In Vitro Genotoxicity Assessment of a Novel Resveratrol Analogue, HS-1793

Novel and safe debranched starch-zinc complexes with endoconcave structure as zinc supplements

Zinc deficiency is a serious risk to human health and growth, especially in children. The development of zinc supplements can effectively reduce this harm. Here, a series of debranched starch‑zinc complexes (DS-Zn) were prepared, whose zinc complexation was inversely proportional to the amylopectin content in the debranched starch (DS). The physicochemical properties of DS-Zn were characterized using the conductivity, XRD, iodine staining and thermogravimetry. Combined with XPS, solid-state 13C NMR and IR, it was elucidated that the structure of DS-Zn is endoconcave structure with 2-O and 3-O of DS on the inner side and 6-O of DS on the outer side, where zinc is located. The DS-Zn exhibits good biosafety including blood, cellular and mutagenicity. In vitro simulations of digestion and zinc-deficient cellular models showed that DS-Zn was more tolerant to the gastrointestinal environment and more effective in zinc supplementation (increased by 33 %) than inorganic zinc supplements. Utilizing the compressibility of starch, DS-Zn was prepared as a more palatable oral cartoon tablet for children. This study will provide important support to advance the development and application of novel starch-based zinc nutritional supplements.

Comparison of the radioprotective effects of the liposomal forms of five natural radioprotectants in alleviating the adverse effects of ionising irradiation on human lymphocytes and skin cells in radiotherapy

This study aims to evaluate the radioprotective effects of liposomes encapsulating curcumin (Lip-CUR), silibinin (Lip-SIL), α-tocopherol (Lip-TOC), quercetin (Lip-QUE) and resveratrol (Lip-RES) in alleviating the adverse effects of ionising irradiation on human lymphoctyes and skin cells in radiotherapy. Liposomes encapsulating the above natural radioprotectants (Lip-NRPs) were prepared by the film hydration method combined with sonication. Their radioprotective effects for the cells against X-irradiation was evaluated using trypan-blue assay and γ-H2AX assay. All prepared Lip-NRPs had a mean diameter less than 240 nm, polydispersity index less than 0.32, and zeta potential more than -23 mV. Among them, the radioprotective effect of Lip-RES was lowest, while that of Lip-QUE was highest. Lip-SIL also exhibited a high radioprotective effect despite its low DPPH-radical scavenging activity (12.9%). The radioprotective effects of Lip-NRPs do not solely depend on the free radical scavenging activity of NRPs but also on their ability to activate cellular mechanisms.

Dicentric chromosome assay using a deep learning-based automated system

The dicentric chromosome assay is the "gold standard" in biodosimetry for estimating radiation exposure. However, its large-scale deployment is limited owing to its time-consuming nature and requirement for expert reviewers. Therefore, a recently developed automated system was evaluated for the dicentric chromosome assay. A previously constructed deep learning-based automatic dose-estimation system (DLADES) was used to construct dose curves and calculate estimated doses. Blood samples from two donors were exposed to cobalt-60 gamma rays (0-4 Gy, 0.8 Gy/min). The DLADES efficiently identified monocentric and dicentric chromosomes but showed impaired recognition of complete cells with 46 chromosomes. We estimated the chromosome number of each "Accepted" sample in the DLADES and sorted similar-quality images by removing outliers using the 1.5IQR method. Eleven of the 12 data points followed Poisson distribution. Blind samples were prepared for each dose to verify the accuracy of the estimated dose generated by the curve. The estimated dose was calculated using Merkle's method. The actual dose for each sample was within the 95% confidence limits of the estimated dose. Sorting similar-quality images using chromosome numbers is crucial for the automated dicentric chromosome assay. We successfully constructed a dose-response curve and determined the estimated dose using the DLADES.

HS‑1793 inhibits cell proliferation in lung cancer by interfering with the interaction between p53 and MDM2

The transcription factor or tumor suppressor protein p53 regulates numerous cellular functions, including cell proliferation, invasion, migration, senescence and apoptosis, in various types of cancer. HS-1793 is an analog of resveratrol, which exhibits anti-cancer effects on various types of cancer, including breast, prostate, colon and renal cancer, and multiple myeloma. However, to the best of our knowledge, the role of HS-1793 in lung cancer remains to be examined. The present study aimed to investigate the anti-cancer effect of HS-1793 on lung cancer and to determine its association with p53. The results revealed that HS-1793 reduced cell proliferation in lung cancer and increased p53 stability, thereby elevating the expression levels of the target genes p21 and mouse double minute 2 homolog (MDM2). When the levels of MDM2, a negative regulator of p53, are increased under normal conditions, MDM2 binds and degrades p53; however, HS-1793 inhibited this binding, confirming that p53 protein stability was increased. In conclusion, the findings of the present study provide new evidence that HS-1793 may inhibit lung cancer proliferation by disrupting the p53-MDM2 interaction.

Chemical Characterization and In Vivo Toxicological Safety Evaluation of Emu Oil

In this study, the physicochemical properties, fatty acid composition, antioxidant activities, and in vitro as well as in vivo toxicological safety of emu oil were investigated. Emu oil was shown to have a low acid and peroxide value, low amounts of carotenoid and phenolic compounds, and high doses of oleic acid and linoleic acid. Furthermore, in a bacterial reverse mutation assay, emu oil demonstrated no change in the amount of revertant colonies for all strains. In a chromosomal assay, no aberrations occurred in any of the emu oil treatment groups (1.25, 2.5, and 5 μg/mL). In the bone marrow micronucleus test, emu oil up to 20 mL/kg showed no significant increase in the incidence of micronucleated polychromatic erythrocytes. Moreover, emu oil up to 19.3 mg/kg body weight did not affect body weight in an acute oral toxicity study. These results are crucial for the adoption of emu oil as an alternative source of edible oil.

Resveratrol analogue, HS-1793, inhibits inflammatory mediator release from macrophages by interfering with the TLR4 mediated NF-κB activation

Resveratrol is known to have anti-inflammatory properties. However, high-dose resveratrol is required for optimal anti-inflammatory effects. HS-1793 is a derivative designed to be metabolically stable and more effective than resveratrol. We tested whether HS-1793 also has anti-inflammatory activity. HS-1793 effectively inhibited the mRNA and protein expression of lipopolysaccharide (LPS)-induced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in macrophages. Therefore, the production of nitric oxide (NO) and prostaglandin E₂ (PGE₂) was significantly attenuated. In addition, HS-1793 completely suppressed the production of inflammatory cytokines enhanced by LPS treatment along with a decrease in Toll-like receptor 4 (TLR4) expression. At the same time, the expression of myeloid differentiation factor 88 (MyD88), IL-1 receptor-associated kinase 1 (IRAK1), and TNF receptor-associated factor 6 (TRAF6) signaling molecules and the nuclear translocation of nuclear factor kappa B (NF-κB)/p65 were also downregulated. We conclusively suggest that HS-1793 also exhibits anti-inflammatory properties by effectively inhibiting TLR4-mediated NF-κB activation.

In vitro assessment of the mutagenic and genotoxic potential of a pure stilbene extract

Stilbenes are secondary metabolites of great interest produced by many plant species due to their important bioactive properties. These phytochemicals have become of increasing interest in the wine industry as a natural alternative to sulphur dioxide, which has been associated with human health risks. However, there is still little toxicological information on stilbenes and the results thus far have been contradictory. Considering the key role of genotoxicity in risk assessment and the need to offer safe products in the market, the aim of this study was to assess the mutagenic and genotoxic potential of a stilbene extract with 99% purity (ST-99 extract). A complete series of different in vitro tests (Ames test, micronucleus (MN) test, and standard and enzyme-modified comet assays) was performed before its use as a preservative in wines. The ST-99 extract induces a significant increase of binucleated cells with micronuclei only in presence of the metabolic fraction S9 at the highest concentration assayed. Neither the Ames test nor the comet assay revealed the extract's genotoxic potential. Further studies are necessary, including in vivo assays, to ensure consumer safety before it can be used.

Genotoxicity of Water Extract from Bark-Removed Rhus verniciflua Stokes

Rhus verniciflua Stokes (RVS) has been traditionally used as an herbal remedy to support the digestive functions in traditional Korean medicine. Additionally, the pharmacological effects of RVS, including antioxidative, antimicrobial and anticancer activities, have been well-reported. The genotoxicity of RVS, however, is elusive; thus, we evaluated the genotoxicity of RVS without bark (RVX) for safe application as a resource of functional food or a medical drug. To evaluate the genotoxicity of RVX, we used a bacterial reverse mutation test, chromosomal aberration test and comet assay, according to the “Organization for Economic Co-operation and Development” (OECD) guidelines. Briefly, for the reverse mutation test, samples (5000, 1667, 556, 185, 62 and 0 μg/plate of RVX or the positive control) were treated with a precultured strain (TA98, TA100, TA1535, TA1537 or WP2µvrA) with or without the S9 mix, in which RVX partially induced a reverse mutation in four bacterial strains. From the chromosomal aberration test and comet assay, the RVX samples (556, 185, 62, 20 and 0 μg/mL of RVX or the positive control) were treated in a Chinese hamster ovary cell line (CHO-K1 cells) in the conditions of the S9 mix absent or S9 mix present and in Chang liver cells and C2C12 myoblasts, respectively. No chromosomal aberrations in CHO-K1 or DNA damage in Chang liver cells and C2C12 myoblasts was observed. In conclusion, our results suggest the non-genotoxicity of RVX, which would be helpful as a reference for the safe application of bark-removed Rhus verniciflua Stokes as functional raw materials in the food, cosmetics or pharmaceutical fields.

Optimization of a pre-metabolization procedure using rat liver S9 and cell-extracted S9 in the Ames fluctuation test

Many environmental pollutants pose a toxicological hazard only after metabolic activation. In vitro bioassays using cell lines or bacteria have often no or reduced metabolic activity, which impedes their use in the risk assessment. To improve the predictive capability of in vitro assays, external metabolization systems like the liver S9 fraction are frequently combined with in vitro toxicity assays. While it is typical for S9 fractions that samples and testing systems are combined in the same exposure system, we propose to separate the metabolism step and toxicity measurement. This allows for a modular combination of metabolic activation by enzymes isolated from rat liver (S9) or a biotechnological alternative (ewoS9^R) with in vitro bioassays that lack metabolic capacity. Benzo(a)pyrene and 2-aminoanthracene were used as model compounds to optimize the conditions for the S9 metabolic degradation/activation step. The Ames assay with Salmonella typhimurium strains TA98 and TA100 was applied to validate the set-up of decoupling the S9 activation/metabolism from the bioassay system. S9 protein concentration of 0.25 mg_protein/mL, a supplement of 0.13 mM NADPH and a pre-incubation time of 100 min are recommended for activation of samples prior to dosing them to in vitro bioassays using the regular dosing protocols of the respective bioassay. EwoS9^R performed equally well as Moltox S9, which is a step forward in developing true animal-free in vitro bioassays. After pre-incubation with S9 fraction, chemicals induced bacteria revertants in both the TA98 and the TA100 assay as efficiently as the standard Ames assay. The pre-incubation of chemicals with S9 fraction could serve for a wide range of cellular in vitro assays to efficiently combine activation and toxicity measurement, which may greatly facilitate the application of these assays for chemical hazard assessment and monitoring of environmental samples.

Subacute Oral Toxicity and Bacterial Mutagenicity Study of a Mixture of Korean Red Ginseng (Panax ginseng C.A. Meyer) and Salvia plebeia R. Br. Extracts

As various populations are rapidly becoming an aging society worldwide and interest in health issues has increased, demand for functional foods including herbal products has increased markedly to maintain a healthy state which has led to safety issues about their intake as an inevitable result. The objective of this study was to identify the safety profile of a Korean red ginseng and Salvia plebeia R. Br. extract mixture (KGC-03-PS) which is a valuable ingredient that can be used as a functional food. In the present study, the subacute oral toxicity and bacterial reverse mutagenicity of KGC-03-PS were evaluated. Sprague Dawley rats were administered KGC-03-PS orally for 28 days by gavage. Daily KGC-03-PS dose concentrations were 0, 500, 1,000, or 2,000 mg/kg body weight (bw) per day. Bacterial reverse mutation test with KGC-03-PS dose levels ranging from 312.5 to 5,000 μg/plate was carried out by OECD test guideline No. 471. Five bacterial strains (Salmonella typhimurium TA98, TA100, TA1535, TA1537, and Escherichia coli WP2) were tested in the presence or absence of metabolic activation by plate incorporation method. There were no toxicological effects related with test substance in the clinical evaluation of subacute oral toxicity test including clinical signs, body weight, and food consumption. Moreover, no toxicological changes related to KGC-03-PS were observed in the hematological and serum biochemical characteristics as well as in the pathological examinations, which included organ weight measurements and in the gross- or histopathological findings. KGC-03-PS did not induce an increase in the number of revertant colonies in all bacterial strains of the bacterial reverse mutation test. The no-observed-adverse-effect level of KGC-03-PS is greater than 2,000 mg/kg bw/day, and KGC-03-PS did not induce genotoxicity related to bacterial reverse mutations under the conditions used in this study.

Subacute oral toxicity and bacterial mutagenicity study of Korean Red Ginseng oil

Background

Red ginseng oil (RGO) is produced by supercritical CO₂ extraction of secondary products derived from Korean Red Ginseng extract. As the use of RGO has increased, product safety concerns have become more important.

Methods

In the present study, the subacute oral toxicity and bacterial reverse mutagenicity of RGO were evaluated. Sprague–Dawley rats were orally administered with RGO for 28 d by gavage. Daily RGO dose concentrations were 0 mg/kg body weight (bw), 500 mg/kg bw, 1,000 mg/kg bw, or 2,000 mg/kg bw per day. Bacterial reverse mutation tests included five bacterial strains (Escherichia coli WP2 and Salmonella typhimurium TA98, TA100, TA1535, and TA1537), which were used in the presence or absence of metabolic activation. The plated incorporation method for mutation test was used with RGO concentrations ranging from 312.5 μg to 5,000 μg per plate.

Results

The subacute oral toxicity test results did not reveal any marked changes in clinical characteristics. There were no toxicological changes related to RGO administration in hematological and serum biochemical characteristics in either control or treatment animals. Furthermore, no gross or histopathological changes related to RGO treatment were observed. The bacterial reverse mutation test results did not reveal, at any RGO concentration level and in all bacterial strains, any increase in the number of revertant colonies in the RGO treatment group compared to that in the negative control group.

Conclusion

The no-observed-adverse-effect level of RGO is greater than 2,000 mg/kg bw and RGO did not induce genotoxicity related to bacterial reverse mutations.

Morin exerts cytoprotective effects against oxidative stress in C2C12 myoblasts via the upregulation of Nrf2-dependent HO-1 expression and the activation of the ERK pathway

In the present study, we investigated the cytoprotective efficacy of morin, a natural flavonoid, against oxidative stress and elucidated the underlying mechanisms in C2C12 myoblasts. Our results indicated that morin treatment prior to hydrogen peroxide (H2O2) exposure significantly increased cell viability and prevented the generation of reactive oxygen species. H2O2-induced comet-like DNA formation and γH2AX phosphorylation were also markedly suppressed by morin with a parallel inhibition of apoptosis in C2C12 myoblasts, suggesting that morin prevented H2O2-induced cellular DNA damage. Furthermore, morin markedly enhanced the expression of heme oxygenase-1 (HO-1) associated with the induction and phosphorylation of nuclear factor-erythroid 2-related factor 2 (Nrf2) and the inhibition of Kelch-like ECH-associated protein 1 (Keap1) expression. Notably, these events were eliminated by transient transfection with Nrf2‑specific small interfering RNA. Additional experiments demonstrated that the activation of the Nrf2/HO-1 pathway by morin was mediated by the extracellular signal‑regulated kinase (ERK) signaling cascade. This phenomenon was confirmed with suppressed Nrf2 phosphorylation and consequently diminished HO-1 expression in cells treated with a pharmacological inhibitor of ERK. Collectively, these results demonstrated that morin augments the cellular antioxidant defense capacity through the activation of Nrf2/HO‑1 signaling, which involves the activation of the ERK pathway, thereby protecting C2C12 myoblasts from H2O2-induced oxidative cytotoxicity.

Resveratrol: How Much Wine Do You Have to Drink to Stay Healthy?

Resveratrol is a naturally occurring stilbene endowed with multiple health-promoting effects. It is produced by certain plants including several dietary sources such as grapes, apples, raspberries, blueberries, plums, peanuts, and products derived therefrom (e.g., wine). Resveratrol can be isolated and purified from these biological sources or synthesized in a few steps with an overall high yield. This compound and its glucoside, the trans-polydatin piceid, have received worldwide attention for their beneficial effects on cardiovascular, inflammatory, neurodegenerative, metabolic, and age-related diseases. These health-promoting effects are particularly attractive given the prevalence of resveratrol-based nutraceuticals and the paradoxical epidemiologic observation that wine consumption is inversely correlated to the incidence of coronary heart disease. However, the notion of resveratrol as a "magic bullet" was recently challenged by clinical trials showing that this polyphenol does not have a substantial influence on health status and mortality risk. In the present review, we discuss the proposed therapeutic attributes and the mode of molecular actions of resveratrol. We also cover recent pharmacologic efforts to improve the poor bioavailability of resveratrol and influence the transition between body systems in humans. We conclude with some thoughts about future research directions that might be meaningful for resolving controversies surrounding resveratrol.

Anti-inflammatory effects of Hwang-Heuk-San, a traditional Korean herbal formulation, on lipopolysaccharide-stimulated murine macrophages

BACKGROUND

Hwang-Heuk-San (HHS), a Korean traditional herbal formula comprising four medicinal herbs, has been used to treat patients with inflammation syndromes and digestive tract cancer for hundreds of years; however, its anti-inflammatory potential is poorly understood. The aim of the present study was to investigate the anti-inflammatory effects of HHS using a lipopolysaccharide (LPS)-activated RAW 264.7 macrophage model.

METHODS

The inhibitory effects of HHS on LPS-induced nitric oxide (NO), interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) production were examined using Griess reagent and enzyme-linked immunosorbent assay (ELISA) detection kits. The effects of HHS on the expression of inducible NO synthase (iNOS), IL-1β and TNF-α, their upstream signal proteins, including nuclear factor κB (NF-κB), mitogen-activated protein kinases (MAPKs), and activator protein (AP-1), were also investigated.

RESULTS

A noncytotoxic concentration of HHS significantly reduced the production of NO, IL-1β and TNF-α in LPS-stimulated RAW 264.7 cells, which was correlated with reduced expression of iNOS, IL-1β and TNF-α at the mRNA and protein levels. HHS efficiently blocked the phosphorylation of MAPKs, especially that of extracellular signal-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK) but not that of the p38 MAPK. The reduced production of inflammatory molecules by HHS was followed by decreased activity of NF-κB and AP-1.

CONCLUSIONS

These results suggest that HHS may offer therapeutic potential for treating inflammatory diseases accompanied by macrophage activation.