Synthesis and Characterization of a Rosmarinic Acid Derivative that Targets Mitochondria and Protects against Radiation-Induced Damage In Vitro

Nutraceutical Properties of Syringic Acid in Civilization Diseases-Review

Civilization diseases account for a worldwide health issue. They result from daily behavioral, environmental, and genetic factors. One of the most significant opportunities to prevent and alleviate the occurrence of these diseases is a diet rich in antioxidants like polyphenols. This review paper is concentrated on syringic acid (SA), one of the representative compounds of phenolic acids subgroups. There are many in vitro and in vivo studies on SA that assess its pivotal effects on oxidative stress and inflammation parameters. It is effective on metabolic risk factors as well, including hyperglycemia, high blood pressure, and hyperlipidemia. SA is one of the prominent polyphenolic compounds that may help address health issues related to civilization diseases.

Exploring Natural Products as Radioprotective Agents for Cancer Therapy: Mechanisms, Challenges, and Opportunities

Radiotherapy is an important cancer treatment. However, in addition to killing tumor cells, radiotherapy causes damage to the surrounding cells and is toxic to normal tissues. Therefore, an effective radioprotective agent that prevents the deleterious effects of ionizing radiation is required. Numerous synthetic substances have been shown to have clear radioprotective effects. However, most of these have not been translated for use in clinical applications due to their high toxicity and side effects. Many medicinal plants have been shown to exhibit various biological activities, including antioxidant, anti-inflammatory, and anticancer activities. In recent years, new agents obtained from natural products have been investigated by radioprotection researchers, due to their abundance of sources, high efficiency, and low toxicity. In this review, we summarize the mechanisms underlying the radioprotective effects of natural products, including ROS scavenging, promotion of DNA damage repair, anti-inflammatory effects, and the inhibition of cell death signaling pathways. In addition, we systematically review natural products with radioprotective properties, including polyphenols, polysaccharides, alkaloids, and saponins. Specifically, we discuss the polyphenols apigenin, genistein, epigallocatechin gallate, quercetin, resveratrol, and curcumin; the polysaccharides astragalus, schisandra, and Hohenbuehelia serotina; the saponins ginsenosides and acanthopanax senticosus; and the alkaloids matrine, ligustrazine, and β-carboline. However, further optimization through structural modification, improved extraction and purification methods, and clinical trials are needed before clinical translation. With a deeper understanding of the radioprotective mechanisms involved and the development of high-throughput screening methods, natural products could become promising novel radioprotective agents.

Flow Synthesis of Nature-Inspired Mitochondria-Targeted Phenolic Derivatives as Potential Neuroprotective Agents

A series of phenolic derivatives designed to selectively target mitochondria were synthesized under flow conditions starting from natural phenolic acids. The two-step continuous flow protocol, performed in Cyrene, a bioavailable dipolar aprotic solvent, allowed the isolation of the MITO compounds in moderate to good yields. The MITO compounds obtained, as a first step, were tested for their safety by cell viability analysis. The cytocompatible dose, in human neuronal cell line SH-SH5Y, depends on the type of compound and the non-toxic dose is between 3.5 and 125 µM. Among the seven MITO compounds synthesized, two of them have shown interesting performances, being able to protect mitochondria from oxidative insult.

Rosmarinic acid ameliorated cardiac dysfunction and mitochondrial injury in diabetic cardiomyopathy mice via activation of the SIRT1/PGC-1α pathway

Mitochondrial injury plays an essential role in the pathogenesis of diabetic cardiomyopathy (DCM). Previous studies demonstrated that rosmarinic acid (RA) treatment prevented high glucose-induced mitochondrial injury in vitro. However, whether RA can ameliorate cardiac function by preventing mitochondrial injury in DCM is unknown. The SIRT1/PGC-1α pathway has emerged as an important regulator of metabolic control and other mitochondrial functions. The present study was undertaken to determine the effects of RA on mitochondrial and cardiac function in DCM as well as the involvement of the SIRT1/PGC-1α pathway. Our results revealed that RA improved cardiac systolic and diastolic function and prevented mitochondrial injury in DCM, as shown by the reduced blood glucose and lipid levels, increased mitochondrial membrane potential levels, improved adenosine triphosphate synthesis, and inhibited apoptosis (P < 0.05). Moreover, RA upregulated the expression of SIRT1 and PGC-1α in DCM mice and high glucose-treated H9c2 cardiomyocytes (P < 0.05). Further mechanistic studies in H9c2 cardiomyocytes revealed that suppression of SIRT1 by Sh-SIRT1 counteracted the effects of RA on high glucose-induced abnormal metabolism of glucose and lipids, oxidative stress and apoptosis (P < 0.05). Taken together, these data indicate that RA prevented mitochondrial injury and cardiac dysfunction in DCM mice, and the SIRT1/PGC-1α pathway mediated the protective effects of RA.

Rosmarinic Acid Prevents Radiation-Induced Pulmonary Fibrosis Through Attenuation of ROS/MYPT1/TGFβ1 Signaling Via miR-19b-3p

The mechanism of pulmonary fibrosis caused by irradiation remains obscure. Since rosmarinic acid (RA) have anti-oxidant and anti-inflammatory properties, we aimed to evaluate the effect of RA on the X-ray-induced lung injury. Male rats received RA (30, 60, or 120 mg/kg) 7 days before 15 Gy of X-ray irradiation. Here, we showed that RA reduced X-ray-induced the expression of inflammatory related factors, and the level of reactive oxygen species. RA down-regulated the phosphorylation of nuclear factor kappa-B (NF-κB). We found that thoracic tumor patients whose lung regions received radiation showed lower level of microRNA-19b-3p (miR-19b-3p). Furthermore, we provided evidence that miR-19b-3p targets myosin phosphatase target subunit 1 (MYPT1), and RA attenuated RhoA/Rock signaling through upregulating miR-19b-3p, leading to the inhibition of fibrosis. In conclusion, RA may be an effective agent to relieve the pulmonary fibrosis caused by radiotherapy of thoracic tumor.

Gd-Complex of a Rosmarinic Acid Conjugate as an Anti-Inflammatory Theranostic Agent via Reactive Oxygen Species Scavenging

Rosmarinic acid (RosA), an important polyphenol, is known for its antioxidant and anti-inflammatory activities. However, its application in theranostics has been rarely reported. Therefore, a new single-molecule anti-inflammatory theranostic compound containing RosA would be of great interest. A gadolinium (Gd) complex of 1,4,7,10-tetraazacyclododecane-1,4,7-trisacetic acid (DO3A) and RosA (Gd(DO3A-RosA)(H₂O)) was synthesized and examined for use as a single-molecule theranostic agent. Its kinetic stability is comparable to that of clinically used macrocyclic magnetic resonance imaging contrast agents. In addition, its relaxivity is higher than that of structurally analogous Gd-BT-DO3A. This agent was evaluated for inflammatory targeting magnetic resonance contrast and showed strong and prolonged enhancement of imaging in inflamed tissues of mice. The theranostic agent also possesses antioxidant and anti-inflammatory activities, as evidenced by reactive oxygen species scavenging, superoxide dismutase activity, and inflammatory factors. The novel RosA-conjugated Gd complex is a promising theranostic agent for the imaging of inflamed tissues, as well as for the treatment of inflammation and oxidative stress.

Rosmarinic acid inhibits nicotine-induced C-reactive protein generation by inhibiting NLRP3 inflammasome activation in smooth muscle cells

Atherosclerosis is widely known to be a chronic inflammatory disease. C-reactive protein (CRP), an important inflammatory factor, plays an essential role in the pathogenesis of atherosclerosis. Nicotine, the main addictive component of cigarette, has been shown to induce the production of CRP. The aim of this study was to investigate the effect of rosmarinic acid (RA), a polyphenol with antiinflammatory activity, on nicotine-induced elevation of CRP in vascular smooth muscle cells (VSMCs). We found that pretreatment of VSMCs with RA attenuated nicotine-induced expression of CRP in a time- and dose-dependant manner. In addition, RA also inhibited the activation of NLR family pyrin domain containing 3 (NLRP3) inflammasome and reactive oxygen species (ROS) production resulting from nicotine treatment in VSMCs. To confirm these findings in vivo, we constructed a nicotine-induced atherosclerosis rat model. RA did not significantly reduce the serum nicotine level of the rats, whereas it significantly decreased the levels of serum lipids, including concentrations of cholesterol, triglycerides, and low-density lipoprotein cholesterol, and the serum level of CRP. RA also led to diminished nicotine-induced activation of NLRP3 inflammasome and elevation in the CRP level in the aortic tissue of the model rats. The results of this study suggested a protective role of RA in nicotine-induced atherosclerosis by inhibiting the ROS-NLRP3 inflammasome-CRP axial, and RA therefore represented a potential effective therapeutic approach to atherosclerosis, in particular for those who smoke.

Influence of diet and metabolism on hematopoietic stem cells and leukemia development following ionizing radiation exposure

PURPOSE

The review aims to discuss the prominence of dietary and metabolic regulators in maintaining hematopoietic stem cell (HSC) function, long-term self-renewal, and differentiation.

RESULTS

Most adult stem cells are preserved in a quiescent, nonmotile state in vivo which acts as a "protective state" for stem cells to reduce endogenous stress provoked by DNA replication and cellular respiration as well as exogenous environmental stress. The dynamic balance between quiescence, self-renewal and differentiation is critical for supporting a functional blood system throughout life of an organism. Stress-conditions, for example ionizing radiation exposure can trigger the blood forming HSCs to proliferate and migrate through extramedullary tissues to expand the number of HSCs and increase hematopoiesis. In addition, a wealth of investigation validated that deregulation of this balance plays a critical pathogenic role in various different hematopoietic diseases including the leukemia development.

CONCLUSION

The review summarizes the current knowledge on how alterations in dietary and metabolic factors could alter the risk of leukemia development following ionizing radiation exposure by inhibiting or even reversing the leukemic progression. Understanding the influence of diet, metabolism, and epigenetics on radiation-induced leukemogenesis may lead to the development of practical interventions to reduce the risk in exposed populations.