Effect of Brazilian green propolis in patients with type 2 diabetes: A double-blind randomized placebo-controlled study

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.

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.

Polyphenols mediated attenuation of diabetes associated cardiovascular complications: A comprehensive review

Background

Diabetes mellitus is a common chronic metabolic disorder that is characterized by increased levels of glucose for prolonged periods of time. Incessant hyperglycemia leads to diabetic complications such as retinopathy, nephropathy, and neuropathy, and cardiovascular complications such as ischemic heart disease, peripheral vascular disease, diabetic cardiomyopathy, stroke, etc. There are many studies that suggest that various polyphenols affect glucose homeostasis and can help to attenuate the complications associated with diabetes.

Objective

This review focuses on the possible role of various dietary polyphenols in palliating diabetes-induced cardiovascular complications. This review also aims to give an overview of the interrelationship among ROS production (due to diabetes), inflammation, glycoxidative stress, and cardiovascular complications as well as the anti-hyperglycemic effects of dietary polyphenols.

Methods

Various scientific databases including Scopus, Web of Science, Google Scholar, PubMed, Science Direct, Springer Link, and Wiley Online Library were used for searching articles that complied with the inclusion and exclusion criteria.

Results

This review lists several polyphenols based on various pre-clinical and clinical studies that have anti-hyperglycemic potential as well as a protective function against cardiovascular complications.

Conclusion

Several pre-clinical and clinical studies suggest that various dietary polyphenols can be a promising intervention for the attenuation of diabetes-associated cardiovascular complications.

Anti-hyperglycemic effects of propolis or metformin in type 2 diabetes mellitus

Background: The aim of this study was to evaluate the effect of propolis or metformin versus placebo on glycemic control in pharmacological treatment-naïve patients with type 2 diabetes mellitus (T2DM). Methods: A double-blind, randomized, placebo-controlled in parallel groups clinical trial was performed in 36 pharmacological treatment-naïve patients with T2DM. They received propolis (300 mg), metformin (850 mg), or placebo twice daily before breakfast and dinner for 12 weeks. At the beginning and end of the study, fasting plasma glucose (FPG), 2-h postload glucose (2-h PG) during a 75-g oral glucose tolerance test, glycated hemoglobin A1c (A1C) and a metabolic profile were measured. Areas under the curve (AUC) of glucose and insulin, total insulin secretion (insulinogenic index), the first phase of insulin secretion (Stumvoll index), and insulin sensitivity (Matsuda index) were calculated. Statistical analyses: Kruskal-Wallis, Mann-Whitney U and Wilcoxon tests. Results: The propolis and metformin groups exhibited significant reductions in FPG (p=0.009 and p=0.001, respectively), 2-h PG (p=0.034 and p=0.001, respectively) levels, AUC of insulin, Stumvoll index, and an increment in the Matsuda index. The comparison of the changes from baseline to the end showed significant differences between placebo and propolis in FPG (p=0.004) and A1C (p=0.049) levels, while between placebo and metformin were in FPG (p=0.002), 2-h PG (p=0.004) and A1C (p=0.007) levels. Conclusions: The administration of propolis and metformin compared to placebo reduced FPG and A1C levels; in addition, metformin decreased 2-h PG, AUC of glucose and insulin, high-density lipoprotein cholesterol, and increased the insulin sensitivity.

Physiological roles of chloride ions in bodily and cellular functions

Physiological roles of Cl-, a major anion in the body, are not well known compared with those of cations. This review article introduces: (1) roles of Cl- in bodily and cellular functions; (2) the range of cytosolic Cl- concentration ([Cl-]c); (3) whether [Cl-]c could change with cell volume change under an isosmotic condition; (4) whether [Cl-]c could change under conditions where multiple Cl- transporters and channels contribute to Cl- influx and efflux in an isosmotic state; (5) whether the change in [Cl-]c could be large enough to act as signals; (6) effects of Cl- on cytoskeletal tubulin polymerization through inhibition of GTPase activity and tubulin polymerization-dependent biological activity; (7) roles of cytosolic Cl- in cell proliferation; (8) Cl--regulatory mechanisms of ciliary motility; (9) roles of Cl- in sweet/umami taste receptors; (10) Cl--regulatory mechanisms of with-no-lysine kinase (WNK); (11) roles of Cl- in regulation of epithelial Na+ transport; (12) relationship between roles of Cl- and H+ in body functions.

The effects of propolis supplementation on high-sensitivity C-reactive protein, testosterone hormone, and metabolic profile in women with polycystic ovary syndrome: A randomized, triple-blinded, placebo-controlled clinical trial

One of the most prevalent ovulation disorders is polycystic ovarian syndrome (PCOS). According to the anti-inflammatory and beneficial effects of propolis, this triple-blind controlled trial was designed to evaluate the effect of propolis on metabolic factors, high-sensitivity C-reactive protein, and testosterone in women with PCOS. Recruited patients from the gynecologist clinic were randomized based on a stratified permuted four-block randomization procedure to supplement with propolis tablets, two tablets/day (500 mg propolis/day) (n = 30) or identical placebo tablets (n = 30) for 12 weeks in 2021 until 2022. Data were collected using a demographic questionnaire, blood samples, and a checklist to record the measured parameters. A total of 57 patients completed the trial. ANCOVA test showed that hip circumference (HC)) p = 0.03), fasting insulin (p = 0.007), homeostatic model assessment for insulin resistance (p = 0.004), testosterone (p = 0.004), and low-density lipoprotein (LDL)/high-density lipoprotein (HDL) (p = 0.02) were significantly decreased in the propolis versus the placebo group after adjustment for confounders. Although fasting blood glucose (p = 0.04) decreased significantly in the propolis group compared to the placebo, after adjusting for confounders, significance was lost (p = 0.09). Supplementation with propolis elicited positive effects on fasting insulin and insulin resistance, in addition to reducing the testosterone level, LDL/HDL, and HC, in PCOS women.

Effects of anthocyanin supplementation in diet on glycemic and related cardiovascular biomarkers in patients with type 2 diabetes: a systematic review and meta-analysis of randomized controlled trials

Purpose

This study is the first systematic review and meta-analysis based on RCTs on the effects of anthocyanins on patients with type 2 diabetes mellitus (T2DM) and the effect on T2DM-related cardiovascular disease.

Methods

RCTs published in English from five electronic databases were evaluated for glycated hemoglobin (HbA1c), fasting blood glucose (FBG), 2-h postprandial blood glucose, fasting insulin, model assessment for insulin resistance, triglycerides (TG), total cholesterol (TC), high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, systolic blood pressure, and diastolic blood pressure. The quality of the studies was rated (Cochrane Risk of Bias tool) and weighted mean differences were calculated (DerSimonian-Laird model with random effects). Leave-one-out sensitivity, subgroup, and publication bias analyses were conducted. The strength of the evidence was rated according to the GRADE guidelines.

Results

In all, 13 RCTs were analyzed out of the 239 identified studies, with a duration longer than 4 weeks (703 participants with T2DM). Our findings indicate that a median dose of 320 mg/day anthocyanins, either from fruit extracts or pure supplements, for a median intervention length of 8 weeks significantly reduced HbA1c [Weighted Mean Difference (WMD) -0.31, p = 0.00], FBG (WMD -0.63, p = 0.00), 2-h postprandial glucose (WMD -1.60, p = 0.00), TG (WMD -0.45, p = 0.01), and LDL (WMD -0.26 p = 0.02). However, the effects of anthocyanins on fasting insulin, HOMA-IR, TC, HDL cholesterol, systolic blood pressure, and diastolic blood pressure in patients with T2DM were not statistically significant. Anthocyanins from fruit extracts or powder exhibited a higher reduction of HbA1c compared to pure anthocyanin supplements.

Conclusion

The significant improvements in glycemic parameters and lipid profile, suggest the benefits of anthocyanins, especially from fruit extract or powder, in the management of T2DM, and their ability to delay the onset of lipid disorder-related diseases such as cardiovascular disease associated with T2DM. The mechanism behind this reduction in glycemic markers could be attributed to the antioxidant and anti-inflammatory activity of anthocyanins. Further research with well-designed RCTs is required to determine the optimal dosage of anthocyanins for the treatment of T2DM and to comprehend the consequences.

Cumulative effects of exercise training and consumption of propolis on managing diabetic dyslipidemia in adult women: a single-blind, randomized, controlled trial with pre-post-intervention assessments

Dyslipidemia is an imbalance of various lipids, and propolis, as a natural resinous viscos mixture made by Apis mellifera L. could improve in this condition. In this single-blind, randomized trial, 60 women with type 2 diabetes and dyslipidemia were divided into four groups: (1) the patients who did not apply the combined training and 500 mg propolis capsules supplement (Control group); (2) subjects performed combined training, including aerobic and resistance training (EXR); (3) subjects received the 500 mg propolis supplement capsules (SUPP); (4) Subjects performed combined training along with receiving the 500 mg propolis supplement capsules (EXR + SUPP). We evaluated the concentration of CTRP12, SFRP5, interleukin-6 (IL6), superoxide dismutase (SOD), malondialdehyde (MDA), adiponectin, and total antioxidant capacity (TAC) before and after the intervention. MDA, TAC, IL6, CTRP12, SFRP5 IL6, adiponectin, and lipid profile levels ameliorated in the EXR + SUPP group. We found that 8 weeks of treatment by combined exercise training and propolis supplement decreased inflammation activity and increased antioxidant defense in women with diabetic dyslipidemia.Trial registration This study was registered in the Iranian Registry of Clinical Trials; IRCT code: IRCT20211229053561N1.

Effects of Iranian propolis on renal function, prooxidant-antioxidant balance, metabolic status, and quality of life in patients with chronic kidney disease: A study protocol of an ongoing randomized, double-blind, placebo-controlled clinical trial

Background

Chronic kidney disease (CKD) is a prevalent and progressive disease that is impacted by hyperglycemia, hypertension (HTN), and oxidative stress (OS). Propolis, a natural resinous mixture produced by honeybees from plant materials, has been shown to possess antioxidant, anti-inflammatory, antihyperglycemic, and antihypertensive properties, along with hepato-renal protective effects. This study aims to evaluate the efficacy of propolis supplementation on patients with CKD.

Methods

This multi-centered, randomized, double-blind, placebo-controlled clinical trial will evaluate the effectiveness of propolis supplementation in 44 eligible patients with CKD. Participants will be randomly allocated to receive either propolis capsule (500 mg, containing 125 mg Iranian alcoholic propolis extract) or placebo, twice daily for three months. The primary outcome is improvement in kidney function parameters of CKD patients, while secondary outcomes include changes in prooxidant-antioxidant balance (PAB), glycemic status, quality of life, and blood pressure (BP). The study will be conducted at Tabriz University of Medical Sciences in Tabriz, Iran.

Discussion

If the results of this study reveal remarkable effectiveness of propolis in improving quality of life and clinical outcomes in patients with CKD, this compound may reach a new milestone as an adjunctive therapy for CKD and it opens a new window for further studies.

Trial registration

Iranian Registry of Clinical Trials, IRCT20191218045798N1. Prospectively registered on 07 June 2020. Updated on 30 August 2021. https://en.irct.ir/trial/48603.

Poplar Propolis Improves Insulin Homeostasis in Non-Diabetic Insulin-Resistant Volunteers with Obesity: A Crossover Randomized Controlled Trial

Propolis, a natural resinous mixture rich in polyphenols, produced by bees from a variety of plant sources, has shown significant therapeutic effects and may prevent the development of certain chronic diseases like type 2 diabetes mellitus (T2DM). The objective of this study was to evaluate the effect of supplementation with standardized poplar propolis extract powder (PPEP) on insulin homeostasis in non-diabetic insulin-resistant volunteers with obesity. In this randomized, controlled, crossover trial, nine non-diabetic insulin-resistant volunteers with obesity, aged 49 ± 7 years, were subjected to two periods of supplementation (placebo and PPEP) for 3 months. Blood samples and anthropomorphic data were collected at baseline and at the end of each phase of the intervention. PPEP supplementation improved insulin sensitivity by significantly decreasing the percentage of insulin-resistant subjects and the insulin sensitivity Matsuda index (ISI-M). According to this study, supplementation with standardized PPEP for 3 months in non-diabetic insulin-resistant volunteers with obesity led to an improvement in insulin homeostasis by its effect on insulin resistance and secretion. This study suggests that poplar propolis has a preventive effect on the physiopathological mechanisms of T2DM and, therefore, that it can help to prevent the development of the disease.

The effects of propolis on pro-oxidant-antioxidant balance, glycemic control, and quality of life in chronic kidney disease: a randomized, double-blind, placebo-controlled trial

Chronic kidney disease (CKD) is a progressive kidney damage with an increasing prevalence. Some evidence suggests that propolis as a novel antioxidant, anti-inflammatory, and immunomodulatory agent may have beneficial effects in CKD. The aim of this study was to evaluate the efficacy of propolis on some kidney function parameters, pro-oxidant-antioxidant balance (PAB), glycemic status, quality of life, and blood pressure (BP) in patients with CKD. In this study, 44 patients with CKD were randomly assigned to receive propolis capsules at a dose of 250 mg daily or placebo for three months. Of 44 randomized individuals, 35 completed the trial. At the end of the intervention (end of month three), improvement in some dimensions of health-related quality of life (HRQoL) (derived from Kidney Disease and Quality of Life Short-Form (KDQOL-[Formula: see text], v. 1.3) questionnaire) were significantly higher in the propolis group than the placebo group, even after adjustment for baseline values, present of diabetes, and age (P < 0.05). Like systolic and diastolic BP, changes in serum creatinine, 24-h urine volume and protein, fasting blood sugar (FBS), hemoglobin A1C (HbA1C), insulin, homeostasis model of assessment-insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), and PAB did not differ significantly between the two groups (P > 0.05). No serious adverse events were reported throughout the study. Propolis supplementation may improve the HRQoL of CKD patients. More studies are needed to validate the adjunct use of propolis for metabolic control of CKD patients.

The effect of Brazilian Green Propolis extract on inflammation in patients with chronic kidney disease on peritoneal dialysis: A randomised double-blind controlled clinical trial

BACKGROUND

Chronic kidney disease (CKD) patients on dialysis display a low-grade systemic inflammatory burden. Nutritional interventions designed to activate the cytoprotective nuclear factor erythroid-2-related factor 2 (Nrf2) and inhibit nuclear factor-kB (NF-κB) have been proposed to mitigate this burden. Several bioactive compounds have been investigated to achieve this, including propolis, a resin produced by Apis mellifera bees. Considering the safety and efficacy of propolis, it could be a strategy to benefit these patients. Still, there are no studies using propolis in patients with CKD on peritoneal dialysis (DP), and clinical studies to support this application are lacking.

HYPOTHESIS/PURPOSE

The objective and novelty of the present study are to evaluate the effects of propolis supplementation on inflammatory markers in patients with CKD on PD.

STUDY DESIGN

A longitudinal, double-blind, placebo-controlled trial with CKD patients on PD.

METHODS

The patients were randomised into two groups: propolis that received four capsules of 100 mg (400 mg/day), containing concentrated and standardised dry EPP-AF® Brazilian green propolis extract) or placebo, four capsules of 100 mg (400 mg/day), of magnesium stearate, silicon dioxide, and microcrystalline cellulose, for two months. Plasma levels of inflammatory cytokines, including tumour necrosis factor (TNF-α) and interleukin-6 (IL-6), were evaluated by ELISA. Quantitative real-time PCR analyses were performed to evaluate the transcriptional expression levels of Nrf2 and NF-κB in peripheral blood mononuclear cells (PBMCs). Plasma malondialdehyde (MDA) levels, a lipid peroxidation marker, was measured as thiobarbituric acid reactive substances (TBARS). Routine biochemical markers, including C-reactive protein (CRP), were analysed using commercial kits. Carotid Intima-Media Thickness (CIMT) was measured with a doppler ultrasonography device. The study was registered on ClinicalTrials.gov under the number NCT04411758.

RESULTS

A total of 19 patients completed the study, ten patients in the propolis group (54 ± 1.0 years, five men, 7.2  (5.1) months on PD) and 9 in the placebo group (47.5 ± 15.2 years, three men, 10.8  (24.3) months on PD). The plasma levels of TNF-α reduced significantly (p = 0.02), and expression of Nrf2 showed a trend to increase (p = 0.07) after propolis supplementation.

CONCLUSION

EPP-AF® Green Propolis extract (400 mg/day) supplementation for two months appears as a potential strategy to mitigate inflammation, reducing TNF-α plasma levels in CKD patients on PD.

Effect of propolis on mood, quality of life, and metabolic profiles in subjects with metabolic syndrome: a randomized clinical trial

Metabolic syndrome (MeS) is a common multifaceted disorder. Plants contain antioxidant bioactive compounds, which are beneficial to improve the health condition of patients with MeS. Propolis is a hive natural product that is composed of various constituent. We aimed to assess the effects of Iranian propolis as a natural and safe agent on indicators of MeS, quality of life and mood status in individuals with MeS. In total, 66 interested eligible patients recruited to the present study. Participants were randomly assigned to consume a tablet at dose of 250 mg of propolis extract, twice daily for 12 weeks or placebo. Propolis supplementation could lead to a significant reduction in waist circumference (WC), increase in physical functioning, general health and the overall score of SF-36 compared with placebo group (P-value < 0.05). However, no significant differences were observed regarding other anthropometric indices and biochemical parameters between two groups (P-value > 0.05). The current study indicated that propolis can be effective in decreasing WC and improving physical health and quality of life, while had no significant effects on other components of MeS among subjects with this syndrome. Clinical trials registration Iran Registry of Clinical Trials.ir IRCT20121216011763N49, registration date 23/12/2020.

Propolis and Their Active Constituents for Chronic Diseases

Propolis is a mass of chemically diverse phytoconstituents with gummy textures that are naturally produced by honeybees upon collection of plant resins for utilization in various life processes in beehives. Since ancient times, propolis has been a unique traditional remedy globally utilized for several purposes, and it has secured value in pharmaceutical and nutraceutical areas in recent years. The chemical composition of propolis comprises diverse constituents and deviations in the precise composition of the honeybee species, plant source used for propolis production by bees, climate conditions and harvesting season. Over 300 molecular structures have been discovered from propolis, and important classes include phenolic acids, flavonoids, terpenoids, benzofurans, benzopyrene and chalcones. Propolis has also been reported to have diverse pharmacological activities, such as antidiabetic, anti-inflammatory, antioxidant, anticancer, immunomodulatory, antibacterial, antiviral, antifungal, and anticaries. As chronic diseases have risen as a global health threat, abundant research has been conducted to track propolis and its constituents as alternative therapies for chronic diseases. Several clinical trials have also revealed the potency of propolis and its constituents for preventing and curing some chronic diseases. This review explores the beneficial effect of propolis and its active constituents with credible mechanisms and computational studies on chronic diseases.

Brazilian green propolis improves gut microbiota dysbiosis and protects against sarcopenic obesity

INTRODUCTION

Brazilian green propolis is an important honeybee product that is considered beneficial for health. Here, we examined the therapeutic potential of dietary supplementation with propolis against sarcopenic obesity using Db/Db mice.

METHODS

Db/m mice fed a normal diet alone and Db/Db mice fed normal diet alone, or supplemented with different amounts of propolis (0.08, 0.4 and 2%), were examined for effects on sarcopenic obesity.

RESULTS

Propolis improved the glucose tolerance (P < 0.001), increased the grip strength (P < 0.001) and the weight of soleus (P = 0.006) and plantaris muscles (P = 0.008). Moreover, propolis improved the non-alcoholic fatty liver disease activity score (P < 0.001) and decreased the expression of genes related to inflammation, liver fibrosis and fatty acid metabolism. Propolis decreased the accumulation of saturated fatty acids in the liver and increased their excretion in faeces. With regard to the innate immunity, propolis decreased the ratio of M1 macrophages (P = 0.008) and Type 1 and 3 innate lymphoid cells to CD45-positive cells (P < 0.001) and increased the ratio of M2 macrophages (P = 0.002) and ILC2s (P = 0.007) in the liver. Additionally, propolis decreased the expression of genes related to muscle atrophy and inflammation and the concentration of saturated fatty acids in the soleus muscle. 16S rRNA phylogenetic sequencing revealed that propolis increased the Bacteroidetes/Firmicutes ratio, and the abundance of Butyricicoccus and Acetivibrio genera. Gut microbiota related to the pentose phosphatase pathway and glycerolipid metabolism was more prevalent after the administration of propolis.

CONCLUSIONS

This is the first study to demonstrate that propolis can improve sarcopenic obesity by improving dysbiosis due to overeating and provides new insights into diet-microbiota interactions during sarcopenic obesity.

The Effect of Four Weeks of Long-Term Endurance Training with and Without Propolis Supplementation on Serum Levels of Betatrophin/ANGPTL8 in Male Athletes

Background: Betatrophin/angiopoietin-like protein (ANGPTL8) is defined as an adipokine that regulates blood glucose and triglyceride levels. Objectives: This study aimed to evaluate the effect of propolis supplementation for the first time on serum levels of the hormone betatrophin, as a drug target in the treatment of dyslipidemia, in male endurance athletes for four weeks. Methods: 44 male athletes with an average age of 22 ± 3 years, a height of 177.5 ± 6.5 cm, and a weight of 76 ± 6 kg were selected in Qazvin. They were randomly divided into four groups: Supplementation, placebo, physical activity, and control. The supplementation and placebo groups received two 500 mg tablets of propolis and cellulose (in terms of shape and color, are similar to the original supplement and have no properties, flavor, and aroma) once after lunch and once after dinner, respectively. The drug treatment lasted for four weeks. The athletes' weight and serum levels of betatrophin were measured at the beginning and the end of 4 weeks of treatment. The ELISA method was used to assess the serum concentration of betatrophin. Analyzes were performed by the ANCOVA method. Results: The results showed that the long-term endurance training plus propolis supplementation would result in significant changes in the betatrophin serum levels and weight in participants (P = 0.001), but in the athletes without supplementation, these changes were not significant (P > 0.05). Conclusions: The results indicated that betatrophin serum levels in endurance athletes are increased by propolis supplementation, and their weight is decreased.

The Antioxidant and Anti-Inflammatory Effects of Flavonoids from Propolis via Nrf2 and NF-κB Pathways

Accumulating evidence shows that oxidative stress and inflammation contribute to the development of cardiovascular disease. It has been suggested that propolis possesses antioxidant and anti-inflammatory activities. In this study, the antioxidant and anti-inflammatory effects of the main flavonoids of propolis (chrysin, pinocembrin, galangin, and pinobanksin) and propolis extract were researched. The results showed that the cellular ROS (Reactive oxygen species) levels, antioxidant enzymes, Nrf2 (Nuclear factor erythroid 2-related factor 2) nuclear translocation, and the expression of NQO1 (NAD(P)H:quinone oxidoreductase 1) and HO-1 (heme oxygenase 1) were regulated by different concentrations of individual flavonoids and propolis extract, which showed good antioxidant and pro-oxidant effects. For example, ROS levels were decreased; SOD and CAT activities were increased; and the expression of HO-1 protein was increased by chrysin. The results demonstrated that NO (Nitric Oxide), NOS (Nitric Oxide Synthase), and the activation of the NF-κB signaling pathway were inhibited in a dose-dependent manner by different concentrations of individual flavonoids and propolis extract. Moreover, the results revealed that the phytochemicals presented antioxidant effects at lower concentrations but pro-oxidant effects and stronger anti-inflammatory effects at higher concentrations. To maintain the balance of antioxidant and anti-inflammatory effects, it is possible that phytochemicals activate the Nrf2 pathway and inhibited the NF-κB (Nuclear factor kappa B) pathway.

Propolis efficacy on SARS-COV viruses: a review on antimicrobial activities and molecular simulations

This current study review provides a brief review of a natural bee product known as propolis and its relevance toward combating SARS-CoV viruses. Propolis has been utilized in medicinal products for centuries due to its excellent biological properties. These include anti-oxidant, immunomodulatory, anti-inflammatory, anti-viral, anti-fungal, and bactericidal activities. Furthermore, studies on molecular simulations show that flavonoids in propolis may reduce viral replication. While further research is needed to validate this theory, it has been observed that COVID-19 patients receiving propolis show earlier viral clearance, enhanced symptom recovery, quicker discharge from hospitals, and a reduced mortality rate relative to other patients. As a result, it appears that propolis could probably be useful in the treatment of SARS-CoV-2-infected patients. Therefore, this review sought to explore the natural properties of propolis and further evaluated past studies that investigated propolis as an alternative product for the treatment of COVID-19 symptoms. In addition, the review also highlights the possible mode of propolis action as well as molecular simulations of propolis compounds that may interact with the SARS-CoV-2 virus. The activity of propolis compounds in decreasing the impact of COVID-19-related comorbidities, the possible roles of such compounds as COVID-19 vaccine adjuvants, and the use of nutraceuticals in COVID-19 treatment, instead of pharmaceuticals, has also been discussed.

Does propolis have any effect on rheumatoid arthritis? A review study

Rheumatoid arthritis (RA) is a chronic autoimmune disease in which inflammation and oxidative stress play a key role in its pathophysiology. Complementary therapies along with medications may be effective in the control of RA. Propolis is a natural substance extracted from beehives, which have confirmed anti-inflammatory and antioxidant effects. The present study aimed to review the possible effects of propolis on inflammation, oxidative stress, and lipid profile in patients with RA. English articles in online databases such as PubMed‑Medline, AMED, Google Scholar, EMBASE, Scopus, and Web of Science databases were searched. Pieces of evidence show that supplementation with propolis may have therapeutic effects on RA patients. Due to increased inflammation and oxidative stress in the affected joints of RA patients, propolis could inhibit the inflammatory cascades by inhibiting the nuclear factor kappa B pathway and reducing reactive oxygen species, malondialdehyde, and interleukin-17 by increasing some antioxidants. Therefore, inflammation and pain reduce, helping improve and control RA in patients. Further investigations are required with larger sample sizes and different doses of propolis to demonstrate the definite effects of propolis on various aspects of RA.

Role of polyphenols in combating Type 2 Diabetes and insulin resistance

Compromised carbohydrate metabolism leading to hyperglycemia is the primary metabolic disorder of non-insulin-dependent diabetes mellitus. Reformed digestion and altered absorption of carbohydrates, exhaustion of glycogen stock, enhanced gluconeogenesis and overproduced hepatic glucose, dysfunction of β-cell, resistance to insulin in peripheral tissue, and impaired insulin signaling pathways are essential reasons for hyperglycemia. Although oral anti-diabetic drugs like α-glucosidase inhibitors, sulfonylureas and insulin therapies are commonly used to manage Type 2 Diabetes (T2D) and hyperglycemia, natural compounds in diet also play a significant role in combating the effect of diabetes. Due to their vast bioavailability and anti-hyperglycemic effect with least or no side effects, polyphenolic compounds have gained wide popularity. Polyphenols such as flavonoids and tannins play a significant role in carbohydrate metabolism by inhibiting key enzymes responsible for the digestion of carbohydrates to glucose like α-glucosidase and α-amylase. Several polyphenols such as resveratrol, epigallocatechin-3-gallate (EGCG) and quercetin enhanced glucose uptake in the muscle and adipocytes by translocating GLUT4 to plasma membrane mainly by the activation of the AMP-activated protein kinase (AMPK) pathway. This review provides an insight into the protective role of polyphenols in T2D, highlighting the aspects of insulin resistance.

The Role of Nutraceutical Containing Polyphenols in Diabetes Prevention

Research in pharmacological therapy has led to the availability of many antidiabetic agents. New recommendations for precision medicine and particularly precision nutrition may greatly contribute to the control and especially to the prevention of diabetes. This scenario greatly encourages the search for novel non-pharmaceutical molecules. In line with this, the daily and long-term consumption of diets rich in phenolic compounds, together with a healthy lifestyle, may have a protective role against the development of type 2 diabetes. In the framework of the described studies, there is clear evidence that the bio accessibility, bioavailability, and the gut microbiota are indeed affected by: the way phenolic compounds are consumed (acutely or chronically; as pure compounds, extracts, or in-side a whole meal) and the amount and the type of phenolic compounds (ex-tractable or non-extractable/macromolecular antioxidants, including non-bioavailable polyphenols and plant matrix complexed structures). In this review, we report possible effects of important, commonly consumed, phenolic-based nutraceuticals in pre-clinical and clinical diabetes studies. We highlight their mechanisms of action and their potential effects in health promotion. Translation of this nutraceutical-based approach still requires more and larger clinical trials for better elucidation of the mechanism of action toward clinical applications.

A comprehensive insight into the molecular and cellular mechanisms of the effects of Propolis on preserving renal function: a systematic review

BACKGROUND

The present systematic review is conducted, focusing on the existing evidence of Propolis's effects due to its various health benefits, mainly antioxidant and anti-inflammatory properties on preserving renal function.

METHODS

A systematic search of PubMed, Scopus, Embase, ProQuest, and Google Scholar was undertaken for relevant papers published from the start until January 2021.

RESULTS

This review revealed that Propolis affects fasting blood sugar (FBS), postprandial blood glucose, advanced glycation end products (AGEs) concentrations, malondialdehyde (MDA) levels, urinary concentrations of reactive oxygen metabolites (Tbars), total oxidant status (TOS), oxidative stress index (OSI), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) formation favorably. The findings on hemoglobin A1C (HbA1C), insulin, homeostasis model assessment of insulin resistance (HOMA-IR), β-cell function (HOMA-β), quantitative insulin sensitivity check index (QUICKI), and lipid profile were controversial. Moreover, a significant reduction in renal nuclear factor kappa B (NF-κB), serum immunoglobulins, renal ED-1+ cells, and urinary monocyte chemoattractant protein-1 (MCP-1) following Propolis supplementation has been reported, while the results on interleukin-6 (IL-6), tumor necrosis factor α (TNF-α), nitric oxide (NO), nitric oxide synthetase (NOS), and high sensitivity C-reactive protein (hs-CRP) were controversial. Furthermore, included studies showed its anti- proteinuria and kidney restoring effects.

CONCLUSION

In this review, both human and animal studies provide us evidences that Propolis could potentially improve the glycemic status, oxidative stress, renal tissue damage, and renal function. Further studies are needed to determine the underlying mechanisms.

The effects of phytochemicals and herbal bio-active compounds on tumour necrosis factor-α in overweight and obese individuals: a clinical review

Obesity is abnormal fat accumulation in the body which acts as a risk factor for various cardiometabolic states. Adipose tissue in excess can release inflammatory factors, including TNF-α and IL-6, and suppress adiponectin production. TNF-α increases the levels of IL-6 and acute phase reactants such as C-reactive protein. Inflammation has a crucial role in developing and progressing various cardiometabolic diseases and a wide range of obesity-related complications. It has been shown that TNF-α has a significant role in the development of insulin resistance. Recently, a growing body of evidence has focused on herbal medicine, phytochemicals and natural bioactive compounds as inexpensive, relatively easy accessible agents with low adverse effects to reduce inflammatory markers such as TNF-α and simultaneously decrease insulin resistance, glucose intolerance, and dyslipidemia in obesity. The main focus of the current review is to summarize the results of the studies, which assessed the effects of phytochemicals and herbal bio-active compounds on serum TNF-α in subjects with overweight or obesity. This review suggests that herbal medicine have favorable effects on the reduction of TNF-α concentration; however, the results were not uniform for different products. Among the reviewed plants, ginger, ginseng, resveratrol, and flaxseed had more promising effects.

Propolis supplementation in obese patients with non-alcoholic fatty liver disease: effects on glucose homeostasis, lipid profile, liver function, anthropometric indices and meta-inflammation

Possible mechanisms of action of propolis in the management of NAFLD.

Propolis: Chemical Constituents, Plant Origin, and Possible Role in the Prevention and Treatment of Obesity and Diabetes

Honeybee products are not only beneficial to human health but also important to the food industry. One such product is propolis, a resinous substance that honeybees collect from certain trees and plants and store inside their hives. Although various health benefits of propolis have been reported, the chemical composition of propolis varies greatly depending on the growing region and plant origin. These differences have led to many misconceptions and conflicting research results. In this paper, we review research findings on how the growing region and plant origin of propolis affects its composition. We also discuss trends in research on the antiobesity and antidiabetes effects of propolis as well as recent findings that a major component of Brazilian green propolis modulates adipocyte function. Finally, we discuss challenges to be tackled in future research on the health benefits of propolis and share our perspective on the future of this field.

Beneficial Effect of Saharan Propolis on Glucose Metabolism in Streptozotocin-induced Diabetic Rats

AIMS

The aim of the study was to evaluate the antihyperglycemic activity of propolis from Saharan region of Morocco.

BACKGROUND

Propolis is known from ancient times for its beneficial action on health.

OBJECTIVE

The study aimed to evaluate the effect of Moroccan propolis aqueous extract from the desert region on glycemia and lipid metabolism.

METHODS

The antihyperglycemic and antidyslipidemic activities of Moroccan propolis aqueous extract were evaluated in streptozotocin-induced diabetic rats. Glycemia was monitored during acute (6h) and subchronic treatments. Histopathological analysis of the liver and the serum lipid profile was also evaluated in addition to the glucose tolerance.

RESULTS

This work demonstrated that the aqueous extract of Moroccan propolis exhibited a significant antihyperglycemic effect in diabetic rats. Histopathological data demonstrated that propolis acts positively on the liver of diabetic rats. In addition, the preliminary phytochemical screening revealed that Moroccan propolis contains several phytochemicals. Finally, Moroccan propolis had a potent antioxidant activity which may be due to the richness in polyphenols content (90.91 mg EAG/1 g of extract).

CONCLUSION

The present study shows that Moroccan propolis from the hot desert region possesses a potent antihyperglycemic effect.

The effects of propolis supplementation on metabolic parameters: A systematic review and meta-analysis of randomized controlled clinical trials

Objective:

Propolis is a sticky, resinous substance produced by honeybees from various plants. Various biological properties of propolis and its extracts have been recognized in previous studies including the antiseptic, anti-inflammatory, antioxidant, antiviral, hepatoprotective, antitumor, antibacterial and antimycotic properties. This study aimed to summarize the effect of propolis on metabolic parameters in human adults using systematic review and meta-analysis.

Materials and Methods:

A comprehensive systematic search was performed in ISI Web of Science, PubMed, Scopus, and Google Scholar up to July 2020 for controlled clinical trials evaluating the impact of propolis on lipid profile and liver enzyme biomarkers. A random effects model was used to calculate the weighted mean difference (WMD) and 95% confidence interval (CI) as the difference between the mean for the intervention and control groups.

Results:

The present meta-analysis included six randomized controlled trials. There was significant reduction in Aspartate Aminotransferase (AST) in comparison to the control groups (WMD=-2.01; 95% CI: -3.93--0.10; p=0.039). However, a non-significant effect was observed in Triglycerides (TG), Total cholesterol (TC), low-density lipoprotein (LDL), High-density lipoprotein (HDL) (WMD=-0.05 mg/dl; 95% CI: -0.27-0.18; p=0.688; WMD=7.08 mg/dl; 95% CI: -37.31-51.46; p=0.755; WMD=-0.94 mg/dl; 95% CI: -6.64-4.77; p=0.747; WMD=3.14 mg/dl; 95% CI: -1.84-8.13; p=0.216, respectively).

Conclusion:

Current meta-analysis revealed that propolis supplementation can reduce AST; nevertheless, there was no significant effect on lipid profile indices and ALT.

Effect of propolis supplementation on athletic performance, body composition, inflammation, and oxidative stress following intense exercise: A triple-blind randomized clinical trial

BACKGROUND

Emerging evidence indicates that propolis as a novel potential antioxidant has unique benefits. This study aimed to evaluate the effect of propolis on oxidative stress, inflammation, body composition, and athletic performance in healthy active subjects.

METHODS

This clinical trial was conducted on 54 male military cadets. Eligible subjects were randomly allocated to receive a single dose of 450 mg propolis twice daily for four weeks or a matching placebo containing microcrystalline cellulose. Cooper 12-min run test and running-based anaerobic sprint test were performed to measure aerobic and anaerobic performance. Blood samples were obtained immediately after Cooper's test to evaluate oxidative stress and inflammation status. Fat mass and fat-free mass were analyzed using bioelectrical impedance.

RESULTS

Mean changes in fat mass, fat-free mass, anaerobic powers, fatigue index, and VO2 max did not differ significantly between the two groups after the adjustment for baseline values (P-value>0.05). A significant change was observed in plasma levels of IL-6 (-1.43 ± 0.11pg/mL), total oxidant status (-3.9 ± 0.2µmol/L), total antioxidant capacity (164 ± 12 µmol/L), malondialdehyde (-0.52 ± 0.03µmol/L), oxidative stress index (-0.45 ± 0.04), and glutathione (48.72±2µmol/L) in the propolis group compared with the placebo group after the adjustment for baseline values and weight changes (P-value<0.05). Although IL-10 concentrations had no significant changes in both groups, the ratio of IL-6/IL-10 significantly reduced in the propolis group compared with the placebo group (-0.174 ± 0.015 versus. 0.051 ± 0.014; P-value: 0.041).

CONCLUSIONS

Our results indicated that propolis might have beneficial effects on oxidative stress and inflammation following intense activities in healthy male subjects.

Effects of propolis supplementation on glycemic status, lipid profiles, inflammation and oxidative stress, liver enzymes, and body weight: a systematic review and meta-analysis of randomized controlled clinical trials

The aim of meta-analysis was to assess the effects of propolis on markers of oxidative stress, lipid profiles, inflammation and glycemic control, liver enzymes, and weight control. The heterogeneity between the included studies was indicated using the Cochrane's Q test and I-square (I2) statistic. 14 trials were included in this meta-analysis. Our meta-analysis indicated a significant reduction in fating glucose (WMD: -17.00; 95% CI: -30.88, -3.11), HbA1C (WMD: -0.42; 95% CI: -0.75, -0.10), and insulin (WMD: -1.75; 95% CI: -3.24, -0.26) and a marginally significant reduction in insulin resistance (WMD: -0.60; 95% CI: -1.20, 0.00) following propolis supplementation in 10, 8, 6, and 5 studies, respectively. Pooling 5 effect sizes, a significant reduction was seen in ALT (WMD: -5.63; 95% CI: -10.59, -0.67) and aspartate aminotransferase (AST) (WMD: -3.09; 95% CI: -5.15, -1.03) following propolis. A significant beneficial effect was observed for CRP (WMD: -1.11; 95% CI: -1.92, -0.29), TNF-α (WMD: -6.71; 95% CI: -9.44, -3.98) and interleukin-6 (IL-6) (WMD: -17.99; 95% CI: -35.56, -0.42) concentrations after propolis supplementation. This study demonstrated the beneficial effects of propolis on FPG, HbA1c, insulin, CRP, TNF-α and liver enzymes levels.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40200-020-00696-w.

Potential Role of Propolis in the Prevention and Treatment of Metabolic Diseases

Propolis is a resinous mixture with a complex chemical composition, produced by honeybees and stingless bees from a variety of vegetal sources. In the last decades, propolis was extensively researched, multiple studies confirming its anti-inflammatory, antioxidant, antimicrobial, and wound-healing properties. More recently, due to an exponential increase in the number of patients with metabolic diseases, there is also a growing interest in the study of antidiabetic, antihyperlipidemic, and anti-obesity effects of propolis. The aim of this review was to evaluate the potential role of propolis in the prevention and treatment of metabolic diseases like diabetes mellitus, dyslipidemia, and obesity. The preclinical in vivo and in vitro pharmacological models investigating antidiabetic, antihyperlipidemic, and anti-obesity effects of propolis were reviewed with a focus on the putative mechanisms of actions of several chemical constituents. Additionally, the available clinical studies and an evaluation of the safety profile of propolis were also presented.

Propolis antiviral and immunomodulatory activity: a review and perspectives for COVID-19 treatment

OBJECTIVES

Viral outbreaks are a frequent concern for humans. A great variety of drugs has been used to treat viral diseases, which are not always safe and effective and may induce adverse effects, indicating the need for new antiviral drugs extracted from natural sources. Propolis is a bee-made product exhibiting many biological properties. An overview of viruses, antiviral immunity, propolis safety and its immunomodulatory and antiviral action is reported, as well as perspectives for coronavirus disease 2019 (COVID-19) treatment. PubMed platform was used for data collection, searching for the keywords "propolis", "virus", "antiviral", "antimicrobial" and "coronavirus".

KEY FINDINGS

Propolis is safe and exerts antiviral and immunomodulatory activity; however, clinical trials should investigate its effects on individuals with viral diseases, in combination or not with antiviral drugs or vaccines.

SUMMARY

Regarding COVID-19, the effects of propolis should be investigated directly on the virus in vitro or on infected individuals alone or in combination with antiviral drugs, due to its immunomodulatory and anti-inflammatory action. Propolis administration simultaneously with vaccines should be analyzed, due to its adjuvant properties, to enhance the individuals' immune response. The search for therapeutic targets may be useful to find out how propolis can help to control COVID-19.

Pharmacokinetics and metabolism of cinnamic acid derivatives and flavonoids after oral administration of Brazilian green propolis in humans

Brazilian green propolis (BGP) has chemical compounds from botanical origin that are mainly cinnamic acid derivatives (artepillin C, baccharin, and drupanin) and flavonoids (kaempferide and 6-methoxykaempferide). These compounds are expected to play an important role in the pharmacological activities of BGP. However, there is little known about the pharmacokinetics and metabolism of these compounds after oral administration of BGP. The aim of this study is to investigate the pharmacokinetics and metabolism of BGP components in humans. Twelve volunteers received 3 capsules containing 360 mg of BGP ethanol extract powder. Plasma samples were collected before and up to 24 h after the intake of BGP capsules. The collected plasma samples with or without hydrolysis by the deconjugating enzyme were analyzed by LC/MS/MS. After enzymatic hydrolysis, the C_max values of artepillin C and drupanin, which were detected mainly in plasma after ingestion of BGP capsules, were 1255 ± 517 and 2893 ± 711 nM, respectively, of which 89.3% and 88.2% were found to be the phenolic glucuronide conjugate. This is the first time that the pharmacokinetics of the BGP components of human metabolites have been reported. Our results could provide useful information for the design and interpretation of studies to investigate the mechanisms and pharmacological effects of BGP.

Protective mechanisms of Taiwanese green propolis toward high glucose-induced inflammation via NLRP3 inflammasome signaling pathway in human gingival fibroblasts

OBJECTIVE

To investigate protective effects of Taiwanese green propolis (TGP) against high glucose-induced inflammatory responses in human gingival fibroblasts (HGFs) through NLRP3 inflammasome signaling pathway.

BACKGROUND

NLRP3 inflammasome has been implicated in the progression of both diabetes mellitus and periodontitis, suggesting a common potential therapeutic target for these diseases. Propolis is renowned for various biological activities, particularly anti-inflammation and antioxidant, representing a promising therapy for many conditions. However, underlying mechanisms remain unclear.

METHODS

The cytotoxicity of TGP was evaluated by cell viability assay. The mRNA levels and protein expression or secretion of various inflammatory molecules and NLRP3 inflammasome-related molecules in high glucose-exposed HGFs with or without pretreatment of TGP (5 μg/ml) were determined by real-time PCR and western blot or specific kits, respectively. Intracellular and mitochondrial ROS measurements, NADPH oxidase activity determination, and subcellular fractions were performed to assess ROS generation. The transcriptional activity of NF-κB was measured by luciferase reporter kit. The signaling components were further differentiated using pharmacological inhibitors of ROS and small interfering RNAs of TLR2, TLR4, or NF-κB.

RESULTS

High glucose could induce IL-1β-driven inflammatory responses in HGFs via the activation of NLRP3 inflammasome regulated by TLR2/TLR4 coupled ROS in NF-κB-dependent manner. TGP had no adverse impact on the cell viability of HGFs at concentrations no greater than 10 μg/ml, and could exert inhibitory effects on high glucose-induced inflammatory responses via the interruption of NLRP3 inflammasome signaling pathway.

CONCLUSION

Taiwanese green propolis could elicit protective effects against IL-1β-driven inflammation in high glucose-exposed HGFs through TLR2/TLR4 combined ROS/NF-κB/NLRP3 inflammasome pathway.

Propolis in Metabolic Syndrome and Its Associated Chronic Diseases: A Narrative Review

Propolis is a resinous product collected by bees from plants to protect and maintain the homeostasis of their hives. Propolis has been used therapeutically by humans for centuries. This review article attempts to analyze the potential use of propolis in metabolic syndrome (MetS) and its associated chronic diseases. MetS and its chronic diseases were shown to be involved in at least seven out of the top 10 causes of death in 2019. Patients with MetS are also at a heightened risk of severe morbidity and mortality in the present COVID-19 pandemic. Propolis with its antioxidant and anti-inflammatory properties is potentially useful in ameliorating the symptoms of MetS and its associated chronic diseases. The aim of this article is to provide a comprehensive review on propolis and its therapeutic benefit in MetS and its chronic diseases, with an emphasis on in vitro and in vivo studies, as well as human clinical trials. Moreover, the molecular and biochemical mechanisms of action of propolis are also discussed. Propolis inhibits the development and manifestation of MetS and its chronic diseases by inhibiting of the expression and interaction of advanced glycation end products (AGEs) and their receptors (RAGEs), inhibiting pro-inflammatory signaling cascades, and promoting the cellular antioxidant systems.

To bee or not to bee? The bee extract propolis as a bioactive compound in the burden of lifestyle diseases

Propolis is a polyphenolic plant resin collected by bees to protect hives against pathogens and temperature drop. It exhibits antibacterial, antioxidant, and antiinflammatory properties. Propolis has been reported to possess antidiabetic properties and display beneficial effects against cardiovascular disease, gut dysbiosis, and chronic kidney disease. It has an excellent clinical safety profile, with no known toxic effects described so far. In this review, we discuss the salutogenic effects of propolis, with particular reference to modulating notable features of chronic kidney disease, notably those involving cardiovascular risks.

Protective effects of propolis on hepatic steatosis and fibrosis among patients with nonalcoholic fatty liver disease (NAFLD) evaluated by real-time two-dimensional shear wave elastography: A randomized clinical trial

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease, while no drugs have been approved for its treatment. The pieces of evidence indicate that propolis as a novel anti-inflammatory agent might be a promising candidate to treat NAFLD. We aimed to evaluate the efficacy of propolis on hepatic steatosis and fibrosis in patients with NAFLD. This randomized clinical trial was conducted on 54 patients with NAFLD. Patients were randomly assigned to receive propolis tablets at a dose of 250 mg twice daily for 4 months or placebo. The improvement in hepatic steatosis and fibrosis was evaluated using two-dimensional shear wave elastography. Improvement in the hepatic steatosis was significantly higher in the propolis group than the placebo group, even after adjustment for baseline value and changes in weight, energy intake, and physical activity (odds ratio [OR]: 5.67; 95% confidence intervals [CI]: 1.41-22.8; p = .014). A significant reduction was observed on the liver stiffness in the propolis group (-0.65 ± 0.56 kPa; p = .001), whereas it increased in the placebo group (0.27 ± 0.59 kPa; p = .037). Also, the intake of propolis significantly decreased high-sensitivity C-reactive protein (hs-CRP) levels compared with the placebo group (-0.371; 95%CI: -0.582 to -0.16 mg/L; p = .01). Changes in serum levels of fasting blood sugar, alanine aminotransferase, aspartate aminotransferase, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, cholesterol, and triglyceride did not differ significantly between the two groups (p > .05). There was no significant improvement in insulin resistance in both groups (p > .05). Propolis seems to have protective effects on hepatic steatosis and fibrosis and to reduce the serum levels of hs-CRP in patients with NAFLD.

Antioxidant Effect of Standardized Extract of Propolis (EPP-AF®) in Healthy Volunteers: A "Before and After" Clinical Study

Background

Propolis is rich in polyphenols, especially flavonoids and phenolic acids, and has significant antioxidant activity, shown mainly in “in vitro” studies.

Objective

The aim of this study was to evaluate the antioxidant efficacy and safety of a standardized propolis extract in healthy volunteers.

Design

A two-phase sequential, open-label, nonrandomized, before and after clinical trial.

Methods

Healthy participants received two EPP-AF® doses (375 and 750 mg/d, P.O, tid) during 7 ± 2 days, starting with the lower doses. Immediately before starting EPP-AF® administration and at the end of each 7-day dosing schedule, blood and urine samples were collected for quantification of 8-OHDG (8-hydroxydeoxyguanosine) and 8-ISO (8-isoprostanes) in urine and GSH (reduced glutathione), GSSG (oxidized glutathione), SOD (superoxide dismutase), FRAP (Ferric Reducing Antioxidant Power), vitamin E, and MDA (malondialdehyde) in plasma.

Results

In our study, we had 34 healthy participants (67.7% women, 30 ± 8 years old, 97% white). The 8-ISO, a biomarker of lipid peroxidation, decreased with both doses of EPP-AF® compared to baseline (8-ISO, 1.1 (0.9–1.3) versus 0.85 (0.75–0.95) and 0.89 (0.74–1.0), ng/mg creatinine, P < 0.05, for 375 and 750 mg/d EPP-AF® doses versus baseline, mean and CI 95%, respectively). 8-OHDG, a biomarker of DNA oxidation, was also reduced compared to baseline with 750 mg/d doses (8-OHDG, 15.7 (13.2–18.1) versus 11.6 (10.2–13.0), baseline versus 750 mg/d, respectively, ng/mg creatinine, P < 0.05). Reduction of biomarkers of oxidative stress damage was accompanied by increased plasma SOD activity (68.8 (66.1–73.3) versus 78.2 (72.2–80.5) and 77.7 (74.1–82.6), %inhibition, P < 0.0001, 375 and 750 mg/d versus baseline, median and interquartile range 25–75%, respectively) and by increased GSH for 375 mg/d EPP-AF® doses (1.23 (1.06–1.34) versus 1.33 (1.06–1.47), μmol/L, P < 0.05).

Conclusion

EPP-AF® reduced biomarkers of oxidative stress cell damage in healthy humans, with increased antioxidant enzymatic capacity, especially of SOD. This trial is registered with the Brazilian Registry of Clinical Trials (ReBEC, RBR-9zmfs9).

Molecular and cellular mechanisms of the effects of Propolis in inflammation, oxidative stress and glycemic control in chronic diseases

Propolis is a sticky, resinous material gather from plants and is blended with wax and other constituents. It is reported to have anti-inflammatory, anti-oxidative and blood glucose-lowering properties. This review aims to summarise evidences for the cellular and molecular mechanism of Propolis in inflammation, oxidative stress, and glycemic control. Propolis stimulate the production and secretion of anti-inflammatory cytokines and to inhibit the production of inflammatory cytokines and due to its various antioxidant and poly-phenolic compounds may has a role in control and treating some of the chronic diseases. Most studies have shown that Propolis may affect metabolic factors including plasma insulin levels, and it has proposed that it could be used in the prevention and treatment of T2D Mellitus. In general, to demonstrate the definite effects of Propolis on chronic diseases, more studies are required using larger sample sizes and various doses of Propolis, using better characterized and standardized agents.

The effect of propolis on anthropometric indices and lipid profile: a systematic review and meta-analysis of randomized controlled trials

Background & objectives

The current evidence base regarding the impact of propolis consumption on lipid profile in humans is equivocal. Thus, we sought to investigate the impact of propolis consumption on anthropometric indices and lipid profile in this meta-analysis.

Methods

Cochrane Library, Scopus, PubMed, and Web of Science electronic databases were searched up to December 2019. A random-effects model used to pool effect size. The leave-one-out method used to conduct sensitivity analysis.

Results

Five RCTs were included in this study. Our findings indicated a significant decrease in triglyceride (TG) (WMD: -3.91 mg/dl, 95% CI: -4.22, -3.60), and a significant increase in high-density lipoprotein (HDL) (WMD: 3.41 mg/dl, 95% CI: 0.05, 6.76), however, for body mass index, weight, cholesterol (CL), and low-density lipoprotein (LDL), no significant alterations were evident.

Conclusion

This study revealed that consumption of propolis is associated with a reduction in TG levels, in addition to an increase in HDL levels. Nevertheless, additional research is required to further delineate the relationship between propolis consumption and lipid profile.

A review of fibroblast growth factor 21 in diabetic cardiomyopathy

FGF21 (fibroblast growth factor 21) is a regulator of metabolism and performs an important role in glucose and lipid metabolism and the maintenance of energy balance. FGF21 is principally expressed in the liver, but it can also be found in the pancreas, skeletal muscle, and adipose tissue. It is known that levels of serum FGF21 are significantly elevated in obese, insulin-resistant patients, and those with metabolic syndrome. Elevated levels of FGF21 in serum during the early stages of various metabolic diseases are considered a compensatory response by the organism. Therefore, FGF21 is considered a hormone in response to stress and an early diagnostic marker of disease. Diabetic cardiomyopathy is a special type of cardiac complication, characterized as a chronic myocardial disorder caused by diabetes. The pathological process includes increased oxidative stress, energy metabolism in myocardial cells, an inflammatory response, and myocardial cell apoptosis. A growing body of evidence suggests that FGF21 has the potential to be an effective drug for the treatment of diabetic cardiomyopathy. Here, we review recent progress on the characteristics of FGF21 in its protective role, especially in pathological processes such as suppressing apoptosis in the myocardium, reducing inflammation in cardiomyocytes, reducing oxidative stress, and promoting fatty acid oxidation. In addition, we explore the possibility that diabetic cardiomyopathy can be delayed through the application of FGF21, providing possible therapeutic targets of the disease.

Flavonoids and type 2 diabetes: Evidence of efficacy in clinical and animal studies and delivery strategies to enhance their therapeutic efficacy

Diabetes mellitus type 2 (T2DM) is a metabolic disorder develops due to the overproduction of free radicals where oxidative stress could contribute it. Possible factors are defective insulin signals, glucose oxidation, and degradation of glycated proteins as well as alteration in glutathione metabolism which induced hyperglycemia. Previous studies revealed a link between T2DM with oxidative stress, inflammation and insulin resistance which are assumed to be regulated by numerous cellular networks such as NF-κB, PI3K/Akt, MAPK, GSK3 and PPARγ. Flavonoids are ubiquitously present in the nature and classified according to their chemical structures for example, flavonols, flavones, flavan-3-ols, anthocyanidins, flavanones, and isoflavones. Flavonoids indicate poor bioavailability which could be improved by employing various nano-delivery systems against the occurrences of T2DM. These bioactive compounds exert versatile anti-diabetic activities via modulating targeted cellular signaling networks, thereby, improving glucose metabolism, α -glycosidase, and glucose transport or aldose reductase by carbohydrate metabolic pathway in pancreatic β-cells, hepatocytes, adipocytes and skeletal myofibres. Moreover, anti-diabetic properties of flavonoids also encounter diabetic related complications. This review article has designed to shed light on the anti-diabetic potential of flavonoids, contribution of oxidative stress, evidence of efficacy in clinical, cellular and animal studies and nano-delivery approaches to enhance their therapeutic efficacy. This article might give some new insights for therapeutic intervention against T2DM in near future.

Effects of Propolis Extract and Propolis-Derived Compounds on Obesity and Diabetes: Knowledge from Cellular and Animal Models

Propolis is a natural product resulting from the mixing of bee secretions with botanical exudates. Since propolis is rich in flavonoids and cinnamic acid derivatives, the application of propolis extracts has been tried in therapies against cancer, inflammation, and metabolic diseases. As metabolic diseases develop relatively slowly in patients, the therapeutic effects of propolis in humans should be evaluated over long periods of time. Moreover, several factors such as medical history, genetic inheritance, and living environment should be taken into consideration in human studies. Animal models, especially mice and rats, have some advantages, as genetic and microbiological variables can be controlled. On the other hand, cellular models allow the investigation of detailed molecular events evoked by propolis and derivative compounds. Taking advantage of animal and cellular models, accumulating evidence suggests that propolis extracts have therapeutic effects on obesity by controlling adipogenesis, adipokine secretion, food intake, and energy expenditure. Studies in animal and cellular models have also indicated that propolis modulates oxidative stress, the accumulation of advanced glycation end products (AGEs), and adipose tissue inflammation, all of which contribute to insulin resistance or defects in insulin secretion. Consequently, propolis treatment may mitigate diabetic complications such as nephropathy, retinopathy, foot ulcers, and non-alcoholic fatty liver disease. This review describes the beneficial effects of propolis on metabolic disorders.

Potential therapeutic effect of Moroccan propolis in hyperglycemia, dyslipidemia, and hepatorenal dysfunction in diabetic rats

OBJECTIVES

The effect of propolis collected in Morocco on blood glucose, lipid profile, liver enzymes, and kidney function was investigated in control and diabetic rats.

MATERIALS AND METHODS

Antioxidant activity of propolis was evaluated with the use of DPPH, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS•+), ferric reducing power and total antioxidant activity assay. To study its effect in streptozotocin (STZ)-induced diabetes, the rats were divided into eight groups; four control and four diabetics. The animals received distilled water, glibenclamide, or propolis extract, 50 mg/kg/BW) or 100 mg/kg/b.wt, daily for 15 days. Blood glucose, triglyceride, lactic acid dehydrogenase, liver enzymes, creatinine, blood urea, lipid profile, and body weight were measured on day 15 after commencement of the treatment.

RESULTS

Propolis has a strong antioxidant activity and high total flavonoids and polyphenols content. Glibenclamide and propolis have no significant effect on lipid parameters, and renal and hepatic function in non-diabetic rats. However, propolis or glibenclamide caused a significant lowering of blood glucose after a single administration and at day 15 after daily administration in diabetic rats (P<0.05). Both interventions significantly lowered lactic acid dehydrogenase, increased body weight, and ameliorated dyslipidemia and abnormal liver and kidney function caused by diabetes. The effect of propolis was dose-dependent and in a high dose it was more potent than glibenclamide.

CONCLUSION

Propolis exhibited strong antihyperglycemic, antihyperlipidemic, and hepato-renal protective effects in diabetes, and significantly lowered the elevated lactic acid dehydrogenase. The study demonstrated for the first-time the effect of Moroccan propolis in diabetes and it will pave the way for clinical investigations.