Radioprotection by plant products: present status and future prospects

Beneficial effects of natural products on cells during ionizing radiation

Natural products like vegetables, fruits, and herbs are widely consumed by humans on a daily basis. These natural products have many biologic and pharmacologic properties. Ionizing radiation (IR) can interact with macromolecules like DNA, which induces serious side effects on cells and tissues. Natural products can directly scavenge free radicals produced by IR, and they can also activate or inhibit enzymes or proteins involved in the oxidative stress. Several natural products have dual biologic effects on normal and cancer cells during radiation and might be of interest for use in patients during radiotherapy. In this review, the effects of natural products on genotoxicity and cell death induced by IR were reviewed and some potentiated compounds were discussed.

Radioprotective effect of epicatechin in cultured human fibroblasts and zebrafish

Radiation-induced normal cell damage limits the delivery of high-dose radiation to targeted cancer. This study investigated the effect of epicatechin (EC), a minor component of green tea extracts, on radiation-induced cellular damage in vitro in primary cultured human fibroblasts and in vivo in a zebrafish model. Cell viability, proliferation and wound-healing efficacy, mitochondrial membrane potential, and reactive oxygen species (ROS) generation as well as changes in the signaling pathway related to apoptosis were investigated in fibroblasts. The therapeutic effects of EC were explored in a zebrafish model. EC increased clonogenic survival and restored the migration ability of the fibroblasts after irradiation. EC inhibited radiation-induced ROS generation, mitochondrial dysfunction and cell death. EC significantly reduced the expression of p-JNK, p-38, and cleaved caspase-3 compared with their significant increase after radiation treatment. EC attenuated the radiation-induced embryotoxicity in a zebrafish model. These results suggest that EC represents an effective means of reducing cellular damage and facilitating wound healing after radiation exposure.

Infusion of Trx-1-overexpressing hucMSC prolongs the survival of acutely irradiated NOD/SCID mice by decreasing excessive inflammatory injury

A protective reagent for ARI should have the ability to repair injured tissue caused by radiation and prevent continuous damage from secondary risk factors. Trx-1 was explored as a candidate therapy for ARI, as it scavenges reactive oxygen species, regulates cell growth and differentiation, participates in immune reactions, and inhibits apoptosis by acting inside and/or outside cells. Trx-1 can also decrease excessive inflammation in ARI by regulating the creation of inflamed media, by inhibiting the activation of complement, and by reducing the chemotaxis, adhesion, and migration of inflammatory cells. As effectively and stably expressing exogenous genes in the long term and regulating immune inflammation and tissue repair, MSC are a good choice for Trx-1 gene therapy. In this study, Trx-1-overexpressing hucMSC-Trx-1 were obtained by adenoviral vector-mediated infection. We first measured the redox capacity of hucMSC-Trx-1 with an antioxidant capacity (T-AOC) assay, a hydrogen peroxide (H2O2) content determination assay in vivo, a H2O2-induced oxidation hemolysis assay, and a lipid peroxidation assay in vitro. Then, we measured survival time, the protection of the hematopoietic system, and the regulation of inflammation in important organs in three treatment groups of NOD/SCID mice (treated with hucMSC-Trx-1, with hucMSC, and with saline) that were exposed to 4.5 Gy (60)Co-γ-ray radiation. The hucMSC-Trx-1 group achieved superior antioxidation results, protecting bone marrow hematopoietic stem cells (Lin(-)CD117(+): hucMSC-Trx-1 vs. hucMSC, P<0.05; hucMSC-Trx-1 vs. NS, P<0.01), promoting the formation of red blood cells and hemoglobin (hucMSC-Trx-1 vs. hucMSC or NS, P<0.05), reducing inflammation and damage in important organs (Bone marrow and lung: hucMSC-Trx-1 vs. NS, P<0.01; hucMSC-Trx-1 vs. hucMSC, P<0.05. Liver and intestine: hucMSC-Trx-1 vs. NS, P<0.05; hucMSC-Trx-1 vs. hucMSC, P<0.05), and prolonging survival (hucMSC-Trx-1 vs. hucMSC or NS, P<0.01). Therefore, hucMSC-Trx-1 combines the merits of gene and cell therapy as a multifunctional radioprotector for ARI.

Radiomodulatory role of Rutin and Quercetin in Swiss Albino mice exposed to the whole body gamma radiation

Context:

Radiation therapy is the prime treatment modality against various cancers. However, its use is limited due to the effects of radiation on normal tissues.

Aims:

In view of this, present study was carried out to evaluate the radioprotective potential of Rutin (RUT) and Quercetin (QRT) in Swiss Albino mice exposed to the whole body gamma radiation. To gain insight into the mechanism of action, RUT and QRT were tested for its antioxidant levels in mice.

Settings and Designs:

Optimum protective dose of RUT and QRT against radiation induced animal mortality was selected by administration of various doses of the RUT and QRT before 10 Gy gamma irradiation.

Materials and Methods:

Swiss Albino mice were used for the assessment of radiation induced sickness along with the survival analysis and anti-oxidative properties of RUT and QRT.

Statistical Analysis Used:

Survival studies were determined using the Kaplan-Meier survival curves.

Results:

The maximum survival was observed with 10 mg/kg. b. wt. and 20 mg/kg. b. wt. of RUT and QRT respectively, this dose was considered as an optimal dose for radioprotection. Treatment of mice with RUT and QRT before irradiation delayed the onset of mortality as compared with the untreated irradiated controls. The oral administration of RUT and QRT resulted in an increase in the radiation tolerance and the dose reduction factor was found to be 1.15 and 1.11 respectively. RUT and QRT pre-treatment significantly (P < 0.01) elevated levels of reduced glutathione, glutathione-S-transferase, catalase, Superoxide dismutase, and a decreased lipid peroxidation in mouse liver homogenate at 24 h after exposure to 4.5 Gy.

Conclusions:

Present findings demonstrate the potential of RUT and QRT in mitigating radiation-induced mortality, which may be attributed to the elevation in the antioxidant status, anti-lipid peroxidative potential.

Radioprotective effects of gallic acid in mice

Radioprotecting ability of the natural polyphenol, gallic acid (3,4,5-trihydroxybenzoic acid, GA), was investigated in Swiss albino mice. Oral administration of GA (100 mg/kg body weight), one hour prior to whole body gamma radiation exposure (2–8 Gy; 6 animals/group), reduced the radiation-induced cellular DNA damage in mouse peripheral blood leukocytes, bone marrow cells, and spleenocytes as revealed by comet assay. The GA administration also prevented the radiation-induced decrease in the levels of the antioxidant enzyme, glutathione peroxidise (GPx), and nonprotein thiol glutathione (GSH) and inhibited the peroxidation of membrane lipids in these animals. Exposure of mice to whole body gamma radiation also caused the formation of micronuclei in blood reticulocytes and chromosomal aberrations in bone marrow cells, and the administration of GA resulted in the inhibition of micronucleus formation and chromosomal aberrations. In irradiated animals, administration of GA elicited an enhancement in the rate of DNA repair process and a significant increase in endogenous spleen colony formation. The administration of GA also prevented the radiation-induced weight loss and mortality in animals (10 animals/group) exposed to lethal dose (10 Gy) of gamma radiation. (For every experiment unirradiated animals without GA administration were taken as normal control; specific dose (Gy) irradiated animals without GA administration serve as radiation control; and unirradiated GA treated animals were taken as drug alone control).

Preventive or potential therapeutic value of nutraceuticals against ionizing radiation-induced oxidative stress in exposed subjects and frequent fliers

Humans are constantly exposed to ionizing radiation deriving from outer space sources or activities related to medical care. Absorption of ionizing radiation doses over a prolonged period of time can result in oxidative damage and cellular dysfunction inducing several diseases, especially in ageing subjects. In this report, we analyze the effects of ionizing radiation, particularly at low doses, in relation to a variety of human pathologies, including cancer, and cardiovascular and retinal diseases. We discuss scientific data in support of protection strategies by safe antioxidant formulations that can provide preventive or potential therapeutic value in response to long-term diseases that may develop following exposure.

Radioprotective agents for the prevention of side effects induced by radioiodine-131 therapy

Radioiodine 131 (131I) has been used worldwide for the ablation of remnant thyroidal tissue after surgery or as the first-line treatment for Graves’ disease. Although the use of 131I is becoming increasingly prevalent, there is evidence suggesting that this treatment is associated with side effects such as salivary gland dysfunction and an increased risk of leukemia. This article aims to review the potential use of radioprotective agents and the side effects induced by 131I therapy. Several synthetic and natural compounds have been investigated in preclinical and clinical studies. The protective agents reduced the toxicity of 131I, mainly in the salivary glands, and mitigated the genetic damage through different mechanisms. There are limited clinical studies evaluating the use of radioprotective agents in patients undergoing radioiodine therapy. However, lemon candies, lemon juice and sugarless chewing gum have been proposed to be beneficial for minimizing the side effects of radioiodine within the salivary glands.

Evidence based herbal drug standardization approach in coping with challenges of holistic management of diabetes: a dreadful lifestyle disorder of 21st century

Plants by virtue of its composition of containing multiple constituents developed during its growth under various environmental stresses providing a plethora of chemical families with medicinal utility. Researchers are exploring this wealth and trying to decode its utility for enhancing health standards of human beings. Diabetes is dreadful lifestyle disorder of 21st century caused due to lack of insulin production or insulin physiological unresponsiveness. The chronic impact of untreated diabetes significantly affects vital organs. The allopathic medicines have five classes of drugs, or otherwise insulin in Type I diabetes, targeting insulin secretion, decreasing effect of glucagon, sensitization of receptors for enhanced glucose uptake etc. In addition, diet management, increased food fiber intake, Resistant Starch intake and routine exercise aid in managing such dangerous metabolic disorder. One of the key factors that limit commercial utility of herbal drugs is standardization. Standardization poses numerous challenges related to marker identification, active principle(s), lack of defined regulations, non-availability of universally acceptable technical standards for testing and implementation of quality control/safety standard (toxicological testing). The present study proposed an integrated herbal drug development & standardization model which is an amalgamation of Classical Approach of Ayurvedic Therapeutics, Reverse Pharmacological Approach based on Observational Therapeutics, Technical Standards for complete product cycle, Chemi-informatics, Herbal Qualitative Structure Activity Relationship and Pharmacophore modeling and, Post-Launch Market Analysis. Further studies are warranted to ensure that an effective herbal drug standardization methodology will be developed, backed by a regulatory standard guide the future research endeavors in more focused manner.

Rasayana drugs from the Ayurvedic system of medicine as possible radioprotective agents in cancer treatment

The use of ionizing radiation, which is the cornerstone of cancer treatment, is compromised by the radiosensitivity of normal tissues. A chemical that can give selective benefit to the normal cells against the deleterious effects of ionizing radiation has been a long-sought goal. However, most of the compounds studied have shown inadequate clinical application owing to their inherent toxicity, undesirable side effects, and high cost. Studies carried out in the past 2 decades have shown that some of the classical Indian Ayurvedic drugs (Amritaprasham, Ashwagandha Rasayana, Brahma Rasayana, Chyavanprasha, Narasimha Rasayana, and Triphala Churna) possess radioprotective effects. In the current review, an attempt is made to summarize the radioprotective observations of these Ayurvedic drugs and the mechanisms responsible for the radioprotective effects.

Management of Radiation Injuries by Panax ginseng Extract

Chemical radiation protection is an important strategy to protect living beings against the deleterious effects of radiation. In the present study, the radioprotective effect of hydro-alcoholic extract of Panax ginseng extract (PGR-HAE) was studied on radiation-induced deleterious alterations in Swiss albino mice. Oral administration of such extract (25 mg/kg b wt/day/animal) for 5 consecutive days, half an h. before whole-body exposure to 6 Gy gamma radiation, enhanced the 30 days survival and also inhibited the radiogenic sickness, weight loss and life shortening. PGR-HAE ameliorated radiation induced depletion in blood constituents at different necropsy intervals between 12 h to 30 d, and significantly increased the number of femoral spleen colony forming units that survived after irradiation. Furthermore, it checked depletion of glutathione and antioxidant enzymes (superoxide dismutase, catalase, and glutathione S-transferase) as well as elevation of lipid peroxidation (LPO) level in blood and liver. The significant reduction in the yield of LPO demonstrates that PGR-HAE protects the membranes against radiation-induced oxidative damage. These findings conclude that such plant extract provides significant radioprotection, and it may be potentially valuable in the prevention of injuries caused during planned and unplanned radiation exposure.

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.

Holy Basil leaf extract decreases tumorigenicity and metastasis of aggressive human pancreatic cancer cells in vitro and in vivo: potential role in therapy

There is an urgent need to develop alternative therapies against lethal pancreatic cancer (PC). Ocimum sanctum ("Holy Basil") has been used for thousands of years in traditional Indian medicine, but its anti-tumorigenic effect remains largely unexplored. Here, we show that extracts of O. sanctum leaves inhibit the proliferation, migration, invasion, and induce apoptosis of PC cells in vitro. The expression of genes that promote the proliferation, migration and invasion of PC cells including activated ERK-1/2, FAK, and p65 (subunit of NF-κB), was downregulated in PC cells after O. sanctum treatment. Intraperitoneal injections of the aqueous extract significantly inhibited the growth of orthotopically transplanted PC cells in vivo (p<0.05). Genes that inhibit metastasis (E-cadherin) and induce apoptosis (BAD) were significantly upregulated in tumors isolated from mice treated with O. sanctum extracts, while genes that promote survival (Bcl-2 and Bcl-xL) and chemo/radiation resistance (AURKA, Chk1 and Survivin) were downregulated. Overall, our study suggests that leaves of O. sanctum could be a potential source of novel anticancer compounds in the future.

Rhododendron tomentosum (Ledum palustre). A review of traditional use based on current research

Rhododendron tomentosum Harmaja (previously: Ledum palustre) is a fragrant evergreen shrub found in peaty soils in northern Europe, Asia and North America, commonly referred to as wild rosemary, marsh tea, marsh rosemary or northern Labrador tea. At least since the eighteenth century it has been used in ethnomedicine for the treatment of various ailments, such as rheumatism, cough, cold and insect bites, as well as a repellent. The essential oil of wild rosemary with the rich polyphenolic fraction possesses analgesic, anti-inflammatory, antimicrobial, antiviral, antifungal and insecticidal potential, demonstrated by in vivo and in vitro studies. In addition, recent scientific research reported the promising antidiabetic, antioxidant and anticancer properties. This review summarizes the information concerning taxonomy, botany, ecology, chemical composition, biological activities, toxicology and traditional and contemporary application of Rhododendron tomentosum plants.

Ocimum sanctum L (Holy Basil or Tulsi) and its phytochemicals in the prevention and treatment of cancer

Ocimum sanctum L. or Ocimum tenuiflorum L, commonly known as the Holy Basil in English or Tulsi in the various Indian languages, is a important medicinal plant in the various traditional and folk systems of medicine in Southeast Asia. Scientific studies have shown it to possess antiinflammatory, analgesic, antipyretic, antidiabetic, hepatoprotective, hypolipidemic, antistress, and immunomodulatory activities. Preclinical studies have also shown that Tulsi and some of its phytochemicals eugenol, rosmarinic acid, apigenin, myretenal, luteolin, β-sitosterol, and carnosic acid prevented chemical-induced skin, liver, oral, and lung cancers and to mediate these effects by increasing the antioxidant activity, altering the gene expressions, inducing apoptosis, and inhibiting angiogenesis and metastasis. The aqueous extract of Tulsi and its flavanoids, orintin, and vicenin are shown to protect mice against γ-radiation-induced sickness and mortality and to selectively protect the normal tissues against the tumoricidal effects of radiation. The other important phytochemicals like eugenol, rosmarinic acid, apigenin, and carnosic acid are also shown to prevent radiation-induced DNA damage. This review summarizes the results related to the chemopreventive and radioprotective properties of Tulsi and also emphasizes aspects that warrant future research to establish its activity and utility in cancer prevention and treatment.

The use of endemic Iranian plant, Echium amoenum, against the ethyl methanesulfonate and the recovery of mutagenic effects

In this study, potential genotoxic effects of ethyl methanesulfonate (EMS) that caused mutagenicity in a variety of organisms were tried to resolve by the methanol and chloroform extract of Echium amoenum (EAmet and EAchl) Fisch. & C.A. Mey. from the family of Boraginaceae, which is an endemic plant, and is used as an alternative treatment among public in Iran. Somatic mutation and recombination test with Drosophila wing was used to determine the genotoxic and antigenotoxic effects in our investigations. For this purpose, 3-day-old transheterozygous larvae of mwh/flr3 genotype of Drosophila melanogaster were used in all our experiments. The larvae were fed chronically on the Drosophila instant medium (DIM) including 1 ppm EMS. However, in another application group, different concentrations (1, 2 and 4 ppm) of EAmet and EAchl were added to DIM including 1 ppm EMS (EMS + EAmet and EMS + EAchl). Then, for the matured individuals, wing preparates were prepared within the mediums that include control group that has only DIM, negative control group that contains dimethyl sulfoxide and application groups in different concentrations that contain EMS, EMS + EAmet and EMS + EAchl. Clone induction frequency for the normal wing phenotype of EMS application group was observed to be 2.00. In the EMS + EAmet application group, the value of 1 ppm EAmet is 1.49, value of 2 ppm EAmet is 1.08 and value of 4 ppm EAmet is 0.72; in the EMS + EAchl application group, the value of 1 ppm is EAchl 1.33, value of 2 ppm EAchl is 0.67 and value of 4 ppm EAchl is 0.56 were determined. This decrease observed between EMS and all application groups in terms of total induction frequency is statistically significant ( p < 0.05). These results concluded that chloroform extracts were more effective than the methanol extracts of E. amoenum.

Radioprotective effect of rhizome extract of Zingiber montanum in Rattus norvegicus

The present study aims at determining the ability of 60% ethanol extract of the rhizome of Zingiber montanum (J. König) A. Dietr. to protect bone marrow cells in vivo from radiation-induced chromosomal aberrations. Albino rats (Rattus norvegicus, 2n = 42) were used to carry out investigations on the radioprotective properties of Z. montanum. Acute toxicity of the extract was determined, and a suitable injectable dose was selected for intra-peritoneal administration. The LD(50) of the extract calculated for 72 h was 2.9 g/kg, and the calculated LD(10) dose was 1.7 g/kg. The calculated maximum tolerated dose of the rhizome extract was 1.3 g/kg. Rats were divided into 12 groups (with or without the administration of extract) and exposed to different radiation doses from 1 to 5 Gy. Whole-body irradiation of rats showed a significant dose-dependent increase in different types of chromosomal aberrations. The most common chromosomal aberrations were breaks, fragments, gaps, rings, endoreduplications and dicentric chromosomes. Ethanol extract of rhizome at a dose of 0.5 g/kg did not show any significant increase in chromosomal aberrations in unirradiated animals as compared to that of the control group. Intra-peritoneal administration of the extract at a dose of 0.5 g/kg considerably reduced the frequency of the aberrations stated above in irradiated animals with DMF value of 1.36 at 1 to 5 Gy dose range of gamma radiation. The incidence of micronucleated polychromatic erythrocytes and micronucleated normochromatic erythrocytes due to the radiation exposure was considerably reduced in extract-treated groups of animals with DMFs 1.34 and 1.17, respectively, as compared to that of the extract-untreated groups. Our results suggest that rhizome extract of Z. montanum may have a potential in protecting normal hematopoietic cells from radiation-induced damage.

Radioprotective effect of alk(en)yl thiosulfates derived from allium vegetables against DNA damage caused by X-ray irradiation in cultured cells: antiradiation potential of onions and garlic

To evaluate a radioprotective effect of sodium n-propyl thiosulfate (NPTS) and sodium 2-propenyl thiosulfate (2PTS) derived from onions and garlic, respectively, rat hepatoma H4IIE cells and mouse lymphoma L5178Y cells were preincubated with each of these compounds for 48 hours at 37°C before receiving 10 Gy of X-ray irradiation. Cell damage caused by the irradiation was quantified as comet tail moment, which represents the degree of DNA damage. X-ray-induced DNA damage was significantly decreased in both H4IIE and L5178Y cells by micromolar concentrations of NPTS and 2PTS compared with the control without the compounds. The protective effect was more potent with 2PTS than NPTS. Onions and garlic have antiradiation potential.

Radioprotective effects of Zingiber officinale Roscoe (ginger): past, present and future

Radiation is an important modality in treating people with cancer especially when surgical intervention is impracticable or might debilitate the patient. However, effective use of ionizing radiation is compromised by the side effects that result from radiation-induced damage to normal tissue. The use of radioprotective compounds, which can selectively protect normal tissues against radiation injury is of immense use because in addition to association with protecting the normal tissue, it will also permits use of higher doses of radiation to obtain better cancer control and possible cure. However, till date no ideal radioprotectors are available as most synthetic compounds are toxic at their optimal concentrations. Plants commonly used as dietary and or therapeutic agents have recently been the focus of attention since in most cases they are non-toxic and are easily accepted for human use. Ginger, the rhizomes of Zingiber officinale Roscoe (Zingiberaceae), has widely been used as both culinary and medicinal agent. Preclinical studies carried out in the last decade has shown that ginger and its phytochemicals dehydrozingerone, zingerone possess radioprotective effects in laboratory animals and in cultured cells in vitro. The hydroalcoholic extract of ginger rhizome when administered either through intraperitoneal or oral route was effective in protecting against gamma radiation-induced sickness and mortality. The phytochemicals dehydrogingerone and zingerone present in ginger are also shown to protect mice against radiation-induced sickness and mortality. Mechanistic studies have indicated that the free radical scavenging, antioxidant affects, anti-inflammatory and anti-clastogenic effects may contribute towards the observed protection. Additionally, studies with tumor bearing mice have also shown that zingerone selectively protects the normal tissues against the tumoricidal effects of radiation. This review for the first time summarizes the results related to the radioprotective properties and also emphasizes the aspects that warrant future research to establish its activity and utility as a radioprotective agent.

The prospective role of plant products in radiotherapy of cancer: a current overview

Treatment of cancer often requires exposure to radiation, which has several limitations involving non-specific toxicity toward normal cells, reducing the efficacy of treatment. Efforts are going on to find chemical compounds which would effectively offer protection to the normal tissues after radiation exposure during radiotherapy of cancer. In this regard, plant-derived compounds might serve as “leads” to design ideal radioprotectors/radiosensitizers. This article reviews some of the recent findings on prospective medicinal plants, phytochemicals, and their analogs, based on both in vitro and in vivo tumor models especially focused with relevance to cancer radiotherapy. Also, pertinent discussion has been presented on the molecular mechanism of apoptotic death in relation to the oxidative stress in cancer cells induced by some of these plant samples and their active constituents.

Toxicity potentials of the nutraceutical Moringa oleifera at supra-supplementation levels

Moringa oleifera Lam. (order -Moringales, family -Moringaceae and genus -Moringa) is a well known nutraceutical used in the treatment of hypercholesterolemia and hyperglycemia, and also, as a nutritional supplementation. Its popularity use raises the question of possible toxicity at supra-supplementation levels. The objective of the study was to ascertain possible acute toxicity with supra-supplementation using Sprague-Dawley (S-D) rats. In experiment 1, human peripheral blood mononuclear cells were given graded doses of Moringa oleifera aqueous leaf extract to induce cytotoxicity. In experiment 2, two groups of rats received low and high dose (LD and HD, respectively) levels (1,000 and 3,000 mg/kgb.wt, respectively) per o.s. alongside negative and positive control rats (0.9% saline and 10mg/mL N-ethyl-N-nitrosourea - administered i.m., respectively). Each group consisted of five rats. Rats were killed after 48 h and the femur bone marrow aspirate examined for polychromatic micronucleated erythrocytes (PCEMN)/normochromatic micronucleated erythrocytes (NCEMN) ratios after Giemsa/Leishman staining. In experiment 3, control, LD and HD groups were established. The LD and HD extracts were administered per o.s. to the respective groups and observed for 14 days. Each group consisted of five rats. Blood was sampled after 48 h and 14 days and examined biochemically and haematologically for acute toxicity. Experiment 1 showed that Moringa oleifera was cytotoxic at 20mg/mL. In experiment 2, PCEMN/NCEMN ratios were: negative control=2.087; LD=1.849; HD=1.397; positive control=1.257. Statistically, LD and HD ratios were significant (p=0.020). Experiment 3 showed that hepatonephro-toxicity was nil with no abnormal haematology results. Genotoxicity results have hitherto not been shown. Moringa oleifera is genotoxic at supra-supplementation levels of 3,000 mg/kg b.wt. However, intake is safe at levels ≤ 1,000 mg/kg b.wt.

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.

Protective effects of polysaccharides from soybean meal against X-ray radiation induced damage in mouse spleen lymphocytes

The aim of this study was to investigate radioprotective effect of the polysaccharides from soybean meal (SMP) against X-ray radiation-induced damage in mouse spleen lymphocytes. MTT and comet assay were performed to evaluate SMP's ability to prevent cell death and DNA damage induced by radiation. The results show that, X-ray radiation (30 KV, 10 mA, 8 min (4 Gy)) can significantly increase cell death and DNA fragmentation of mouse spleen lymphocytes. Pretreatment with SMP for 2 h before radiation could increase cell viability, moreover, the SMP can reduce X-ray radiation-induced DNA damage. The percentage of tail DNA and the tail moment of the SMP groups were significantly lower than those of the radiation alone group (p < 0.05). These results suggest SMP may be a good candidate as a radioprotective agent.

Medical radiation countermeasures for nuclear and radiological emergencies: Current status and future perspectives

Nuclear and radiological emergencies (NREs) occurred globally and recent incidences in India are indicating toward the need for comprehensive medical preparedness required both at incident site and hospitals. The enhanced threat attributed toward insurgency is another causative factor of worry. The response capabilities and operational readiness of responders (both health and non-health service providers) in contaminated environment need to be supported by advancement in R & D and technological efforts to develop prophylactics and radiation mitigators. It is essential to develop phase 1 alternatives of such drugs for unseen threats as a part of initial preparedness. At the incident site and hospital level, external decontamination procedures need to be standardized and supported by protective clothing and Shudika kits developed by INMAS. The medical management of exposure requires systematic approach to perform triage, resuscitation and curative care. The internal contamination requires decorporation agents to be administered based on procedural diagnostics. Various key issues pertaining to policy decisions, R & D promotion, community awareness, specialized infrastructure for NREs preparedness has been discussed. The present review is an attempt to provide vital information about the current status of various radiation countermeasures and future perspective(s) ahead.

Physico-chemical studies on the evaluation of the antioxidant activity of herbal extracts and active principles of some Indian medicinal plants

Understanding of the efficacy and mechanism for the reaction of the biologically important radicals with natural and/or synthetic antioxidants is the first step towards the development of future therapeutic agents. The kinetic parameters e.g., formation and decay rate constants predict the efficacy of an antioxidant and its fate after reaction. These parameters also dictate the ease with which competing reactions would occur in a bio-environment. The spectroscopic parameters provide the clue to the site of free radical attack to these antioxidants. Here, in this article an attempt has been made to show the use of physico-chemical methods in the evaluation of antioxidant activity of some important medicinal plants commonly used in India and the subcontinent. The systems chosen here for discussions are herbal extracts as such, curcumin from turmeric, methoxy phenols from Indian spices, dehydrogingerdione from ginger and bakuchiol from Psoralea corylifolia. All the examples shown in this article illustrate the potential of the pulse radiolysis coupled with kinetic spectroscopy and other physicochemical techniques for the study of antioxidants either in the form of mixture as in herbal extract or as an isolated compound.

Triphala, Ayurvedic formulation for treating and preventing cancer: a review

BACKGROUND

Triphala (Sanskrit tri = three and phala = fruits), composed of the three medicinal fruits Phyllanthus emblica L. or Emblica officinalis Gaertn., Terminalia chebula Retz., and Terminalia belerica Retz. is an important herbal preparation in the traditional Indian system of medicine, Ayurveda. Triphala is an antioxidant-rich herbal formulation and possesses diverse beneficial properties. It is a widely prescribed Ayurvedic drug and is used as a colon cleanser, digestive, diuretic, and laxative. Cancer is a major cause of death, and globally studies are being conducted to prevent cancer or to develop effective nontoxic therapeutic agents. Experimental studies in the past decade have shown that Triphala is useful in the prevention of cancer and that it also possesses antineoplastic, radioprotective and chemoprotective effects.

CONCLUSIONS

This review for the first time summarizes these results, with emphasis on published observations. Furthermore, the possible mechanisms responsible for the beneficial effects and lacunas in the existing knowledge that need to be bridged are also discussed.

Radiation-Induced Testicular Injury and Its Amelioration by Tinospora cordifolia (An Indian Medicinal Plant) Extract

The primary objective of this investigation is to determine the deleterious effects of sub lethal gamma radiation on testes and their possible inhibition by Tinospora cordifolia extract (TCE). For this purpose, one group of male Swiss albino mice was exposed to 7.5 Gy gamma radiation to serve as the irradiated control, while the other group received TCE (75 mg/kg b. wt./day) orally for 5 consecutive days half an hr before irradiation to serve as experimental. Exposure of animals to 7.5 Gy gamma radiation resulted into significant decrease in body weight, tissue weight, testes- body weight ratio and tubular diameter up to 15 days of irradiation. Cent percent mortality was recorded by day 17th in irradiated control, whereas all animals survived in experimental group. TCE pretreatment rendered significant increase in body weight, tissue weight, testes- body weight ratio and tubular diameter at various intervals as compared to irradiated group. Radiation induced histological lesions in testicular architecture were observed more severe in irradiated control then the experimental. TCE administration before irradiation significantly ameliorated radiation induced elevation in lipid peroxidation and decline in glutathione concentration in testes. These observations indicate the radio- protective potential of Tinospora cordifolia root extract in testicular constituents against gamma irradiation in mice.

Tea polyphenols protect against irradiation-induced injury in submandibular glands' cells: a preliminary study

AIM

To study the protective effect of tea polyphenols (TPs) on submandibular glands affected by radiation injury.

METHODS

Sixty rats were randomly divided into radiation group (R-group, N = 30) and TP-pre-treated-radiation group (TPR-group, N = 30). The rats were intragastrically administered with TP or normal sodium from 14 days before radiation, continuously daily, until the experiment. All the rats in both groups were irradiated with a single exposure dose of 15 Gy gamma rays that were delivered to the head and neck areas. Ten rats of each group were anatomised on the 3rd, 6th and 30th day after irradiation, respectively. The submandibular glands of the rats were removed for the study. The morphologic changes of the submandibular glands were observed by transmission electron microscopy (TEM). The terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP)-biotin nick-end labelling (TUNEL) method was used to detect apoptosis of the submandibular glands' cells.

RESULTS

Electron microscope observation of the submandibular glands showed that the lesions of the TPR-group were mild. Change in apoptosis of the cells was not obvious compared with the R-group. The cell apotosis was typical after irradiation in the R-group. Apoptosis index that was detected in the cells of submandibular glands of the TPR-group was statistically significantly decreased compared with the R-group (P < 0.01) on the 3rd, 6th and 30th day after irradiation.

CONCLUSION

TP could protect submandibular glands from radiation injuries, and the protection mechanism may be realised by anti-apoptosis.

The Use of 3,5,4'-Tri-O-acetylresveratrol as a Potential Pro-drug for Resveratrol Protects Mice from γ-Irradiation-Induced Death

Currently, no drugs are available to protect humans from γ-irradiation-induced death. Because reactive oxygen species are produced upon exposure to γ-irradiation and directly responsible for the resulting death, we hypothesized that antioxidants found in foodstuffs may provide a safe and potent means of antioxidant-dependent radioprotection. Here, we describe our studies investigating the radioprotective properties of resveratrol and 3,5,4'-tri-O-acetylresveratrol. Each of these natural antioxidants was found to protect live cells after γ-irradiation. In mice, the use of 3,5,4'-tri-O-acetylresveratrol with Cremophor EL was particularly effective, indicating that this natural antioxidant may be a leading candidate for radioprotective drug development.

Effects of ferulic acid on hematopoietic cell recovery in whole-body gamma irradiated mice

PURPOSE

The objective of this study was to investigate the mechanism for ferulic acid (FA)-induced radioprotection by evaluating the recovery of bone marrow cells and peripheral blood hematology.

MATERIALS AND METHODS

Balb/c mice were irradiated at a dose of 2.5 Gy using cobalt-60 gamma resources. Following irradiation, FA was administered intragastrically for seven consecutive days. Hematopoietic progenitor colony-forming cell assays were used to assess the reconstitution of bone marrow after radiation-induced myelosuppression. Cytokine levels were investigated using enzyme-linked immunosorbent assay and Western blot analysis.

RESULTS

The results demonstrated that FA treatment enhanced hematopoietic progenitor cell activity resulting in accelerated blood cell recovery. FA administration increased levels of granulocyte-colony stimulating factor (G-CSF) and erythropoietin.

CONCLUSION

These results suggest radioprotective efficacy by FA may be a result of early recovery of hematopoietic cells due to enhanced production of G-CSF and erythropoietin.

Comparative investigations on the protective effects of rhodioside, ciwujianoside-B and astragaloside IV on radiation injuries of the hematopoietic system in mice

The aim of this study was to investigate the protective effects of three glycosides (rhodioside, ciwujianoside-B and astragaloside IV) on the hematopoietic system in the mice exposed to γ-rays, and to examine the possible mechanisms involved. Mice were pretreated with the glycosides (40 mg/kg, i.g.) daily for 7 days prior to radiation. The survival of mice pretreated with three glycosides after total body irradiation (6.0 Gy) was examined. Peripheral blood leucocytes and endogenous spleen colony counts, colony-forming unit-granulocyte macrophage assay, analysis of DNA content and apoptosis rate determination were performed to evaluate the effects of the three glycosides on hematogenesis. The fragmentation of double-stranded DNA in lymphocytes was detected by the comet assay. The changes in cell cycle were analysed by flow cytometry. Furthermore, the expression levels of Bcl-2, Bax and nuclear factor-kappa B (NF-κB) were measured by western blot and the electrophoretic mobility shift assay. The results showed that pretreatment with all of the glycosides improved survival time and increased the number of leucocytes, spleen colonies and granulocyte-macrophage colonies in mice exposed to 6.0 Gy γ-radiation. Rhodioside showed more protective efficacy than both ciwujianoside-B and astragaloside IV. All three glycosides significantly increased the proliferation abilities of bone marrow cells, and decreased the ratio of cells in G(0)/G(1) phase. Further analysis showed that these three glycosides were able to decrease DNA damage and the increment in the Bax/Bcl-2 ratio induced by radiation. In summary, the three glycosides showed radioprotective effects on the hematopoietic system in mice, which was associated with changes in the cell cycle, a reduction in DNA damage, and down-regulation of the ratio of Bax/Bcl-2 in bone marrow cells exposed to radiation.