Phytochemicals: A potential next generation agent for radioprotection.

BACKGROUND: Radiation hazards are accountable for extensive damage in the biological system and acts as a public health burden. Owing to the rapid increasing in radiation technology, both Ionizing radiation (IR) from natural and man made source poses detrimental outcome to public health. IR releases free radicals which induces oxidative stress and deleterious biological damage by modulating radiation induced signalling intermediates. The efficacy of existing therapeutic approach and treatment strategy are limited owing to their toxicity and associated side effects. Indian system of traditional medicine is enriched with prospective phytochemicals with potential radioprotection ability. PURPOSE: The present review elucidated and summarized the potential role of plant derived novel chemical compound with prospective radioprotective potential. METHOD: So far as the traditional system of Indian medicine is concerned, plant kingdom is enriched with potential bioactive molecules with diverse pharmacological activities. We reviewed several compounds mostly secondary metabolites from plant origin using various search engines. RESULTS: Both compounds from land plants and marine source exhibited antioxidant antiinflammatory, free radical scavenging ability. These compounds have tremendous potential in fine-tuning of several signalling intermediates, which are actively participated in the progression and development of a pathological condition associated with radiation stress. CONCLUSION: Development and explore of an operational radioprotective agent from originated from plant source that can be used as a novel molecular tool to eliminate the widespread damage caused by space exploration, ionizing radiation, nuclear war and radiotherapy has been significantly appreciated. Through extensive literature search we highlighted several compounds from both land plant and marine origin can be implemented for a better therapeutic potential against radiation induced injury. Furthermore, extensive clinical trials must be carried out in near future for better therapeutic modality and clinical efficacy.

Whole body protection to lethally irradiated mice by oral administration of semipurified fraction of Podophyllum hexandrum and post irradiation treatment of Picrorhiza kurroa.

OBJECTIVE: to evaluate the radioprotective potential of alcoholic fraction of Podophyllum hexandrum rhizomes (REC-2001) individually as well as in combination with Picrorhiza kurroa administered orally in lethally irradiated Swiss albino mice. METHODS: The study was divided into different treatment groups. Whole body survival was observed upto 30 days in all the treatment groups. Besides survival, toxicity of REC-2001 was also evaluated. All the groups were studied for spleen endogenous colony forming units (CFUs), plasma antioxidant potential and hematological variables, using standard techniques. RESULTS: Animals in radiation alone group died with in 12 days of exposure. Single dose of REC-2001 which did not bring any toxic manifestation/mortality (MTD) was found to be 155 mg/kg b.w. On administration of 250 mg/kg b.w. (single dose) 50% of the animals died (LD50), while a dose of 350 mg/kg b.w. of REC-2001 brought 100% death. Oral administration of single dose of REC-2001 (25 mg /kg b.w. -1h) prior to irradiation (10 Gy) was observed rendering up to 48% protection. Survival enhanced to the level of 55% when the animals had pre- treatment of REC-2001 (25 mg /kg b.w. -1h) followed by irradiation (10 Gy) and post treatment with a single dose of Picrorhiza kurroa rhizome extract (pkre, 8 mg/kg b.w.+1h). Radiation induced plasma antioxidant status was significantly (P < 0.02) countered by REC-2001 administration. Post treatment of pkre elevated CFU counts (P < 0.05). Total leukocytes count and hemoglobin content in REC-2001 pretreated and pkre post treated group approached normal limits within 30 days of the study. CONCLUSION: REC-2001 in combination with pkre holds promise for further studies to achieve radioprotection against lethal radiation by oral administration.

Radioprotective potential of an herbal extract of Tinospora cordifolia.

A preparation of Tinospora cordifolia (RTc) administered i.p. (200 mg/kg b.w.) to strain "A" male mice 1 h before whole body gamma-irradiation was evaluated for its radioprotective efficacy in terms of whole body survival, spleen colony forming units (CFU), hematological parameters, cell cycle progression, and micronuclei induction. Preirradiation treatment with RTc rendered 76.3% survival (30 days), compared to 100% mortality in irradiated control and prevented radiation induced weight loss. On 10th postirradiation day, the endogenous CFU counts in spleen were decreased with increasing radiation doses 12.0 (5 Gy), 2.16 (7.5 Gy) and 0.33 (10 Gy) but pre-irradiation administration of 200 mg/kg b.w. of RTc increased CFU counts to 31.16, 21.83 and 3.00 respectively. Pre-irradiation RTc treatment could restore total lymphocyte counts (TLC) by the 15th day to normal. It also increased the S-phase cell population that was reduced following 2 Gy irradiation in a time dependent manner. 2 Gy irradiation-induced micronuclei were also decreased by a pre-irradiation administration of RTc from 2.9 to 0.52%. Because the radioprotective manifestation of RTc observed in several systems in experimental animals can be exploited for human applications.