirect effects are mainly caused by the generation of reactive oxygen species due to radiolysis of water molecules. Acute and persistent oxidative stress associates to radiation-induced biological damages. Biological impacts of atomic radiation exposure can be deterministic (in a period range a posteriori of the event and because of destructive tissue/organ harm) or stochastic (irregular, for example cell mutation related pathologies and heritable infections). Potential countermeasures according to a specific scenario require considering basic issues, e.g., the type of radiation, people directly affected and first responders, range of doses received and whether the exposure or contamination has affected the total body or is partial. This review focuses on available medical countermeasures (radioprotectors, radiomitigators, radionuclide scavengers), biodosimetry (biological and biophysical techniques that can be quantitatively correlated with the magnitude of the radiation dose received), and strategies to implement the response to an accidental radiation exposure. In the case of large-scale atomic or radiological events, the most ideal choice for triage, dose assessment and victim classification, is the utilization of global biodosimetry networks, in combination with the automation of strategies based on modular platforms.

Momordica. charantia-Derived Extracellular Vesicles-Like Nanovesicles Protect Cardiomyocytes Against Radiation Injury via Attenuating DNA Damage and Mitochondria Dysfunction

Thoracic radiotherapy patients have higher risks of developing radiation-induced heart disease (RIHD). Ionizing radiation generates excessive reactive oxygens species (ROS) causing oxidative stress, while Momordica. charantia and its extract have antioxidant activity. Plant-derived extracellular vesicles (EVs) is emerging as novel therapeutic agent. Therefore, we explored the protective effects of Momordica. charantia-derived EVs-like nanovesicles (MCELNs) against RIHD. Using density gradient centrifugation, we successfully isolated MCELNs with similar shape, size, and markers as EVs. Confocal imaging revealed that rat cardiomyocytes H9C2 cells internalized PKH67 labeled MCELNs time-dependently. In vitro assay identified that MCELNs promoted cell proliferation, suppressed cell apoptosis, and alleviated the DNA damage in irradiated (16 Gy, X-ray) H9C2 cells. Moreover, elevated mitochondria ROS in irradiated H9C2 cells were scavenged by MCELNs, protecting mitochondria function with re-balanced mitochondria membrane potential. Furthermore, the phosphorylation of ROS-related proteins was recovered with increased ratios of p-AKT/AKT and p-ERK/ERK in MCELNs treated irradiated H9C2 cells. Last, intraperitoneal administration of MCELNs mitigated myocardial injury and fibrosis in a thoracic radiation mice model. Our data demonstrated the potential protective effects of MCELNs against RIHD. The MCELNs shed light on preventive regime development for radiation-related toxicity.

Plant based radioprotectors as an adjunct to radiotherapy: advantages and limitations

Radioprotectors are agents that have the potential to act against radiation damage to cells. These are equally invaluable in radiation protection, both in intentional and unintentional radiation exposure. It is however, complex to use a universal radioprotector that could be beneficial in diverse contexts such as in radiotherapy, nuclear accidents, and space travel, as each of these circumstances have unique requirements. In a clinical setting such as in radiotherapy, a radioprotector is used to increase the efficacy of cancer treatment. The protective agent must act against radiation damage selectively in normal healthy cells while enhancing the radiation damage imparted on cancer cells. In the context of radiotherapy, plant-based compounds offer a more reliable solution over synthetic ones as the former are less expensive, less toxic, possess synergistic phytochemical activity, and are environmentally friendly. Phytochemicals with both radioprotective and anticancer properties may enhance the treatment efficacy by two-fold. Hence, plant based radioprotective agents offer a promising field to progress forward, and to expand the boundaries of radiation protection. This review is an account on radioprotective properties of phytochemicals and complications encountered in the development of the ideal radioprotector to be used as an adjunct in radiotherapy.

Development of nanotechnology-mediated precision radiotherapy for anti-metastasis and radioprotection

Radiotherapy (RT), including external beam RT and internal radiation therapy, uses high-energy ionizing radiation to kill tumor cells.

Natural radioprotectors on current and future perspectives: A mini-review

Radiation therapy is used as the primary treatment for cancer. Eighty percent of cancer patients require radiation therapy during treatment or for medical purposes. During treatment, radiation causes various biological defects in the cells. The prevalence of cytotoxicity limits the dose used for effective treatment. This method is designed to strike a balance between removing cancer cells and protecting normal tissues. Unfortunately, effective radiation is unavailable once acute toxicity occurs during clinical radiation therapy. Therefore, a lot of research interest is needed in the discovery of radioprotective drugs to accelerate treatment to reduce this toxicity (i.e., normal tissue toxicity to cancer cell death). Radiation protectors may be chemicals or drugs that minimize the damage caused due to radiation therapy in living organisms. The determination of effective and nontoxic radiation protection is an essential goal for radiation oncologists and basic radiobiologists. However, despite the advantages, many radioprotectors were found to have disadvantages which include cost, less duration, toxicity, and effect on the central nervous system. Therefore in recent years, the focus has been diverted to finding out optimal natural products to act as radioprotectors. Natural radiation protectors are plant compounds that protect normal (noncancerous) cells from damage from radiation therapy. Natural herbal products are nontoxic with proven therapeutic benefits and have long been used to treat various diseases. In conclusion, we find that there are various radiation protectors with different purposes and mechanisms of action.

Podophyllum hexandrum and its active constituents: Novel radioprotectants

Human exposure to radiation has expanded considerably in recent years, due to a wide range of medical, agricultural, and industrial applications. Despite its beneficial utilities, radiation is also known to have a deleterious effect on cells and tissues, largely through the creation of free radicals, which cause severe damage to biological systems through processes such as DNA double/single-strand fragmentation, protein modification, and upregulation of lipid peroxidation pathways. In addition, radiation damages genetic material while inducing hereditary genotoxicity. Developing measures to counter radiation-induced damage is thus considered to be of significant importance. Considering the inherent capability of plants to survive radiative conditions, certain plants and natural compounds have been the subject of investigations to explore and harness their natural radioprotective abilities. Podophyllum hexandrum, an Indian medicinal plant with several known traditional phytotherapeutic uses, is considered in particular to be of immense therapeutic importance. Recent studies have been conducted to validate its radioprotective potential alongside discovering its protective mechanisms following γ-radiation-induced mortality and disorder in both mice and human cells. These findings show that Podophyllum and its constituents/natural compounds protect the lungs, gastrointestinal tissues, hemopoietic system, and testis by inducing DNA repair pathways, apoptosis inhibition, free radical scavenging, metal chelation, anti-oxidation and anti-inflammatory mechanisms. In this review, we have provided an updated, comprehensive summary of ionizing radiations and their impacts on biological systems, highlighting the mechanistic and radioprotective role of natural compounds from Podophyllum hexandrum.

Potential radioprotective properties of arbutin against ionising radiation on human leukocytes in vitro

Arbutin is a simple phenolic glucoside biosynthesised in many plant families. Some of the everyday foods that contain arbutin are species of the genus Origanum, peaches, cereal products, coffee and tea and Arctostaphyllos uva ursi L. leaves. Arbutin possesses various beneficial effects in the organism, and was confirmed effective in the treatment of urinary tract infections as well as in preventing skin hyperpigmentation. It shows antioxidant and anti-inflammatory properties, and antitumor activity. The aim of this study was to explore potential radioprotective properties of arbutin in concentrations of 11.4 μg/mL, 57 μg/mL, 200 μg/mL and 400 μg/mL administered as a pre-treatment for one hour before exposing human leukocytes to ionising radiation at a therapeutic dose of 2 Gy. The alkaline comet assay was used to establish the levels of primary DNA damage, and cytokinesis-block micronucleus (CBMN) cytome assay to determine the level of cytogenetic damage. None of the tested concentrations of single arbutin showed genotoxic and cytotoxic effects. Even at the lowest tested concentration, 11.4 μg/mL, arbutin demonstrated remarkable potential for radioprotection in vitro, observed both at the level of primary DNA damage, and using CBMN cytome assay. The best dose reduction compared with amifostine was observed after pre-treatment with the highest concentration of arbutin, corresponding to 400 μg/mL. Promising results obtained on the leukocyte model speak in favour of extending similar experiments on other cell and animal models.

Low Dose Ionising Radiation-Induced Hormesis: Therapeutic Implications to Human Health

The concept of radiation-induced hormesis, whereby a low dose is beneficial and a high dose is detrimental, has been gaining attention in the fields of molecular biology, environmental toxicology and radiation biology. There is a growing body of literature that recognises the importance of hormetic dose response not only in the radiation field, but also with molecular agents. However, there is continuing debate on the magnitude and mechanism of radiation hormetic dose response, which could make further contributions, as a research tool, to science and perhaps eventually to public health due to potential therapeutic benefits for society. The biological phenomena of low dose ionising radiation (LDIR) includes bystander effects, adaptive response, hypersensitivity, radioresistance and genomic instability. In this review, the beneficial and the detrimental effects of LDIR-induced hormesis are explored, together with an overview of its underlying cellular and molecular mechanisms that may potentially provide an insight to the therapeutic implications to human health in the future.

A review of pears (Pyrus spp.), ancient functional food for modern times

BACKGROUND

Pears have been world-widely used as a sweet and nutritious food and a folk medicine for more than two millennia.

METHODS

We conducted a review from ancient literatures to current reports to extract evidence-based functions of pears.

RESULTS

We found that pears have many active compounds, e.g., flavonoids, triterpenoids, and phenolic acids including arbutin, chlorogenic acid, malaxinic acid, etc. Most of researchers agree that the beneficial compounds are concentrated in the peels. From various in vitro, in vivo, and human studies, the medicinal functions of pears can be summarized as anti-diabetic,-obese, -hyperlipidemic, -inflammatory, -mutagenic, and -carcinogenic effects, detoxification of xenobiotics, respiratory and cardio-protective effects, and skin whitening effects. Therefore, pears seem to be even effective for prevention from Covid-19 or PM2.5 among high susceptible people with multiple underlying diseases.

CONCLUSION

For the current or post Covid-19 era, pears have potential for functional food or medicine for both of communicable and non-communicable disease.

Radioprotective Effect of Thymoquinone in X-irradiated Rats

BACKGROUND

Thymoquinone, has anti-inflammatory, anti-oxidant, and cardio protection properties. This study aimed to evaluate the radioprotective effect of thymoquinone in whole body X-irradiated rats.

METHODS

This study conducted on 40 male adult Wistar albino rats randomized into the following groups: Group I: Control rats did not receive thymoquinone or ionizing radiation. Group II: Whole-body irradiated rats with 6 Gy of X-ray. Group III: Rats orally intubated with thymoquinone (10 mg/kg/day) for 7 days then subjected to whole-body irradiation with 6 Gy then supplemented with thymoquinone for another 7 days. Group IV: Rats orally intubated with thymoquinone (20 mg/kg/day) for 7 days then subjected to whole-body irradiation with 6 Gy then supplemented with thymoquinone (20 mg/kg/day) for another 7 days. LDH, CK-MB, ALT, AST, MDA, TAC, Catalase activity, GPX, GSR and GSH were measured.

RESULTS

Lipid peroxidation biomarker in the blood of X-irradiated rats significantly increased and accompanied by decrease in the levels of GSH, GSR, GPX, catalase as well as TAC. Moreover, exposure to IR significantly increases cardiac and liver enzymes. However, administration of TQ to X-irradiated rats with either 10 mg/kg or 20 mg/kg have the same reform effects and significantly protects rats against adverse effects of IR.

CONCLUSION

Exposure to X-ray leads to significant changes in cellular biochemical and morphological conditions. Administration of TQ before radiation treatment significantly decreases the adverse effects of IR. TQ can improve cardiac function, decrease myocardial enzyme levels and inhibit oxidative stress.

Could Polyphenols Really Be a Good Radioprotective Strategy?

Currently, radiotherapy is one of the most effective strategies to treat cancer. However, deleterious toxicity against normal cells indicate for the need to selectively protect them. Reactive oxygen and nitrogen species reinforce ionizing radiation cytotoxicity, and compounds able to scavenge these species or enhance antioxidant enzymes (e.g., superoxide dismutase, catalase, and glutathione peroxidase) should be properly investigated. Antioxidant plant-derived compounds, such as phenols and polyphenols, could represent a valuable alternative to synthetic compounds to be used as radio-protective agents. In fact, their dose-dependent antioxidant/pro-oxidant efficacy could provide a high degree of protection to normal tissues, with little or no protection to tumor cells. The present review provides an update of the current scientific knowledge of polyphenols in pure forms or in plant extracts with good evidence concerning their possible radiomodulating action. Indeed, with few exceptions, to date, the fragmentary data available mostly derive from in vitro studies, which do not find comfort in preclinical and/or clinical studies. On the contrary, when preclinical studies are reported, especially regarding the bioactivity of a plant extract, its chemical composition is not taken into account, avoiding any standardization and compromising data reproducibility.

Effects of radiation and role of plants in radioprotection: A critical review

Radiation can be lethal at high doses, whereas controlled doses are useful in medical applications. Other applications include power generation, agriculture sterilization, nuclear weapons, and archeology. Radiation damages genetic material, which is reflected in genotoxicity and can cause hereditary damage. In the medical field, it is essential to avoid the harmful effects of radiation. Radiation countermeasures and the need for radioprotective agents have been explored in recent years. Considering plants that evolve in radiative conditions, their ability to protect organisms against radiation has been studied and demonstrated. Crude extracts, fractioned extracts, isolated phytocompounds, and plant polysaccharides from various plants have been used in radioprotection studies, and their efficiency has been proven in various in vitro and in vivo experimental models. It is important to identify the mechanism of action to develop a potent plant-based radioprotective agent. To identify this protective mechanism, it is necessary to understand the damage caused by radiation in biological systems. This review intends to discuss the effects of ionizing radiation on biological systems and evaluate plant-based radioprotectants that have tested thus far as well as their mechanism of action in protecting against the toxic effects of radiation. From the review, the mechanism of radioprotection exhibited by the plant-based products could be understood. Meanwhile, we strongly suggest that the potential products identified so far should undergo clinical trials for critically evaluating their effects and for developing an ideal and compatible radioprotectant with no side-effects.

Antimelanogenesis Effects of Theasinensin A

Theasinensin A (TSA) is a major group of catechin dimers mainly found in oolong tea and black tea. This compound is also manufactured with epigallocatechin gallate (EGCG) as a substrate and is refined after the enzyme reaction. In previous studies, TSA has been reported to be effective against inflammation. However, the effect of these substances on skin melanin formation remains unknown. In this study, we unraveled the role of TSA in melanogenesis using mouse melanoma B16F10 cells and normal human epidermal melanocytes (NHEMs) through reverse transcription polymerase chain reaction (RT-PCR), Western blotting analysis, luciferase reporter assay, and enzyme-linked immunosorbent assay analysis. TSA inhibited melanin formation and secretion in α-melanocyte stimulating hormone (α-MSH)-induced B16F10 cells and NHEMs. TSA down-regulated the mRNA expression of tyrosinase (Tyr), tyrosinase-related protein 1 (Tyrp1), and Tyrp2, which are all related to melanin formation in these cells. TSA was able to suppress the activities of certain proteins in the melanocortin 1 receptor (MC1R) signaling pathway associated with melanin synthesis in B16F10 cells: cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB), protein kinase A (PKA), tyrosinase, and microphthalmia-associated transcription factor (MITF). We also confirmed α-MSH-mediated CREB activities through a luciferase reporter assay, and that the quantities of cAMP were reduced by TSA in the enzyme linked immunosorbent assay (ELISA) results. Based on these findings, TSA should be considered an effective inhibitor of hyperpigmentation.

Fucoxanthin alters the apelin-13/APJ pathway in certain organs of γ-irradiated mice

Apelin-13 and APJ are implicated in different key physiological processes. This work aims at exploring the radioprotective effect of fucoxanthin (FX) on γ-radiation (RAD)-induced changes in the apelin-13/APJ pathway, which causes damage in the liver, kidney, lung and spleen of mice. Mice were administered FX (10 mg kg-1 day-1, i.p) and exposed to γ-radiation (2.5 Gy week-1) for four consecutive weeks. The treatment of irradiated mice by FX resulted in a significant amendment in protein expression of the apelin-13/APJ/NF-κB signalling pathway concurrently with reduced hypoxia (hypoxia-inducible factor-1α), suppressed oxidative stress marker (malondialdehyde), enhanced antioxidant defence mechanisms (reduced glutathione and glutathione peroxidase), a modulated inflammatory response [interleukin-6 (IL-6), monocyte chemoattractant protein-1, IL-10 and α-7-nicotinic acetylcholine receptor) and ameliorated angiogenic regulators [matrix metalloproteinase (MMP-2), MMP-9 and tissue inhibitor of metalloproteinase-1), as well as the tissue damage indicator (lactate dehydrogenase) in organ tissues. In addition, there were significant improvement in serum inflammatory markers tumour necrosis factor-α, IL-10, IL-1β and C-reactive protein compared with irradiated mice. The histopathological investigation of the FX + RAD organ tissues support the biochemical findings where the improvements in the tissues' architecture were obvious when compared with those of RAD. FX was thus shown to have a noticeable radioprotective action mediated through its regulatory effect on the apelin-13/APJ/NF-κB signalling pathway attributed to its antioxidant and anti-inflammatory activity that was reflected in different physiological processes. It could be recommended to use FX in cases of radiation exposure to protect normal tissues.

Evaluation of Epigallocatechin-3-Gallate as a Radioprotective Agent During Radiotherapy of Lung Cancer Patients: A 5-Year Survival Analysis of a Phase 2 Study

Background

Previous analysis of the study (NCT02577393) had demonstrated the application of epigallocatechin-3-gallate (EGCG) could be safe and effective in the prevention and treatment of acute radiation esophagitis in patients with advanced lung cancer. EGCG seemed to improve the response rate of small cell lung cancer (SCLC) to radiotherapy in a subgroup analysis. This research continued to analyze the impact of EGCG application on cancer-radiation efficacy and patient survival.

Methods

All patients with SCLC in the NCT02577393 study were included. Patients were randomized into EGCG group or conventional therapy group as protocol. The primary endpoints of the study were radiation response rate and progression-free survival (PFS). Overall survival (OS) and the efficacy of EGCG in the treatment of esophagitis were assessed as secondary endpoints.

Results

A total of 83 patients with lung cancer in the NCT02577393 study were screened, and all 38 patients with SCLC were eligible for analysis. No significant differences with regard to baseline demographic and clinical characteristics were observed between the two groups. The objective response rate (ORR) was higher than that of conventionally treated patients (84.6 vs 50%, P = 0.045), while the median PFS and OS were not significantly prolonged. At data cut-off (1 January 2021), 5-year PFS was 33% with EGCG versus 9.3% with conventional treatment, and 5-year OS was 30.3% versus 33.3%, respectively. The mean adjusted esophagitis index and pain index of patients with EGCG application were lower than conventional treatment (5.15 ± 2.75 vs 7.17 ± 1.99, P = 0.030; 8.62 ± 5.04 vs 15.42 ± 5.04, P < 0.001).

Conclusion

The study indicates EGCG may alleviate some esophagitis-related indexes in SCLC patients exposed to ionizing radiation without reducing survival. However, this conclusion should be confirmed by further studies with large sample size.

Melatonin exerts a neuroprotective effect against γ-radiation-induced brain injury in the rat through the modulation of neurotransmitters, inflammatory cytokines, oxidative stress, and apoptosis

The current study aimed to investigate the ameliorative effect of melatonin (MLT) against brain injury in rats undergoing whole-body exposure to γ-radiation. Male Wistar rats were whole-body exposed to 4-Gy γ-radiation from a cesium-137 source. MLT (10 mg/kg) was orally administrated 30 minutes before irradiation and continued once daily for 1 and 7 days after exposure. In the irradiated rats, the plasma levels of glutamate were increased, while the gamma-aminobutyric acid (GABA) levels were decreased, and MLT improved the disturbed glutamate and GABA levels. These effects paralleled an increase in pro-inflammatory cytokines (IL-1b, IL-6, and TNF-a) and C-reactive protein as well as a decrease in IL-10 in the plasma of the irradiated rats. MLT treatment markedly reduced these effects, indicating its anti-inflammatory impact. Immunohistochemical studies demonstrated a remarkable upregulation of caspase-3 and P53 expression, indicating the increased apoptosis in the brain of irradiated rats. MLT significantly downregulated the expression of these parameters compared with that in the irradiated rats, indicating its anti-apoptotic effect. Oxidative stress is developed in the brain as evidenced by increased levels of malondialdehyde; decreased activities of superoxide dismutase, catalase, and glutathione peroxidase; and decreased content of glutathione in the brain. MLT remarkably ameliorated the development of oxidative stress in the brain of the irradiated rats indicating its antioxidant impact. The histopathological results were consistent with the biochemical and immunohistochemical results and showed that MLT remarkably protected the histological structure of brain tissue compared with that in the irradiated rats. In conclusion, MLT showed potential neuroprotective properties by increasing the release of neurotransmitters, antioxidants, and anti-inflammatory factors and reducing pro-inflammatory cytokines and apoptosis in the brain of irradiated rats. MLT can be beneficial in clinical and occupational settings requiring radiation exposure; however, additional studies are required to elucidate its neuroprotective effect in humans.

Radioprotective effects of centipedegrass extract on NIH-3T3 fibroblasts via anti-oxidative activity

Centipedegrass originates from China and South America, and has been reported to contain several C-glycosyl flavones and phenolic compounds, including maysin and luteolin. The present study aimed to investigate the radioprotective activity of centipedegrass extract (CGE) in radiation exposed-fibroblasts and to assess the affected molecular pathway. The radioprotective effects of CGE were determined in NIH-3T3 cells using Cell Counting Kit-8 and morphological changes were observed. Reactive oxygen species (ROS) levels and the apoptotic profile of NIH-3T3 cells were also measured. The expression levels of B-cell lymphoma-2 (Bcl-2) family proteins [Bcl-2, Bcl-2 like protein 4 (Bax), Bcl-2-associated death promoter (Bad), caspase-3, poly(ADP-ribose) polymerase (PARP)], AKT and MAPK family proteins (ERK, p38 and JNK) were measured in vitro. The results demonstrated that when 3T3 fibroblasts pretreated with CGE were subjected to H2O2-induced cell damage, their viability was significantly decreased. Additionally, CGE pretreatment decreased ROS levels and the protein expression levels of cleaved PARP upon H2O2 treatment, indicating that CGE induced cytoprotective effects against H2O2-induced oxidative stress. Moreover, significant protective effects of CGE against intracellular ROS, induced upon exposure to ionizing radiation (IR), were observed. The protective effects of CGE pretreatment were also determined by morphological observation of NIH-3T3 cells following exposure to IR. CGE pretreatment increased the expression levels of anti-apoptotic signals (Bcl-2, p-BAD) and decreased the levels of pro-apoptotic signals (Bax, Bad), and led to cleavage of PARP and caspase-3 proteins. Additionally, in cells pretreated with CGE, the phosphorylation of AKT and ERK was increased and that of p38 and JNK was decreased compared with in cells subjected only to IR. These results indicated that CGE may act as a radioprotector due to its anti-oxidative activity, restoring cell homeostasis and redox balance in radiation-exposed fibroblast cells. Therefore, it could be suggested that CGE may be an effective candidate in the treatment of oxidative stress-related diseases and in radioprotection.

Radioprotective Role of Natural Polyphenols: From Sources to Mechanisms

The identification and development of radioprotective agents has emerged as a subject matter of research during recent years due to the growing usage of ionizing radiation in different areas of human life. Previous work on synthetic radioprotectors has achieved limited progress because of the numerous issues associated with toxicity. Compounds extracted from plants have potential to serve as lead candidates for developing ideal radioprotectors due to their low cost, safety and selectivity. Polyphenols are the most abundant and commonly dispersed group of biologically active molecules possessing broad range of pharmacological activities. Polyphenols have displayed efficacy for radioprotection during various investigations and can be administered at high doses with lesser toxicity. Detoxification of free radicals, modulating inflammatory responses, DNA repair, stimulation of hematopoietic recovery, and immune functions are the main mechanisms for radiation protection with polyphenols. Epicatechin, epigallocatechin-3-gallate, apigenin, caffeic acid phenylethylester, and silibinin provide cytoprotection together with the suppression of many pro-inflammatory cytokines owing to their free radical scavenging, anti-oxidant, and anti-inflammatory properties. Curcumin, resveratrol, quercetin, gallic acid, and rutin's radioprotective properties are regulated primarily by direct or indirect decline in cellular stress. Thus, polyphenols may serve as potential candidates for radioprotection in the near future, however, extensive investigations are still required to better understand their protection mechanisms.

External modulators and redox homeostasis: Scenario in radiation-induced bystander cells

Redox homeostasis is imperative to maintain normal physiologic and metabolic functions. Radiotherapy disturbs this balance and induces genomic instability in diseased cells. However, radiation-induced effects propagate beyond the targeted cells, affecting the adjacent non-targeted cells (bystander effects). The cellular impact of radiation, thus, encompasses both targeted and non-targeted effects. Use of external modulators along with radiation can increase radio-therapeutic efficiency. The modulators' classification as protectors or sensitizers depends on interactions with damaged DNA molecules. Thus, it is necessary to realize the functions of various radio-sensitizers or radio-protectors in both irradiated and bystander cells. This review focuses on some modulators of radiation-induced bystander effects (RIBE) and their action mechanisms. Knowledge about the underlying signaling cross-talk may promote selective sensitization of radiation-targeted cells and protection of bystander cells.

Pre-clinical evaluation of an innovative oral nano-formulation of baicalein for modulation of radiation responses

There is an unmet medical need for non-toxic and effective radiation countermeasures for prevention of radiation toxicity during planned exposures. We have earlier shown that intraperitoneal administration of baicalein (BCL) offers significant survival benefit in animal model. Safety, tolerability, pharmacokinetics (PK) and pharmacodynamics of baicalein has been reported in pre-clinical model systems and also in healthy human volunteers. However, clinical translation of baicalein is hindered owing to poor bioavailability due to lipophilicity. In view of this, we fabricated and characterized in-situ solid lipid nanoparticles of baicalein (SLNB) with effective drug entrapment and release kinetics. SLNB offered significant protection to murine splenic lymphocytes against 4 Gy ionizing radiation (IR) induced apoptosis. Oral administration of SLNB exhibited ~70% protection to mice against whole body irradiation (WBI 7.5 Gy) induced mortality. Oral relative bioavailability of BCL was enhanced by over ~300% after entrapment in the SLNB as compared to BCL. Oral dosing of SLNB resulted in transient increase in neutrophil abundance in peripheral blood. Interestingly, we observed that treatment of human lung cancer cells (A549) with radioprotective dose of SLNB exhibited radio-sensitization as evinced by decrease in survival and clonogenic potential. Contrary to antioxidant nature of baicalein in normal cells, SLNB treatment induced significant increase in cellular ROS levels in A549 cells probably due to higher uptake and inhibition of TrxR. Thus, a pharmaceutically acceptable SLNB exhibited improved bioavailability, better radioprotection to normal cells and sensitized cancer cells to radiation induced killing as compared to BCL suggesting its possible utility as an adjuvant during cancer radiotherapy.