Chemical genoprotection: reducing biological damage to as low as reasonably achievable levels

Occupational exposures and cancer risk in commercial laundry and dry cleaning industries: a scoping review

BACKGROUND

The laundry and dry cleaning industries are critical for maintaining cleanliness and hygiene in our daily lives. However, they have also been identified as sources of hazardous chemical exposure for workers, leading to potentially severe health implications. Despite mounting evidence that solvents like perchloroethylene and trichloroethylene are carcinogenic, they remain commonly used in the industry. Additionally, while alternative solvents are increasingly being utilized in response to indications of adverse health and environmental effects, there remains a significant gap in our understanding of the potential risks associated with exposure to these new agents.

METHODS

This study aims to identify gaps in the literature concerning worker exposure to contemporary toxic chemicals in the laundry and dry cleaning industry and their associated carcinogenic risks. A scoping review of peer-reviewed publications from 2012 to 2022 was conducted to achieve this objective, focusing on studies that detailed chemical exposures, sampling methods, and workers within the laundry and dry cleaning sector.

RESULTS

In this scoping review, 12 relevant papers were assessed. A majority (66%) examined perchloroethylene exposure, with one notable finding revealing that biomarkers from dry cleaners had significant micronuclei frequency and DNA damage, even when exposed to PCE at levels below occupational exposure limits. Similarly, another study supported these results, finding an increase in early DNA damage among exposed workers. Separate studies on TCE and benzene presented varied exposure levels and health risks, raising concern due to their IARC Group 1 carcinogen classification. Information on alternative solvents was limited, highlighting gaps in health outcome data, exposure guidelines, and carcinogenic classifications.

CONCLUSION

Research on health outcomes, specifically carcinogenicity from solvent exposure in dry cleaning, is limited, with 66% of studies not monitoring health implications, particularly for emerging solvents. Further, findings indicated potential DNA damage from perchloroethylene, even below set occupational limits, emphasizing the need to reevaluate safety limits. As alternative solvents like butylal and high-flashpoint hydrocarbons become more prevalent, investigations into the effects of their exposure are necessary to safeguard workers' health. This scoping review is registered with the Open Science Framework, registration DOI: https://doi.org/10.17605/OSF.IO/Q8FR3 .

Paradoxical Radiosensitizing Effect of Carnosic Acid on B16F10 Metastatic Melanoma Cells: A New Treatment Strategy

Carnosic acid (CA) is a phenolic diterpene characterized by its high antioxidant activity; it is used in industrial, cosmetic, and nutritional applications. We evaluated the radioprotective capacity of CA on cells directly exposed to X-rays and non-irradiated cells that received signals from X-ray treated cells (radiation induced bystander effect, RIBE). The genoprotective capacity was studied by in vivo and in vitro micronucleus assays. Radioprotective capacity was evaluated by clonogenic cell survival, MTT, apoptosis and intracellular glutathione assays comparing radiosensitive cells (human prostate epithelium, PNT2) with radioresistant cells (murine metastatic melanoma, B16F10). CA was found to exhibit a genoprotective capacity in cells exposed to radiation (p < 0.001) and in RIBE (p < 0.01). In PNT2 cells, considered as normal cells in our study, CA achieved 97% cell survival after exposure to 20 Gy of X-rays, eliminating 67% of radiation-induced cell death (p < 0.001), decreasing apoptosis (p < 0.001), and increasing the GSH/GSSH ratio (p < 0.01). However, the administration of CA to B16F10 cells decreased cell survival by 32%, increased cell death by 200% (p < 0.001) compared to irradiated cells, and increased cell death by 100% (p < 0.001) in RIBE bystander cells (p < 0.01). Furthermore, it increased apoptosis (p < 0.001) and decreased the GSH/GSSG ratio (p < 0.01), expressing a paradoxical radiosensitizing effect in these cells. Knowing the potential mechanisms of action of substances such as CA could help to create new applications that would protect healthy cells and exclusively damage neoplastic cells, thus presenting a new desirable strategy for cancer patients in need of radiotherapy.

Genoprotective Effect of Some Flavonoids against Genotoxic Damage Induced by X-rays In Vivo: Relationship between Structure and Activity

Flavonoids constitute a group of polyphenolic compounds characterized by a common gamma-benzo- pyrone structure considered in numerous biological systems to possess antioxidant capacity. Among the different applications of flavonoids, its genoprotective capacity against damage induced by ionizing radiation stands out, which has been related to antioxidant activity and its chemical structure. In this study, we determined the frequency of appearance of micronucleus in vivo by means of the micronucleus assay. This was conducted in mice treated with different flavonoids before and after exposure to 470 mGy X-rays; thereafter, their bone marrow polychromatophilic erythrocytes were evaluated to establish the structural factors enhancing the observed genoprotective effect. Our results in vivo show that the presence of a monomeric flavan-3-ol type structure, with absence of carbonyl group in position C4 of ring C, absence of conjugation between the carbons bearing the C2 = C3 double bond and the said ring, presence of a catechol group in ring B and characteristic hydroxylation in positions 5 and 7 of ring A are the structural characteristics that determine the highest degree of genoprotection. Additionally, a certain degree of polymerization of this flavonoid monomer, but maintaining significant levels of monomers and dimers, contributes to increasing the degree of genoprotection in the animals studied at both times of their administration (before and after exposure to X-rays).

Phytochemicals: Potential Therapeutic Modulators of Radiation Induced Signaling Pathways

Ionizing radiation results in extensive damage to biological systems. The massive amount of ionizing radiation from nuclear accidents, radiation therapy (RT), space exploration, and the nuclear battlefield leads to damage to biological systems. Radiation injuries, such as inflammation, fibrosis, and atrophy, are characterized by genomic instability, apoptosis, necrosis, and oncogenic transformation, mediated by the activation or inhibition of specific signaling pathways. Exposure of tumors or normal cells to different doses of ionizing radiation could lead to the generation of free radical species, which can release signal mediators and lead to harmful effects. Although previous FDA-approved agents effectively mitigate radiation-associated toxicities, their use is limited due to their high cellular toxicities. Preclinical and clinical findings reveal that phytochemicals derived from plants that exhibit potent antioxidant activities efficiently target several signaling pathways. This review examined the prospective roles played by some phytochemicals in altering signal pathways associated with radiation response.

Radioprotective Role of Vitamins C and E against the Gamma Ray-Induced Damage to the Chemical Structure of Bovine Serum Albumin

Radioprotective effects of vitamin C and vitamin E as a water-soluble and a lipid-soluble agent, respectively, were investigated at the molecular level during the imposition of gamma radiation-induced structural changes to bovine serum albumin (BSA) at the therapeutic dose of 3 Gy. Secondary and tertiary structural changes of control and irradiated BSA samples were investigated using circular dichroism and fluorescence spectroscopy. The preirradiation tests showed nonspecific and reversible binding of vitamins C and E to BSA. Secondary and tertiary structures of irradiated BSA considerably changed in the absence of the vitamins. Upon irradiation, α-helices of BSA transitioned to beta motifs and random coils, and the fluorescence emission intensity decreased relative to nonirradiated BSA. In the presence of the vitamins C or E, however, the irradiated BSA was protected from these structural changes caused by reactive oxygen species (ROS). The two vitamins exhibited different patterns of attachment to the protein surface, as inspected by blind docking, and their mechanisms of protection were different. The hydrophilicity of vitamin C resulted in the predominant scavenging of ROS in the solvent, whereas hydrophobic vitamin E localized on the nonpolar patches of the BSA surface, where it did not only form a barrier for diffusing ROS but also encountered them as an antioxidant and neutralized them thanks to the moderate BSA binding constant. Very low concentrations of vitamins C or E (0.005 mg/mL) appear to be sufficient to prevent the oxidative damage of BSA.

Radiation-Induced Bystander Effect: Loss of Radioprotective Capacity of Rosmarinic Acid In Vivo and In Vitro

In radiation oncology, the modulation of the bystander effect is a target both for the destruction of tumor cells and to protect healthy cells. With this objective, we determine whether the radioprotective capacity of rosmarinic acid (RA) can affect the intensity of these effects. Genoprotective capacity was obtained by determining the micronuclei frequencies in in vivo and in vitro assays and the cell survival was determined by the (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay) (MTT) assay in three cell lines (PNT2, TRAMPC1 and B16F10), both in direct exposure to X-rays and after the production of radiation-induced bystander effect. The administration of RA in irradiated cells produced a decrease in the frequency of micronuclei both in vivo and in vitro, and an increase in cell survival, as expression of its radioprotective effect (p < 0.001) attributable to its ability to scavenge radio-induced free radicals (ROS). However, RA does not achieve any modification in the animals receiving serum or in the cultures treated with the irradiated medium, which expresses an absence of radioprotective capacity. The results suggest that ROS participates in the formation of signals in directly irradiated cells, but only certain subtypes of ROS, the cytotoxic products of lipid peroxidation, participate in the creation of lesions in recipient cells.

Effect of Rosmarinic Acid and Ionizing Radiation on Glutathione in Melanoma B16F10 Cells: A Translational Opportunity

To explain a paradoxical radiosensitizing effect of rosmarinic acid (RA) on the melanoma B16F10 cells, we analyzed the glutathione (GSH) intracellular production on this cell (traditionally considered radioresistant) in comparison with human prostate epithelial cells (PNT2) (considered to be radiosensitive). In PNT2 cells, the administration of RA increased the total GSH content during the first 3 h (p < 0.01) as well as increased the GSH/oxidized glutathione (GSSG) ratio in all irradiated cultures during all periods studied (1h and 3h) (p < 0.001), portraying an increase in the radioprotective capacity. However, in B16F10 cells, administration of RA had no effect on the total intracellular GSH levels, decreasing the GSH/GSSG ratio (p < 0.01); in addition, it caused a significant reduction in the GSH/GSSG ratio in irradiated cells (p < 0.001), an expression of radioinduced cell damage. In B16F10 cells, the administration of RA possibly activates the metabolic pathway of eumelanin synthesis that would consume intracellular GSH, thereby reducing its possible use as a protector against oxidative stress. The administration of this type of substance during radiotherapy could potentially protect healthy cells for which RA is a powerful radioprotector, and at the same time, cause significant damage to melanoma cells for which it could act as a radiosensitive agent.

Genotoxicity and subchronic toxicity studies of supercritical carbon dioxide and acetone extracts of rosemary

Toxicology studies conducted with oil-soluble rosemary extracts to support authorization as a food additive (antioxidant) in the EU include an Ames test using a supercritical carbon dioxide extract (D74), a full 90-day study using D74 and an acetone extract (F62), and an investigative 90-day study with a 28-day recovery period (using D74 only). D74 was non-mutagenic in the Ames test. In the full 90-day study, where rats (20/sex/group) were either provided control diet or diets containing D74 (300, 600, or 2400 mg/kg) or F62 (3800 mg/kg), liver enlargement and hepatocellular hypertrophy were observed. To determine a mode of action and assess the reversibility of the hepatic effects, an investigative 90-day study was conducted using female rats (10/group receiving control diet or diet containing 2400 mg/kg D74). Liver enlargement was fully reversible after 28 days and microsomal enzyme analysis revealed reversible induction of cytochrome P450 enzymes (CYP2A1, CYP2A2, CYP2C11, CYP2E1, and CYP4A), demonstrating that the hepatic effects were adaptive and of no toxicological concern. Therefore, the highest dietary concentrations were established as the NOAELs. The investigative 90-day study NOAEL (providing 64 mg/kg bw/day carnosol and carnosic acid [the primary antioxidant components]) was used to establish a temporary ADI for rosemary extracts.

An endophytic Penicillium oxalicum isolated from Citrus limon possesses antioxidant and genoprotective potential

AIMS

This study aimed at isolating endophytic fungi from Citrus limon (L.) possessing antioxidative and genoprotective potential.

METHODS AND RESULTS

Endophytic fungi were screened for antioxidant activity using 2,2-diphenyl,1-picryl hydrazyl radical scavenging assay and maximum activity (79·70%) was exhibited by culture MP1 identified to be Penicillium oxalicum on the basis of morphological and molecular characteristics. The ethyl acetate extract of MP1 was subjected to silica column chromatography followed by LH 20 column chromatography for purification of active metabolites. The partially purified active fraction of P. oxalicum MP1 possessed good antioxidant activity as detected using various assays. It also exhibited a strong DNA damage protection potential on pUC19 plasmid DNA treated with Fenton reagent. On exposure to active fraction of MP1 significant reduction (P < 0·05) in nuclear deformities (like nuclear buds, micronuclei, nuclear ridges and binucleated cells) was observed in human lymphocytes pretreated with a toxic concentration of H₂ O₂ . In vivo genoprotectivity studies were conducted in fresh water fish Channa punctatus pretreated with a damaging compound 4-nonyl phenol. The active fraction of P. oxalicum MP1 caused a reduction of 94·7 and 66·60% in micronuclei and aberrant cell formation, respectively. A significant reduction (P < 0·05) in tail length and tail DNA parameters was also observed in comet assay.

CONCLUSION

The endophytic P. oxalicum isolated in this study has the potential to produce metabolites possessing antioxidant and genoprotective activities.

SIGNIFICANCE AND IMPACT OF THE STUDY

The isolated culture can be exploited in the field of therapeutics by virtue of its in vitro and in vivo genoprotective potential.

Radioprotective and Antimutagenic Effects of Pycnanthus angolensis Warb Seed Extract against Damage Induced by X Rays

Although different studies have demonstrated different applications of Pycnanthus angolensis extracts in traditional African and Asian medicine, its possible antimutagenic or genoprotective capacities have never been explored. We studied these capabilities of Pycnanthus angolensis seed extract (PASE) by means of the two micronucleus assays, determining the frequency of micronucleus (MN) yield in mouse bone marrow (in vivo) and in human lymphocytes blocked by cytochalasin B (in vitro). PASE exhibited a significant genoprotective capacity (p < 0.001) against X-rays with a protection factor of 35% in both in vivo and in vitro assays. Further, its radioprotective effects were determined by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-tetrazolium bromide (MTT) cell viability test in two cell lines: one being radiosensitive (i.e., human prostate epithelium (PNT2) cells) and the other being radioresistant (i.e., B16F10 melanoma cells). In the radiosensitive cells, PASE showed a protection factor of 35.5%, thus eliminating 43.8% of X-ray-induced cell death (p < 0.001) and a dose reduction factor of 2.5. In the radioresistant cells, a protection factor of 29% (p < 0.001) with a dose reduction factor of 4 was realized. PASE elicited a greater radioprotective capacity than the substances currently used in radiation oncology and, thus, could be developed as a nutraceutical radioprotectant for workers and patients exposed to ionizing radiation.

Natural Products for the Management and Prevention of Breast Cancer

Among all types of cancer, breast cancer is one of the most challenging diseases, which is responsible for a large number of cancer related deaths. Hormonal therapy, surgery, chemotherapy, and radiotherapy have been used as treatment of breast cancer, for a very long time. Due to severe side effects and multidrug resistance, these treatment approaches become increasingly ineffective. However, adoption of complementary treatment approach can be a big solution for this situation, as it is evident that compounds derived from natural source have a great deal of anticancer activity. Natural compounds can fight against aggressiveness of breast cancer, inhibit cancerous cell proliferation, and modulate cancer related pathways. A large number of research works are now focusing on the natural and dietary compounds and trying to find out new and more effective treatment strategies for the breast cancer patients. In this review, we discussed some significant natural chemical compounds with their mechanisms of actions, which can be very effective against the breast cancer and can be more potent by their proper modifications and further clinical research. Future research focusing on the natural anti-breast-cancer agents can open a new horizon in breast cancer treatment, which will play a great role in enhancing the survival rate of breast cancer patients.

Radioprotective agents to prevent cellular damage due to ionizing radiation

Medical imaging has become a central component of patient care to ensure early and accurate diagnosis. Unfortunately, many imaging modalities use ionizing radiation to generate images. Ionizing radiation even in low doses can cause direct DNA damage and generate reactive oxygen species and free radicals, leading to DNA, protein, and lipid membrane damage. This cell damage can lead to apoptosis, necrosis, teratogenesis, or carcinogenesis. As many as 2% of cancers (and an associated 15,000 deaths annually) can be linked to computed tomography exposure alone. Radioprotective agents have been investigated using various models including cells, animals, and recently humans. The data suggest that radioprotective agents working through a variety of mechanisms have the potential to decrease free radical damage produced by ionizing radiation. Radioprotective agents may be useful as an adjunct to medical imaging to reduced patient morbidity and mortality due to ionizing radiation exposure. Some radioprotective agents can be found in high quantities in antioxidant rich foods, suggesting that a specific diet recommendation could be beneficial in radioprotection.

DOSE REFERENCE LEVELS IN SPANISH INTRAORAL DENTAL RADIOLOGY: STABILISATION OF THE INCORPORATION OF DIGITAL SYSTEMS IN DENTAL CLINICAL PRACTICES

A total of 34 044 official quality assurance reports in dental radiodiagnostic surgery from 16 regions of Spain, compiled from 2002 to 2014, were studied in order to determine the progress of diagnostic reference levels (DRLs) for obtaining diagnostic images under normal conditions for clinical practice in Spanish dental clinics. A DRL of 2.8 mGy was set in 2014, which represents a 41.7 % decrease compared with that of 2002 (4.8 mGy). Over the same time period, the mean dose fell by 55.2 %. However, over the last 3 y, the stabilisation of the mean dose administered to patients has been observed with only a 6.7 % reduction in DRLs, which corresponds to the stabilisation of dental radiodiagnostic surgery on replacing the use of radiographic film with digital imaging systems.

[Decrease in toxicity and therapeutic effect of zoledronic acid in combination therapy with different antioxidant extracts]

BACKGROUND

Zoledronic acid is used in the treatment of cancer-related diseases, although its use has been associated with avascular osteonecrosis.

AIMS

To determine the possible protective effect of a range of antioxidant substances against the inhibition of human prostate epithelial cell growth (PNT2) and transgenic adenocarcinoma mouse prostate tumour cells (TRAMP-C1), in treatments combining zoledronic acid and ionising radiation (IR).

MATERIAL AND METHOD

Cell survival is studied via cell viability assays (MTT) for 2 cell lines in isolated and combined treatments with zoledronic acid and/or IR, as well as the effect of adding 3 antioxidant substances.

RESULTS

Zoledronic acid displays a significant cytotoxic effect over PNT2 and TRAMP-C1 cells (P<.001). The administration of antioxidants together with the zoledronic acid shows a protective effect for normal prostate cells, yet not so for prostate tumour cells. However, the administration of rosmarinic acid and apigenin in treatments combined with zoledronic acid provides a protective effect from the harmful effects of applying ionizing radiation, not only for normal PNT2 cells, but also for tumour cells.

CONCLUSION

The use of antioxidant substances decreases the cytotoxic effect of zoledronic acid over non-tumour cells, and as such could be used in benign diseases. Furthermore, in the combined treatment using ionising radiation, these antioxidants also produced a protective effect in tumour cells, thus reducing the therapeutic effect sought by combining the treatment with radiation.

Toxicity of a dental adhesive compared with ionizing radiation and zoledronic acid

Background

To determine the toxicity of aqueous dilutions of a universal self-priming dental adhesive (DA) and comparing these with those elicited by exposure to ionizing radiation (IR), Zoledronic acid (Z) treatment and the synergic effects of the combined treatment with IR+Z.

Material and Methods

The genotoxic effect of DA was determined by the increase in the frequency of micronuclei in cytokinesis-blocked in cultured human lymphocytes before and after exposure to 2Gy of X-rays. The cytotoxic effect was studied by using the MTT cell viability test in normal prostate cell lines (PNT2) after exposure to different X-ray doses (0Gy-20Gy). The cell lines divided into different groups and treated with different test substances: DA in presence of O2, DA in absence of O2, Z-treated and control.

Results

An in vitro dose-dependent and time-dependent cytotoxic effect of DA, Z and IR on PNT2 cells (p>0.001) was demonstrated. DA without-O2, following the recommendations of manufacturers, had a more pronounced effect of increasing cell death than DA with-O2 (p<0.001). In the genotoxicity assay, DA at 25% of its original concentration significantly increased chromosome damage (p<0.001). The samples studied were found to be toxic, and the samples photo-polymerized in absence of O2 showed a bigger cytotoxic effect comparable to the additive toxic effect showed by the combined treatment of IR+Z.

Conclusions

Additional effort should be carried out to develop adhesives, which would reduce the release of hazardous substances; since toxic effects are similar to that reported by other agents whose clinical use is controlled by the health authorities.

Key words: Micronucleus, toxicity, dental adhesive, zolendronic acid, radiation effects.

Synthesis of novel tetrahydrobenzazepine derivatives and their cytoprotective effect on human lymphocytes

Cytoprotective compounds such as amifostine play an important role in chemo- and radiotherapy due to their ability to reduce the side effects of these treatments. Our work was initiated with the intention to design, synthesise and test a new class of heterocyclic compounds that would have an antioxidative profile with the potential to be further developed as cytoprotective agents. The design was based on the privileged tetrahydrobenzazepine scaffold found in many natural products with a wide range of biological properties. This structure was further functionalised with moieties known to possess antioxidative features such as tertiary amine and styrene double bond. A series of eight tetrahydrobenzazepine derivatives of isoquinoline, 3,4-dihydro-β-carboline and pyridine were synthesised employing the Heck reaction as a key transformation. Some of the prepared compounds were tested for their in vitro effects on chromosome aberrations in peripheral human lymphocytes using the cytochalasin-B blocked micronucleus (MN) assay. Three tetrahydrobenzoazepine derivatives showed significant cytoprotective properties, comparable or even better to those of the radioprotective agent amifostine.

Green tea compounds in breast cancer prevention and treatment

Breast cancer is the most common cancer among women. In recent years, many in vitro and in vivo studies indicate that green tea possesses anti-cancer effects. The epidemiological studies, however, have produced inconclusive results in humans. Likewise, results from animal models about the preventive or therapeutic effects of green tea components are inconclusive. The mechanisms by which green tea intake may influence the risk of breast cancer in humans remain elusive mechanisms by which green tea intake may influence. Here, we review recent studies of green tea polyphenols and their applications in the prevention and treatment of breast cancer. Furthermore, we discuss the effect of green tea components on breast cancer by reviewing epidemiological studies, animal model studies and clinical trials. At last, we discuss the mechanisms by which green tea components suppress the development and recurrence of breast cancer. A better understanding of the mechanisms will improve the utilization of green tea in breast cancer prevention and therapy and pave the way to novel prevention and treatment strategies for breast cancer.

Genotoxicity and cytotoxicity of sevoflurane in two human cell lines in vitro with ionizing radiation

OBJECTIVE

To determine the in vitro toxicity of different concentrations of sevoflurane in cells exposed to X-ray.

METHODS

The genotoxic effects of sevofluorane were studied by means of the micronucleus test in cytokinesis-blocked cells of irradiated human lymphocytes. Subsequently, its cytotoxic effects on PNT2 (normal prostate) cells was determined using the cell viability test (MTT) and compared with those induced by different doses of X-rays.

RESULTS

A dose- and time-dependent cytotoxic effect of sevofluorane on PNT2 cells was determined (p >0.001) and a dose-dependent genotoxic effect of sevofluorane was established (p >0.001). However, at volumes lower than 30 μL of sevofluorane at 100%, a non-toxic effect on PNT2 cells was shown.

CONCLUSION

Sevofluorane demonstrates a genotoxic capacity as determined in vitro by micronucleus test in cytokinesis-blocked cells of irradiated human lymphocytes.

Green tea polyphenol epigallocatechin-3-gallate (EGCG) as adjuvant in cancer therapy

BACKGROUND & AIMS

Green tea catechins, especially epigallocatechin-3-gallate (EGCG), have been associated with cancer prevention and treatment. This has resulted in an increased number of studies evaluating the effects derived from the use of this compound in combination with chemo/radiotherapy. This review aims at compiling latest literature on this subject.

METHODS

Keywords including EGCG, cancer, chemotherapy, radiotherapy and side effects, were searched using PubMed and ScienceDirect databases to identify, analyze, and summarize the research literature on this topic. Most of the studies on this subject up to date are preclinical. Relevance of the findings, impact factor, and date of publication were critical parameters for the studies to be included in the review.

RESULTS

Additive and synergistic effects of EGCG when combined with conventional cancer therapies have been proposed, and its anti-inflammatory and antioxidant activities have been related to amelioration of cancer therapy side effects. However, antagonistic interactions with certain anticancer drugs might limit its clinical use.

CONCLUSIONS

The use of EGCG could enhance the effect of conventional cancer therapies through additive or synergistic effects as well as through amelioration of deleterious side effects. Further research, especially at the clinical level, is needed to ascertain the potential role of EGCG as adjuvant in cancer therapy.

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.

Safety evaluation and nutritional composition of a Fraxinus excelsior seed extract, FraxiPure™

A natural extract obtained from the seeds of Fraxinus excelsior L. (FraxiPure™) has been previously reported to reduce glycemia in animal models and in humans. The objective of this work was to evaluate the safety of FraxiPure™ at in vitro, in vivo and human levels. In addition, nutritional analyses revealed an extract high in carbohydrates, with minor levels of protein, dietary fiber, glucose and sucrose. IC(50) and IC(90) values of 1.447 and 2.530 mg/mL, respectively, after 72 h incubation were calculated using the MTT assay. FraxiPure™ conferred a magnitude of protection of 69.2% against the formation of micronuclei in irradiated human lymphocytes as determined by the micronucleus assay. An LD(50) of greater than 2500 mg/kg was concluded following an acute oral toxicity study in Sprague-Dawley rats. A human safety evaluation in a double-blind, placebo-controlled parallel study of 100 healthy volunteers revealed no significant differences between daily consumption of 1000 mg of FraxiPure™ for 90 days and placebo (maltodextrin) for any of the biochemical or hematological parameters studied. Numbers of adverse events were similar in both groups, and were deemed mild to moderate. These results demonstrate, for the first time, the safety and tolerability of FraxiPure™ for consumption in healthy subjects.

Evolution of diagnostic reference levels in Spanish intraoral radiology

A total of 16 175 official reports of quality assurance on dental radiodiagnostic surgeries from 16 Spanish autonomous regions compiled during 2002-09 were studied to determine the evolution of diagnostic reference levels (DRLs) for obtaining a diagnostic image in the normal conditions of clinical practice in Spanish dental clinics. A DRL of 3.1 mGy was set in 2009, which represents a 35.4 % decrease compared with the dose determined in 2002 (4.8 mGy). During the same period, the mean dose fell by only 17.2 %. The DRL recommended by the European Union in 2004 for intraoral radiology is 4 mGy, and this study shows that 83.4 % of the installations used a dose below this. Of the installations using indirect or direct digital systems 1.1 and 1.2 %, respectively, used doses higher than those recommended, while 14.2 % of those using radiographic film exceeded this limit.

Zoledronic acid and radiation: toxicity, synergy or radiosensitization?

INTRODUCTION

Zoledronic acid (Z) is a bisphosphonate used in hypercalcaemia-related cancer, in complications for bone metastasis and in postmenopausal osteoporosis and it has been related to osteoradionecrosis, especially when associated with radiation to the head and neck structures.

OBJECTIVES

To determine the radiosensitization capacity of zoledronic acid in the combined treatment with ionizing radiation (IR) by evaluating its genotoxic and cytotoxic capacities in non-tumoral cells.

MATERIALS AND METHODS

The genotoxic effect of Z was studied by means of the micronucleus test in cytokinesis-blocked cells of human lymphocytes irradiated before and after a 2 Gy irradiation, while the cytotoxic effect was studied by a cell viability test in the PNT2 cell line before and after exposure to different X-ray doses (0-20 Gy) in four groups (Z alone, radiation alone, Z + IR and IR + Z).

RESULTS

A dose-dependent and time-dependent cytotoxic effect of Z and IR on PNT2 cells in vitro (p > 0.001) was demonstrated. With the concentrations recommended for humans, the combined treatment had a more pronounced effect than individual treatments (p < 0.001). The effect was synergic (CI < 1), increasing the Z enhancement ratio (2.6) and sensitization factor (56 %); the effect of Z was always greater after IR exposure. In the genotoxic effect, only the administration of Z after irradiation (IR + Z) increased chromosome damage (p < 0.001) and the sensibilization factor (35.7 %).

CONCLUSION

High concentrations of Z are toxic, but the concentrations recommended for clinical practice in humans give it the characteristics of a radiosensitization agent, whose effect is even greater when administered after IR.

Study of Radioprotective Effect of Green Tea against Gamma Irradiation Using Micronucleus Assay on Binucleated Human Lymphocytes

OBJECTIVES

The aim of this study was to investigate the radioprotective effect of green tea against genotoxicity induced by gamma irradiation in cultured blood lymphocytes from 5 human volunteers.

MATERIALS AND METHODS

Peripheral blood samples were collected from volunteers before and 1, 3 and 5 hr after drinking a decoction 4 g green tea in 280 ml boiling water for 5 constitutive days with the same quantity. At each time point, the whole blood samples were exposed to 200 cGy of (60) Co gamma irradiation and then were cultured with mitogenic stimulation to determine the chromosomal aberration in micronucleus assay on cytokinesis-blocked binucleated cells.

RESULTS

As expected, for each volunteer, the results showed a significant increase in the incidence of micronuclei after exposure to gamma irradiation as compared to non-irradiated control samples. Only lymphocytes blood sample collected 3 hr after drinking green tea exhibited a significant decrease in incidence of micronuclei compared to non-treated irradiated samples.

CONCLUSION

These results suggest the radioprotective ability of green tea against ionizing radiation in human lymphocytes, at specified time after consumptior.