Baicalein protects mice against radiation-induced DNA damages and genotoxicity

Baicalein attenuates oxidative damage in mice haematopoietic cells through regulation of PDGFRβ

Platelet-derived growth factor receptor β (PDGFRβ) plays a crucial role in murine haematopoiesis. Baicalein (BAI), a naturally occurring flavonoid, can alleviate disease damage through anti-oxidative, anti-apoptotic, and anti-inflammatory mechanisms. However, whether BAI attenuates oxidative damage in murine haematopoietic cells by PDGFRβ remains unexplored. In this study, we utilized a tert-butyl hydroperoxide (TBHP)-induced BaF3 cell injury model and an ionising radiation (IR)-induced mice injury model to investigate the impact of the presence or absence of PDGFRβ on the pharmacological effects of BAI. In addition, the BAI-PDGFRβ interaction was characterized by molecular docking and dynamics simulations. The results show that a specific concentration of BAI led to increased cell viability, reduced reactive oxygen species (ROS) content, upregulated nuclear factor erythroid 2-related factor 2 (NRF2) expression, and its downstream target genes heme oxygenase 1 (HO-1) and NAD(P)H Quinone Dehydrogenase 1 (NQO1), and activated protein kinase B (AKT) pathway in cells expressing PDGFRβ plasmid and experiencing damage. Similarly, BAI elevated lineage-Sca1+cKIT+ (LSK) cell proportion, promoted haematopoietic restoration, enhanced NRF2-mediated antioxidant response in PDGFRβ+/+ mice. However, despite BAI usage, PDGFRβ knockout mice (PDGFRβ-/-) showed lower LSK proportion and less antioxidant capacity than the total body irradiation (TBI) group. Furthermore, we demonstrated an interaction between BAI and PDGFRβ at the molecular level. Collectively, our results indicate that BAI attenuates oxidative stress injury and helps promote haematopoietic cell recovery through regulation of PDGFRβ.

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.

Protective and therapeutic effects of Scutellaria baicalensis and its main active ingredients baicalin and baicalein against natural toxicities and physical hazards: a review of mechanisms

OBJECTIVES

Scutellaria baicalensis (SB) has been traditionally used to combat a variety of conditions ranging from ischemic heart disease to cancer. The protective effects of SB are due to the action of two main flavonoids baicalin (BA) and baicalein (BE). This paper aimed to provide a narrative review of the protective and antidotal effects of SB and its main constituents against natural toxicities and physical hazards.

EVIDENCE ACQUISITION

Scientific databases Medline, Scopus, and Web of Science were thoroughly searched, based on different keywords for in vivo, in vitro and clinical studies which reported protective or therapeutic effects of SB or its constituents in natural and physical toxicities.

RESULTS

Numerous studies have reported that treatment with BE, BA, or total SB extract prevents or counteracts the detrimental toxic effects of various natural compounds and physical hazards. The toxic agents include mycotoxins, lipopolysaccharide, multiple plants and animal-derived substances as well as physical factors which negatively affected vital organs such as CNS, liver, kidneys, lung and heart. Increasing the expression of radical scavenging enzymes and glutathione content as well as inhibition of pro-inflammatory cytokines and pro-apoptotic mediators were important mechanisms of action.

CONCLUSION

Different studies on the Chinese skullcap have exhibited that its total root extract, BA or BE can act as potential antidotes or protective agents against the damage induced by natural toxins and physical factors by alleviating oxidative stress and inflammation. However, the scarcity of high-quality clinical evidence means that further clinical studies are required to reach a more definitive conclusion.

Phytochemicals Targeting Oxidative Stress, Interconnected Neuroinflammatory, and Neuroapoptotic Pathways Following Radiation

The radiation for therapeutic purposes has shown positive effects in different contexts; however, it can increase the risk of many age-related and neurodegenerative diseases such as Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), Huntington's disease (HD), and Parkinson's disease (PD). These different outcomes highlight a dose-response phenomenon called hormesis. Prevailing studies indicate that high doses of radiation could play several destructive roles in triggering oxidative stress, neuroapoptosis, and neuroinflammation in neurodegeneration. However, there is a lack of effective treatments in combating radiation-induced neurodegeneration, and the present drugs suffer from some drawbacks, including side effects and drug resistance. Among natural entities, polyphenols are suggested as multi-target agents affecting the dysregulated pathogenic mechanisms in neurodegenerative disease. This review discusses the destructive effects of radiation on the induction of neurodegenerative diseases by dysregulating oxidative stress, apoptosis, and inflammation. We also describe the promising effects of polyphenols and other candidate phytochemicals in preventing and treating radiation-induced neurodegenerative disorders, aiming to find novel/potential therapeutic compounds against such disorders.

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.

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.

Radioprotective Effects of Plants from the Lamiaceae Family

BACKGROUND

Edible and medicinal plants are still an interesting source of promising biologically active substances to drug discovery and development. At a time of increasing cancer incidence in the world, alleviating the bothersome side effects of radiotherapy in debilitated cancer patients is becoming an important challenge.

OBJECTIVE

The aim of the study was to overview the literature data concerning the radioprotective activity of extracts, essential oils, and some chemical compounds obtained from 12 species belonging to the Lamiaceae family, gathering of numerous spice and medicinal plants rich in valuable phytochemicals.

RESULTS AND CONCLUSION

The analysis of available publications showed radioprotective effectiveness of essential oils and complex extracts containing phenolic acids and flavonoids in various in vitro and in vivo models. Relatively welldocumented preventive properties exhibited the following species: Mentha × piperita, Ocimum tenuiflorum, Origanum vulgare, and Rosmarinus officinalis. However, few plants such as Lavandula angustifolia, Mentha arvensis, M. spicata, Plectranthus amboinicus, Salvia miltiorrhiza, S. officinalis, Scutellaria baicalensis, and Zataria multiflora should be more investigated in the future. Among the mechanisms of radioprotective effects of well-studied extracts and phytochemicals, it can be mentioned mainly the protection against chromosomal damage, scavenging free radicals, decreasing of lipid peroxidation and elevating of glutathione, superoxide dismutase, catalase, and alkaline phosphatase enzyme levels as well as the reduction the cell death. The plant substances protected the gastrointestinal tract, bone marrow and lung fibroblasts. In conclusion, studied species of Lamiaceae family and their active chemical compounds are potent in alleviating the side effects of radiotherapy and should be considered as a complementary therapy.

Baicalein ameliorates ionizing radiation-induced injuries by rebalancing gut microbiota and inhibiting apoptosis

AIMS

Ionizing radiation (IR) induces injuries to the hematopoietic and intestinal systems, which are the leading cause of death. Baicalein, a plant-derived flavonoid, shows anti-oxidative stress, anti-apoptosis, anti-inflammation effects in many diseases. In this study, we evaluated the effects and mechanism of baicalein on IR induced intestinal and hematopoietic injuries.

MAIN METHODS

Mice were divided into three groups: Control, IR and IR + Baicalein. All of mice were intraperitoneally administered with 100 mg/kg baicalein or normal saline for 1 h before IR, and then a day post-IR. The changes in intestinal structure, function and molecular expression were observed by pathological experiments and western blot. 16S rRNA gene sequencing was performed to analyze gut microbiota and further predicted metabolic pathways through Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Hematopoietic function was evaluated by peripheral blood cells count and by flow cytometry analysis of hematopoietic cells composition.

KEY FINDINGS

Baicalein improved intestinal structure and the ability of proliferation and regeneration after mice exposed to IR, in which the rebalance of gut microbial composition played an important role. KEGG results showed that p53-related apoptotic pathways played important roles in the composition changes of gut microbiota. Then we observed that baicalein inhibited the activation of p53 and p53 mediated mitochondrial apoptosis and death receptor apoptosis in the intestine. In addition, IR induced injuries to hematopoietic system also could be ameliorated by baicalein.

SIGNIFICANCE

These results provide new insights into the mechanism of baicalein and support the potential of baicalein as a radioprotective medicine.

Sitagliptin Mitigates Total Body Irradiation-Induced Hematopoietic Injury in Mice

Sitagliptin, an inhibitor of the dipeptidyl peptidase IV (DPP4), has been implicated in the regulation of type 2 diabetes. However, the role and mechanism of sitagliptin administration in total body irradiation (TBI)- induced hematopoietic cells injury are unclear. In this study, we demonstrated that sitagliptin had therapeutic effects on hematopoietic damage, which protected mice from 7.5 Gy TBI-induced death, increased the numbers and colony formation ability of hematopoietic cells. These therapeutic effects might be attributed to the inhibition of NOX4-mediated oxidative stress in hematopoietic cells, and the alleviation of inflammation was also helpful. Therefore, sitagliptin has potential as an effective radiotherapeutic agent for ameliorating TBI-induced hematopoietic injury.

An Overview of the Cellular Mechanisms of Flavonoids Radioprotective Effects

Considering the remarkable application of radiotherapy in the treatment and diagnosis of various diseases and even nuclear war, it is important to protect healthy tissues and people at risk from the radiation. Currently, there is no ideal and safe radioprotective agent available and we are seeing a great effort to find these agents from natural sources. Phenolic compounds, as well as flavonoid, are presented widely as the second metabolite in plants and they have been considered for investigation according to their benefits for human health, healing and preventing many disorders. The major bioactive benefits of flavonoids include antioxidant, anti-inflammatory, anti-tumor, anti-aging, anti-bacterial and viral, neuroprotection and radioprotective effects. Their lower toxicity and oral administration have made it suitable for radiotherapy patient, radiation, military forces, and even the general public. This review attempts to provide a summary of the main molecular mechanisms involved in flavonoid radio-protective effects. Data of these studies will provide a comprehensive perspective to flavonoids and can help to optimize their effects in radioprotection procedures.

Baicalein Mitigates Radiation-Induced Enteritis by Improving Endothelial Dysfunction

Background and Aims: Radiation-induced intestinal injury occurred in application of radiotherapy for abdominal and pelvic cancers or in nuclear accidents. Radiation-induced enteritis may be considered an ideal model of gastrointestinal inflammation. The endothelium is a crucial component of inflammation, and the endothelial dysfunction following radiation exposure induces the intestinal proinflammatory response and progression of radiation enteritis. Baicalein (5,6,7-trihydroxyflavonoid) is a flavonoid from Scutellaria baicalensis used in oriental herbal medicine. Baicalein has been found to have multiple beneficial properties including antioxidant, anti-inflammatory, anti-allergic, and anti-cancer activities. Here, we investigated the therapeutic effects of baicalein on endothelial dysfunction in radiation-induced intestinal inflammation. Materials and Methods: We performed histological analysis, bacterial translocation, and intestinal permeability assays and also assessed infiltration of leukocytes and inflammatory cytokine expression using a mouse model of radiation-induced enteritis. In addition, to investigate the effect of baicalein in endothelial dysfunction, we analyzed endothelial-derived adherent molecules in human umbilical vein endothelial cells (HUVECs) and irradiated intestinal tissue. Results: Histological damage such as shortening of villi length and impaired intestinal crypt function was observed in the radiation-induced enteritis mouse model. Intestinal damage was attenuated in baicalein-treated groups with improvement of intestinal barrier function. Baicalein inhibited the expression of radiation-induced adherent molecules in HUVECs and intestine of irradiated mouse and decreased leukocyte infiltration in the radiation-induced enteritis. Conclusions: Baicalein could accelerate crypt regeneration via recovery of endothelial damage. Therefore, baicalein has a therapeutic effect on radiation-induced intestinal inflammation by attenuating endothelial damage.

The effect of lycopene supplementation on radiation-induced micronuclei in mice reticulocytes in vivo

Lycopene (LYC) is a natural pigment present in tomatoes and other red fruits and vegetables including red carrots, red peppers, watermelons, pink grapefruits, apricots, pink guavas, and papaya. There is some evidence that LYC may provide protection against mutations induced by ionizing radiation. The study aimed to investigate whether the genetic material of reticulocytes (RET) could be protected from radiation-induced damage by LYC. Mice were treated with LYC [0.15 mg/kg bodyweight (bw), 0.30 mg/kg bw], acute and fractionated irradiation (0.5 Gy, 1 Gy applied daily), or with both agents (0.5 Gy + 0.15 mg/kg bw LYC, 0.5 Gy + 0.30 mg/kg bw LYC, 1 Gy + 0.15 mg/kg bw LYC, 1 Gy + 0.30 mg/kg LYC). LYC supplementation was started at 24 h or 1 week after the first irradiation. Irradiation significantly enhanced the frequency of micronuclei (MN) in RET. LYC treatment at a dose of 0.15 mg/kg bw 24 h after starting fractionated radiation at 1 Gy significantly decreased (41-68%, p < 0.0125) the level of MN in peripheral blood and bone marrow RET. LYC supplementation at 0.30 mg/kg bw did not significantly alter the frequency of MN in peripheral blood, but significantly increased the frequency of bone marrow RET MN. LYC treatment on day 8 following the first radiation exposure showed results similar (92-117%, p > 0.24) to those obtained with irradiation alone. Lycopene may act as a radiomitigator but must be administered at low doses and as soon as possible after irradiation. Contrary, combined exposure with high doses of irradiation and LYC may enhance the mutagenic effect of irradiation.

Prevention from radiation damage by natural products

BACKGROUND

Radiotherapy is a mainstay of cancer treatment since decades. Ionizing radiation (IR) is used for destruction of cancer cells and shrinkage of tumors. However, the increase of radioresistance in cancer cells and radiation toxicity to normal tissues are severe concerns. The exposure to radiation generates intracellular reactive oxygen species (ROS), which leads to DNA damage by lipid peroxidation, removal of thiol groups from cellular and membrane proteins, strand breaks and base alterations.

HYPOTHESIS

Plants have to deal with radiation-induced damage (UV-light of sun, other natural radiation sources). Therefore, it is worth speculating that radioprotective mechanisms have evolved during evolution of life. We hypothesize that natural products from plants may also protect from radiation damage caused as adverse side effects of cancer radiotherapy.

METHODS

The basis of this systematic review, we searched the relevant literature in the PubMed database.

RESULTS

Flavonoids, such as genistein, epigallocatechin-3-gallate, epicatechin, apigenin and silibinin mainly act as antioxidant, free radical scavenging and anti-inflammatory compounds, thus, providing cytoprotection in addition to downregulation of several pro-inflammatory cytokines. Comparable effects have been found in phenylpropanoids, especially caffeic acid phenylethylester, curcumin, thymol and zingerone. Besides, resveratrol and quercetin are the most important cytoprotective polyphenols. Their radioprotective effects are mediated by a wide range of mechanisms mainly leading to direct or indirect reduction of cellular stress. Ascorbic acid is broadly used as antioxidant, but it has also shown activity in reducing cellular damage after irradiation mainly due to its antioxidant capabilities. The metal ion chelator, gallic acid, represents another natural product attenuating cellular damage caused by radiation.

CONCLUSIONS

Some secondary metabolites from plants reveal radioprotective features against cellular damage caused by irradiation. These results warrant further analysis to develop phytochemicals as radioprotectors for clinical use.

2,3,7,8-TCDD-mediated toxicity in peripheral blood mononuclear cells is alleviated by the antioxidants present in Gelidiella acerosa: an in vitro study

Seaweeds have been used as a source of traditional medicine worldwide for the treatment of various ailments, mainly due to their ability to quench the free radicals. The present study aims at evaluating the protective effect of methanolic extract of Gelidiella acerosa, an edible red seaweed against 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced toxicity in peripheral blood mononuclear cells (PBMC). For evaluating the protective effect of G. acerosa, PBMC were divided into four groups: vehicle control, TCDD (10 nM), TCDD + G. acerosa (300 μg/ml), and G. acerosa alone treated. Scavenging of intracellular reactive oxygen species (ROS) induced by TCDD was assessed by the dichloro-dihydro-fluorescein diacetate (DCFH-DA) method. Alterations at macromolecular level were quantified through lipid peroxidation (LPO) level, protein carbonyl content (PCC) level, and comet assay. The cellular morphology upon TCDD toxicity and G. acerosa treatment was obtained by light microscopy and histopathological studies. The chemical composition present in the methanolic extract of G. acerosa was determined by gas chromatography-mass spectrometry (GC-MS) analysis. The results reveal that 10 nM TCDD caused significant (P < 0.05) reduction in cell viability (94.10 ± 0.99), and treatment with 300 μg/ml extract increased the cell viability (99.24 ± 0.69). TCDD treatment resulted in a significant increase in the production of ROS, LPO (114 ± 0.09), and PCC (15.13 ± 1.53) compared to the control, whereas co-treatment with G. acerosa significantly (P < 0.05) mitigated the effects. Further, G. acerosa significantly (P < 0.05) prevented TCDD-induced genotoxicity and cell damage. GC-MS analysis showed the presence of n-hexadecanoic acid (retention time (RT) 13.15), cholesterol (RT 28.80), α-D-glucopyranose, 4-O-α-D-galactopyranosyl (RT 20.01), and azulene (RT 4.20). The findings suggest that G. acerosa has a strong protective ability against TCDD-induced cytotoxicity, oxidative stress, and DNA damage.

Effect of treatment with baicalein on the intracerebral tumor growth and survival of orthotopic glioma models

Baicalein, a widely used Chinese herbal medicine, has been proved as a promising chemopreventive compound for many cancers. The aim of this work was to assess the anti-tumor effect of baicalein in the orthotopic glioma models. It was found that treatment of mice with U87 gliomas with baicalein (20 and 40 mg/kg/day, i.p.) significantly inhibited the intracerebral tumor growth and prolonged the survival. Furthermore, treatment with baicalein suppressed cell proliferation, promoted apoptosis, and arrested cell cycle in U87 gliomas. In addition, treatment with baicalein reduced tumor permeability, attenuated edema of tumors and brains, and improved tight junctions in gliomas. Finally, treatment with baicalein reduced the expression of HIF-1α, VEGF, and VEGFR2 in U87 gliomas. In addition, treatment with baicalein also markedly suppressed tumor growth and prolonged the survival of rats with 9L gliomas. In conclusion, baicalein has an obvious anti-tumor activity in the orthotopic glioma models. Our results suggested that treatment with baicalein might be an effective therapy for recurrent malignant brain cancers through suppressing tumor growth and alleviating edema.

Long-circulating nanoliposomes (LCNs) sustained delivery of baicalein (BAI) with desired oral bioavailability in vivo

Long-circulating nanoliposomes (LCNs) containing Baicalein (BAI) were prepared by diethyl ether injection method in this paper. Using soybean phosphatidylcholine (SPC) and cholesterol (CHOL) as the carrier ingredients, BAI-loaded LCNs were formulated in optimized condition with encapsulation efficiency (EE) of 41.5±4.77%. The average diameter of BAI-loaded LCNs was ∼709 nm determined by dynamic light scattering (PDI 0.43). Drug storage stability study showed that BAI-loaded LCNs were highly stable in phosphate-buffered saline (PBS, pH 7.4) at 4 °C. Additionally, the pharmacokinetic behaviors of BAI-loaded LCNs were studied using Kunming mice as experimental animals. Parallelly, free BAI solution was studied as control. As expected, it is found that LCNs-encapsulated BAI yields greater BAI oral bioavailability with 4.52 times of free BAI. These results suggest the potential applications of LCNs for the delivery of BAI.