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

Dietary agents in the prevention of radiation-induced nausea and vomiting (RINV): review addressing the scientific observations, benefits, lacunae and future direction

PURPOSE

Radiation-induced Nausea and Vomiting (RINV) is an important side effect and conservative estimates are that 50-80% of the patients undergoing curative radiotherapy (RT) will experience some sought of retching, nausea, and/or vomiting during the course of their treatment. Conventionally, antiemetic drugs like the 5-hydroxytryptamine receptor antagonists and steroids are the mainstay of treatment. However, the use of these agents, especially steroids, can cause side effects and thereby negate the proposed benefits. The antiemetic effects of Centella asiatica (Indian pennywort), Hippophae rhamnoides (Sea buckthorn), oil of Mentha spicata (Spearmint) and the rhizomes of Zingiber officinale (ginger) have been addressed.

CONCLUSIONS

Results indicate that Indian pennywort, Sea buckthorn, Spearmint oil and ginger are beneficial in mitigating RINV. Also, of the four plants investigated in preclinical models of study, mint oil and ginger seem to be more useful and merit structured systematic translational studies to ascertain the benefit of these two agents.

In vivo protective efficacy of astaxanthin against ionizing radiation-induced DNA damage

Astaxanthin, a carotenoid pigment, is believed to be effective in the repair of DNA damage. Our study evaluates the effect of astaxanthin on DNA damage in rats exposed to whole-body radiotherapy using the comet assay. Thirty-two male rats were randomly divided into four groups (control, ionizing radiation, astaxanthin, and radiation+astaxanthin). The radiation and radiation+astaxanthin groups were exposed to X-rays at a dose of 8 gray (0.62 gray/min). Astaxanthin was administered at 4 mg/kg by gavage for 7 days starting from irradiation. The %TailDNA parameter was chosen as an indicator of DNA damage and the results were compared using one-way ANOVA. %TailDNA was 3.24 ± 3.12 in the control group, 2.85 ± 2.73 in the astaxanthin group, 4.11 ± 7.90 in the radiation group, and 3.59 ± 4.05 in the radiation+astaxanthin group. There was a significant increase in DNA damage in the radiation group, compared with the control and astaxanthin groups (p < .001). DNA damage was reduced in the radiation+astaxanthin group compared with the radiation group (p < .05). Although this decrease did not reduce damage to the level of the control group, it was significant. The decrease in radiation-induced DNA damage by astaxanthin administration in our study supports the hypothesis that astaxanthin is a promising agent for against/reducing DNA damage.

Natural radioprotectors on current and future perspectives: A mini-review

Radiation therapy is used as the primary treatment for cancer. Eighty percent of cancer patients require radiation therapy during treatment or for medical purposes. During treatment, radiation causes various biological defects in the cells. The prevalence of cytotoxicity limits the dose used for effective treatment. This method is designed to strike a balance between removing cancer cells and protecting normal tissues. Unfortunately, effective radiation is unavailable once acute toxicity occurs during clinical radiation therapy. Therefore, a lot of research interest is needed in the discovery of radioprotective drugs to accelerate treatment to reduce this toxicity (i.e., normal tissue toxicity to cancer cell death). Radiation protectors may be chemicals or drugs that minimize the damage caused due to radiation therapy in living organisms. The determination of effective and nontoxic radiation protection is an essential goal for radiation oncologists and basic radiobiologists. However, despite the advantages, many radioprotectors were found to have disadvantages which include cost, less duration, toxicity, and effect on the central nervous system. Therefore in recent years, the focus has been diverted to finding out optimal natural products to act as radioprotectors. Natural radiation protectors are plant compounds that protect normal (noncancerous) cells from damage from radiation therapy. Natural herbal products are nontoxic with proven therapeutic benefits and have long been used to treat various diseases. In conclusion, we find that there are various radiation protectors with different purposes and mechanisms of action.

Pterocarpus santalinus L. extract mitigates gamma radiation-inflicted derangements in BALB/c mice by Nrf2 upregulation

Plant-based natural extracts contain several nutrients and bioactive compounds, such as phenolics and flavonoids, that possess various health-promoting activities. This study investigated the effects of polyphenols from Pterocarpus santalinus hydroalcoholic extract (PSHE) against gamma radiation-induced derangements via the upregulation of Nrf2. Ultra High Performance Liquid Chromatography Coupled to High Resolution Mass Spectrometry (UHPLC-HRMS/MS) analysis was performed to identify the possible radioprotectors. In vivo and in vitro studies, namely Real-Time-PCR (RT-PCR) analysis, Reactive Oxygen Species (ROS) scavenging activity, lipid peroxidation and GSH levels, DNA damage and cell death studies, anti-inflammatory (Sandwich ELISA), immunomodulatory studies (antibody staining), and model free radical scavenging assays, were performed. Vanillic acid, protocatechuic acid, para-hydroxybenzoic acid, chlorogenic acid, TNF-α inhibitor (Eudesmin), isoflavone (Daidzein 7-o-glucoside), astragalin (Kaempferol 3-o-glycoside), and other polyphenols were identified in PSHE using UHPLC-HRMS/MS analysis. Prophylactic administration of PSHE (-1 h) rendered more than 33% survival in mice exposed to 8 Gy whole-body-irradiation with increased mice survival and recovery of bone marrow and spleen cellularity. Real-time RT-PCR analysis showed that PSHE treatment (50 µg/mL) upregulated Nrf2, HO-1, and GPX-1 in mice splenocytes. At 50 µg/mL, PSHE reduced ROSscavenging activity, mitochondrial and spleen membrane lipid peroxidation levels, DNA damage, and cell death, and increased GSH levels. At 10 µg/mL, PSHE treatment diminished the content of IL-6 and TNF-α. At 50 µg/mL, PSHE suppressed lymphocyte proliferation. These findings indicate that polyphenols of PSHE possess marked antioxidant, anti-inflammatory, and immunomodulatory capacities, which play important roles in the prevention of radiation damage.

Medicinally important aromatic plants with radioprotective activity

Aromatic plants are often used as natural medicines because of their remedial and inherent pharmacological properties. Looking into natural resources, particularly products of plant origin, has become an exciting area of research in drug discovery and development. Aromatic plants are mainly exploited for essential oil extraction for applications in industries, for example, in cosmetics, flavoring and fragrance, spices, pesticides, repellents and herbal beverages. Although several medicinal plants have been studied to treat various conventional ailments only a handful studies are available on aromatic plants, especially for radioprotection. Many plant extracts have been reported to contain antioxidants that scavenge free radicals produced due to radiation exposure, thus imparting radioprotective efficacy. The present review focuses on a subset of medicinally important aromatic plants with radioprotective activity.