Antioxidant action of propolis on mouse lungs exposed to short-term cigarette smoke

Effects of Propolis Consumption on Liver Enzymes and Obesity Indices in Adults: A Systematic Review and Dose-Response Meta-Analysis

Background

Propolis, a natural resin produced by bees, has been studied for its potential effects on liver enzymes and obesity indices. However, a meta-analysis is necessary to comprehensively understand the impact of propolis on obesity and liver function.

Objectives

This meta-analysis of randomized controlled trials (RCTs) sought to evaluate the effects of propolis consumption on liver enzymes and obesity indices in adults.

Methods

A systematic literature search up to December 2023 was completed in PubMed/Medline, Scopus, and Web of Science, to identify eligible RCTs. Heterogeneity tests of the selected trials were performed using the I 2 statistic. Random-effects models were assessed on the basis of the heterogeneity tests, and pooled data were determined as weighted mean differences (WMDs) with a 95% confidence interval (CI).

Results

A pooled analysis of 24 trials showed that propolis consumption led to a significant reduction in alanine aminotransferase (ALT) (WMD: -2.58; 95% CI: -4.64, -0.52; P = 0.01), aspartate aminotransferase (AST) (WMD: -1.84; 95% CI: -3.01, -0.67; P = 0.002), and alkaline phosphatase (ALP) (WMD: -24.90; 95% CI: -42.13, -7.67; P = 0.005) in comparison with the control group. However, there were no significant effects on gamma-glutamyl transferase (GGT), body weight, BMI (in kg/m2), fat mass, body fat percentage, fat-free mass, adiponectin, waist circumference, hip circumference, and waist-hip ratio in comparison with the control group.

Conclusions

We discovered that consuming propolis can lead to a significant decrease in ALT, AST, and ALP levels, without causing significant changes in GGT, anthropometric indices, and adiponectin levels. However, future well-designed RCTs with large numbers of participants and extended durations, focusing on precise propolis dosage and ingredients, are necessary.

Treatment with Bixin-Loaded Polymeric Nanoparticles Prevents Cigarette Smoke-Induced Acute Lung Inflammation and Oxidative Stress in Mice

The use of annatto pigments has been evaluated as a therapeutic strategy in animal models of several health disorders. Beneficial effects were generally attributed to the inhibition of oxidative stress. Bixin is the main pigment present in annatto seeds and has emerged as an important scavenger of reactive oxygen (ROS) and nitrogen species (RNS). However, this carotenoid is highly hydrophobic, affecting its therapeutic applicability. Therefore, bixin represents an attractive target for nanotechnology to improve its pharmacokinetic parameters. In this study, we prepared bixin nanoparticles (npBX) and evaluated if they could prevent pulmonary inflammation and oxidative stress induced by cigarette smoke (CS). C57BL/6 mice were exposed to CS and treated daily (by gavage) with different concentrations of npBX (6, 12 and 18%) or blank nanoparticles (npBL, 18%). The negative control group was sham smoked and received 18% npBL. On day 6, the animals were euthanized, and bronchoalveolar lavage fluid (BALF), as well as lungs, were collected for analysis. CS exposure led to an increase in ROS and nitrite production, which was absent in animals treated with npBX. In addition, npBX treatment significantly reduced leukocyte numbers and TNF-α levels in the BALF of CS-exposed mice, and it strongly inhibited CS-induced increases in MDA and PNK in lung homogenates. Interestingly, npBX protective effects against oxidative stress seemed not to act via Nrf2 activation in the CS + npBX 18% group. In conclusion, npBX prevented oxidative stress and acute lung inflammation in a murine model of CS-induced acute lung inflammation.

The antiviral and immunomodulatory activities of propolis: An update and future perspectives for respiratory diseases

Propolis is a complex natural product that possesses antioxidant, anti-inflammatory, immunomodulatory, antibacterial, and antiviral properties mainly attributed to the high content in flavonoids, phenolic acids, and their derivatives. The chemical composition of propolis is multifarious, as it depends on the botanical sources from which honeybees collect resins and exudates. Nevertheless, despite this variability propolis may have a general pharmacological value, and this review systematically compiles, for the first time, the existing preclinical and clinical evidence of propolis activities as an antiviral and immunomodulatory agent, focusing on the possible application in respiratory diseases. In vitro and in vivo assays have demonstrated propolis broad-spectrum effects on viral infectivity and replication, as well as the modulatory actions on cytokine production and immune cell activation as part of both innate and adaptive immune responses. Clinical trials confirmed propolis undeniable potential as an effective therapeutic agent; however, the lack of rigorous randomized clinical trials in the context of respiratory diseases is tangible. Since propolis is available as a dietary supplement, possible use for the prevention of respiratory diseases and their deleterious inflammatory drawbacks on the respiratory tract in humans is considered and discussed. This review opens up new perspectives on the clinical investigation of neglected propolis biological properties which, now more than ever, are particularly relevant with respect to the recent outbreaks of pandemic respiratory infections.

Protective effects of propolis extract against nicotine-evoked pulmonary and hepatic damage

There is increasing interest in the use of natural products to treat many diseases, considering the minimal toxicity, availability, and low cost. Propolis, a natural resinous product produced by honeybees, has been proven for its antioxidant and anti-inflammatory properties. Therefore, this study was designed to investigate the protective potential of propolis extract against nicotine-induced pulmonary and hepatic damage in rats. Sprague Dawley rats were divided into six groups: control, propolis (200 and 300 mg/kg, p.o.), nicotine (10 mg/kg, i.p), and nicotine plus propolis-treated groups. Nicotine and propolis were given every day for 8 weeks. Then, blood and bronchoalveolar lavage fluid (BALF) were collected for assessing liver and lung functions. Liver and lung tissues were also harvested to assess oxidative stress and inflammatory biomarkers in addition to histopathological and immunohistochemical analysis. Both doses of propolis significantly decreased AST, ALT, ALP, and total and differential cell counts in a dose-dependent manner. Propolis extract significantly attenuated oxidative stress in both lung and liver tissues. The restoration of antioxidant status (GSH level, SOD activities) and reduction of nitric oxide and MDA content was more so in propolis 300-treated than propolis 200-treated group. This was parallel to the improvement seen in histopathological examination. Propolis 200 and 300 significantly decreased Nrf2 expression and increased HO-1 expression in a dose-dependent manner. Moreover, immunohistochemical examination revealed that propolis 200 and 300 decreased the expression of iNOS in lung and liver tissues while decreased TNF-α expression in lung tissues only. Propolis extract could have a protective potential against nicotine-induced pulmonary and hepatic damage via activating Nrf2/HO-1 signaling.

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.

Antioxidant Property of the Egyptian Propolis Extract Versus Aluminum Silicate Intoxication on a Rat's Lung: Histopathological Studies

In this study, we evaluated the inflammatory responses induced by aluminum silicate (AS) cytotoxicity in rat lungs. The prophylactic effect of propolis extract was evaluated in 60 adult male albino rats. The rats were divided into six groups: (1) a normal, healthy control group; (2) a normal group fed with 200 mL of propolis extract/Kg; (3) a low-dose positive control group injected with 5 mg/kg of AS; (4) a treated group given propolis and a low dose of AS; (5) a high-dose positive control group injected with 20 mg/kg of AS; and (6) a treated group given propolis with a high-dose of AS. At the end of the two-month experiment, the rats’ lungs were removed. For each pair of lungs, one portion was subjected to biochemical analysis and the other underwent hematoxylin and eosin (H&E) staining in order to study its histology. The rats that received AS doses displayed significant disorders in their antioxidant contents as well as in their enzymatic activities and their histopathological structures revealed severe damage to their lung tissues. Upon the rats being treated with propolis, the enzymatic and antioxidant contents improved and partial improvements in the lung structures appeared, including minimized congestion, a reduced hemorrhage of blood vessels and preserved bronchioles, alveolar ducts, and alveoli. The prophylactic effectiveness of propolis extract on the cytotoxicity of AS, owing to the antioxidant properties of propolis, were studied.

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.

Tempol reduces inflammation and oxidative damage in cigarette smoke-exposed mice by decreasing neutrophil infiltration and activating the Nrf2 pathway

Cigarette smoke is a complex mixture capable of triggering inflammation and oxidative damage in animals at pulmonary and systemic levels. Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl) reduces tissue injury associated with inflammation in vivo by mechanisms that are not completely understood. Here we evaluated the effect of tempol on inflammation and oxidative damage induced by acute exposure to cigarette smoke in vivo. Male C57BL/6 mice (n = 32) were divided into 4 groups (n = 8 each): 1) control group exposed to ambient air (GC), 2) animals exposed to cigarette smoke for 5 days (CSG), mice treated 3) prior or 4) concomitantly with tempol (50 mg/kg/day) and exposed to cigarette smoke for 5 days. The results showed that the total number of leukocytes and neutrophils increased in the respiratory tract and lung parenchyma of mice exposed to cigarette smoke. Likewise, MPO levels and activity as well as lipid peroxidation and lung protein nitration and carbonylation also increased. Administration of tempol before or during exposure to cigarette smoke inhibited all the above parameters. Tempol also reduced the pulmonary expression of the inflammatory cytokines Il-6, Il-1β and Il-17 to basal levels and of Tnf-α by approximately 50%. In contrast, tempol restored Il-10 and Tgf-β levels and enhanced the expression of Nrf2-associated genes, such as Ho-1 and Gpx2. Accordingly, total GPx activity increased in lung homogenates of tempol-treated animals. Taken together, our results show that tempol protects mouse lungs from inflammation and oxidative damage resulting from exposure to cigarette smoke, likely through reduction of leukocyte infiltration and increased transcription of some of the Nrf2-controlled genes.

Tobacco-Free Cigarette Smoke Exposure Induces Anxiety and Panic-Related Behaviours in Male Wistar Rats

Smokers, who generally present with lung damage, are more anxious than non-smokers and have an associated augmented risk of panic. Considering that lung damage signals specific neural pathways that are related to affective responses, the aim of the present study was to evaluate the influence of pulmonary injury on anxiety and panic-like behaviours in animals exposed to cigarette smoke with and without tobacco. Male Wistar rats were divided into the following groups: a control group (CG); a regular cigarette group (RC); and a tobacco-free cigarette (TFC) group. Animals were exposed to twelve cigarettes per day for eight consecutive days. The animals were then exposed to an elevated T-maze and an open field. The RC and TFC groups presented increases in inflammatory cell inflow, antioxidant enzyme activity, and TBARS levels, and a decrease in the GSH/GSSG ratio was observed in the TFC group. Exposure to RC smoke reduced anxiety and panic-related behaviours. On the other hand, TFC induced anxiety and panic-related behaviours. Thus, our results contradict the concept that nicotine is solely accountable for shifted behavioural patterns caused by smoking, in that exposure to TFC smoke causes anxiety and panic-related behaviours.

Chemical characterization and cytotoxic activity evaluation of Lebanese propolis

Chemical composition, anti-proliferative and proapoptotic activity as well as the effect of various fractions of Lebanese propolis on the cell cycle distribution were evaluated on Jurkat leukemic T-cells, glioblastoma U251 cells, and breast adenocarcinoma MDA-MB-231 cells using cytotoxic assays, flow cytometry as well as western blot analysis. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis revealed that ferulic acid, chrysin, pinocembrin, galangin are major constituents of the ethanolic crude extract of the Lebanese propolis, while the hexane fraction mostly contains chrysin, pinocembrin, galangin but at similar levels. Furthermore chemical analysis was performed using gas chromatography-mass spectrometry (GC-MS) to identify major compounds in the hexane fraction. Reduction of cell viability was observed in Jurkat cells exposed to the ethanolic crude extract and the hexane fraction, while viability of U251 and MDA-MB-231 cells was only affected upon exposure to the hexane fraction; the other fractions (aqueous phase, methylene chloride, and ethyl acetate) were without effect. Maximum toxic effect was obtained when Jurkat cells were cultivated with 90μg/ml of both the crude extract and hexane faction. Toxicity started early after 24h of incubation and remained till 72h. Interestingly, the decrease in cell viability was accompanied by a significant increase in p53 protein expression levels and PARP cleavage. Cell cycle distribution showed an increase in the SubG0 fraction in Jurkat, U251 and MDA-MB-231 cells after 24h incubation with the hexane fraction. This increase in SubG0 was further investigated in Jurkat cells by annexinV/PI and showed an increase in the percentage of cells in early and late apoptosis as well as necrosis. In conclusion, Lebanese propolis exhibited significant cytotoxicity and anti-proliferative activity promising enough that warrant further investigations on the molecular targets and mechanisms of action of Lebanese propolis.

Time Course of the Phenotype of Blood and Bone Marrow Monocytes and Macrophages in the Lung after Cigarette Smoke Exposure In Vivo

Alveolar macrophages play a central role in the pathogenesis of chronic obstructive pulmonary disease (COPD). Monocytes are recruited from blood during inflammation and then mature into alveolar macrophages. The aim of this study was to investigate the effect of cigarette smoke (CS) at different times in lung macrophages and monocytes from blood and bone marrow in mice. Male mice (C57BL/6, n = 45) were divided into groups: control, CS 5 days, CS 14 days and CS 30 days. Five days’ CS exposure induced a pronounced influx of neutrophils and macrophages in the lung associated with increased levels of keratinocyte chemoattractant (KC), tumor necrosis factor-α (TNF-α), nitric oxide (NO) and matrix metalloproteinase (MMP)-12. After 14 days of CS exposure, neutrophil recruitment and cytokine production were greatly reduced. Moreover, chronic CS exposure led to increased recruitment of macrophages (with high expression of CD206), transforming growth factor-β (TGF-β) production as well as no detection of TNF-α, interleukin (IL)-6 and KC. CS can also change the monocyte phenotype in the blood and bone marrow, with an increase in Ly6C^low cells. These results show for the first time that CS can change not only macrophage polarization but also monocyte. These results suggest that continued recruitment of Ly6C^low monocytes may help the distinct renewing macrophage M2 population required for COPD progression.

Effects of bee propolis supplementation on glycemic control, lipid profile and insulin resistance indices in patients with type 2 diabetes: a randomized, double-blind clinical trial

BACKGROUND

Propolis, a natural resinous substance made by bees from material extracted from plants, flowers and bee's wax, has shown great therapeutic effects and been widely used in food and drug industries. Recently, some researchers have studied the effect of this substance in the treatment of diabetes.

OBJECTIVE

The purpose of this trial was to determine the effect of bee propolis on glycemic control, serum lipid profile and insulin resistance indices in patients with type 2 diabetes (T2D).

DESIGN, SETTING, PARTICIPANTS AND INTERVENTIONS

This randomized clinical trial involved 66 patients with T2D, which were randomly divided into two groups of intervention (IG) and placebo (PG). IG received 300 mg three times a day for a total of 900 mg/d of propolis pills, while PG received similar pills, lacking propolis, on the same schedule for 12 weeks.

MAIN OUTCOME MEASURES

Fasting blood glucose (FBG), hemoglobin A1c (HbA1c), total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglyceride (TG), serum insulin and insulin resistance indices were the main outcome measures.

RESULTS

The mean change in FBG between the IG ((17.76 ± 27.72) mg/dL decrease) and the PG ((6.48 ± 42.77) mg/dL increase) was significantly different (P = 0.01). Change in mean HbA1c had a similar pattern to FBG. The mean change in TC between the IG ((5.16 ± 43.80) mg/dL increase) and the PG ((28.9 ± 27.4) mg/dL increase) was also significantly different (P = 0.01), showing the protective role of propolis against the increase in TC. The change in mean LDL was similar to mean TC. There was no significant difference in other lipids or insulin resistance indices between the two groups.

CONCLUSION

Based on this study, the daily intake of 900 mg of bee propolis supplement for 12 weeks results in improvement of glycemic and some serum lipid levels in patients with T2D.

TRIAL REGISTRATION

This study is registered on the website of Iranian Ministry of Health (www.irct.ir) with proprietary code of IRCT2014080218659N1.

Structure Elucidation and Botanical Characterization of Diterpenes from a Specific Type of Bee Glue

Investigation of the single plant source bee glue type originating from Southern Australia resulted in the isolation and structure elucidation of major serrulatane diterpenes, novel 7,8,18-trihydroxyserrulat-14-ene (1), along with its oxidized product, 5,18-epoxyserrulat-14-en-7,8-dione (3) and known (18RS)-5,18-epoxyserrulat-14-en-8,18-diol (2). Exploration into the botanical origin revealed Myoporum insulare R. Br, as the plant source of the bee glue materials. This discovery was made through comparative analysis of the myoporum bee glue samples collected from the beehives, analyses of plant resinous exudate, and resin carried on the hind legs of bees foraging for bee glue.

Biological properties of propolis extracts: Something new from an ancient product

Natural products are an interesting source of new therapeutics, especially for cancer therapy as 70% of them have botany origin. Propolis, a resinous mixture that honey bees collect and transform from tree buds, sap flows, or other botanical sources, has been used by ethnobotany and traditional practitioners as early in Egypt as 3000 BCE. Enriched in flavonoids, phenol acids and terpene derivatives, propolis has been widely used for its antibacterial, antifungal and anti-inflammatory properties. Even though it is a challenge to standardize propolis composition, chemical analyses have pointed out interesting molecules that also present anti-oxidant and anti-proliferative properties that are of interest in the field of anti-cancer therapy. This review describes the various geographical origins and compositions of propolis, and analyzes how the main compounds of propolis could modulate cell signaling. A focus is made on the putative use of propolis in prostate cancer.

Brazilian red propolis attenuates hypertension and renal damage in 5/6 renal ablation model

The pathogenic role of inflammation and oxidative stress in chronic kidney disease (CKD) is well known. Anti-inflammatories and antioxidant drugs has demonstrated significant renoprotection in experimental nephropathies. Moreover, the inclusion of natural antioxidants derived from food and herbal extracts (such as polyphenols, curcumin and lycopene) as an adjuvant therapy for slowing CKD progression has been largely tested. Brazilian propolis is a honeybee product, whose anti-inflammatory, antimicrobial and antioxidant effects have been widely shown in models of sepsis, cancer, skin irritation and liver fibrosis. Furthermore, previous studies demonstrated that this compound promotes vasodilation and reduces hypertension. However, potential renoprotective effects of propolis in CKD have never been investigated. The aim of this study was to evaluate the effects of a subtype of Brazilian propolis, the Red Propolis (RP), in the 5/6 renal ablation model (Nx). Adult male Wistar rats underwent Nx and were divided into untreated (Nx) and RP-treated (Nx+RP) groups, after 30 days of surgery; when rats already exhibited marked hypertension and proteinuria. Animals were observed for 90 days from the surgery day, when Nx+RP group showed significant reduction of hypertension, proteinuria, serum creatinine retention, glomerulosclerosis, renal macrophage infiltration and oxidative stress, compared to age-matched untreated Nx rats, which worsened progressively over time. In conclusion, RP treatment attenuated hypertension and structural renal damage in Nx model. Reduction of renal inflammation and oxidative stress could be a plausible mechanism to explain this renoprotection.

Propolis: A Complex Natural Product with a Plethora of Biological Activities That Can Be Explored for Drug Development

The health industry has always used natural products as a rich, promising, and alternative source of drugs that are used in the health system. Propolis, a natural resinous product known for centuries, is a complex product obtained by honey bees from substances collected from parts of different plants, buds, and exudates in different geographic areas. Propolis has been attracting scientific attention since it has many biological and pharmacological properties, which are related to its chemical composition. Several in vitro and in vivo studies have been performed to characterize and understand the diverse bioactivities of propolis and its isolated compounds, as well as to evaluate and validate its potential. Yet, there is a lack of information concerning clinical effectiveness. The goal of this review is to discuss the potential of propolis for the development of new drugs by presenting published data concerning the chemical composition and the biological properties of this natural compound from different geographic origins.