Historical and current perspectives on therapeutic potential of higher basidiomycetes: an overview

Mushrooms are macroscopic fungi which can be either epigeous or hypogeous and is estimated to be 140,000 on earth, yet only 10% are known. Since ancient time, it played a diverse role in human history for mycolatry, mycophagy and as medicine in folklore and religion. Many Asian and western countries consider mushrooms as panacea for a large number of diseases and utilized for consumption as a gourmet food for its taste as well as flavor. In recent years, scientific research fraternities have confirmed that various extracts and metabolites of mushrooms used traditionally are able to treat a wide range of diseases due to their balanced modulation of multiple targets thereby providing a greater therapeutic effect or equivalent curative effect to that of modern medicine. Medicinal mushrooms especially those belonging to higher basidiomycete groups are reservoir of bioactive compounds with multiple therapeutic properties. The present review provides historical importance as well as an updated information on pharmacologically relevant higher basidiomycetes belong to the genus Agaricus, Auricularia, Phellinus, Ganoderma, Pleurotus, Trametes and Lentinus and their biologically active secondary metabolites. This will help the researchers to understand various type of secondary metabolites, their therapeutic role and related in vivo or in vitro work at a glance. The mounting evidences from several scientific community across the globe, regarding various therapeutic applications of mushroom extracts, unarguably make it an advance research area worth mass attention.

Mitigating Acetaminophen-Induced Hepatotoxicity by Using a Water-Alcohol Extract of Phellinus caryophylli (Agaricomycetes) in a Murine Model

This study investigates the hepatoprotective effect of a water-alcohol extract of the medicinal mushroom Phellinus caryophylli (Racib.) G. Cunn. (PCE) against acetaminophen (APAP)-induced hepatotoxicity in Swiss albino mice. The mice orally received APAP (150 mg/kg body weight), followed by PCE extract (250 or 500 mg/kg body weight). The liver damage induced by APAP was analyzed on the basis of blood serum parameters (glutamate pyruvate transaminase, glutamate oxaloacetate transaminase, and alkaline phosphatase), antioxidant assays (reduced glutathione and glutathione peroxidase), and tissue peroxidation based on malondialdehyde level. The molecular mechanism underlying the prevention of APAP-induced damage by PCE was also analyzed. Liver damage was confirmed on the basis of increased serum parameter values, decreased antioxidant levels, and cellular and molecular alterations, which PCE restored in a dose-dependent manner. At a transcriptional level, PCE downregulated expression of the preapoptototic gene Bax and the inflammatory gene Cox2 but upregulated the antiapoptotic gene Bcl2 in the mice that received APAP. PCE exerted a hepatoprotective effect by preventing apoptotic and inflammatory events caused by APAP. Thus, this study demonstrates a hepatoprotective effect of PCE, which could be explored further for managing hepatopathy.

Reduction of Gamma Radiation-Induced Damage by Hydro-Alcoholic Extract of Nardostachys jatamansi

The search for a nontoxic radioprotector has not yielded any promising results. Many antioxidant compounds, though effective under in vitro conditions as radioprotectors, have failed under in vivo settings due to their toxicity. The Indian medical system of Ayurveda uses a variety of plants with antioxidant potential, and these may be harboring molecules with radioprotective properties. In the present work, the radioprotective property of Nardostachys jatamansi was investigated. A hydro-alcoholic extract of this plant provided protection to the cellular DNA and membrane from 4 Gy gamma radiation. Depletion of cellular antioxidant status was also prevented by this extract. Molecular-level analysis in the intestines of mice revealed a lower bax/bcl2 ratio suggestive of a reduction of radiation-induced apoptosis. Expression levels of the DNA repair gene atm were elevated, along with a reduction in the expression of the inflammatory gene cox2. The extract also provided a survival advantage to mice exposed to lethal doses of gamma radiation. These results suggest a possible radioprotective role for Nardostachys jatamansi.

Mitigation of whole-body gamma radiation-induced damages by Clerodendron infortunatum in mammalian organisms

Several phytoceuticals and extracts of medicinal plants are reported to mitigate deleterious effects of ionizing radiation. The potential of hydro-alcoholic extract of Clerodendron infortunatum (CIE) for providing protection to mice exposed to gamma radiation was investigated. Oral administration of CIE bestowed a survival advantage to mice exposed to lethal doses of gamma radiation. Radiation-induced depletion of the total blood count and bone marrow cellularity were prevented by treatment with CIE. Damage to the cellular DNA (as was evident from the comet assay and the micronucleus index) was also found to be decreased upon CIE administration. Radiation-induced damages to intestinal crypt cells was also reduced by CIE. Studies on gene expression in intestinal cells revealed that there was a marked increase in the Bax/Bcl-2 ratio in mice exposed to whole-body 4 Gy gamma radiation, and that administration of CIE resulted in significant lowering of this ratio, suggestive of reduction of radiation-induced apoptosis. Also, in the intestinal tissue of irradiated animals, following CIE treatment, levels of expression of the DNA repair gene Atm were found to be elevated, and there was reduction in the expression of the inflammatory Cox-2 gene. Thus, our results suggest a beneficial use of Clerodendron infortunatum for mitigating radiation toxicity.

Protective effect of ayurvedic formulations against doxorubicin-induced cardiotoxicity: Preliminary studies on Brahma Rasayana and Chyavanaprash

AIM OF STUDY

The present work aimed to examine the efficacy of two ayurvedic formulations, Brahma Rasayana (BRM) and Chyavanaprash (CHM) to alleviate doxorubicin (DOX) induced acute cardiotoxicity.

MATERIALS AND METHODS

Swiss albino mice were administered with DOX (25 mg/kg, i.p.) and two doses of BRM or CHM (1 and 2 g/kg). Cardiotoxicity was assessed by measuring the levels of various antioxidant parameters in the heart as well as release of marker enzymes in the serum was assayed. Histology of the heart was also performed to check for DOX-induced damages.

RESULTS

Administration of either BRM or CHM (1 and 2 g/kg) maintained the antioxidant status in the heart thereby preventing tissue damage as well as the release of marker enzymes. DOX-induced variation of cardiac architecture was also prevented by BRM and CHM administration.

CONCLUSION

BRM and CHM administration could prevent DOX-induced acute cardiotoxicity.

Sanazole directed targeting of silver nanoparticle drug complex to tumor mass: a preclinical investigation in murine model

AIM OF STUDY

To explore sanazole (AK) directed targeting of the antineoplastic drug doxorubicin (DOX) complexed with silver nanoparticles (SNs) to tumor growth in a murine model.

MATERIALS AND METHODS

Sanazole (AK) and DOX were complexed with SNs, individually and in combination to obtain SN-AK, SN-DOX, and SN-AK-DOX. Solid tumors were developed on hind limbs of Swiss albino mice by transplanting Dalton's lymphoma ascitess (DLAs) tumor cells. Induction of cytotoxicity and apoptosis in the DLA cells by AK and DOX complexed with SN, individually and in combination, were examined under in vitro conditions by incubating the cells with them. SN, AK, DOX, SN-AK, SN-DOX, AK-DOX, and SN-AK-DOX were administered orally to the tumor bearing mice and the therapeutic efficacy of AK-directed targeting of SN-DOX complexes to achieve tumor control was monitored.

RESULTS

Under in vitro conditions, SN, AK, DOX, SN-AK, SN-DOX, AK-DOX, and SN-AK-DOX induced cytotoxicity and apoptosis in DLA cells to varying extents. The SN-AK-DOX complex showed higher level of cytotoxicity and apoptosis-induction in DLA cells. Similarly, administration of SN, AK, DOX, SN-AK, SN-DOX, AK-DOX, and SN-AK-DOX resulted in significant reduction in tumor volume and delay in tumor growth. The animals treated with SN-AK-DOX had the highest reduction in tumor volume and tumor growth. In fact, the tumor was almost absent in the animals of this group after the treatment.

CONCLUSION

The SN complex of sanazole and doxorubicin together (SN-AK-DOX) has high anticancer activity under in vivo conditions and has great potential in tumor therapy.

Ascorbic acid glucoside reduces neurotoxicity and glutathione depletion in mouse brain induced by nitrotriazole radiosensitazer

AIM

To investigate the potential of the anti-oxidant ascorbic acid glucoside (AA-2G) to modulate neurotoxicity induced by high doses of nitrotriazole radiosensitizer.

MATERIALS AND METHODS

Male and female C56Bl/6xCBA hybrid mice aged 8-14 weeks (weight 18-24 g) were used. Nitrotriazole drug radiosensitizer sanazole at a high dose of 2, 1 g/kg was per os administered to induce neurotoxicity at mice. Ascorbic acid glucoside was given 30 min before the sanazole administration. Serum ascorbic acid, brain glutathione level, as well as behavioral performance using open field apparatus were measured.

RESULTS

Administration of high (non-therapeutic) doses of the nitrotriazole drug sanazole results in neurotoxicity in mice as evidenced from behavioral performance, emotional activity and depletion of the cellular antioxidant, glutathione, in the brain. The serum levels of ascorbic acid was also found reduced in high dose sanazole treated animals. Per os administration of ascorbic acid glucoside significantly reduced the neurotoxicity. This effect was associated with the prevention of glutathione depletion in mouse brain and restoring the ascorbic acid level in serum.

CONCLUSION

Administration of ascorbic acid glucoside, but not ascorbic acid, before sanazole administration protected from sanazole-induced neurotoxicity by preventing the decrease in the brain reduced glutathione level and providing high level of ascorbic acid in plasma.

Ayurvedic formulations ameliorate cisplatin-induced nephrotoxicity: preclinical studies on Brahma Rasayana and Chyavanaprash

AIM OF STUDY

To explore the ability of two Ayurvedic formulations, Brahma Rasayana (BRM) and Chyavanaprash (CHM) in alleviating Cisplatin (Cis-dichlorodiammineplatinum [II] CDDP) induced acute nephrotoxicity.

MATERIALS AND METHODS

Swiss albino mice were administered with CDDP (12 mg/kg, i.p) and two doses of BRM or CHM (1 and 2 g/kg). Various antioxidant parameters in the kidney as well as release of marker enzymes in the serum were assayed. Histology of the kidney was also performed to check for CDDP induced damages.

RESULTS

Administration of either BRM or CHM (1 and 2 g/kg) maintained the antioxidant status in the kidney thereby preventing tissue damage as well as the release of marker enzymes. CDDP induced variation of renal architecture was also prevented by BRM and CHM administration.

CONCLUSION

BRM and CHM administration could prevent CDDP induced acute renal toxicity.

A novel microplate-based assay for screening radioprotectors and its validation based on DNA and membrane system

Ionizing radiation leads to damage at various cellular and sub-cellular levels and can be prevented by radioprotectors. There are many in vitro and in vivo but rather expensive assays for screening of radioprotectors from natural and synthetic sources. We have developed a cell free radioprotector screening assay which involves bleaching of crocin pigment, isolated from saffron by radiolytic products of water. Any molecules/compounds which can inhibit the bleaching of the crocin will act as a radioprotector. The developed assay was further validated by the existing in vitro assays. Different radioprotectors have different level for inhibition of bleaching of crocin. The trends of radioprotection offered by crocin bleaching assay, plasmid relaxation and lipid peroxidation are TMG>FA>VA>Amifos>Trox, TMG>VA>FA>Amifos>Trox, and TMG>FA>Trox>VA>Amifos, respectively. We are getting different trends for different assays. This is because different drugs have different mechanisms of radioprotection in different assay systems. In conclusion, the crocin bleaching assay developed here is a simple, fast and economical screening assay and it will have great value in radioprotection programme for screening many potential compounds for radioprotection.

Prevention of γ-radiation induced cellular genotoxicity by tempol: protection of hematopoietic system

Tempol (TPL) under in vitro conditions reduced the extent of gamma radiation induced membrane lipid peroxidation and disappearance of covalently closed circular form of plasmid pBR322. TPL protected cellular DNA from radiation-induced damage in various tissues under ex vivo and in vivo conditions as evidenced by comet assay. TPL also prevented radiation induced micronuclei formation (in peripheral blood leucocytes) and chromosomal aberrations (in bone marrow cells) in whole body irradiated mice. TPL enhanced the rate of repair of cellular DNA (blood leucocytes and bone marrow cells) damage when administered immediately after radiation exposure as revealed from the increased Cellular DNA Repair Index (CRI). The studies thus provided compelling evidence to reveal the effectiveness of TPL to protect hematopoietic system from radiation injury.

Protection of DNA and membrane from γ-radiation induced damage by the extract of Acorus calamus Linn.: An in vitro study

Acorus calamus, an ethnomedicinally important plant, was investigated for its protecting activity against radiation induced DNA and membrane damage. The in vitro free radical scavenging activity of the extract (water:ethanol, 1:1) of A. calamus was studied by parameters viz DPPH (1,1-diphenyl-2-picryl-hydrazyl) radical scavenging activity, hydroxyl radical scavenging activity, and superoxide radical scavenging activity. Membrane damage due to radiation exposure was measured as the peroxidation of lipids in terms of thiobarbituric acid reacting substance (TBARS). The in vitro DNA damage was monitored by assessing the radiation induced relaxation of supercoiled plasmid DNA (pBR322). Damage to cellular DNA induced by γ-radiation (6Gy) was monitored by alkaline single cell gel electrophoresis or comet assay in murine cells and human peripheral blood leukocytes. Enhancement of DNA repair mechanism was also monitored. The extract effectively scavenged free radicals in a concentration dependent manner. Presence of A. calamus extract during irradiation prevented peroxidation of membrane lipids in mouse liver homogenate. It helped to reduce the disappearance of the covalently closed circular (ccc) form of plasmid DNA following exposure to γ-radiation. Also the A. calamus extract effectively protected DNA from radiation induced strand breaks and enhanced the DNA repair process. Hence A. calamus extract can be used as a good source of natural radioprotecting agent.

Amelioration of cisplatin-induced nephrotoxicity by extracts of Hemidesmus indicus and Acorus calamus

Administration of commonly used anticancer drug cisplatin [cis-diamminedichloroplatinum (II)] at pharmacologically relevant concentrations (12 mg/kg body weight) resulted in severe renal toxicity as evidenced from histopathological observations and biochemical alterations in the renal tissue. The extracts of medicinal plants Hemidesmus indicus L. (Apocynaceae) and Acorus calamus L. (Araceae) protected the renal tissue effectively from cisplatin-induced toxicity. Treatment of cisplatin-administered animals with the plant extracts could prevent the drug-induced oxidative damage in the renal tissue as evidenced from the decreased levels of lipid peroxidation and enhanced activities of the antioxidants in the renal tissue. Cisplatin treatment increased serum urea level to 41.3 +/- 2.86 mg/dL and administration of the extracts of H. indicus and A. calamus brought down the level to 34.54 +/- 0.37 and 30.12 +/- 0.95 mg/dL, respectively. Serum creatinine levels were increased to 1.1 +/- 0.02 mg/dL following cisplatin administration, and treatment with extracts of H. indicus and A. calamus brought this down to 0.76 +/- 0.09 and 0.61 +/- 0.06 mg/dL, respectively. The histopathological observations indicated that treatment with the H. indicus and A. calamus extracts restored the cisplatin-induced structural alterations in the renal tissue.

Protection of DNA and membranes from gamma-radiation induced damages by Centella asiatica

Objectives

The objective of the present study was to examine the ability of Centella asiatica extract to offer protection to DNA and membranes against the deleterious effects of ionizing radiation exposure.

Methods

Protection of DNA under in-vitro conditions of irradiation was estimated using plasmid relaxation assay. For in-vivo studies the extract was administered orally to mice exposed to whole-body γ-radiation. The ability of the extract to offer protection against whole-body γ-radiation exposure was analysed by performing an alkaline comet assay on mouse bone marrow cells. The extent of lipid peroxidation was estimated using the TBARS (thio-barbituric acid reacting substances) method, in order to monitor membrane damage. Radiation-induced mortality of the animals following a lethal dose of γ-radiation was also examined.

Key findings

Centella asiatica extract significantly reduced radiation-induced damage to DNA. The extent of radiation-induced mortality and lipid peroxidation was also found to be considerably reduced in animals administered with the extract.

Conclusions

Centella asiatica rendered radioprotection to DNA and membranes against radiation exposure, both in vitro and in vivo. We have earlier reported that administration of the extract can prevent a radiation-induced decline in antioxidant enzyme levels. This suggests that radioprotection by Centella asiatica extract could be mediated by mechanisms that act in a synergistic manner, especially involving antioxidant activity.

Radiation protection by 6-palmitoyl ascorbic acid-2-glucoside: studies on DNA damage in vitro, ex vivo, in vivo and oxidative stress in vivo

A palmitoyl derivative of ascorbic acid 2-glucoside, 6-palmitoyl ascorbic acid-2-glucoside (PAsAG), which possess good antioxidant properties, is examined for radioprotection in vitro, ex vivo and in vivo models. PAsAG protected plasmid DNA from gamma-radiation induced damages under in vitro conditions. Presence of 1.6 mM PAsAG inhibited the disappearance of ccc (covalently closed circular) form of plasmid pBR322 with a dose modifying factor of 1.5. Comet assay studies on mouse spleen cells exposed to 6 Gy gamma-radiation (ex vivo) in presence and absence of PAsAG revealed that cellular DNA was effectively protected by this compound from radiation induced damages. Oral administration of 80 mg/kg body weight of PAsAG to mice 1 hour prior to 6 Gy whole body gamma-radiation exposure, efficiently protected cellular DNA in tissues such as spleen, bone marrow and blood, from radiation induced damages as indicated by alkaline comet assay. Oxidative stress in tissues such as liver and brain of mice, following whole body exposure to various doses of gamma-radiation (2-8 Gy), monitored as levels of GSH and peroxidation of lipids, were found considerably reduced when PAsAG was orally administered (80 mg/kg body weight) to the mice one hour prior to the radiation exposure. PAsAG administration improved the per cent survival of mice following exposure to 10 Gy whole body gamma-radiation. Thus PAsAG could act as a radioprotector under in vitro, ex vivo and in vivo conditions of ionizing-radiation exposure.

Amelioration of cisplatin induced nephrotoxicity in Swiss albino mice by Rubia cordifolia extract

BACKGROUND

Cisplatin is one of the most effective chemotherapeutics against a wide range of cancers including head, neck, ovarian and lung cancers. But its usefulness is limited by its toxicity to normal tissues, including cells of the kidney proximal tubule. The purpose of the present study is to investigate whether the hydro-alcoholic extract of Rubia cordifolia could decrease the intensity of toxicity in Swiss albino mice.

MATERIALS AND METHODS

Cisplatin at a dose of 12 mg/kg body wt was administered intraperitoneally to Swiss albino mice. Another set of animals was given hydro-alcoholic extract of Rubia cordifolia at different doses along with cisplatin treatment. The antioxidant levels, serum creatinine, serum urea etc. were analyzed.

RESULTS

The extract could significantly decrease the cisplatin induced nephrotoxicity as inferred from the tissue antioxidant status in the drug administered animals. Remarkable change was observed in serum creatinine and urea levels. Lipid peroxidation in the kidney and liver tissues was also considerably reduced in Rubia cordifolia extract treated animals.

CONCLUSION

Hydro-alcoholic extracts of Rubia cordifolia are effective in reducing the renal damage caused by the cancer chemotherapeutic drug cisplatin. Since Rubia cordifolia has been in use as an important ingredient in the traditional Ayurvedic system of medicine, it could be safe and beneficial to use this herbal extract as an adjuvant to ameliorate renal damage in patients undergoing cancer chemotherapy with cisplatin.

Prevention of cisplatin-induced nephrotoxicity by glucosides of ascorbic acid and alpha-tocopherol

BACKGROUND

Cisplatin is one of the most widely used cytotoxic therapeutic agents for the treatment of cancer. This drug, at effective higher doses, causes many physiological adverse effects such as nephrotoxicity and genotoxicity. The toxicity of the drug has been attributed to the induction of oxidative free radicals.

METHODS

Following intraperitoneal administration of cisplatin and ascorbic acid monoglucoside (AsAG) or alpha-tocopherol monoglucoside (TMG), investigations were conducted on levels of serum urea and creatinine, peroxidation of lipids in renal tissues, renal antioxidants and histopathology of renal tissue.

RESULTS

Administration of cisplatin to mice induced a marked renal failure, characterized by significant increase in serum urea and creatinine levels in addition to severe alterations in renal tissue architecture. Cisplatin also induced oxidative stress as indicated by increased lipid peroxidation and decreased levels of reduced glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase in renal tissues. Administration of AsAG or TMG markedly reduced the cisplatin-induced higher plasma creatinine and urea levels and counteracted the deleterious effects of cisplatin on oxidative stress markers and protected the tissues from the cisplatin-induced lipid peroxidation.

CONCLUSION

These results indicated that AsAG or TMG has a protective effect against cisplatin-induced renal damage in mice. The protection is mediated by preventing the decline of antioxidant status. The results have implications in use of AsAG or TMG in human application for protecting against drug-induced nephrotoxicity.

Polysaccharides isolated from Ganoderma lucidum occurring in Southern parts of India, protects radiation induced damages both in vitro and in vivo

The in vivo and in vitro radioprotective property of the polysaccharides isolated from Ganoderma lucidum were determined by survival studies, induction of micronucleus in reticulocytes of mice, strand breaks in plasmid pBR322 DNA and inhibition of lipid peroxidation (TBARS assay). Polysaccharides were administered as a single dose after whole body exposure to 10Gy (60)Co γ-radiation to Swiss albino mice. At a dose of 500μg/kg body wt, the polysaccharides were most effective in protecting animals from radiation induced loss of lethality. Administration of 500μg/kg body wt to animal exposed to 10Gy gamma radiation resulted in more than 60% survival on the 30th day compared to the dose of 300mg/kg/body wt administration of amifostine, a clinically used radioprotective drug. The induction of micronuclei was reduced by the administration of polysaccharides. The decrease in micronuclei induction was dose dependent. Thus following 4Gy exposure the micronuclei in polychromatic erythrocytes (MNCE) was reduced from 28.16±3.049 to 16.0243±2.074 and 6.30±2.422 by polysaccharides at doses of 250μg/kg body wt and 500μg/kg body wt, respectively, and to 10.4±2.581 by amifostine at a dose of 300mg/kg body wt. The results indicate the significant protective effect of Ganoderma polysaccharides against radiation induced damages. The findings thus suggest the potential use of Ganoderma polysaccharides as novel radioprotective agent.

A phase I trial of tocoferol monoglucoside in patients undergoing hemi-body radiation

PURPOSE

To evaluate Tocoferol monoglucoside (TMG), a water soluble vit. E. in a phase I trial, as a radiation protector in those undergoing hemi-body radiation for disseminated disease.

MATERIALS AND METHODS

Patients scheduled to receive modified hemi-body radiation were accrued for the study. Patients not only had disseminated skeletal disease but, were heavily pretreated Seven patients were accrued for the study. Patients received 1 and 2 gms of TMG. 30-40 minutes before hemibody radiation. A dose of 600 cGy was delivered on telecobalt equipment at mid plane. Immediate Toxicities were evaluated as well as response to pain.

RESULTS

All the seven patients underwent radiation uneventfully. There was no drug related toxicity. Pain relief was adequate.

CONCLUSION

Tocoferol monoglucoside an effective antioxidant with no significant acute toxicity, when administered in a dose of 1 or 2 gms per oral route. TMG being water-soluble can have global antioxidant and radio protective effects. This needs further clinical evaluation.

Preferential radioprotection to DNA of normal tissues by ferulic acid under ex vivo and in vivo conditions in tumor bearing mice

Our previous study showed that ferulic acid (FA) offered good radioprotection under in vitro and in vivo conditions to DNA and enhanced the DNA repair process in the peripheral blood leucocytes of mice in vivo. This study concerns radioprotection of normal versus tumor cells. Administration of FA (50 mg/kg body weight) to mice bearing fibrosarcoma tumor, 1 h prior to/ or immediately after radiation exposure (4 Gy) showed preferential radioprotection to normal cells i.e. peripheral blood leucocytes and bone marrow cells in comparison to tumor cells. This preferential protection under in vivo conditions could be attributed to poor vasculature in the tumor or peculiar characteristics of the tumor cells either to restrict its entry inside the cells or metabolize or inactivate the drug. To resolve these ex vivo study was carried out using bone marrow and tumor cells. It was found that under ex vivo condition also only bone marrow cells were protected by FA. Thus the studies revealed that FA showed preferential protection to normal cells under both in vivo and ex vivo conditions.

Protection of DNA and membrane from gamma radiation induced damage by gallic acid

Gallic acid (3,4,5-trihydroxybenzoic acid, GA) is a naturally occurring plant phenol. In vitro and in vivo studies have shown that this phytochemical protected DNA and membranes against ionizing radiation. Rat liver microsomes and plasmid pBR322 DNA were exposed to various doses of gamma radiation in presence and absence of GA. Exposure of the microsomes to gamma radiation resulted in the formation of peroxides of membrane lipids measured as thiobarbituric acid reactive substances and presence of GA during irradiation prevented the formation of lipid peroxidation. Gamma irradiation of plasmid DNA resulted in induction of strand breaks in DNA resulting in disappearance of the supercoiled (ccc) form. Presence of GA during irradiation protected the DNA from undergoing the strand breaks. In in vivo studies it was found that whole body exposure of mice to gamma radiation (4 Gy) increased the formation of lipid peroxides in various tissues and damage to cellular DNA (as measured by alkaline comet assay) in peripheral blood leucocytes. Administration of GA to mice prior to whole body radiation exposure reduced the peroxidation of lipids and the damage to the cellular DNA indicating in vivo radiation protection of membranes and DNA by GA.

Radiation protection by Terminalia chebula: some mechanistic aspects

Radioprotective ability of the aqueous extract of the fruit of Terminalia chebula (TCE) was evaluated for its antioxidant and radioprotective abilities. TCE (50 microg) was able to neutralise 1,1-diphenyl-2-picrylhydrazyl, a stable free radical by 92.9%. The free radical neutralizing ability of TCE was comparable to that of ascorbate (100 microM) 93.5% and gallic acid (100 microM) 91.5% and was higher than that of the diethyldithiocarbamate (200 microM) 55.4%, suggesting the free radical activity of TCE. TCE protected the plasmid DNA pBR322 from undergoing the radiation-induced strand breaks. Radiation damage converts the supercoiled form (ccc) of plasmid to open circular form (oc); the presence of TCE during radiation exposure protected the plasmid from undergoing these damages. The administration of TCE (80 mg/kg body weight, i.p.) prior to whole body irradiation of mice (4 Gy) resulted in a reduction of peroxidation of membrane lipids in the mice liver as well as a decrease in radiation-induced damage to DNA, as assayed by single-cell gel electrophoresis (comet assay). TCE also protected the human lymphocytes from undergoing the gamma radiation-induced damage to DNA exposed in vitro to 2 Gy gamma-radiation. These results suggest the radioprotective ability of TCE.

Protection of cellular DNA from γ-radiation-induced damages and enhancement in DNA repair by troxerutin

The effect of troxerutin on gamma-radiation-induced DNA strand breaks in different tissues of mice in vivo and formations of the micronuclei were studied in human peripheral blood lymphocytes ex vivo and mice blood reticulocytes in vivo. Treatments with 1 mM troxerutin significantly inhibited the micronuclei induction in the human lymphocytes. Troxerutin protected the human peripheral blood leucocytes from radiation-induced DNA strand breaks in a concentration dependent manner under ex vivo condition of irradiation (2 Gy). Intraperitoneal administration of troxerutin (175 mg/kg body weight) to mice before and after whole body radiation exposure inhibited micronuclei formation in blood reticulocytes significantly. The administration of different doses (75, 125 and 175 mg/kg body weight) of troxerutin 1 h prior to 4 Gy gamma-radiation exposure showed dose-dependent decrease in the yield of DNA strand breaks in murine blood leucocytes and bone marrow cells. The dose-dependent protection was more pronounced in bone marrow cells than in blood leucocytes. Administration of 175 mg/kg body weight of the drug (i.p.) 1 h prior or immediately after whole body irradiation of mice showed that the decrease in strand breaks depended on the post-irradiation interval at which the analysis was done. The observed time-dependent decrease in the DNA strand breaks could be attributed to enhanced DNA repair in troxerutin administered animals. Thus in addition to anti-erythrocytic, anti-thrombic, fibrinolytic and oedema-protective rheological activity, troxerutin offers protection against gamma-radiation-induced micronuclei formation and DNA strand breaks and enhances repair of radiation-induced DNA strand breaks.

Radiation protection of DNA by ferulic acid under in vitro and in vivo conditions

The effect of ferulic acid was studied on gamma-radiation-induced relaxation of plasmid pBR322 DNA and induction of DNA strand breaks in peripheral blood leukocytes and bone marrow cells of mice exposed to whole body gamma-radiation. Presence of 0.5 mM ferulic acid significantly inhibited the disappearance of supercoiled (ccc) plasmid pBR322 with a dose modifying factor (DMF) of 2.0. Intraperitoneal administration of different amounts (50, 75 and 100 mg/kg body weight) of ferulic acid 1 h prior to 4 Gy gamma-radiation exposure showed dose-dependent decrease in the yield of DNA strands breaks in murine peripheral blood leukocytes and bone marrow cells as evidenced from comet assay. The dose-dependent protection was more pronounced in bone marrow cells than in the blood leukocytes. It was observed that there was a time-dependent disappearance of radiation induced strand breaks in blood leukocytes (as evidenced from comet parameters) following whole body radiation exposure commensuration with DNA repair. Administration of 50 mg/kg body weight of ferulic acid after whole body irradiation of mice resulted disappearance of DNA strand breaks at a faster rate compared to irradiated controls, suggesting enhanced DNA repair in ferulic acid treated animals.

Radiation protection of DNA and membranein vitro by extract ofHemidesmus indicus

Radioprotective effect of H. indicus root extract on lipid peroxidation in rat liver microsomes and plasmid DNA was examined. Hemidesmus indicus (HI) root extract was found to protect microsomal membranes as evident from reduction in lipid peroxidation values. The extract could also protect DNA from radiation induced strand breaks.

Redox reactions and fluorescence spectroscopic behaviour of trifluoperazine at the surface of colloidal silica

Fluorescence spectroscopic behaviour and redox reactions of trifluoperazine (TFP) were studied in aqueous solutions in the presence of silica (SiO2) particles. The effect of surface heterogeneity on the secondary reactions of the transients was determined using optical absorption and fluorescence techniques. It appears that electrostatic interaction is the driving force for adsorption of TFP over SiO2 particle. Contrary to the change in fluorescence intensity with time observed in an aqueous solution, fluorescence intensity of TFP did not change significantly with time over the surface of SiO2. Fluorescence microscopic observations of spleen cells treated with TFP over SiO2 showed that the drug got distributed in cells similar to that observed in homogeneous aqueous solution.

Preparation and preliminary biological evaluation of a 177Lu labeled sanazole derivative for possible use in targeting tumor hypoxia

The preparation of a polyazamacrocyclic-nitrotriazole conjugate for radiolabeling with the therapeutic radioisotope viz. (177)Lu is described. The nitroimidazole used for the present study is [N-2'(carboxyethyl)-2-(3'-nitro-1'-triazolyl)acetamide], the carboxylic acid derivative of sanazole, which possesses an optimal combination of desired properties such as, selective toxicity for hypoxic cells, lowered lipophilicity resulting in lowered neurotoxicity. The bifunctional chelating agent is a DOTA derivative viz. 1,4,7,10-tetraaza-1-(4'-aminobenzylacetamido)-cyclododecane-4,7,10- triacetic acid (p-amino-DOTA-anilide). (177)Lu was produced in adequate specific activity (110TBq/g) and high radionuclidic purity (approximately 100%) by irradiating enriched (60.6% (176)Lu) Lu(2)O(3) target and used for radiolabeling of the sanazole-BFCA conjugate. approximately 98% Complexation yield was achieved under optimized conditions. The complex has been characterized by paper chromatography and HPLC studies. Bioevaluation studies in Swiss mice bearing fibrosarcoma tumors revealed moderate tumor uptake (0.88%/g at 1h post-injection) with favorable tumor to blood (4.00 at 1h post-injection) and tumor to muscle (4.63 at 1h post-injection) ratios.

Radioprotection of normal tissues in tumor-bearing mice by troxerutin

The flavanoid derivative troxerutin, used clinically for treating venous disorders, protected biomembranes and cellular DNA against the deleterious effects of gamma-radiation. The peroxidation of lipids (measured as thiobarbituric acid-reacting substances, or TBARS) in rat liver microsomal and mitochondrial membranes resulting from gamma-irradiation up to doses of 500 Gy in vitro was prevented by 0.2 mM troxerutin. The administration of troxerutin (175 mg/kg body weight) to tumor-bearing mice by ip one hour prior to 4 Gy whole-body gamma-irradiation significantly decreased the radiation-induced peroxidation of lipids in tissues such as liver and spleen, but there was no reduction of lipid peroxidation in tumor. The effect of troxerutin in gamma-radiation-induced DNA strand breaks in different tissues of tumor-bearing mice was studied by comet assay. The administration of troxerutin to tumor-bearing animals protected cellular DNA against radiation-induced strand breaks. This was evidenced from decreases in comet tail length, tail moment, and percent of DNA in the tails in cells of normal tissues such as blood leukocytes and bone marrow, and these parameters were not altered in cells of fibrosarcoma tumor. The results revealed that troxerutin could preferentially protect normal tissues against radiation-induced damages in tumor-bearing animals.

Radiation protection by diethyldithiocarbamate: protection of membrane and DNA in vitro and in vivo against gamma-radiation

Diethyldithiocarbamate (DDTC) is studied for its antioxidant and radioprotective abilities. DDTC at a concentration of 0.5 mM reduced DPPH radical. DDTC reduced the damage to deoxyribose resulting from hydroxyl radicals generated by Fenton reaction, indicating that the radioprotective abilities of this compound could be due to the free radical scavenging. DDTC protected rat liver microsomal membranes in vitro from peroxidative damage in lipids (measured as TBARS) resulting from 50 Gy gamma-radiation. It also protected plasmid pBR322 DNA from radiation-induced strand breaks. An oral administration of DDTC to mice before whole body gamma-radiation exposure (4 Gy) resulted in a reduction of radiation-induced lipid peroxides in the liver homogenates. An administration of DDTC to mice before gamma-radiation reduced the radiation-induced DNA damage as studied by single cell gel-electrophoresis (comet assay). The comet parameters such as tail length, tail moment, and percent of DNA in tail were found to increase in the blood leukocytes of mice exposed to 4 Gy gamma-radiation. When DDTC was administered to mice before the radiation exposure, the increase in the comet parameters as a result of radiation was prevented, indicating a protection of cellular DNA. The present study has implication for the potential use of DDTC as a radioprotector.

Radiosensitizer sanazole (AK-2123) enhances gamma-radiation-induced apoptosis in murine fibrosarcoma

Sanazole (AK-2123) (N-2'-methoxy ethyl)-2-(3"-nitro-1"-triazolyl)acetamide, which has completed phase III clinical trials as a radiosensitizer, enhanced gamma-radiation induced apoptosis in murine fibrosarcoma upon i.p. administration at 40 mg/kg body weight one hour prior to irradiation. A microscopic examination of Giemsa-May-Grunwald stained cells has shown a higher frequency of condensed nuclei and fragmented nuclei in the tumor cells. The administration of sanazole to tumor-bearing animals enhanced the radiation-induced internucleosomal fragmentation in the nuclear genome of tumor cells. Higher levels of caspase-3 activity were also observed in the cell extracts of tumours from AK-2123 administered mice. Exposure to gamma-radiation of AK-2123-treated mouse further enhanced the caspase-3 activity, indicating the induction of apoptosis. The radiation sensitization property of sanazole was discernible by comparing the relative tumor diameter following irradiation after i.p. administration of AK-2123 and irradiation alone; it was higher during the first few days followed by the treatment.

Genetic alterations in cervical cancer

In the pathogenesis of cervical cancer the role of human papillomavirus (HPV) infection is well established. However, other than HPV infection the genetics of cervical cancer remains poorly understood. In the pathogenesis of cervical cancel three major factors are involved, two of which are related to the presence of HPV and the third is the recurrent genetic alterations not linked to HPV infection. Several chromosomal regions with recurrent loss of heterozygosity (LOH) in cervical cancer have been identified. However; the putative tumor suppressor genes located in these chromosomal locations are yet to be identified. Recurrent amplifications have been mapped to the short arm of chromosome 3 in invasive cancer. Microsatellite instability and mutator phenotype do not play a major role in cervical carcinogenesis. As in other cancers, cervical cancer too requires the accumulation of genetic alterations for carcinogenesis to occur. Identification of these alterations could help to provide a better understanding of the disease and thus improve treatment.

Genetic alterations in the coding region of the bak gene in uterine cervical carcinoma

A significant frequency of mutations (six missense and one silent) was found, for the first time, at the coding region of the bak gene (exons 3, 4 and 6) in 42 carcinomas of the uterine cervix, while no mutations were detected in 32 non-neoplastic cervix tissues. Bak mutations were observed more frequently in the advanced stage and mutated cancer tissues were more resistant to radiotherapy, although trends were not statistically significant because of small sample size.

Protection of DNA and microsomal membranes in vitro by Glycyrrhiza glabra L. against gamma irradiation

The radioprotective effect of the root extract of Glycyrrhiza glabra L on lipid peroxidation in rat liver microsomes and plasmid pBR322 DNA was investigated. The extract was found to protect microsomal membranes, as evident from reduction in lipid peroxidation, and could also protect plasmid DNA from radiation-induced strand breaks.