The effect of propolis supplementation in improving antioxidant status: A systematic review and meta-analysis of controlled clinical trials

Nature's Remedies: Exploring the Potential of Propolis to Alleviate Non-Motor Manifestations of Parkinson's Disease

Parkinson's disease (PD) is a complex neurodegenerative disorder with debilitating non-motor symptoms, including gastrointestinal dysfunction, cardiovascular abnormalities, mood and anxiety disorders, cognitive decline, sleep disturbances, respiratory dysfunction, and pain. Despite their significant impact on quality of life, these symptoms are often inadequately addressed. Propolis is a natural bee-derived product, rich in bioactive compounds with anti-inflammatory, antioxidant, immunomodulatory, and neuroprotective properties, which holds potential in PD due to its multitarget and multipathway actions, addressing various underlying mechanisms of non-motor symptom diseases. Preclinical and clinical studies suggest that propolis may influence key pathological mechanisms in PD's non-motor symptoms. Evidence points to its potential benefits in improving cognition, mood disorders, gastrointestinal health, and alleviating cardiovascular and sleep-related issues. Although research on propolis in non-motor symptoms of PD remains scarce, findings from related conditions suggest its ability to influence mechanisms associated with these symptoms. This review underscores the underexplored therapeutic potential of propolis in non-motor symptoms of PD, drawing on existing evidence and advocating for further research to fully assess its role in addressing these symptoms and improving patient outcomes.

Open, Randomised, Controlled Study to Evaluate the Role of a Dietary Supplement Containing Pelargonium sidoides Extract, Honey, Propolis, and Zinc as Adjuvant Treatment in Children with Acute Tonsillopharyngitis

BACKGROUND/OBJECTIVES

A common reason for a pediatrician's visit is acute tonsillopharyngitis (ATR), which is usually caused by viruses. A dietary supplement comprising Pelargonium sidoides extract, honey, propolis, and zinc was proposed as an effective adjuvant for the management of respiratory tract infections. The study aimed to determine the efficacy of this dietary supplement in conjunction with standard of care (SoC) compared to SoC alone, in a pediatric population affected by ATR.

METHODS

This open randomized study (registered on ClinicalTrials.gov: NCT04899401) involved three Romanian sites specialized in pediatric care. The primary endpoints were changes in Tonsillitis Severity Score and the number of patients failing to respond (evaluating the use of ibuprofen or high-dose paracetamol as a rescue medication). One hundred and thirty children, distributed into two groups, were enrolled and treated for six days.

RESULTS

The results showed an overall better performance in terms of efficacy of dietary supplement + SoC, compared to SoC alone, with lower total Tonsillitis Severity Score ratings on day 6 (p = 0.002) and lower sub-scores related to erythema and throat pain on day 6. No adverse events were reported. Investigators found compliance to be optimal.

CONCLUSIONS

The administration of the dietary supplement + SoC in pediatric patients with ATR was found to be safe and superior to the administration of SoC alone in terms of efficacy. The results confirmed that the tested dietary supplement is an optimum effective adjuvant in the treatment of respiratory tract infections and is suitable for the daily clinical practice of pediatricians.

The impact of propolis supplementation on inflammatory biomarkers: A meta-analysis and systematic review of randomized controlled clinical trials

Recent interventional investigations suggest the beneficial impact of propolis supplementation on inflammatory biomarkers; however, the results have not been summarized in a comprehensive meta-analysis. We conducted this meta-analysis to summarize all available data and provide clear evidence for whether propolis supplementation affects inflammatory biomarkers. This systematic review with meta-analysis was performed by searching databases (PubMed/Medline, Web of Science, Scopus, and Embase) until February 2024. It included randomized clinical trials (RCTs) assessing the effects of propolis supplementation on inflammatory biomarkers in adults. This review included 20 RCTs with a total of 1139 participants. The propolis supplementation significantly reduced IL-6 (WMD = -2.48; 95 % CI: -4.62, -0.34; P = 0.023) and TNF-α (WMD = -0.86; 95 % CI: -1.45, -0.26; P = 0.005) compared with control groups. Although the CRP concentration was not reduced (WMD = 0.01; 95 % CI: -0.03, 0.05, P = 0.646), a significant reduction in CRP levels was revealed in supplementation durations ≥ 10 weeks. These results suggest that propolis has a beneficial effect on TNF-α and IL-6 levels and may be an effective adjunctive therapy for diseases where inflammation is a key factor in the etiology. Due to the limited number of studies, clinical diversity, and other limitations, it is necessary to conduct more high-quality studies to provide more precise and comprehensive recommendations.

Effects of propolis supplementation on prooxidant-antioxidant balance, oxidative stress biomarkers, and body composition in obese patients with NAFLD: A double-blind randomized controlled clinical trial

Background

Oxidative stress is one of the main hits in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Propolis (PRP), a natural substance made by bees from plant extracts, has been reported to have antioxidant properties. The present clinical trial investigated the effect of Iranian PRP on prooxidant-antioxidant balance (PAB), oxidative stress biomarkers, and body composition in obese patients with NAFLD.

Methods

In the present double-blind, randomized controlled clinical trial, 44 obese patients with NAFLD were randomly allocated to either Iranian PRP (1500 mg/d) or placebo (1500 mg/d) accompanied by a calorie-restricted diet (CRD) for eight weeks. PAB, oxidative stress biomarkers, and body composition were assessed at baseline and the end of the study.

Results

There was a significant reduction in PAB levels over the trial in both groups. However, the between-group difference was not significant at the endpoint. At the end of the study, the inter-group comparison showed a significant decrease in serum glutathione peroxidase level in the placebo group compared to the PRP group after adjusting for confounding variables based on models 1 (P=0.027) and 2 (P=0.028). No significant within- or between-group differences in other studied oxidative stress biomarkers were found. Moreover, no between-group differences were observed for body composition and dietary intakes of energy and antioxidant micronutrients.

Conclusion

Iranian PRP supplementation (1500 mg/d) for eight weeks could prevent the reduction of glutathione peroxidase levels compared to the control group. However, it could not affect other oxidative stress biomarkers, body composition, or dietary intakes of energy and antioxidant micronutrients.

In-Depth Phytochemical Profile by LC-MS/MS, Mineral Content by ICP-MS, and In-Vitro Antioxidant, Antidiabetic, Antiepilepsy, Anticholinergic, and Antiglaucoma Properties of Bitlis Propolis

Propolis is very significant in terms of its phytochemical content and biological activity among bee products. In this study, the antioxidant activities (total phenolic and flavonoid, Fe3+, Cu2+ (CUPRAC), Fe3+-TPTZ (FRAP) reducing, and DPPH•, ABTS•+ scavenging assays) of propolis collected from the Bitlis province of Türkiye were determined. In addition, the carbonic anhydrase I and II isoenzymes (hCA I and hCA II), α-glycosidase, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) inhibition activity and phytochemical profile of propolis and mineral content were determined by LC-MS/MS and ICP-MS, respectively. In propolis, 31 phytochemicals were found, and the highest concentration of acacetin (23.604 mg/g) was detected. It is seen that the phytochemicals in propolis provide antioxidant properties. The mineral content was screened for 18 elements and determined to be rich in the elements that make up the salt content. Total phenolic content was 215.14 mg GAE/g, and total flavonoid content was 79.11 mg QE/g. The Fe3+ reduction result was 0.940 (µg/mL), CUPRAC 1.183 (µg/mL), FRAP 0.963 (µg/mL), DPPH• scavenging IC50: 16.7 (µg/mL), and ABTS IC50: 8.01 (µg/mL). hCA I enzyme inhibition results in IC50: 7.19 (µg/mL), hCA II 8.15, AChE 5.17, BChE 7.50, and α-Glycosidase 5.72. As a result of this study, it was determined that Bitlis propolis has high antioxidant properties and a rich phytochemical content. It was also observed that it is an effective enzyme inhibitor against epilepsy, glaucoma, Alzheimer's, and diabetes, which are important diseases, and it can be evaluated in the treatment of these diseases and drug production.

Effects of Propolis Consumption on Glycemic Indices and Liver Enzymes in Adults: A Grading of Recommendations Assessment, Development, and Valuation-assessed Systematic Review and Dose-Response Meta-analysis

PURPOSE

Even though various randomized controlled trials (RCTs) have assessed the effect of propolis on glycemic indices and liver enzyme concentrations in adults, results have been inconsistent, without conclusive evidence. This systematic review and meta-analysis of RCTs sought to evaluate the effects of propolis consumption on glycemic indices and liver enzymes, fasting blood glucose, insulin, homeostatic model assessment of insulin resistance, glycosylated hemoglobin, alanine transaminase, aspartate aminotransferase, and gamma-glutamyl transferase in adults.

METHODS

Two independent researchers systematically searched PubMed, EMBASE, Scopus, Web of Science, and the Cochrane Library for English-language RCTs published up to April 2024. The results were generated through a random-effects model and presented as the weighted mean difference (WMD) with a 95% CI. The Cochrane Risk of Bias Tool for RCTs and Grading of Recommendations Assessment, Development, and Evaluation assessment were used to evaluate quality assessment and certainty of evidence.

FINDINGS

A total of 21 RCTs were included. A pooled analysis of 24 trials reported that propolis consumption led to a significant reduction in fasting blood glucose (WMD, -9.75 mg/dL; 95% CI, -16.14 to -3.35), insulin (WMD, -1.64 µU/mL; 95% CI, -2.61 to -0.68), glycosylated hemoglobin (WMD, -0.46%; 95% CI, -0.71 to -0.21), homeostatic model assessment of insulin resistance (WMD, -0.54; 95% CI, -0.98 to -0.09), alanine transaminase (WMD, -2.60 IU/L; 95% CI, -4.58 to -0.61), and aspartate aminotransferase (WMD, -2.07 IU/L; 95% CI, -3.05 to -1.09). However, there were no significant effects on gamma-glutamyl transferase in comparison with the control group.

IMPLICATIONS

This meta-analysis has shown that propolis supplementation may have beneficial effects on glycemic indices and liver enzymes. Future high-quality, long-term RCTs are needed to confirm our results.

CLINICALTRIALS

gov identifiers: CRD42024524763. (Clin Ther. 2024;46:XXX-XXX) © 2024 Elsevier HS Journals, Inc.

Propolis supplementation can reduce serum level of interleukin-6, C-reactive protein, and tumor necrosis factor-α: an updated systematic review and dose-response meta-analysis on randomized clinical trials

BACKGROUND

New evidence suggested that propolis might reduce serum levels of inflammatory mediators; therefore, in this study we aimed to prove the potential effect of propolis on serum levels of interleukin-6 (IL-6), C-reactive protein (CRP), and tumor necrosis factor-alpha (TNF-α) through conducting a systematic review and meta-analysis.

METHODS

Databases including PubMed, ClinicalTrials.gov, Scopus, Cochrane Library, and ISI Web of Science were searched until October 2023. In the present meta-analysis, we detected the overall effect sizes using extracted standard mean differences (SMD) and the standard deviations (SDs) from both study groups through DerSimonian and Laird method. Exploring the statistical heterogeneity was done through Cochran's Q test and I-squared statistic.

RESULTS

In total, seventeen and sixteen studies were included in the systematic review and meta-analysis, respectively. The overall estimate indicated that the propolis significantly reduced serum levels of IL-6 (SMD = -3.47, 95% confidence interval (95%CI): -5.1, -1.84; p < 0.001), CRP (SMD= -1.73, 95%CI: -2.82, -0.65; p = 0.002), and TNF-α (SMD= -1.42, 95%CI= -2.15, -0.68; p < 0.001). These results also revealed geographical region and propolis dose were the critical points to get the beneficial effects.

CONCLUSION

According to our result, propolis supplementation can decrease serum levels of IL-6, CRP, and TNF-α; therefore, it might be considered as complementary therapy for the treatment of certain chronic diseases.

The relationship of redox signaling with the risk for atherosclerosis

Oxidative balance plays a pivotal role in physiological homeostasis, and many diseases, particularly age-related conditions, are closely associated with oxidative imbalance. While the strategic role of oxidative regulation in various diseases is well-established, the specific involvement of oxidative stress in atherosclerosis remains elusive. Atherosclerosis is a chronic inflammatory disorder characterized by plaque formation within the arteries. Alterations in the oxidative status of vascular tissues are linked to the onset, progression, and outcome of atherosclerosis. This review examines the role of redox signaling in atherosclerosis, including its impact on risk factors such as dyslipidemia, hyperglycemia, inflammation, and unhealthy lifestyle, along with dysregulation, vascular homeostasis, immune system interaction, and therapeutic considerations. Understanding redox signal transduction and the regulation of redox signaling will offer valuable insights into the pathogenesis of atherosclerosis and guide the development of novel therapeutic strategies.

Effects of dietary compounds on nuclear factor erythroid 2-related factor 2 (Nrf2) modulation in chronic kidney disease: a systematic review of clinical trials

Nuclear factor-erythroid 2-related factor 2 (Nrf2) is an important transcription factor that activates antioxidant genes and increases detoxifying enzymes. Studies have shown that dietary compounds can activate the Nrf2 expression and improve the antioxidant response in patients with exacerbated oxidative stress, such as chronic kidney disease (CKD). We aimed to evaluate the efficacy of nutritional interventions on Nrf2 expression and phase II antioxidant enzymes in clinical trials in CKD. We searched PubMed, Lilacs, Embase, Scopus, and Cochrane Library databases of published clinical trials and the Cochrane tool was used for the quality assessment of the studies included. We reported this review according to the PRISMA and it was registered in PROSPERO (42023389619). Thirty-nine studies were included in this review; nine evaluated the Nrf2 expression and three showed an increase in its expression. Twenty-three studies found an increase in the antioxidant enzyme levels, including superoxide dismutase, catalase, and glutathione peroxidase. Moreover, a high risk of bias was found in most of the studies and high heterogeneity in the designs, type, and duration of supplementation administered. These results suggest that dietary supplementations have a promising effect on the antioxidant enzyme response, however, it is recommended that further studies should be carried out.

The Effectiveness of a Dietary Supplement with Honey, Propolis, Pelargonium sidoides Extract, and Zinc in Children Affected by Acute Tonsillopharyngitis: An Open, Randomized, and Controlled Trial

Physicians are currently finding products for pediatric respiratory diseases of viral etiology to reduce the inappropriate use of antibiotic therapy. This study evaluated PediaFlù (Pediatrica S.r.l.), a dietary supplement already on the market composed of honey, propolis, Pelargonium sidoides extract, and zinc (DSHPP), in children affected by acute tonsillopharyngitis (ATR). The open-label, randomized, and controlled study compared DSHPP + standard of care (SoC) versus SoC alone for six days. Children between 3 and 10 years with an ATR ≤ 48 h, a negative rapid test for beta-hemolytic Streptococcus, or a culture identification of nasal and/or pharyngeal exudates were included. A tonsillitis severity score (TSS) and the number of treatment failures (using ibuprofen or high-dose paracetamol as rescue medication) were the primary endpoints. DSHPP+ SoC showed better performance than SoC alone for TSS sub-scores: throat pain and erythema on day 6 (p < 0.001 and p < 0.05), swallowing (p < 0.01 on day 4), and TSS total score on days 4 and 6 (p < 0.05 and p < 0.001). Only one patient (SoC group) had treatment failure for ibuprofen administration. No adverse events were reported. DSHPP is an optimal adjuvant in the treatment of URTI and could potentially be useful in the daily clinical practice of paediatricians evaluating the correct antibiotic prescription.

Propolis as an autophagy modulator in relation to its roles in redox balance and inflammation regulation

Autophagy is a degradation process that is evolutionarily conserved and is essential in maintaining cellular and physiological homeostasis through lysosomal removal and elimination of damaged peptides, proteins and cellular organelles. The dysregulation of autophagy is implicated in various diseases and disorders, including cancers, infection-related, and metabolic syndrome-related diseases. Propolis has been demonstrated in various studies including many human clinical trials to have antimicrobial, antioxidant, anti-inflammatory, immune-modulator, neuro-protective, and anti-cancer. Nevertheless, the autophagy modulation properties of propolis have not been extensively studied and explored. The role of propolis and its bioactive compounds in modulating cellular autophagy is possibly due to their dual role in redox balance and inflammation. The present review attempts to discuss the activities of propolis as an autophagy modulator in biological models in relation to various diseases/disorders which has implications in the development of propolis-based nutraceuticals, functional foods, and complementary therapies.

A novel black poplar propolis extract with promising health-promoting properties: focus on its chemical composition, antioxidant, anti-inflammatory, and anti-genotoxic activities

Propolis is a resinous mixture produced by honeybees which has been used since ancient times for its useful properties. However, its chemical composition and bioactivity may vary, depending on the geographical area of origin and the type of tree bees use for collecting pollen. In this context, this research aimed to investigate the total phenolic content (using the Folin-Ciocalteu assay) and the total antioxidant capacity (using the FRAP, DPPH, and ABTS assays) of three black poplar (Populus nigra L.) propolis (BPP) solutions (S1, S2, and S3), as well as the chemical composition (HPLC-ESI-MSn) and biological activities (effect on cell viability, genotoxic/antigenotoxic properties, and anti-inflammatory activity, and effect on ROS production) of the one which showed the highest antioxidant activity (S1). The hydroalcoholic BPP solution S1 was a prototype of an innovative, research-type product by an Italian nutraceutical manufacturer. In contrast, hydroalcoholic BPP solutions S2 and S3 were conventional products purchased from local pharmacy stores. For the three extracts, 50 phenolic compounds, encompassing phenolic acids and flavonoids, were identified. In summary, the results showed an interesting chemical profile and the remarkable antioxidant, antigenotoxic, anti-inflammatory and ROS-modulating activities of the innovative BPP extract S1, paving the way for future research. In vivo investigations will be a possible line to take, which may help corroborate the hypothesis of the potential health benefits of this product, and even stimulate further ameliorations of the new prototype.

3,3'-O-dimethylquercetin: A bi-functional vasodilator isolated from green propolis of the Caatinga Mimosa tenuiflora

In the search for novel, bi-functional compounds acting as CaV1.2 channel blockers and K+ channel stimulators, which represent an effective therapy for hypertension, 3,3'-O-dimethylquercetin was isolated for the first time from Brazilian Caatinga green propolis. Its effects were investigated through electrophysiological, functional, and computational approaches. In rat tail artery myocytes, 3,3'-O-dimethylquercetin blocked Ba2+ currents through CaV1.2 channels (IBa1.2) in a concentration-dependent manner, with the inhibition being reversed upon washout. The compound also shifted the voltage dependence of the steady-state inactivation curve to more negative potentials without affecting the slope of the inactivation and activation curves. Furthermore, the flavonoid stimulated KCa1.1 channel currents (IKCa1.1). In silico simulations provided additional evidence for the binding of 3,3'-O-dimethylquercetin to KCa1.1 and CaV1.2 channels and elucidated its mechanism of action. In depolarized rat tail artery rings, the flavonoid induced a concentration-dependent relaxation. Moreover, in rat aorta rings its antispasmodic effect was inversely related to the transmembrane K+ gradient. In conclusion, 3,3'-O-dimethylquercetin demonstrates effective in vitro vasodilatory properties, encouraging the exploration of its scaffold to develop novel derivatives for potential use in the treatment of hypertension.

Exploring the Prospective Role of Propolis in Modifying Aging Hallmarks

Aging populations worldwide are placing age-related diseases at the forefront of the research agenda. The therapeutic potential of natural substances, especially propolis and its components, has led to these products being promising agents for alleviating several cellular and molecular-level changes associated with age-related diseases. With this in mind, scientists have introduced a contextual framework to guide future aging research, called the hallmarks of aging. This framework encompasses various mechanisms including genomic instability, epigenetic changes, mitochondrial dysfunction, inflammation, impaired nutrient sensing, and altered intercellular communication. Propolis, with its rich array of bioactive compounds, functions as a potent functional food, modulating metabolism, gut microbiota, inflammation, and immune response, offering significant health benefits. Studies emphasize propolis' properties, such as antitumor, cardioprotective, and neuroprotective effects, as well as its ability to mitigate inflammation, oxidative stress, DNA damage, and pathogenic gut bacteria growth. This article underscores current scientific evidence supporting propolis' role in controlling molecular and cellular characteristics linked to aging and its hallmarks, hypothesizing its potential in geroscience research. The aim is to discover novel therapeutic strategies to improve health and quality of life in older individuals, addressing existing deficits and perspectives in this research area.