Quercetin ameliorates gamma radiation-induced DNA damage and biochemical changes in human peripheral blood lymphocytes

In vitro effect of Lenzites betulinus mushroom against therapy-induced DNA damage in peripheral blood lymphocytes of patients with acute coronary syndrome

ETHNOPHARMACOLOGICAL RELEVANCE

Acute coronary syndrome (ACS) represents a group of diseases that are the result of reduced blood flow to the heart. There are natural products, based on mushrooms, used traditionally in the treatment of cardiovascular diseases.

AIM OF THE STUDY

Assessment of the potential protective effect of L. betulinus mushroom against therapy-induced DNA damage in lymphocytes of patients with ACS in relation to the phytochemical properties of the mushroom.

MATERIALS AND METHODS

The study included 30 ACS patients and 30 healthy controls. The genotoxic potential of acetone and ethanol extract of L. betulinus was evaluated using the comet assay. The contents of minerals were determined by inductively coupled plasma optical emission spectrometry. Determination of sugars and organic acids was performed using a DIONEX ICS 3000 DP liquid chromatography system. Analysis of fatty acids was performed at Focus GC coupled with PolarisQ mass spectrometer. The total phenolic and flavonoid contents in the mushroom extracts were measured using spectrophotometric methods. The qualitative and quantitative content of polyphenolic compounds was investigated by the UHPLC-DADMS/MS method.

RESULTS

The comet assay showed that both mushroom extracts did not increase the level of DNA damage in the lymphocytes of healthy individuals, while they significantly decreased the %DNA damage and genetic damage index (p < 0.0005) in the therapy-induced lymphocytes of patients. The mushroom was very rich in phytochemical composition. The results showed that the most abundant components in the mushroom were phosphorus, potassium, sodium, sulfur, and calcium among minerals and glucose, fructose, galactose, sorbitol, and turanose among carbohydrates. Among organic acids were present in higher concentrations malic, citric, and maleic acids, while among fatty acids, the most abundant were trans-linoleic, cis-oleic, palmitic, docosahexaenoic and eicosadienoic acids. The results showed that the highest amount of total phenols and flavonoids in the mushroom extracts were obtained in the acetone extract. The most abundant polyphenolic compounds were chlorogenic acid and quercetin in both extracts of mushroom.

CONCLUSIONS

This study indicates that L. betulinus can be considered a mushroom with a high nutritional and functional value. Extracts of the mushroom were not genotoxic in tested concentrations in cultured human lymphocytes of healthy individuals, while in ACS patients they manifested a protective effect against therapy-induced DNA damage. The acetone extract showed a stronger protective effect against therapy-induced DNA damage, which is consistent with its phytochemical composition.

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.

Antioxidative and anti-cytogenotoxic potential of Lysiphyllum strychnifolium (Craib) A. Schmitz extracts against cadmium-induced toxicity in human embryonic kidney (HEK293) and dermal fibroblast (HDF) cells

Exposure to cadmium (Cd) results in bioaccumulation and irreversible damage; this encourages an investigation of alternatives to address Cd toxicity, using natural compounds. Lysiphyllum strychnifolium, a well-known Thai medicinal plant, was investigated for its phytochemical compounds and corresponding bioactivities, including antioxidant and anti-cytogenotoxic effects against Cd toxicity in HEK293 renal and HDF dermal cell models. The crude extract of L. strychnifolium (LsCrude) was partitioned into four fractions, using sequential polarity solvents (hexane, dichloromethane, ethyl acetate, and water, denoted as LsH, LsD, LsE, and LsW, respectively). The extraction yields were 1.79 %, 5.08 %, 8.53 %, and 70.25 % (w/w), respectively. Phytochemical screening revealed the presence of tannins, alkaloids, and flavonoids in LsCrude and its fractions, except for LsH. LsE exhibited the highest concentrations of phenolics (286.83 ± 6.83 mg GAE/g extract) and flavonoids (86.36 ± 1.29 mg QE/g extract). Subsequent 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging and ferric-reducing ability of plasma (FRAP) reducing powder assays demonstrated the high antioxidant capacity of LsCrude and its fractions. The lowest IC50 value (9.11 ± 0.43 μg/mL) in the DPPH assay corresponded to LsW, whereas the highest total FRAP value (6.06 ± 0.70 mg QE Eq./g dry mass) corresponded to LsE. MTT and alkaline comet assays revealed the lack of toxicity of the extracts, which were considered safe. Upon exposure to Cd at the CC50 level, HEK293 cells treated with LsE suppressed Cd-induced damage. HDF cells treated with LsCrude, LsD, or LsE attenuated Cd-induced damage. In the pre-treatment, LsD protected the HDF cells against Cd-mediated cytogenotoxicity. These anti-cytogenotoxic potentials are likely due to the antioxidant properties of the phytochemicals. Our findings highlight the cyto-geno-protective properties of L. strychnifolium stem extracts against Cd toxicity in HEK293 and HDF cells, and provide a novel approach for combating oxidative stress and DNA damage caused by environmental pollutants.

The Potential Role of Gossypetin in the Treatment of Diabetes Mellitus and Its Associated Complications: A Review

Type 2 diabetes mellitus (T2DM) is a metabolic disorder caused by insulin resistance and dysfunctional beta (β)-cells in the pancreas. Hyperglycaemia is a characteristic of uncontrolled diabetes which eventually leads to fatal organ system damage. In T2DM, free radicals are continuously produced, causing extensive tissue damage and subsequent macro-and microvascular complications. The standard approach to managing T2DM is pharmacological treatment with anti-diabetic medications. However, patients' adherence to treatment is frequently decreased by the side effects and expense of medications, which has a detrimental impact on their health outcomes. Quercetin, a flavonoid, is a one of the most potent anti-oxidants which ameliorates T2DM. Thus, there is an increased demand to investigate quercetin and its derivatives, as it is hypothesised that similar structured compounds may exhibit similar biological activity. Gossypetin is a hexahydroxylated flavonoid found in the calyx of Hibiscus sabdariffa. Gossypetin has a similar chemical structure to quercetin with an extra hydroxyl group. Furthermore, previous literature has elucidated that gossypetin exhibits neuroprotective, hepatoprotective, reproprotective and nephroprotective properties. The mechanisms underlying gossypetin's therapeutic potential have been linked to its anti-oxidant, anti-inflammatory and immunomodulatory properties. Hence, this review highlights the potential role of gossypetin in the treatment of diabetes and its associated complications.

Polyphenols as Potential Protectors against Radiation-Induced Adverse Effects in Patients with Thoracic Cancer

Radiotherapy is one of the standard treatment approaches used against thoracic cancers, occasionally combined with chemotherapy, immunotherapy and molecular targeted therapy. However, these cancers are often not highly sensitive to standard of care treatments, making the use of high dose radiotherapy necessary, which is linked with high rates of radiation-induced adverse effects in healthy tissues of the thorax. These tissues remain therefore dose-limiting factors in radiation oncology despite recent technological advances in treatment planning and delivery of irradiation. Polyphenols are metabolites found in plants that have been suggested to improve the therapeutic window by sensitizing the tumor to radiotherapy, while simultaneously protecting normal cells from therapy-induced damage by preventing DNA damage, as well as having anti-oxidant, anti-inflammatory or immunomodulatory properties. This review focuses on the radioprotective effect of polyphenols and the molecular mechanisms underlying these effects in the normal tissue, especially in the lung, heart and esophagus.

Phytochemicals: A potential next generation agent for radioprotection

BACKGROUND

Radiation hazards are accountable for extensive damage in the biological system and acts as a public health burden. Owing to the rapid increasing in radiation technology, both Ionizing radiation (IR) from natural and man made source poses detrimental outcome to public health. IR releases free radicals which induces oxidative stress and deleterious biological damage by modulating radiation induced signalling intermediates. The efficacy of existing therapeutic approach and treatment strategy are limited owing to their toxicity and associated side effects. Indian system of traditional medicine is enriched with prospective phytochemicals with potential radioprotection ability.

PURPOSE

The present review elucidated and summarized the potential role of plant derived novel chemical compound with prospective radioprotective potential.

METHOD

So far as the traditional system of Indian medicine is concerned, plant kingdom is enriched with potential bioactive molecules with diverse pharmacological activities. We reviewed several compounds mostly secondary metabolites from plant origin using various search engines.

RESULTS

Both compounds from land plants and marine source exhibited antioxidant antiinflammatory, free radical scavenging ability. These compounds have tremendous potential in fine-tuning of several signalling intermediates, which are actively participated in the progression and development of a pathological condition associated with radiation stress.

CONCLUSION

Development and explore of an operational radioprotective agent from originated from plant source that can be used as a novel molecular tool to eliminate the widespread damage caused by space exploration, ionizing radiation, nuclear war and radiotherapy has been significantly appreciated. Through extensive literature search we highlighted several compounds from both land plant and marine origin can be implemented for a better therapeutic potential against radiation induced injury. Furthermore, extensive clinical trials must be carried out in near future for better therapeutic modality and clinical efficacy.

Indian Indigenous Fruits as Radioprotective Agents: Past, Present and Future

Ionising radiation has been an important modality in cancer treatment and its value is immense when surgical intervention is risky or might debilitate/adversely affect the patient. However, the beneficial effect of radiation modality is negated by the damage to the adjacent healthy tissue in the field of radiation. Under these situations, the use of radioprotective compounds that can selectively protect normal tissues against radiation injury is considered very useful. However, research spanning over half a century has shown that there are no ideal radioprotectors available. The United States Food and Drug Administration (FDA or USFDA) approved amifostine or WR-2721 (Walter Reed-2721) [chemically S-2-(3-aminopropyl-amino) ethyl phosphorothioic acid] is toxic at their optimal concentrations. This has necessitated the need for agents that are safe and easily acceptable to humans.

BACKGROUND

Dietary agents with beneficial effects like free radical scavenging, antioxidant and immunomodulatory effects are recognized as applicable and have been investigated for their radioprotective properties. Studies in these lines have shown that the fruits of Aegle marmelos (stone apple or bael), Emblica officinalis or Phyllanthus emblica(Indian gooseberry/amla), Eugenia jambolana or Syzygium jambolana (black plum / jamun), Mangifera indica (mango) and Grewia asiatica (phalsa or falsa) that are originally reported to be indigenous to India have been investigated for their usefulness as a radioprotective agent.

OBJECTIVE

The objective of this review is to summarize beneficial effects of the Indian indigenous fruits stone apple, mango, Indian gooseberry, black plum, and phalsa in mitigating radiation-induced side effects, emphasize the underlying mechanism of action for the beneficial effects and address aspects that merit detail investigations for these fruits to move towards clinical application in the near future.

METHODS

The authors data mined in Google Scholar, PubMed, Embase, and the Cochrane Library for publications in the field from 1981 up to July 2020. The focus was on the radioprotection and the mechanism responsible for the beneficial effects, and accordingly, the articles were collated and analyzed.

RESULTS

This article emphasizes the usefulness of stone apple, mango, Indian gooseberry, black plum, and phalsa as radioprotective agents. From a mechanistic view, reports are suggestive that the beneficial effects are mediated by triggering free radical scavenging, antioxidant, anti-mutagenic and anti-inflammatory effects.

CONCLUSION

For the first time, this review addresses the beneficial effects of mango, Indian gooseberry, black plum, stone apple and phalsa as radioprotective agents. The authors suggest that future studies should be directed at understanding the selective radioprotective effects with tumor-bearing laboratory animals to understand their usefulness as radioprotective drug/s during radiotherapy and as a food supplement to protect people getting exposed to low doses of radiation in occupational settings. Phase I clinical trial studies are also required to ascertain the optimal dose and the schedule to be followed with the standardized extract of these fruits. The most important aspect is that these fruits are a part of the diet, have been consumed since the beginning of mankind, are non-toxic, possess diverse medicinal properties, have easy acceptability all of which will help take research forward and be of benefit to patients, occupational workers, agribased sectors and pharma industries.

Genotoxic and cytotoxic properties of two medical plants (Teucrium arduini L.and Teucrium flavum L.) in relation to their polyphenolic contents

A large number of species belonging to the genus Teucrium are used in pharmacy and traditional medicine for the treatment of different diseases. This study aimed to evaluate the polyphenolic composition as well as genotoxic and cytotoxic effects of methanolic extracts from T. arduini and T. flavum, two native species found in Montenegro. We determined the total phenolic and flavonoid contents of these plants using spectrophotometric methods; the qualitative content of polyphenolic compounds was investigated by high-performance liquid chromatography (HPLC). Genotoxicity in cultured human lymphocytes was measured in the cytokinesis-block micronucleus assay (CBMN) and comet assay in the range between 125 and 1000 μg/mL. Cytotoxicity was assessed by the MTT viability assay in normal human MRC-5 fibroblasts and MDA-MB-231 breast carcinoma cells. The content of total phenolics and flavonoids in T. arduini extract was higher than in T. flavum (200.35 mg GA/g vs. 171.08 mg GA/g; 96.32 mg RU/g vs. 78.14 mg RU/g). The polyphenolic composition of both extracts was qualitatively similar and eight phenol compounds were identified. The most commonly present phenol was caffeic acid and among four flavonoids, the most common was quercetin. Both plant extracts were genotoxic in both the CBMN and comet assays at concentrations of 250, 500 and 1000 μg/mL. After 72 h of exposure, the extracts of T. arduini and T. flavum were found to induce cytotoxicity in MRC-5 fibroblasts but not in MDA-MB-231 breast cancer cells. The results suggest that the constituents of both plant species are genotoxic and cytotoxic, therefore these extracts warrant additional evaluation to be safely applied in humans.

Study of the Potential Radiomitigator Effect of Quercetin on Human Lymphocytes

Several substances of synthetic and natural origin have been studied to determine their ability to protect the body from damage caused by ionizing radiation. Among these substances, quercetin has been shown to be a naturally occurring molecule with high radioprotective and radiomitigator potential due to its antioxidant properties. The objective of this work was to ascertain the potential radiomitigator effect of quercetin on chromosome aberration yield in lymphocytes of in vitro-irradiated human peripheral blood. At first, the DPPH (2,2-diphenyl-1-picryl-hydrazyl) radical capture test was performed to determine the antioxidant activity of quercetin and to select the concentrations to be tested. The blood was irradiated at doses of 2.5, 3.5, and 4.5 Gy and lymphocytes were cultured with quercetin at preselected concentrations of 37.5 and 75 μM. Then, the slides were prepared for scoring unstable chromosome aberrations (dicentrics, rings, and fragments). The results showed that the lymphocytes irradiated and later exposed to quercetin presented a lower frequency of chromosomal alterations compared to the control sample which was irradiated and not exposed to quercetin. The results suggest a potential radiomitigator effect of the flavonoid quercetin on human lymphocytes exposed, in vitro, to ionizing radiation. This effect may be related to decrease in the release of cytokines (INF-γ, PGE2, IL-1β, IL6, IL-8) involved in the proinflammatory processes as well as downregulation of NF-kB and reduction of expression TGF-β.

Protective Effect of Selenium-Enriched Ricegrass Juice against Cadmium-Induced Toxicity and DNA Damage in HEK293 Kidney Cells

Cadmium (Cd) contamination in food is a problem endangering human health. Cd detoxication is an interesting topic particularly using food which provides no side effects. Ricegrass juice is a squeezed juice from young rice leaves which is introduced as a functional drink rich in polyphenol components. Se-enrichment into ricegrass is initiated to provide extra advantages of their functional properties. The protective role of ricegrass juice (RG) and Se-enriched ricegrass juice (Se-RG) against Cd toxicity during pre-, co- and post-treatment on HEK293 kidney cells were investigated. Results confirmed that RG and Se-RG had very low toxicity for kidney cells. Both extracts showed a protective role during pre-treatment and co-treatment against Cd toxicity by exerting a reduction in malondialdehyde (MDA) content and the percentage of DNA damage in tail and tail length of the comets over the Cd-treated cells. However, the Se-RG indicated additional benefits in all properties over RG. High Se content in Se-RG resulted in more protective effects of the regular ricegrass juice. In summary, this study provides clear evidence that Se-enriched ricegrass juice has potential to be developed as a functional food to protect the human body from Cd contamination via the reduction of oxidative stress and DNA damage.

Bioactive compounds and pharmacological and food applications ofSyzygium cumini– a review

The present review explores the nutritional, phytochemical and pharmacological potential as well as diverse food usages ofSyzygium cumini.

Bioactive compounds and pharmacological and food applications ofSyzygium cumini– a review

The present review explores the nutritional, phytochemical and pharmacological potential as well as diverse food usages ofSyzygium cumini.

In Vitro Bioassay-guided Isolation of Radioprotective Fractions from Extracts of Pinus koraiensis Bark

Objective

The aim of this study was to evaluate radioprotective effect of extracts of Pinus koraiensis bark and its fractions on rat splenocytes by using bioassay-guided isolation in order to obtain the best active fraction.

Materials and Methods

P. koraiensis bark was ground and extracted with water, 40% acetone, 95% ethanol. Bio-guided assay was selected as an evaluation method to further fractionate radioprotective component from P. koraiensis bark extract. Total phenolic and flavonoid contents in fractions were also measured. Rat splenocytes were prepared by using mechanical trituration method. DNA damage was assessed as comet parameters (tail DNA%, tail length, tail moment, olive tail moment). The levels of malondialdehyde (MDA), and activity of superoxide dismutase (SOD), catalase (CAT) in cultured rat splenocytes were also measured.

Results

The radioprotective effects decreased from rutin >95% ethanol extracts of Pinus koraiensis bark (95EEP) >40AEP > WEP. The stimulating effects decreased from rutin > n-butanol extract (NBE) > EAE. The results demonstrate that there exists toxic ingredients (PEE and dichloromethane extract), proliferative-promoting, radioprotective component (EAE and NBE) in 95EEP. fraction eluted from n-butanol fractions of 95EEP with 50% methanol solution (NBEPKB-50ME), a fraction of NBE result from bio-guided isolation, demonstrates good radioprotective efficacy on rat splenocytes. NBEPKB-50ME pretreated rat splenocytes demonstrated progressively reduced levels of MDA when compared with γ-ray exposed cells. Different dose of NBEPKB-50ME pretreatment with 8 Gy-irration showed an increase in enzymatic antioxidant.

Conclusions

Proliferative-promoting efficacy, radioprotective effect of different solvents extracts of the bark of P. koraiensis were investigated in this work. NBEPKB-50ME was the best elution in NBE, especially in restoring SOD, CAT activities, content of GSH, decreasing DNA damage.

SUMMARY

The radioprotective effects decreased from rutin > 95EEP > 40AEP > WEP. The extract of Petroleum ether, dichloromethane extract (DME) of 95% ethanol extract of P. koraiensis (PEE, DME) show toxic effect on rat splenocytes. The extract of Ethyl acetate, n-butanol extract of 95% ethanol extract of P. koraiensis (EAE, NBE) show proliferative-promoting, radioprotective effect on rat splenocytesSingle-cell gel electrophoresis was used to evaluate the spleen cell DNA damage parameters affected by gamma-radiation and addition of best component NBEPKB-50Me from extract of P. koraiensis barkNBEPKB-50ME pretreatment with 8 Gy-irradiation showed an increase in enzymatic antioxidant capacity. NBEPKB-50ME pretreated (80, 160, 320, 480 mg/ml) rat splenocytes demonstrated progressively reduced levels of MDA when compared with g-ray exposed cells. Abbreviations used: MDA: Malondialdehyde; SOD: Superoxide dismutase; CAT: Catalase; PEE: Petroleum ether Extract; DME: Dichloromethane extract; EAE: Ethyl acetate extract; NBE: n-butanol extract; WAP: Water extracts of Pinus koraiensis bark; 40AEP: 40% acetone extracts of Pinus koraiensis bark; 95EEP: 95% ethanol extracts of Pinus koraiensis bark; TPC: Total phenolic content; TFC: Total flavonoid content; NBEPKB-50ME: Fraction eluted from n-Butanol fractions of 95EEP with 50% methanol solution.

Anti-prostate cancer potential of gossypetin via inducing apoptotic and autophagic cell death

Gossypetin (GTIN), a naturally occurring hexahydroxy flavone, has been shown to possess antimutagenic, antioxidant, antimicrobial, and antiatherosclerotic effects. Here, we investigated the mechanism(s) underlying the anticancer potential of GTIN. In this study, investigations were showed that GTIN preferentially induces programed cell death of prostate cancer (PCa) cells in vitro and in vivo. MTT data showed that GTIN exhibited the anti-proliferation effect on human PCa cells in a dose- and time-dependent manner. Among two kinds of PCa cells, androgen-dependent LNCaP cells were the most susceptible to GTIN. GTIN was evaluated for apoptotic and autophagic activities in LNCaP cells, but not in androgen-independent DU145 cells with mutant Atg5 and resistant to autophagy. Molecular data showed the apoptotic effect of GTIN at a high dose in PCa cells might be mediated via mitochondrial pathway. The lower dose of GTIN-induced autophagy enhances LNCaP cell death, and is dependent on class III PI3K and Atg5 pathway. Finally, GTIN was evidenced by its inhibition on the growth of LNCaP cells in xenograft tumor studies. As a result, our data presented the first evidence of GTIN as an inducer of apoptotic and autophagic cell death in LNCaP cells, and provide a new mechanism for its anticancer activity.

The Radioprotective Effect of Resveratrol Against Genotoxicity Induced by γ-Irradiation in Mice Blood Lymphocytes

In this study, we evaluated whether the protective potential of resveratrol (RSV; 3,5,4'-trihydroxy-trans-stilbene) against γ-radiation caused damages in peripheral blood lymphocyte of mice. Resveratrol as a polyphenolic compound scavenges free radicals. Various doses of RSV were administered intraperitoneally 2 hours to adult male mice before a single dose of whole-body γ-irradiation (2 Gy). To assess the protective ability of RSV, the alkaline comet assay in blood lymphocyte of mice was performed and the total comet score was evaluated. The results of the alkaline comet assay showed that RSV significantly inhibited radiation-induced DNA damage. We observed that RSV protects blood lymphocyte against radiation-induced damage in mice.

A comparative study on the radioprotective potential of the polyphenolic glycoconjugates from medicinal plants of Rosaceae and Asteraceae families versus their aglycones

Radioprotective potential of the polyphenolic glycoconjugates, isolated from flowers of Sanguisorba officinalis L. (So) and Erigeron canadensis L. (Ec), and from leaves of Fragaria vesca L. (Fv) and Rubus plicatus Whe. Et N. E. (Rp) as well as their aglycones (SoA, EcA, FvA and RpA, respectively), against γ-radiation-induced lipid peroxidation in human plasma and DNA damage in lymphocytes, were investigated in vitro. These properties were assessed by measuring the concentration of thiobarbituric acid reactive substances (TBARS) and using the alkaline comet assay, and were compared to the protective effects of rutin (R) and quercetin (Q). Cytotoxicity of the glycoconjugates/aglycones towards L929 mouse fibroblasts and human lymphocytes were also measured. Plant products from S. officinalis, similar to Q, were able to reduce the most radiation-induced lipid peroxidation as well as DNA damage and extent of oxidative damage to the DNA basis. Contrary to the pure flavonoids, where Q was shown to be significantly more effective than its glycoside R, the results did not show more benefit with application of SoA/EcA over So/Ec in terms of lipid peroxidation inhibition. Moreover, glycoconjugates Ec and So showed much higher capacity in protecting lymphocytes against radiation-induced genotoxicity which may suggest that between the polyphenolic and polysaccharide parts exist some synergistic effects. There were no significant differences between Fv versus FvA or Rp versus RpA in terms of the provided radioprotection. Summarizing, plant glycoconjugates isolated by the multi-step method offered sufficient radioprotection. In addition, they possess many advantages, compared to the synthetic polyphenolic compounds or the plant extracts, such as water-solubility and minor toxicity.

Ameliorative effects of gallic acid, quercetin and limonene on urethane-induced genotoxicity and oxidative stress in Drosophila melanogaster

The main objective of our present work was to ascertain the efficacy of Drosophila melanogaster model for assessing antigenotoxic and antioxidant effects of dietary phytochemicals gallic acid (GA), quercetin (QC) and limonene (Lim) against urethane (URE), a genotoxic environmental carcinogen. Oregon-K (ORK) adult male flies were fed GA, QC and Lim in combination with URE (20 mM) in 10% sucrose for 72 h. Third instar larvae were fed instant medium containing the above phytochemicals and URE for 24 h. Sex-linked recessive lethal (SLRL) test and assays for estimating glutathione content (GSH), glutathione S-transferase (GST), catalase (CAT), superoxide dismutase (SOD) and lipid peroxidation (MDA content) were performed. Adult feeding experiments demonstrated that co-treatment of flies with URE and the test phytochemicals has significantly decreased the frequencies of SLRL mutations in all the germ cell stages when compared to that with URE alone. Larval feeding experiments also showed a similar pattern. The above results correlate well with antioxidative potentials of the test agents where we observed the elevated enzymatic levels with a significant reduction in MDA level in Drosophila larvae. The results further suggest that the dietary phytochemicals have an antioxidant and antimutagenic property which can be assessed using D. melanogaster.

Polyphenolic-polysaccharide conjugates from plants of Rosaceae/Asteraceae family as potential radioprotectors

Polyphenolic-polysaccharide macromolecular, water-soluble glycoconjugates, isolated from the selected medicinal plants of Rosaceae/Asteraceae family: from leaves of Fragaria vesca L., Rubus plicatus Whe. et N. E., and from flowering parts of Sanguisorba officinalis L., and Erigeron canadensis L., were investigated for their ability to protect proteins and lipids of human plasma against γ-radiation-induced oxidative damage. Treatment of plasma with plant conjugates (6, 30, 150 μg/ml) prior exposure to 100 Gy radiation resulted in a significant inhibition of lipid peroxidation, evaluated by TBARS levels; conjugates isolated from E. canadensis and R. plicatus and a reference flavonoid quercetin showed similar high potential (approx. 70% inhibition, at 6 μg/ml). The conjugates prevented radiation-induced oxidation of protein thiols and significantly improved plasma total antioxidant capacity, estimated with Ellman's reagent and ABTS(.+) assay, respectively. The results demonstrate by the first time a significant radioprotective capability of the polyphenolic-polysaccharide conjugates isolated from E. canadensis, R. plicatus, S. officinalis and to the less extent from F. vesca. The abilities of these substances to inhibit radiation-induced lipid peroxidation and thiol oxidation in plasma seems to be mediated, but not limited to ROS scavenging activity.

Utilization of cytogenetic biomarkers as a tool for assessment of radiation injury and evaluation of radiomodulatory effects of various medicinal plants - a review

Systematic biological measurement of “cytogenetic endpoints” has helped phenomenally in assessment of risks associated with radiation exposure. There has been a surge in recent times for the usage of radioactive materials in health care, agriculture, industrial, and nuclear power sectors. The likelihood of radiation exposure from accidental or occupational means is always higher in an overburdened ecosystem that is continuously challenged to meet the population demands. Risks associated with radiation exposure in this era of modern industrial growth are minimal as international regulations for maintaining the safety standards are stringent and strictly adhered to, however, a recent disaster like “Fukushima” impels us to think beyond. The major objective of radiobiology is the development of an orally effective radio-modifier that provides protection from radiation exposure. Once available for mass usage, these compounds will not only be useful for providing selective protection against accidental and occupational radiation exposure but also help to permit use of higher doses of radiation during treatment of various malignancies curtailing unwarranted adverse effects imposed on normal tissues. Bio-active compounds isolated from natural sources enriched with antioxidants possess unique immune-modulating properties, thus providing a double edged benefit over synthetic radioprotectors. We aim to provide here a comprehensive overview of the various agents originating from plant sources that portrayed promising radioprotection in various experimental models with special emphasis on studies that used cytogenetic biomarkers. The agents will include crude extracts of various medicinal plants, purified fractions, and herbal preparations.

Sea Buckthorn Leaf Extract Protects Jejunum and Bone Marrow of (60)Cobalt-Gamma-Irradiated Mice by Regulating Apoptosis and Tissue Regeneration

A single dose (30 mg/kg body weight) of standardized sea buckthorn leaf extract (SBL-1), administered 30 min before whole body ⁶⁰Co-gamma-irradiation (lethal dose, 10 Gy), protected >90% of mice population. The purpose of this study was to investigate the mechanism of action of SBL-1 on jejunum and bone marrow, quantify key bioactive compounds, and analyze chemical composition of SBL-1. Study with 9-week-old inbred male Swiss albino Strain ‘A' mice demonstrated that SBL-1 treatment before ⁶⁰Co-gamma-irradiation (10 Gy) significantly (p < 0.05) countered radiation induced decreases in jejunum crypts (1.27-fold), villi number (1.41-fold), villus height (1.25-fold), villus cellularity (2.27-fold), cryptal Paneth cells (1.89-fold), and Bcl2 level (1.54-fold). It countered radiation induced increases in cryptal apoptotic cells (1.64-fold) and Bax levels (1.88-fold). It also countered radiation (2 Gy and 3 Gy) induced bone marrow apoptosis (1.59-fold and 1.85-fold) and micronuclei frequency (1.72-fold and 2.6-fold). SBL-1 rendered radiation protection by promoting cryptal stem cells proliferation, by regulating apoptosis, and by countering radiation induced chromosomal damage. Quercetin, Ellagic acid, Gallic acid, high contents polyphenols, tannins, and thiols detected in SBL-1 may have contributed to radiation protection by neutralization of radiation induced oxidative species, supporting stem cell proliferation and tissue regeneration.

Radio-protective effect of cinnamic acid, a phenolic phytochemical, on genomic instability induced by X-rays in human blood lymphocytes in vitro

The present study was designed to determine the protective activity of cinnamic acid against induction by X-rays of genomic instability in normal human blood lymphocytes. This radio-protective activity was assessed by use of the cytokinesis-block micronucleus test and the alkaline comet assay, with human blood lymphocytes isolated from two healthy donors. A Siemens Mevatron MD2 (Siemens AG, USA, 1994) linear accelerator was used for the irradiation with 1 or 2 Gy. Treatment of the lymphocytes with cinnamic acid prior to irradiation reduced the number of micronuclei when compared with that in control samples. Treatment with cinnamic acid without irradiation did not increase the number of micronuclei and did not show a cytostatic effect in the lymphocytes. The results of the alkaline comet assay revealed that cinnamic acid reduces the DNA damage induced by X-rays, showing a significant radio-protective effect. Cinnamic acid decreased the frequency of irradiation-induced micronuclei by 16-55% and reduced DNA breakage by 17-50%, as determined by the alkaline comet assay. Cinnamic acid may thus act as a radio-protective compound, and future studies may focus on elucidating the mechanism by which cinnamic acid offers radioprotection.

Does quercetin protect human red blood cell membranes against γ-irradiation?

OBJECTIVES

Radioprotective potential of quercetin, a powerful free radical scavenger, was investigated in human red blood cells (RBCs) and in isolated RBC membranes exposed to γ-irradiation-induced oxidative stress.

METHODS

RBCs and RBC membrane suspensions were irradiated (50 Gy) in the presence of quercetin (2-50 µM). Oxidative damage of the membranes was analysed by protein carbonyl measurement (enzyme-linked immunosorbent assay). In RBCs, the concentration of glutathione (GSH) was determined. Lipid peroxidation in RBCs, and for comparison in plasma and peripheral lymphocytes, was quantified by the amount of thiobarbituric acid-reactive substances (TBARS). Radiation-induced damage of the RBC membrane integrity was evaluated by the degree of haemolysis.

RESULTS

Quercetin (50 µM) brought back the level of carbonyls to normal in γ-irradiated RBC membrane proteins and inhibited radiation-induced lipid peroxidation in plasma and lymphocytes, by 75 and 96%, respectively. However, it moderately decreased reduced/oxidized glutathione (GSH/GSSG) ratio and significantly increased TBARS concentrations, by 60 and 28% in irradiated and non-irradiated RBCs, respectively. Haemolysis rate was much higher in RBCs irradiated in the presence of quercetin vs. non antioxidant.

DISCUSSION

In non-cellular systems (RBC membranes or plasma) and in lymphocytes, quercetin shows antioxidative/radioprotective activity but in whole RBCs it acts as a pro-oxidant and a cytotoxic substance. The possible mechanisms of such action are discussed.

Studies on black tea (Camellia sinensis) extract as a potential antioxidant and a probable radioprotector

Positive health effects of tea (Camellia sinensis) on a wide range of physiological problems and diseases are well known and are in part due to its copious antioxidant content. The effect of black tea extract (BTE), which is rich in polyphenolic antioxidants, against the consequences of radiation exposure has not been properly identified. The functional properties of BTE were analyzed and its radioprotective effect on V79 cells was explored in the present study. BTE scavenged free radicals and inhibited Fenton reaction-mediated 2-deoxyribose degradation and lipid peroxidation in a dose-dependent fashion, establishing its antioxidant properties. The radioprotective effects of BTE on strand break induction in pBR322 plasmid DNA were 100 % at 80 μg/ml and higher. In V79 cells, BTE was effective in decreasing the frequency of radiation-induced micronucleated cells and the yields of reactive oxygen species (ROS) and also in restoring the integrity of cellular mitochondrial membrane potential significantly. BTE exerted maximum protection against radiation-induced damage in V79 at a dose of 5 μg/ml. Due to the functional properties of BTE-flavonoids, which have been identified by HPLC, it is envisaged that the key player in radioprotection is elimination of ROS.

Polyphenolic fraction of Pilea microphylla (L.) protects Chinese hamster lung fibroblasts against γ-radiation-induced cytotoxicity and genotoxicity

Present study was designed to compare cytoprotective and antigenotoxic activity of the polyphenolic fraction of Pilea microphylla (PM1) with that of its active polyphenolic constituents against γ-radiation in V79 cells. PM1 was standardized with respect to the polyphenols present by RP-HPLC. It was evaluated for its free radical scavenging potential using Fenton reaction-induced DNA damage and lipid peroxidation. Further, PM1 was subjected against γ-radiation-induced cytotoxicity and genotoxicity in V79 cells. PM1 significantly reduced free radical-mediated calf thymus DNA damage and lipid peroxidation. Among the concentrations tested (12.5, 25 and 50 μg/ml) for radioprotection, PM1 at 25 μg/ml exhibited maximum protection. Further, when compared with constituent polyphenols viz., rutin, quercetin and chlorogenic acid (concentrations equivalent to that present in PM1-25 μg/ml), a combination of polyphenols was found most effective in preventing γ-radiation-induced cytotoxicity and genotoxicity. To conclude, radioprotection is possibly a synergistic effect of the phytochemicals present in the herbal extract, rather than any single component.

Phenylpropanoids in radioregulation: double edged sword

Radiotherapy, frequently used for treatment of solid tumors, carries two main obstacles including acquired radioresistance in cancer cells during radiotherapy and normal tissue injury. Phenylpropanoids, which are naturally occurring phytochemicals found in plants, have been identified as potential radiotherapeutic agents due to their anti-cancer activity and relatively safe levels of cytotoxicity. Various studies have proposed that these compounds could not only sensitize cancer cells to radiation resulting in inhibition of growth and cell death but also protect normal cells against radiation-induced damage. This review is intended to provide an overview of recent investigations on the usage of phenylpropanoids in combination with radiotherapy in cancer treatment.

In vitro and in vivo evaluation of the anticarcinogenic and cancer chemopreventive potential of a flavonoid-rich fraction from a traditional Indian herb Selaginella bryopteris

Prevention of cancer through nutritional intervention has gained significant recognition in recent years. Evidence revealed from mechanistic investigations coupled with molecular epidemiology show an inverse association of dietary flavonoids intake with cancer risk. The chemopreventive and anticarcinogenic potential of Selaginella bryopteris, a traditional Indian herb referred to as ‘Sanjeevani’ in the Ayurvedic system of medicine, was examined in the present study. Comprehensive in vitro and in vivo studies were conducted on the flavonoid-rich benzene fraction of the aqueous extract that demonstrated a significant cytoprotective activity. Biomarkers of chemoprevention such as proliferative index and status of cell-cycle regulatory proteins, antioxidant property, anti-inflammatory effect, reversal of stress-induced senescence and genoprotective effect were investigated in human and murine cell cultures. Chemopreventive potential was assessed in benzopyrene-induced lung carcinogenesis and 7,12-dimethyl benz(a)anthracene-mediated skin papillomagenesis test models. Inhibition of DNA fragmentation, unperturbed cell-cycle regulation, maintenance of intracellular antioxidant defence, anti-inflammatory activity, prevention of stress-induced senescence and genoprotective effects against methyl isocyanate carcinogenicity was observed. Medium-term anticarcinogenicity and two-stage skin papillomagenesis tests strongly substantiated our in vitro observations. Results from the present study provide evidence of anticarcinogenic and chemopreventive activities of S. bryopteris hitherto unreported and reaffirm the nutritional significance of flavonoids in cancer prevention.

Protective effects of selenocystine against γ-radiation-induced genotoxicity in Swiss albino mice

Selenocystine (CysSeSeCys), a diselenide aminoacid exhibiting glutathione peroxidase-like activity and selective antitumor effects, was examined for in vivo antigenotoxic and antioxidant activity in Swiss albino mice after exposure to a sublethal dose (5 Gy) of γ-radiation. For this, CysSeSeCys was administered intraperitoneally (i.p.) to mice at a dosage of 0.5 mg/kg body weight for 5 consecutive days prior to whole-body γ-irradiation. When examined in the hepatic tissue, CysSeSeCys administration reduced the DNA damage at 30 min after radiation exposure by increasing the rate of DNA repair. Since antigenotoxic agents could alter the expression of genes involved in cell cycle arrest and DNA repair, the transcriptional changes in p53, p21 and GADD45α were monitored in the hepatic tissue by real-time PCR. The results show that CysSeSeCys alone causes moderate induction of these three genes. However, CysSeSeCys pretreatment resulted in a suppression of radiation-induced enhancement of p21 and GADD45α expression, but did not affect p53 expression. Further analysis of radiation-induced oxidative stress markers in the same tissue indicated that CysSeSeCys significantly inhibits lipid peroxidation and prevents the depletion of antioxidant enzymes and glutathione (GSH) levels. Additionally, it also prevents radiation-induced DNA damage in other radiation sensitive cellular systems like peripheral leukocytes and bone marrow, which was evident by a decrease in comet parameters and micronucleated polychromatic erythrocytes (mn-PCEs) frequency, respectively. Based on these observations, it is concluded that CysSeSeCys exhibits antigenotoxic effects, reduces radiation-induced oxidative stress, and is a promising candidate for future exploration as a radioprotector.

Radioprotective activity of Gentiana lutea extract and mangiferin

Radioprotective/sensitizing actions of Gentiana lutea aqueous-ethanol extract and mangiferin on radiation-induced effects on different types of cells were investigated. The study focused on the decreasing survival of normal human immunocompetent cells, the survival of the malignant cells in vitro, and the survival of ex vivo irradiated cells before and after consumption of the extract by healthy volunteers. The in vitro experiments showed that mangiferin could inhibit cytotoxic action of ionizing irradiation (doses of 6 and 8 Gy) only on normal resting human PBMC, not stimulated for proliferation. Orally consumed G. lutea extract showed the potential to reduce the cytotoxic effect of x-ray irradiation on normal human immunocompetent cells PBMC of some healthy people, without changing the susceptibility of malignant cells to be destroyed by irradiation. Since the radioprotective effect was individually dependent, further clinical studies are needed.

Curcumin, resveratrol and flavonoids as anti-inflammatory, cyto- and DNA-protective dietary compounds

Numerous dietary compounds, ubiquitous in fruits, vegetables and spices have been isolated and evaluated during recent years for their therapeutic potential. These compounds include flavonoid and non-flavonoid polyphenols, which describe beneficial effects against a variety of ailments. The notion that these plant products have health promoting effects emerged because their intake was related to a reduced incidence of cancer, cardiovascular, neurological, respiratory, and age-related diseases. Exposure of the body to a stressful environment challenges cell survival and increases the risk of chronic disease developing. The polyphenols afford protection against various stress-induced toxicities through modulating intercellular cascades which inhibit inflammatory molecule synthesis, the formation of free radicals, nuclear damage and induce antioxidant enzyme expression. These responses have the potential to increase life expectancy. The present review article focuses on curcumin, resveratrol, and flavonoids and seeks to summarize their anti-inflammatory, cytoprotective and DNA-protective properties.

Antioxidant potential of sesamol and its role on radiation-induced DNA damage in whole-body irradiated Swiss albino mice

Sesamol (SM) is a dietary phytochemical present in the processed sesame oil. In this present study we have evaluated the antioxidant potential of SM and its role in the protection of radiation-induced DNA damage in γ-irradiated mice. The antioxidant properties of SM were evaluated by using different in vitro antioxidant assays. SM shows scavenging effect against hydroxyl (OH), superoxide anion (O(2)(-)), nitric oxide, 2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid radical cation (ABTS(+)) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. Our results demonstrate that SM exhibits strong antioxidant property in all the in vitro assays. When mice were exposed to 7 Gy γ-radiations there was an increase in % tail DNA, tail length, tail moment and Olive tail moment in blood lymphocytes. SM (100mg/kg b.wt) pretreatment significantly decreased the % tail DNA, tail length, tail moment and Olive tail moment in irradiated mice lymphocytes. These results suggest that SM protects γ-radiation-induced DNA damage in mice lymphocytes, which may be attributed to its antioxidant property.

Protective effect of ascorbic acid against oxidative damage induced by hydrogen peroxide in cultured human peripheral blood lymphocytes

Hydrogen peroxide is one of the reactive oxygen species for cellular injury. It is overproduced during oxidative stress and is known to damage proteins, nucleic acids and cell membranes. The present study was aimed to study the protective effect of ascorbic acid against the toxic doses of hydrogen peroxide using lipid peroxidation and cytokinesis blocked micronucleus assay. Hydrogen peroxide was studied at 50, 100 and 200μM and was found to increase a dose dependent increase in lipid peroxidation and micronuclei frequency. The treatment of 100 and 200μM of hydrogen peroxide separately along with 20, 40 and 80μM of ascorbic acid showed a dose dependent decrease in the lipid peroxidation and micronuclei frequency. The results suggest a protective effect of ascorbic acid against the hydrogen peroxide induced oxidative damage in cultured human peripheral blood lymphocytes.