Ionizing radiations produce deleterious effects in the living organisms and the rapid technological advancement has increased human exposure to ionizing radiations enormously. There is a need to protect humans against such effects of ionizing radiation. Attempts to protect against the deleterious effects of ionizing radiations by pharmacological intervention were made as early as 1949 and efforts are continued to search radioprotectors, which may be of great help for human application. This review mainly dwells on the radioprotective potential of plant and herbal extracts. The results obtained from in vitro and in vivo studies indicate that several botanicals such as Gingko biloba, Centella asiatica, Hippophae rhamnoides, Ocimum sanctum, Panax ginseng, Podophyllum hexandrum, Amaranthus paniculatus, Emblica officinalis, Phyllanthus amarus, Piper longum, Tinospora cordifoila, Mentha arvensis, Mentha piperita, Syzygium cumini, Zingiber officinale, Ageratum conyzoides, Aegle marmelos and Aphanamixis polystachya protect against radiation-induced lethality, lipid peroxidation and DNA damage. The fractionation-guided evaluation may help to develop new radioprotectors of desired activities.

Aim: Free radicals are an outcome of various metabolic activities and their excess production leads to many diseases. Therefore, it is necessary to neutralize excess free radicals. Materials & methods: Free-radical scavenging activity of various extracts of Schima wallichii was evaluated using standard protocols. Results: Chloroform, ethanol and aqueous extracts of S. wallichii scavenged DPPH, hydroxyl, superoxide, nitric oxide and ABTS free radicals and increased ferric-reducing antioxidant potential in a concentration-dependent manner. A total of 1000 μg/ml of all the extracts and ethanol extract showed highest total flavonoids and phenol contents, respectively. Conclusion: The different extracts of S. wallichii scavenged different free radicals efficiently due to the presence of flavonoids and polyphenols and may be helpful in free radical-induced diseases. Lay abstract Free radicals induce several health disorders including cancer, and their excess generation needs to be controlled. Our study demonstrates that Schima wallichii scavenged DPPH, hydroxyl, superoxide, nitric oxide, ABTS free radicals and increased ferric-reducing antioxidant potential in a concentration-dependent manner. It could be one of the agents able to mitigate excess free-radical generation and ward off free radical-induced inflammation and diseases.

The anticancer activity of dichloromethane extract of guduchi [Tinospora cordifolia (WILLD.) MIERS ex HOOK. F. & THOMS. Family: Menispermaceae (TCE)] in the mice transplanted with Ehrlich ascites carcinoma (EAC) was investigated. The EAC mice receiving 25, 30, 40, 50 and 100 mg/kg, TCE showed a dose dependent elevation in tumor-free survival and a highest number of survivors were observed at 50 mg/kg TCE, which was considered as an optimum dose for its neoplastic action. The average survival time (AST) and median survival time (MST) for this dose were approximately 56 and 55 d, respectively when compared with 19 d of non-drug treated controls. Administration of 50 mg/kg TCE resulted in 100% long-term survivors (up to 90 d). An attempt was also made to evaluate the effectiveness of TCE in the various stages of tumor development, where 50 mg/kg TCE was administered intraperitoneally after 1, 3, 6, 9, 12 or 15 d of tumor inoculation and these days have been arbitrarily designated as stage I, II, III, IV or V, respectively for reasons of clarity. The greatest anticancer activity was recorded for stage I, II and III where number of long term survivors (LTS) was approximately 33, 25 and 17%, respectively. However, treatment of mice at stage IV and V did not increase LTS, despite an increase in AST and MST. The EAC mice receiving 50 mg/kg TCE showed a time dependent depletion in the glutathione (GSH) activity up to 12 h post-treatment and marginal elevation thereafter. This depletion in GSH was accompanied by a drastic elevation in lipid peroxidation (LPx) and a maximum elevation in LPx was observed at 6 h that declined gradually thereafter. TCE exerted cytotoxic effect on tumor cells by reducing the GSH concentration and increase in LPx simultaneously.

Radiofrequency radiations (RFRs) emitted by mobile phone base stations have raised concerns on its adverse impact on humans residing in the vicinity of mobile phone base stations. Therefore, the present study was envisaged to evaluate the effect of RFR on the DNA damage and antioxidant status in cultured human peripheral blood lymphocytes (HPBLs) of individuals residing in the vicinity of mobile phone base stations and comparing it with healthy controls. The study groups matched for various demographic data including age, gender, dietary pattern, smoking habit, alcohol consumption, duration of mobile phone use and average daily mobile phone use. The RF power density of the exposed individuals was significantly higher (p < 0.0001) when compared to the control group. The HPBLs were cultured and the DNA damage was assessed by cytokinesis blocked micronucleus (MN) assay in the binucleate lymphocytes. The analyses of data from the exposed group (n = 40), residing within a perimeter of 80 m of mobile base stations, showed significantly (p < 0.0001) higher frequency of micronuclei when compared to the control group, residing 300 m away from the mobile base station/s. The analysis of various antioxidants in the plasma of exposed individuals revealed a significant attrition in glutathione (GSH) concentration (p < 0.01), activities of catalase (CAT) (p < 0.001) and superoxide dismutase (SOD) (p < 0.001) and rise in lipid peroxidation (LOO) when compared to controls. Multiple linear regression analyses revealed a significant association among reduced GSH concentration (p < 0.05), CAT (p < 0.001) and SOD (p < 0.001) activities and elevated MN frequency (p < 0.001) and LOO (p < 0.001) with increasing RF power density.