Flavonoids of Rosa roxburghii Tratt Act as Radioprotectors FRT;radioprotection;survival rate;AHH-1;CFU-S; Background: To study the radioprotective effects of flavonoids from Rosa roxburghii Tratt (FRT). Materials and Methods: The radioprotective effects of FRT were investigated by examining cell viability, 30-day survival of mice and the number of colony-forming units in spleen (CFU-S) after total-body 60Co irradiation. Results: The survival rates of irradiated cells gradually increased with increasing concentrations of FRT. The survival rate was the highest at 87% with a concentration of $30{\mu}g/mL$. Pretreatment with FRT was needed to realize its radioprotective activity in mice at the dose of 60 mg/kg. With the increasing doses of 30 mg/kg, 60 mg/kg and 120 mg/kg, the numbers of CFU-S increased, and were significantly different compared with the control group. Conclusions: Pretreatment with FRT prior to irradiation resulted in significantly higher cell survival at 24 h after 5 Gy radiation, increased 30-day survival in mice after exposure to a potentially lethal dose of 8 Gy, and resulted in a higher number of CFU-S in mice after exposure to a dose of 6 Gy. These results collectively indicate that FRT is an effective radioprotective agent.

Background: Since its discovery, poly (ADP-ribose) polymerase 1 (PARP-1) has been extensively studied due to its regulatory role in numerous biologically crucial pathways. PARP inhibitors have opened new therapeutic avenues for cancer patients and have gained approval as standalone treatments for certain types of cancer. With continued advancements in the research of PARP inhibitors, we can fully realize their potential as therapeutic targets for various diseases.Purpose: To assess the current understanding of PARP-1 mechanisms in radioprotection and radiotherapy based on the literature.Methods: We searched the PubMed database and summarized information on PARP inhibitors, the interaction of PARP-1 with DNA, and the relationships between PARP-1 and p53/ROS, NF-κB/DNA-PK, and caspase3/AIF, respectively.Results: The enzyme PARP-1 plays a crucial role in repairing DNA damage and modifying proteins. Cells exposed to radiation can experience DNA damage, such as single-, intra-, or inter-strand damage. This damage, associated with replication fork stagnation, triggers DNA repair mechanisms, including those involving PARP-1. The activity of PARP-1 increases 500-fold on DNA binding. Studies on PARP-1-knockdown mice have shown that the protein regulates the response to radiation. A lack of PARP-1 also increases the organism’s sensitivity to radiation injury. PARP-1 has been found positively or negatively regulate the expression of specific genes through its modulation of key transcription factors and other molecules, including NF-κB, p53, Caspase 3, reactive oxygen species (ROS), and apoptosis-inducing factor (AIF).Conclusion: This review provides a comprehensive analysis of the physiological and pathological roles of PARP-1 and examines the impact of PARP-1 inhibitors under conditions of ionizing radiation exposure. The review also emphasizes the challenges and opportunities for developing PARP-1 inhibitors to improve the clinical outcomes of ionizing radiation damage.

Purpose: To perform a qualitative and quantitative analysis of catechin and quercetin in flavonoids extracted from Rosa roxburghii Tratt.Methods: Total flavonoids were determined using ultraviolet spectrophotometry (UV) at 500 nm. The optimal gradient program started with 15 % methanol and was kept within a period of 0 – 20 min, while 25 % methanol was kept within 20 – 33 min. Subsequently, the concentration of methanol was reduced to 15 % and was held for 10 min until the next injection. Mass spectrometry spray voltage was 4,000 V, ionization temperature 350 °C, atomizer pressure 35 psi, nitrogen flow rate 8 L/min, and mass scan range 200 – 800 m/z. The detection wavelength used for catechin and quercetin was 270 and 368 nm, respectively.Results: Based on the UV results, Rosa roxburghii Tratt content was 73.85 %, which is in agreement with the national standard. Liquid chromatography-mass spectrometry (LC-MS) results indicate that Rosa roxburghii Tratt flavonoids contained quercetin, 34.26 %, with relative standard deviation (RSD) of 2.88 % and catechin content of 2.97 % with RSD of 1.49 %.Conclusion: The proposed measurement method for determining the content of flavonoids in Rosa roxburghii Tratt has the advantage of simplicity, feasibility, good repeatability, and rapid and accurate analysis.Keywords: Rosa roxburghii Tratt, Flavonoids, Catechin, Quercetin

Purpose: The purpose of this study was to conduct research in mice to determine the radioprotective effects of troxerutin. Thirty-day survival, oxidative status and histological changes in the liver were all evaluated. Materials and methods: Troxerutin was administered orally to mice for six days before irradiation with different doses (6, 7, 8 and 10 Gy) of γ-rays and the mice were observed for 30 days after radiation to calculate 30-day survival and median lethal dose of 30 days (LD50/30). Its radioprotective efficacy was compared with the positive drug amifostine which is currently the most effective radioprotector. The animals pretreated with troxerutin for 6 days were sacrificed on day 11 after radiation (6 Gy) in order to make 10% homogenate and histological sections of liver. Antioxidant enzymes were detected in strict accordance with kit requirements. Histological liver sections were examined by hematoxylin-eosin (HE) staining. Results: Pretreatment with troxerutin resulted in a significantly higher 30-day survival rate for 70% of mice compared with 30% of irradiation group after exposure to a potentially lethal dose of 8 Gy; LD50/30 of drug treatment group was 9 Gy compared with 7.7 Gy for irradiation group. The results indicated that troxerutin increased the activity of various antioxidant enzymes, such as superoxide dismutase (SOD) in mice liver, which was reduced by radiation treatment. Maleic dialdehyde (MDA) levels were significantly reduced by troxerutin, which was increased after 6 Gy radiation. These results were further confirmed by histopathological examinations which indicated that pre-administration with the effective dose of troxerutin reduced the hepatic damage induced by radiation. Conclusions: Administration of troxerutin before irradiation, provided higher survival of experimental mice, improvement of biochemical parameters, and preserved major histological parameters of the liver. These results collectively indicate that troxerutin is an effective radioprotective agent.