E-Stilbenes: General Chemical and Biological Aspects, Potential Pharmacological Activity Based on the Nrf2 Pathway

Stilbenes are phytoalexins, and their biosynthesis can occur through a natural route (shikimate precursor) or an alternative route (in microorganism cultures). The latter is a metabolic engineering strategy to enhance production due to stilbenes recognized pharmacological and medicinal potential. It is believed that in the human body, these potential activities can be modulated by the regulation of the nuclear factor erythroid derived 2 (Nrf2), which increases the expression of antioxidant enzymes. Given this, our review aims to critically analyze evidence regarding E-stilbenes in human metabolism and the Nrf2 activation pathway, with an emphasis on inflammatory and oxidative stress aspects related to the pathophysiology of chronic and metabolic diseases. In this comprehensive literature review, it can be observed that despite the broad number of stilbenes, those most frequently explored in clinical trials and preclinical studies (in vitro and in vivo) were resveratrol, piceatannol, pterostilbene, polydatin, stilbestrol, and pinosylvin. In some cases, depending on the dose/concentration and chemical nature of the stilbene, it was possible to identify activation of the Nrf2 pathway. Furthermore, the use of some experimental models presented a challenge in comparing results. In view of the above, it can be suggested that E-stilbenes have a relationship with the Nrf2 pathway, whether directly or indirectly, through different biological pathways, and in different diseases or conditions that are mainly related to inflammation and oxidative stress.

The role played by oral antioxidant therapies in preventing and treating preeclampsia: An updated meta-analysis

AIMS

Performing an up-to-date meta-analysis of oral antioxidant therapies and determining whether they are effective in preventing and/or treating preeclampsia (PE).

DATA SYNTHESIS

Search was performed in PubMed, CENTRAL, LILACS, Web of Science, and ScienceDirect databases. The risk of bias was assessed based on using Cochrane Collaboration's tool. A funnel plot was created, and Egger's and Peter's test was carried out to assess publication bias in the primary outcome of prevention studies. The overall quality of the evidence was assessed based on using the Grading of Recommendations Assessment, Developing and Evaluation (GRADE) tool; a formal protocol was published in the PROSPERO database (registration number CRD42022348992). In total, 32 studies were taken into consideration for analysis purposes; 22 studies focused on investigating preeclampsia prevention methods, whereas 10 focused on its treatment. Significant results associated with the incidence of preeclampsia were observed in prevention studies comprising 11,198 subjects and 1106 events in the control groups, as well as 11,156 subjects and 1048 events in the intervention groups (relative risk [RR]: 0.86, 95% confidence interval [CI]: [0.75, 0.99], P = 0.03; I² = 44%, P = 0.02). With respect to outcomes associated with treatment studies, only intrauterine growth restriction has shown significant effects. Egger's and Peter's test has evidenced publication bias. Six outcomes in prevention studies were classified as having low quality and two as having moderate quality, whereas all three outcomes assessed in treatment studies were classified as having moderate quality.

CONCLUSIONS

Antioxidant therapy has shown beneficial effects on preeclampsia prevention; moreover, the positive impact of this therapy on intrauterine growth restriction was observed during the disease treatment.

Hyperferritinemia worsens the perinatal outcomes of conceptions of pregnancies with preeclampsia

BACKGROUND AND AIMS

To analyze the prevalence of hyperferritinemia in pregnant women with preeclampsia and its association with adverse perinatal outcomes.

METHODS

A cross-sectional study carried out in 2017 with a convenience sample of pregnant women with preeclampsia attended at a high-risk maternity hospital in Alagoas, Brazil. Socioeconomic, lifestyle, clinical and biochemical data were collected through a structured questionnaire. Type of delivery, gestational age, weight and length at birth, and Apgar score were analyzed as outcome variables. Women were dichotomized according to the serum ferritin level (150 ng/mL). Poisson regression models were used to analyze the effect of hyperferritinemia on the outcome variables. Estimates were presented as prevalence ratio with 95% confidence intervals (PR [95% CI]).

RESULTS

Based on the Fisher's exact statistical teste and in the proportions of the neonatal outcome (birth weight), with a statistical significance of 5%, the statistical power of the sample studied was 83%. Two hundred six pregnant women with preeclampsia were recruited, which 8.74% presented hyperferritinemia. Except for ferritin level, there were no differences in C-reactive protein (CRP), hemoglobin, Glutamate Oxaloacetate Transaminase (GOT) and Pyruvic Glutamic Transaminase (PGT) levels between women with or without hyperferritinemia. After adjusting for potential confounders, hyperferritinemia was associated with low birth weight (2.19 [2.13-3.89 95%CI]), low birth length (7.76 [2.52-23.8 95% CI]) and being born small for gestational age (3.14 [1.36-7.28 95% CI]).

CONCLUSION

In the presence of hyperferritinemia, preeclampsia patients were associated with a higher rate of unfavorable neonatal outcomes.

Oral antioxidant therapy for prevention and treatment of preeclampsia: Meta-analysis of randomized controlled trials

AIMS

To determine whether oral antioxidant therapies, of various types and doses, are able to prevent or treat women with preeclampsia.

DATA SYNTHESIS

The following databases were searched: MEDLINE, CENTRAL, LILACS, and Web of Science. Inclusion criteria were: a) randomized clinical trials; b) oral antioxidant supplementation; c) study in pregnant women; d) control group, treated or not with placebo. Papers were excluded if they evaluated antioxidant nutrient supplementation associated with other non-antioxidant therapies. Data were extracted and the risk of bias of each study was assessed. Heterogeneity was analyzed using the Cochran Q test, and I2 statistics and pre-specified sensitivity analyses were performed. Meta-analyses were conducted on prevention and treatment studies, separately. The primary outcome was the incidence of preeclampsia in prevention trials, and of perinatal death in treatment trials. Twenty-nine studies were included in the analysis, 19 for prevention and 10 for treatment. The antioxidants used in these studies were vitamins C and E, selenium, l-arginine, allicin, lycopene and coenzyme Q10, none of which showed beneficial effects on the prevention of preeclampsia (RR: 0.89, CI 95%: [0.79-1.02], P = 0.09; I² = 39%, P = 0.04) and other outcomes. The antioxidants used in the treatment studies were vitamins C and E, N-acetylcysteine, l-arginine, and resveratrol. A beneficial effect was found in intrauterine growth restriction.

CONCLUSIONS

Antioxidant therapy had no effects in the prevention of preeclampsia but did show beneficial effects in intrauterine growth restriction, when used in the treatment of this condition.

Bacterial leakage in root canals filled with conventional and MTA-based sealers

AIM

To evaluate bacterial leakage after filling root canals with several endodontic sealers, including MTA-based materials.

METHODOLOGY

One hundred and thirty single-rooted extracted human teeth were randomly divided into experimental groups (n = 15) and two control groups (n = 5). Six root canal sealers were namely: AH Plus (AHP), Sealer 26 (S26), Epiphany SE (ESE), Sealapex (SEL), Active GP (AGP), Endofill (EDF), and two MTA-based sealers were namely: Endo CPM Sealer (CPM) and MTA-based sealer (MTAS, MTA Sealer). Teeth in the control groups were either filled with no sealer or made completely impermeable. Root canals were prepared and filled with either gutta-percha and one of the sealers or with Resilon and Epiphany SE. Teeth were sterilized by ethylene oxide prior to the bacterial leakage experiments using Enterococcus faecalis. Leakage was evaluated every 24 h for 16 weeks. Data were analysed by the Kaplan-Meier, Kruskal-Wallis and Dunn tests at 5% significance.

RESULTS

Control groups had either immediate leakage or no leakage. During 120 days, significantly more leaking samples were detected for AGP, CPM and MTAS (P < 0.05). The best sealing ability was observed for AH Plus and Sealapex (P < 0.05).

CONCLUSIONS

All sealers evaluated allowed bacterial leakage. The MTA-based sealers had the most leakage.

Stabilizing oils from smoked pink salmon (Oncorhynchus gorbuscha)

Smoking of meats and fish is one of the earliest preservation technologies developed by humans. In this study, the smoking process was evaluated as a method for reducing oxidation of pink salmon (Oncorhynchus gorbuscha) oils and also maintaining the quality of oil in aged fish prior to oil extraction. Salmon heads that were subjected to high temperatures (95 degrees C) during smoking unexpectedly produced oils with fewer products of oxidation than their unprocessed counterparts, as measured by peroxide value (PV), thiobarbituric acid reactive substances (TBARS), and fatty acids (FA). Higher temperatures and longer smoking times resulted in correspondingly lower quantities of oxidative products in the oils. Fatty acid methyl ester (FAME) analysis of smoke-processed oils confirmed that polyunsaturated fatty acids (PUFA) were not being destroyed. Smoke-processing also imparted antioxidant potential to the extracted oils. Even when antioxidants, such as ethoxyquin or butylated hydroxytoluene, were added to raw oils, the smoke-processed oils still maintained lower levels of oxidation after 14 d of storage. However, decreased antioxidant capacity of smoke-processed oils was noted when they were heated above 75 degrees C. Vitamin studies supported the antioxidant results, with smoke-processed oils displaying higher levels of alpha-tocopherol than raw oils. Results suggest that smoking salmon prior to oil extraction can protect valuable PUFA-rich oils from oxidation. Improved preservation methods for marine oils may extend their usefulness when added as a supplement to enhance levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in foods.

Effect of milk protein concentrate on lipid oxidation and formation of fishy volatiles in herring mince (Clupea harengus) during frozen storage

The effect of milk protein concentrate (MPC) at 0, 2, 4, and 6% on lipid oxidation and volatile formation in frozen stored herring mince (-18 degrees C) was evaluated by analyzing samples at 0, 2, and 4 months for fatty acid composition, volatiles, and thiobarbituric acid reactive substances (TBARS). Sensory evaluation was also conducted to assess the intensity of fishy odor, and the volatiles were analyzed using static headspace gas chromatography-mass spectrometry (SHGC-MS). The addition of 4 and 6% MPC to herring mince resulted in a 33% and 50% reduction of TBARS, respectively, at month 4 and lessened the intensity of fishy odor throughout storage. However, MPC did not protect fatty acids from enzymatic degradation unless it was added immediately after mincing. Volatile analysis using SHGC-MS showed that 4% MPC was able to reduce headspace volatiles associated with fishy odor. MPC is most effective for reducing 4-heptenal, 3-methyl-1-butanol, 2-hexenal, and 1-penten-3-ol, which are known to be potent odorants associated with lipid oxidation.