Brazilian propolis ethanol extract and its component kaempferol induce myeloid-derived suppressor cells from macrophages of mice in vivo and in vitro

Therapeutic potential of propolis in alleviating inflammatory response and promoting wound healing in skin burn

Burns can cause inflammation and delayed healing, necessitating alternative therapies due to the limitations of conventional treatments. Propolis, a natural bee-produced substance, has shown promise in facilitating burn healing. This literature review provides a comprehensive overview of propolis' mechanisms of action, wound-healing properties, and its application in treating skin burns. Propolis contains bioactive compounds with antimicrobial, antioxidant, and anti-inflammatory properties, making it a promising candidate for managing skin burn injuries. It helps prevent infections, neutralize harmful free radicals, and promote a well-balanced inflammatory response. Moreover, propolis aids in wound closure, tissue regeneration, collagen synthesis, cellular proliferation, and angiogenesis, contributing to tissue regeneration and remodeling. The article discusses various propolis extracts, extraction methods, chemical composition, and optimized formulations like ointments and creams for burn wound treatment. Considerations regarding dosage and safety are addressed. Further research is needed to fully understand propolis' mechanisms, determine optimal formulations, and establish suitable clinical dosages. Nevertheless, propolis' natural origin and demonstrated benefits make it a compelling avenue for burn care exploration, potentially complementing existing therapies and improving burn management outcomes.

Flow cytometric detection of CD11b+ Gr-1+ cells in nontumor-bearing mice: A propolis-elicited model

Myeloid-derived suppressor cells (MDSCs) are a heterogenous myeloid lineage population whose conventional surface phenotype is CD11b+ Gr-1+. Due to their rarity and fragility, analyses using primary isolated MDSCs are extremely difficult. However, counting CD11b+ Gr-1+ cells in associated tissues such as tumors and inflammatory lesions provides critical information regarding MDSC involvement in immune disorders in the tissues. Specific MDSC markers have not been identified, limiting our ability to apply histochemical approaches during MDSCs research. However, profiling surface antigens using multi-colorimetric flow cytometry enables us to easily monitor the abundance of MDSCs in vivo. Monitoring of mouse MDSCs and their subpopulations using flow cytometry is well established. In this article, I exemplify a conventional method of monitoring CD11b+ Gr-1+ cells in mouse adipose tissue after administration of Brazilian propolis ethanol extract, which is a strong inducer of MDSCs.

Recent Update on the Anti-Inflammatory Activities of Propolis

In recent years, research has demonstrated the efficacy propolis as a potential raw material for pharmaceuticals and nutraceuticals. There is limited report detailing the mechanisms of action of propolis and its bioactive compounds in relation to their anti-inflammatory properties. Thus, the aim of the present review is to examine the latest experimental evidence (2017-2022) regarding the anti-inflammatory properties of propolis. A systematic scoping review methodology was implemented. After applying the exclusion criteria, a total of 166 research publications were identified and retrieved from Scopus, Web of Science, and Pubmed. Several key themes related to the anti-inflammatory properties of propolis were subsequently identified, namely in relation to cancers, oral health, metabolic syndrome, organ toxicity and inflammation, immune system, wound healing, and pathogenic infections. Based on the latest experimental evidence, propolis is demonstrated to possess various mechanisms of action in modulating inflammation towards the regulatory balance and anti-inflammatory environment. In general, we summarize that propolis acts as an anti-inflammatory substance by inhibiting and downregulating TLR4, MyD88, IRAK4, TRIF, NLRP inflammasomes, NF-κB, and their associated pro-inflammatory cytokines such as IL-1β, IL-6, IFN-γ, and TNF-α. Propolis also reduces the migration of immune cells such as macrophages and neutrophils, possibly by downregulating the chemokines CXCL9 and CXCL10.

Effect of Shenling Baizhu powder on immunity to diarrheal disease: A systematic review and meta-analysis

Background: Diarrhea is one of the leading causes of death worldwide and is associated with immune dysfunction. The modulatory effects of Shenling Baizhu powder (SLBZS) on immune function in diarrheal disease have been validated in various animal models. However, the results of these studies have not been systematically evaluated. This study aimed to evaluate the preclinical data on SLBZS for the treatment of diarrhea from an immunological perspective. Methods: PubMed, Embase, Cochrane Library, CNKI, Wanfang Database, VIP, and Chinese Medicine Database were searched for all animal trials on SLBZS for the treatment of diarrhea published up to April 2022. Standardized mean differences (SMD) were used as effect sizes in the meta-analysis of continuous variables, including immune organs, immune cells, and immune cytokines. Subgroup analysis was performed according to animal species and disease models. The GRADE was used to assess the quality of evidence. Results: A total of 26 studies were included. Meta-analysis showed that compared to those in the model group, SLBZS significantly increased body weight [SMD = 1.54, 95% confidence interval (CI) (1.06, 2.02)], spleen mass [SMD = 1.42, 95% CI (0.98, 1.87)], thymus mass [SMD = 1.11, 95% CI (0.69, 1.53)], macrophage phagocytic capacity (SMD = 1.07, 95% CI [0.59, 1.54]), sIgA [SMD = 1.04, 95% CI (0.33, 1.74)], RBC-C3b-RR [SMD = 1.16, 95% CI (0.65, 1.67)], IL-2 [SMD = 1.52, 95% CI (0.89, 2.14)] and decreased diarrhea scores [SMD = -1.40, 95% CI (-2.03, -0.87)], RBC-IC-RR [SMD = -1.40, 95% CI (-1.94, -0.87)], and IL-8 [SMD = -2.80, 95% CI (-3.54, -2.07)]. Subgroup analysis showed that SLBZS regulated TNF-α, IL-1β, and IL-10 in rats and mice, and improved IL-6 and IL-10 in different diseases, with differences between subgroups (p < 0.05). Owing to heterogeneity, the reliability of the results remains to be verified. The quality of evidence was "very low". Conclusion: SLBZS improve diarrhea symptoms by enhancing immune function. It has curative effects with differences between different species and diseases, however, because the reporting in the original studies was too unclear to be assessed, the analysis was inconclusive. For higher quality evidences, future research should pay attention to the scientific rigor of the experimental design and the completeness of the reported results.

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.

Emerging Roles of Myeloid-Derived Suppressor Cells in Diabetes

Diabetes is a syndrome characterized by hyperglycemia with or without insulin resistance. Its etiology is attributed to the combined action of genes, environment and immune cells. Myeloid-derived suppressor cell (MDSC) is a heterogeneous population of immature cells with immunosuppressive ability. In recent years, different studies have debated the quantity, activity changes and roles of MDSC in the diabetic microenvironment. However, the emerging roles of MDSC have not been fully documented with regard to their interactions with diabetes. Here, the manifestations of MDSC and their subsets are reviewed with regard to the incidence of diabetes and diabetic complications. The possible drugs targeting MDSC are discussed with regard to their potential of treating diabetes. We believe that understanding MDSC will offer opportunities to explain pathological characteristics of different diabetes. MDSC also will be used for personalized immunotherapy of diabetes.

Red Propolis as a Source of Antimicrobial Phytochemicals: Extraction Using High-Performance Alternative Solvents

Propolis is a resinous material rich in flavonoids and involved in several biological activities such as antimicrobial, fungicide, and antiparasitic functions. Conventionally, ethanolic solutions are used to obtain propolis phytochemicals, which restrict their use in some cultures. Given this, we developed an alcohol-free high-performance extractive approach to recover antibacterial and antioxidants phytochemicals from red propolis. Thus, aqueous-solutions of ionic liquids (IL) and eutectic solvents were used and then tested for their total flavonoids, antioxidant, and antimicrobial activities. The surface-responsive technique was applied regarding some variables, namely, the time of extraction, the number of extractions, and cavitation power (W), to optimize the process (in terms of higher yields of flavonoids and better antioxidant activity). After that, four extractions with the same biomass (repetitions) using 1-hexyl-3-methylimidazolium chloride [C6mim]Cl, under the operational conditions fixed at 3.3 min and 300 W, were able to recover 394.39 ± 36.30 mg RuE. g-1 of total flavonoids, with total antioxidant capacity evaluated up to 7595.77 ± 5.48 μmol TE. g-1 dried biomass, besides inhibiting the growth of Staphylococcus aureus and Salmonella enteritidis bacteria (inhibition halo of 23.0 ± 1.0 and 15.7 ± 2.1, respectively). Aiming at the development of new technologies, the antimicrobial effect also presented by [C6mim]Cl may be appealing, and future studies are required to understand possible synergistic actions with propolis phytochemicals. Thereby, we successfully applied a completely alcohol-free method to obtain antimicrobials phytochemicals and highly antioxidants from red propolis, representing an optimized process to replace the conventional extracts produced until now.

Extracts of Poplar Buds (Populus balsamifera L., Populus nigra L.) and Lithuanian Propolis: Comparison of Their Composition and Biological Activities

Balsam poplar and black poplar (Populus balsamifera L. and Populus nigra L.) buds that grow in Lithuania are the primary source of propolis, therefore it is proper to evaluate and compare the composition of these raw plant materials and propolis quantitatively and qualitatively. Propolis and balsamic poplar bud extract are dominated by p-coumaric acid and black poplar-caffeic acid. Antioxidant activity was evaluated by DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), FRAP (ferric-reducing antioxidant power) and CUPRAC (cupric reducing antioxidant capacity) methods and all extracts showed antioxidant activity, and obtained results correlated with the obtained amounts of phenolic compounds and flavonoids in the extracts. Studies of antimicrobial activity have shown that all extracts have a growth inhibitory effect against Staphylococcus aureus and Candida albicans, but the extract of balsam poplar buds showed the most significant effect of such kind. Considering the results of the research, it can be stated that balsam poplar buds cultured in Lithuania are the primary raw material of propolis, which is rich in phenolic compounds with antioxidant properties and is a promising raw material for pharmaceutical purposes.

Chemical and biological characteristics of propolis from Apis mellifera caucasica from the Ardahan and Erzurum provinces of Turkey: a comparative study

The aim of this study was to compare the biological activities of ethanolic propolis extracts of Apis mellifera caucasica obtained from Ardahan and Erzurum provinces of Turkey. Samples were tested for antioxidant, anticytotoxic, anticarcinogenic, antibacterial, and antifungal potentials using different techniques. Propolis samples from the two provinces had different mineral and organic compositions related to their geographical origin. The ferric reducing antioxidant power (FRAP) test showed superiority of Ardahan propolis over the Erzurum. Regardless of origin and the presence of mitomycin C in the culture medium, propolis enhanced human peripheral lymphocyte viability, which depended on the duration and propolis concentration. Antiperoxidative activity on MCF-7 breast cancer cells was concentration-dependent. Erzurum propolis showed the highest anticarcinogenic activity at the concentrations of 62.5 μg/mL and 125 μg/ mL, which dropped at higher concentrations. All propolis samples also showed antibacterial activity against the tested human pathogens similar to ampicillin and penicillin controls, except for Pseudomonas aeruginosa. However, they did not exert any antifungal activity against Candida albicans and Yarrowia lipolytica. In conclusion, propolis samples from both provinces showed promising biological activities, but further research should focus on finding the right concentrations for optimal effect and include the cell necrosis pathway to get a better idea of the anticarcinogenic effects.

Salt-dependent hypertension and inflammation: targeting the gut-brain axis and the immune system with Brazilian green propolis

Systemic arterial hypertension (SAH) is a major health problem around the world and its development has been associated with exceeding salt consumption by the modern society. The mechanisms by which salt consumption increase blood pressure (BP) involve several homeostatic systems but many details have not yet been fully elucidated. Evidences accumulated over the last 60 decades raised the involvement of the immune system in the hypertension development and opened a range of possibilities for new therapeutic targets. Green propolis is a promising natural product with potent anti-inflammatory properties acting on specific targets, most of them participating in the gut-brain axis of the sodium-dependent hypertension. New anti-hypertensive products reinforce the therapeutic arsenal improving the corollary of choices, especially in those cases where patients are resistant or refractory to conventional therapy. This review sought to bring the newest advances in the field articulating evidences that show a cross-talking between inflammation and the central mechanisms involved with the sodium-dependent hypertension as well as the stablished actions of green propolis and some of its biologically active compounds on the immune cells and cytokines that would be involved with its anti-hypertensive properties.

Cuban Brown Propolis Interferes in the Crosstalk between Colorectal Cancer Cells and M2 Macrophages

Tumor-associated macrophages (TAMs), primarily the M2 phenotype, are involved in the progression and metastasis of colorectal cancer (CRC). Cuban brown propolis (Cp) and its main component Nemorosone (Nem) displays an antiproliferative effect on different cancer cells, including CRC cell lines. However, whether Cp and Nem could exploit its effect on CRC cells by targeting their relationship with TAMs remains to be elucidated. In this study, we differentiated the human monocytic THP-1 cells to M2 macrophages and confirmed this transition by immunofluorescence (IF) staining, qRT-PCR and zymography. An MTT assay was performed to determine the effect of Cp and Nem on the viability of CRC HT-29 cells co-cultured with M2 macrophages. Furthermore, the migration and invasion abilities of HT-29 cells were determined by Transwell assays and the expression levels of epithelial–mesenchymal transition (EMT) markers were analyzed by IF staining. We demonstrated that Cp and Nem reduced the viability of M2 macrophages and, accordingly, the activity of the MMP-9 metalloprotein. Moreover, we demonstrated that M2 macrophages produce soluble factors that positively regulate HT-29 cell growth, migration and invasion. These M2-mediated effects were counteracted by Cp and Nem treatments, which also played a role in regulating the expression of the EMT markers E-cadherin and vimentin. Taken together, our results indicate that Nem contained in Cp interferes in the crosstalk between CRC cells and TAMs, by targeting M2 macrophages.

Natural constituents from food sources as therapeutic agents for obesity and metabolic diseases targeting adipose tissue inflammation

Adipose tissue, an endocrine and paracrine organ, plays critical roles in the regulation of whole-body metabolic homeostasis. Obesity is accompanied with a chronic low-grade inflammation status in adipose tissue, which disrupts its endocrine function and results in metabolic derangements, such as type 2 diabetes. Dietary bioactive components, such as flavonoids, polyphenols and unsaturated fatty acids from fruits and vegetables, have been widely revealed to alleviate both systemic and adipose tissue inflammation, and improve metabolic disorders. Remarkably, some dietary bioactive components mitigate the inflammatory response in adipocytes, macrophages, and other immune cells, and modulate the crosstalk between adipocytes and macrophages or other immune cells, in adipose tissue. Epidemiological and preclinical studies related to these substances have indicated beneficial effects on adipose tissue inflammation. The main purpose of this review is to provide a comprehensive and up-to-date state of knowledge on dietary components targeting adipose tissue inflammation and their underlying mechanisms. These natural products have great potential to be developed as functional food or lead compounds for treating and/or preventing metabolic disorders.

Green propolis increases myeloid suppressor cells and CD4+Foxp3+ cells and reduces Th2 inflammation in the lungs after allergen exposure

ETHNOPHARMACOLOGICAL RELEVANCE

Propolis is a natural product produced by honeybees used as a medicine at least to 300 BC. In the last decades, several studies showed biological and pharmacological properties of propolis, witch scientifically explains the empirical use for centuries. The anti-inflammatory activity of propolis with the purpose to reduce Th2 inflammation has been evaluated in allergic asthma. However, it remains to be determined how propolis negatively regulates the immune response after allergen re-exposure.

AIM OF THE STUDY

We hypothesized that the anti-inflammatory activity of propolis is dependent on the induction of myeloid derived suppressor cells (MDSC) and regulatory T cells.

MATERIALS AND METHODS

To assess this hypothesis, we used an ovalbumin-induced asthma model to evaluate the effect of EPP-AF® dry extract from Brazilian green propolis.

RESULTS

Propolis treatment decreased pulmonary inflammation and mucus production as well as eosinophils and IL-5 in the broncoalveolar lavage. Propolis enhanced also in vitro differentiation and in vivo frequency of lung MDSC and CD4⁺Foxp3⁺ regulatory T cells.

CONCLUSIONS

Together these results confirm the immunomodulatory potential of propolis during sensitization and challenge with allergen. In addition, the collecting findings show, for the first time, that propolis increases the frequency of MDSC and CD4⁺Foxp3⁺ regulatory T cells in the lungs, and suggest that it could be use as target for development of new immunotherapy or adjuvant immunotherapy for asthma.

Propolis and Its Combination with Boric Acid Protect Against Ischemia/Reperfusion-Induced Acute Kidney Injury by Inhibiting Oxidative Stress, Inflammation, DNA Damage, and Apoptosis in Rats

Ischemia reperfusion (I/R) injury which causes kidney dysfunction is one of the most studied diseases directly linked to oxidative stress. In this regard, it is important to protect cells against damage by inducing antioxidant response. Herein, we aimed to evaluate the therapeutic roles and possible mechanisms of propolis and boric acid in kidney I/R injury based on relevant basic research and clinical studies. Sprague-Dawley rats were subjected to 50 min of ischemia followed by 3 h of reperfusion. Animals were randomly divided into a control group (the abdominal wall was just opened and closed), an I/R injury group, the propolis intervention group (200 mg/kg, intragastric administration, 1 h before ischemia), boric acid intervention group (14 mg/kg, intragastric administration 1 h before ischemia), and the propolis + boric acid intervention group (intragastric administration 1 h before ischemia). Kidney function, the antioxidant defensive system, and renal damage were assessed. In addition, the oxidative stress and inflammatory status were estimated in renal tissue. Furthermore, DNA damageand apoptosis were detected by immunohistochemistry. When compared with I/R group, propolis alone and especially propolis + boric acid groups significantly improved functional parameters. While the antioxidant response was increased, renal injury size and apoptosis were significantly decreased in both groups. Also, the MDA and TNF-α levels besides the 8-OHdG formation were downregulated. According to these outcomes, it can be said that especially propolis together with boric acid ameliorates kidney injury caused by I/R through acting as an antioxidant, anti-inflammatory, and antiapoptotic agent. In conclusion, propolis alone and its combination with boric acid could be developed as therapeutic agents against serious renal I/R injuries.

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.