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The radioprotective effect of bael (Aegle marmelos, AME) extract was studied in Swiss albino mice against radiation-induced changes in the peripheral blood, spleen colony forming units, and intestinal mucosa. The mice were treated with 250 mg/kg body weight of AME orally once daily for five consecutive days before exposure to an acute dose of 7 Gy of gamma radiation after the last administration. The peripheral blood was collected and evaluated for red blood cell (RBC), hemoglobin, total leukocyte count (TLC), and lymphocyte count on days one and seven postirradiation. The nucleated bone marrow cells were isolated and tested for colony-forming units (CFUs) in spleen at days one and seven. AME protected mice against the radiation-induced decline in hemoglobin, total leukocyte, and lymphocytes counts and the clonogenicity of hemopoietic progenitor cells assessed by the exogenous spleen colony-forming assay. Irradiation of mice caused a significant decline in the villus height and crypt number with an increase in goblet and dead cells in the small intestine, where the maximum changes were observed on day one postirradiation, indicating a severe damage, and signs of recovery at day seven postirradiation. Treatment of mice with AME before irradiation elevated the peripheral cell count as well as villus height and the crypt number accompanied by a decline in goblet and dead cells when compared with the irradiation control. The recovery and regeneration were faster in AME pretreated animals than the irradiation alone. AME pretreatment significantly decreased lipid peroxidation accompanied by a significant elevation in the GSH concentration in the mouse intestine. The data clearly indicate that the AME significantly reduced the deleterious effect of radiation in the intestine and bone marrow of mouse and could be a useful agent in reducing the side effects of therapeutic radiation.

The radioprotective activity of the hydroalcoholic extract of jamun seeds (SCE) was studied in mice exposed to different doses of gamma radiation. The mice were injected with 0, 5, 10, 20, 40, 60, 80, 100, 120, 140 or 160 mg/kg body weight of SCE, before exposure to 10 Gy of gamma radiation, to select the optimum dose of radiation protection. The 80 mg/kg SCE was found to offer highest protection, therefore, further studies were carried out using this dose. The drug was more effective when administered through the intraperitoneal route at equimolar doses than the oral route. Since higher survival was observed for the i.p. route (50%), than the oral route (29.2%), all other studies were carried out by injecting SCE intraperitoneally. The mice treated with 80 mg/kg body weight SCE intraperitoneally before exposure to 6, 7, 8, 9, 10 and 11 Gy of gamma radiation showed reduction in the symptoms of radiation sickness and mortality at all exposure doses and caused a significant increase in the animal survival when compared with the concurrent double distilled water (DDW) + irradiation group. The SCE treatment protected mice against the gastrointestinal as well as bone marrow deaths and the DRF was found to be 1.24.

Effects of 20 mg/kg body weight of abana (ABE) on radiation-induced sickness and mortality in mice exposed to 7 Gy to 12 Gy of gamma irradiation were studied. Treatment of mice with abana 1 h before irradiation delayed the onset of mortality and reduced the symptoms of radiation sickness when compared with the non-drug treated irradiated controls (double distilled water, DDW). Abana provided protection against both the gastrointestinal and haemopoietic deaths. However, animals of both the ABE+irradiation and DDW+irradiation groups did not survive up to 30 days post-irradiation beyond 11 Gy irradiation. The LD(50/30) was found to be 8.5 Gy for the DDW+irradiation group and 10.3 Gy for ABE+irradiation group. The administration of abana resulted in an increase in radiation tolerance by 1.8 Gy, and the dose modification factor (DMF) was found to be 1.2. The irradiation of animals resulted in a dose dependent elevation in lipid peroxidation, and a reduction in glutathione (GSH) concentration on day 31 post-irradiation. Treatment of mice with abana before irradiation caused a significant depletion in lipid peroxidation followed by a significant elevation in GSH concentration in the liver of mice at day 31 post-irradiation. Abana scavenged (*)OH, DPPH, ABTS(*+) and NO(*) in a concentration dependent manner in vitro. Our results indicate that the radioprotective activity of abana may be due to free radical scavenging and increased GSH level in irradiated mice.

The effect of various doses (5, 10, 20, 40, 60, 80, 100, 120, 140 and 160 mg/kg b. wt.) of 50% ethanolic extract of Septilin (a herbal preparation) was studied on the radiation-induced mortality in mice exposed to 10 Gy of gamma-irradiation. Treatment of mice with different doses of Septilin, consecutively for 5 days before irradiation, delayed the onset of mortality and reduced the symptoms of radiation sickness when compared with the non-drug treated irradiated controls. All doses of Septilin provided protection against gastrointestinal (GI) deaths (death within 10 days of irradiation). However, the best protection was observed at 100 mg/kg b. wt. of Septilin, as the number of survivors after 30 days post-irradiation was highest (58.33%) in this group when compared with the other doses of Septilin. The number of survivors was 1.75 fold greater for 100 mg/kg Septilin when compared with the 2-mercaptopropionylglycine (MPG, 33.33%) which was used as a positive control. The LD(50) of Septilin was 1250 mg/kg as against the optimum protective dose of 100 mg/kg. Our study demonstrates Septilin as a good radioprotective agent., (Copyright (c) 2004 John Wiley & Sons, Ltd.)

The effect of various doses of 50% ethanolic extract of chyavanaprasha (an Ayurvedic rejuvenating herbal preparation) was studied on the survival of mice exposed to 10 Gy of gamma-radiation. Treatment with chyavanaprasha, consecutively for fi ve days before irradiation, delayed symptoms of radiation sickness and onset of mortality when compared with the non-drug treated irradiated controls. All doses of chyavanaprasha provided a significant protection against gastrointestinal (GI) death (death of animals within 10 days after exposure to radiation), however, highest protection against GI death was observed for 15 mg/kg chyavanaprasha. Chyavanaprasha also provided a significant protection against the bone marrow death after 10 to 40 mg/kg. However, the best protection was seen for 15 mg/kg, where the highest number of survivors was observed at the end of 30 days post-irradiation. The drug was non-toxic up to a dose of 6 g/kg b. wt., the highest drug dose that could be tested. Our study demonstrates that chyavanaprasha can provide good radioprotection at a very low non-toxic dose., (Copyright 2004 John Wiley & Sons, Ltd.)

The effect of 5, 10, 20, 40 and 80 mg/kg b. wt. of hydroalcoholic extract of geriforte (an Ayurvedic herbal medicine) administered intraperitoneally was studied on the radiation-induced mortality in mice exposed to 10 Gy of gamma-radiation. Treatment of mice with different doses of geriforte consecutively for 5 days before irradiation delayed the onset of mortality and reduced the symptoms of radiation sickness when compared with the non-drug treated irradiated controls. A maximum protection was observed for 10 mg/kg geriforte, where a highest number of survivors were reported by 30 days post-irradiation and further experiments were carried out using this dose of geriforte. The mice were treated with 10 mg/kg b. wt. geriforte or double distilled water (DDW) and exposed to 7, 8, 9, 10 and 11 Gy of gamma radiation and observed for the induction of symptoms of radiation sickness and mortality up to 30 days post-irradiation. The geriforte treatment protected the mice against the GI death as well as bone marrow deaths and the dose reduction factor (DRF) was found to be 1.14. Toxicity study showed that geriforte was non-toxic up to a dose of 4250 mg/kg, where no drug-induced mortality was observed. The LD50 dose of geriforte was found to be 4750 mg/kg b. wt. To understand the mechanism of action of geriforte, free radical scavenging activity of the drug was evaluated. Geriforte was found to scavenge *OH, O2*- ABTS*+ and NO* in a dose-dependent manner. Our study demonstrates that geriforte is a good radioprotective agent and the optimum protective dose of 10 mg/kg was 1/475th of the LD50 dose.

The effect of various doses (0, 5, 10, 20, 40, 80, 100, 120 and 160 mg/kg b. wt.) of 50% ethanolic extract of mentat (a herbal preparation) was studied on the survival of mice exposed to 10 Gy of gamma-radiation. Treatment of mice with different doses of mentat consecutively for fi ve days before irradiation delayed the onset of mortality and reduced the symptoms of radiation sickness when compared with the non-drug treated irradiated controls. Most of the doses of mentat provided protection against the gastrointestinal (GI) death, however, the highest protection against GI death was observed for 80 mg/kg mentat. This was also true for bone marrow deaths, where the highest number of survivors were observed at 30 days post-irradiation in this group (i.e. 80 mg/kg) when compared with the other doses of mentat. The evaluation of acute toxicity showed that mentat was non-toxic up to a dose of 1.5 g/kg b. wt., where no drug-induced mortality was observed. The LD50 dose of mentat was found to be 1.75 g/kg b. wt. Our study demonstrates that mentat can provide good radioprotection at a dose of 80 mg/kg, which is far below its toxic dose., (Copyright 2003 John Wiley & Sons, Ltd.)

The radioprotective effect of a hydroalcoholic extract of Aegle marmelos (AME) was evaluated in cultured human peripheral blood lymphocytes (HPBLs) by the micronucleus assay. The optimum protective dose of the extract was selected by treating HPBLs with 1.25, 2.5, 5, 6.25, 10, 20, 40, 60, 80 and 100 microg/ml AME before exposure to 3 Gy gamma-radiation and then evaluating the micronucleus frequency in cytokinesis blocked HPBLs. Treatment of HPBLs with different doses of AME reduced the frequency of radiation-induced micronuclei significantly, with the greatest reduction in micronucleus induction being observed for 5 microg/ml AME. Therefore, this dose of AME was considered as the optimum dose for radioprotection and further studies were carried out treating the HPBLs with 5 microg/ml AME before exposure to different doses (0, 0.5, 1, 2, 3 and 4 Gy) of gamma-radiation. The irradiation of HPBLs with different doses of gamma-radiation caused a dose-dependent increase in the frequency of lymphocytes bearing one, two and multiple micronuclei, while treatment of HPBLs with 5 microg/ml AME significantly reduced the frequency of lymphocytes bearing one, two and multiple micronuclei when compared with the irradiated control. The dose-response relationship for both groups was linear. To understand the mechanism of action of AME separate experiments were conducted to evaluate the free radical scavenging of OH, O2(-), DPPH, ABTS(+) and NO in vitro. AME was found to inhibit free radicals in a dose-dependent manner up to a dose of 200 microg/ml for the majority of radicals and plateaued thereafter. Our study demonstrates that AME at 5 microg/ml protected HPBLs against radiation-induced DNA damage and genomic instability and its radioprotective activity may be by scavenging of radiation-induced free radicals and increased oxidant status.

The effects of various concentrations (5, 10, 20, 30, 40, 50, 60, and 80 mg/kg body weight (b.wt.) of the leaf extracts of Syzygium cumini Linn. and Eugenia cumini (SCE, black plum, Jamun, family Myrtaceae) on the radiation-induced sickness and mortality in mice exposed to 10 Gy gamma-irradiation were studied. The treatment of mice with different doses of SCE, consecutively for five days before irradation, delayed the onset of mortality and reduced the symptoms of radiation sickness when compared with the nondrug-treated irradiated controls. All doses of SCE provied protection against the gastrointestinal death increasing the survival by 66.66% after treatment with 20, 30, and 40 mg/kg SCE versus a 12% survival in the irradiated control group (oil + irradiation). Similarly, SCE provided protection against the radiation-induced bone marrow death in mice treated with 10-60 mg/kg b.wt. of SCE. However, the best protection was obtained for 30 mg/kg b.wt. SCE, where the number of, survivors after 30 days post-irradiation was highest (41.66%) when compared with the other doses of SCE.

The effect of 5, 10, 20, 40, 60, 80, 100, 120, and 160 mg/kg body weight (b.wt.) of aqueous extract of cystone (an ayurvedic herbal medicine) administered intraperitoneally was studied on the radiation-induced mortality in mice exposed to 10 Gy of gamma-radiation. Treatment of mice with different doses of cystone, consecutively for five days before irradiation, delayed the onset of mortality and reduced the symptoms of radiation sickness when compared with the non-drug treated irradiated controls. The pretreatment of mice with different doses of cystone before exposure to 10 Gy of gamma-radiation resulted in a dose-dependent elevation in the survival up to 40 mg/kg b.wt., where the highest number of survival (55.55%) was observed by 30 days post irradiation, when compared with the 10 Gy irradiated control (6.66%). Thereafter, the number of survivors declined and reached a nadir at 160 mg/kg, where no survivors could be observed. The optimum protection against irradiation was observed for 40 mg/kg cystone, where the highest number of survivors were reported by 30 days post irradiation and it was 8.34-fold greater than that of the irradiated control group.

The effect of 0, 5, 6.25, 10, 12.5, 20, 25, 40, 50 and 80 mg/kg b. wt. of aqueous extract of triphala (an Ayurvedic herbal medicine) administrered intraperitoneally was studied on the radiation-induced mortality in mice exposed to 10 Gy of gamma-radiation. Treatment of mice with different doses of triphala consecutively for five days before irradiation delayed the onset of mortality and reduced the symptoms of radiation sickness when compared with the non-drug treated irradiated controls. The highest protection against GI (gastrointestinal) death was observed for 12.5 mg/kg triphala, where a highest number of survivors were reported up to 10 days post-irradiation. While 10 mg/kg triphala i.p. provided the best protection as evidenced by the highest number of survivors after 30 days post-irradiation in this group when compared with the other doses of triphala. Toxicity study showed that triphala was non-toxic up to a dose of 240 mg/kg, where no drug-induced mortality was observed. The LD50 dose i.p. of triphala was found to be 280 mg/kg b. wt. Our study demonstrates the ability of triphala as a good radioprotective agent and the optimum protective dose of triphala was 1/28 of its LD50 dose.