Effects of Greek Honey and Propolis on Oxidative Stress and Biochemical Parameters in Regular Blood Donors

Protective Effects of Propolis Supplementation on Aflatoxin B1-Induced Oxidative Stress, Antioxidant Status, Intestinal Barrier Damage, and Gut Microbiota in Rats

Aflatoxin B1 (AFB1) is common in the diets of humans and animals and often leads to adverse health effects. Propolis, with its strong antioxidant activity, can reduce oxidative stress and modulate gut microbiota composition. However, the underlying mechanism by which propolis alleviates AFB1-induced intestinal barrier damage remains unclear. This study was designed to investigate the protective effects of oral propolis supplementation in AFB1-exposed rats. Thirty-two male Sprague-Dawley rats were divided into four groups: control, AFB1, propolis, and AFB1+propolis. After 4 weeks, serum oxidative stress markers were examined, and gut microbiota was analyzed by 16S rRNA sequencing. Intestinal sections were processed by Hematoxylin & Eosin staining, and the expression level of tight junction proteins was assessed by immunostaining. Propolis supplementation in AFB1-exposed rats tended to decrease oxidative stress, and it also restructured the gut microbiota by preventing a decrease in the relative abundances of Lactobacillus, Roseburia, and Phascolarctobacterium. Propolis restored intestinal permeability impaired by AFB1 by ameliorating intestinal morphological damage and increasing the expression levels of tight junction proteins. Propolis supplementation may contribute to the modulation of gut microbiota by alleviating oxidative stress and improving intestinal barrier damage in AFB1-exposed rats.

Effects of propolis consumption on blood pressure, lipid profile and glycemic parameters in adults: a GRADE-assessed systematic review and dose-response meta-analysis

Propolis, as a by-product of honey production, has shown several beneficial effects on cardiovascular risks in past randomised controlled trials, although the findings are not conclusive. In this review, we intend to evaluate the effects of propolis consumption on cardiovascular risk factors by conducting a meta-analysis. The Web of Science, Medline and Scopus databases were comprehensively searched until September 2023. Eligible studies were identified by screening, and their data were extracted. Weighted mean differences with a 95 % CI for each outcome were estimated using the random-effects model. This meta-analysis revealed that propolis consumption led to a significant decrease in the levels of TAG (weighted mean differences (WMD): -10·44 mg/dl 95 % CI: -16·58, -4·31; P = 0·001), LDL-cholesterol (WMD: -9·31 mg/dl; 95 % CI: -13·50, -5·12 mg; P < 0·001), fasting blood glucose (WMD: -7·30 mg/dl; 95 % CI: -11·58, -3·02; P = 0·001), HbA1c (WMD: -0·32 %; 95 % CI: -0·60, -0·05; P = 0·01), insulin (WMD: -1·36 μU/ml; 95 % CI: -2·36, -0·36; P = 0·007), homeostatic model assessment for insulin resistance (WMD: -0·39; 95 % CI: -0·74, -0·03; P = 0·020) and systolic blood pressure (WMD: -2·24 mmHg 95 % CI: -4·08, -0·39; P = 0·010), compared with the control groups. Furthermore, propolis consumption had a significant increasing effect on HDL-cholesterol levels (WMD: 2·03 mg/dl; 95 % CI: 0·24, 3·83; P = 0·020). In contrast, the consumption of propolis had no significant effect on total cholesterol and diastolic blood pressure levels. This systematic review and dose-response meta-analysis suggested that propolis intake may be effective in cardiometabolic improvement in adults. Further, well-designed studies are required to confirm and elucidate all aspects of these findings.

Oxidative Status and Lipid Metabolism Analytes in Dogs with Mast Cell Tumors: A Preliminary Study

Mast cell tumors (MCTs) are common skin neoplasms in dogs. Prognostic indicators include histologic grade, clinical stage, high Ki-67 index, elevated argyrophilic nucleolus organizer regions (AgNOR) index, c-kit mutations, and recurrence after surgery. Blood serum redox status has been shown to correlate with prognostic factors in canine lymphoma and mammary tumors. This study aimed to assess the correlation between established prognostic factors and serum redox status and lipid metabolism analytes in dogs with MCTs. Dogs with cutaneous (n = 33) or subcutaneous (n = 6) MCTs, without comorbidities, were studied. Staging was evaluated based on cytology of regional lymph nodes and ultrasound-guided liver and spleen aspiration cytology. Histologic grading and immunohistochemical staining for Ki-67 and KIT patterns were performed on excised tumor specimens. Dogs were categorized by Patnaik grading (1-3), Kiupel grading (low/high), metastatic status, Ki-67 positive nuclei per cm2 (>23 or ≤23), and KIT pattern (I, II-III). Paraoxonase-1, Butyrylcholinesterase, Cupric Reducing Antioxidant Capacity (CUPRAC), Diacron Reactive Oxygen Metabolites (d-ROMs), and oxy-adsorbent levels were measured before any therapeutic intervention. ANOVA and independent t-tests were used to detect differences in the mean values among groups. Paraoxonase-1 activity was significantly lower in Patnaik grade 3 (p = 0.003) and Kiupel high-grade (p = 0.022) MCTs. No significant differences were found in CUPRAC, d-ROMs, or oxy-adsorbent levels across different prognostic groups. This study found a significant correlation between histologic grading and Paraoxonase-1 activity, suggesting a potential role of Paraoxonase-1 as a prognostic biomarker in canine MCTs.

In Vivo Anti-Alzheimer and Antioxidant Properties of Avocado (Persea americana Mill.) Honey from Southern Spain

There is growing evidence that Alzheimer's disease (AD) can be prevented by reducing risk factors involved in its pathophysiology. Food-derived bioactive molecules can help in the prevention and reduction of the progression of AD. Honey, a good source of antioxidants and bioactive molecules, has been tied to many health benefits, including those from neurological origin. Monofloral avocado honey (AH) has recently been characterized but its biomedical properties are still unknown. The aim of this study is to further its characterization, focusing on the phenolic profile. Moreover, its antioxidant capacity was assayed both in vitro and in vivo. Finally, a deep analysis on the pathophysiological features of AD such as oxidative stress, amyloid-β aggregation, and protein-tau-induced neurotoxicity were evaluated by using the experimental model C. elegans. AH exerted a high antioxidant capacity in vitro and in vivo. No toxicity was found in C. elegans at the dosages used. AH prevented ROS accumulation under AAPH-induced oxidative stress. Additionally, AH exerted a great anti-amyloidogenic capacity, which is relevant from the point of view of AD prevention. AH exacerbated the locomotive impairment in a C. elegans model of tauopathy, although the real contribution of AH remains unclear. The mechanisms under the observed effects might be attributed to an upregulation of daf-16 as well as to a strong ROS scavenging activity. These results increase the interest to study the biomedical applications of AH; however, more research is needed to deepen the mechanisms under the observed effects.

A Preliminary Study about the Role of Reactive Oxygen Species and Inflammatory Process after COVID-19 Vaccination and COVID-19 Disease

During the last couple of critical years, worldwide, there have been more than 550 million confirmed cases of COVID-19, including more than 6 million deaths (reported by the WHO); with respect to these cases, several vaccines, mainly mRNA vaccines, seem to prevent and protect from SARS-CoV-2 infection. We hypothesize that oxidative stress is one of the key factors playing an important role in both the generation and development of various kinds of disease, as well as antibody generation, as many biological paths can generate reactive oxygen species (ROS), and cellular activities can be modulated when ROS/antioxidant balance is interrupted. A pilot study was conducted in two stages during the COVID-19 pandemic in 2021 involving 222 participants between the ages of 26 and 66 years. ROS levels were measured before an after vaccination in the blood samples of 20 individuals who were vaccinated with two doses of mRNA vaccine, and an increase in ROS levels was observed after the first dose, with no modifications observed until the day before the second vaccination dose. A statistically significant difference (p < 0.001) was observed between time points 3 and 4 (before and after second dose), when participants were vaccinated for the second time, and ROS levels decreased from 21,758 to 17,580 a.u. In the second stage, blood was collected from 28 participants 45 days after COVID-19 infection (Group A), from 131 participants 45 days after receiving two doses of mRNA vaccine against COVID-19 (Group B), and from 13 healthy individuals as a control group (Group C). Additionally, antibodies levels were measured in all groups to investigate a possible correlation with ROS levels. A strong negative correlation was found between free radicals and disease antibodies in Group A (r = −0.45, p = 0.001), especially in the male subgroup (r = −0.88, p = 0.001), as well as in the female subgroup (r = −0.24, p < 0.001). Furthermore, no significant correlation (only a negative trend) was found with antibodies derived from vaccination in Group B (r = −0.01), and a negative trend was observed in the female subgroup, whereas a positive trend was observed in the male subgroup.