Propolis extract protects against radiation-induced intestinal mucositis through anti-apoptotic mechanisms

Liposomal propolis loaded xanthan gum-salep hydrogels: Preparation, characterization, and in vitro bioaccessibility of phenolics

Liposomes are gaining interest in food and pharmaceutical applications due to their biocompatibility and non-toxicity. However, they suffer from low colloidal stability, leakage of encapsulated substances, and poor resistance to intestinal digestive conditions. To address these issues, propolis extract (PE) was encapsulated within a hybrid system combining liposomes and hydrogels. PE encapsulated in phosphatidylcholine liposome formulations incorporated with two different food additives: polyethylene sorbitan monooleate (T80) and ammonium phosphatide (AMP) was embedded in xanthan gum-salep hydrogels. The embedded liposomes protected their structure and did not change the flow behaviour of the hydrogels. AMP-liposomal gels exhibited a stronger solid character. The mucoadhesiveness of liposomal gels was mostly governed by the higher xanthan gum ratio, while PE loading also yielded higher mucoadhesiveness. The bioaccessibility (BI%) of the phenolic compounds ranged from 10.13 to 582.75 % in the liposomal gel. The proposed hybrid encapsulation method not only provided enhanced solubility to hydrophobic PE but also protected its phenolic compounds against simulated digestion conditions. Moreover, converting aqueous liposomes into gel structures would also expand their application range in various functional food formulations.

Effects of aqueous and ethanolic extracts of Chinese propolis on dental pulp stem cell viability, migration and cytokine expression

Background

Propolis is a natural substance produced by honeybees that has various biological properties including, anti-inflammatory, antioxidant and antimicrobial properties. Although previous studies have evaluated the antimicrobial effects of propolis in dentistry, its effects on dental pulp stem cell (DPSC) viability, migration, and differentiation are yet not well understood. The objective of this study was to investigate the effects of Chinese propolis on viability/proliferation, migration, differentiation and cytokine expression in DPSCs.

Methods

Commercially available DPSCs (Lonza) were treated with aqueous extract of propolis (AEP) or ethanolic extract of propolis (EEP), and viability/proliferation was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assays and quantification of nuclear staining. DPSC differentiation into mineralizing cells was evaluated with Alizarin red staining and cell migration was assessed using Boyden Chamber Transwell inserts. Cytokine expression was measured by RT-qPCR. AEP and EEP at 0.03 and 0.1 mg/mL did not affect DPSC viability/proliferation for up to 7-days treatment.

Results

Higher doses (0.33-33 mg/mL) induced a dose dependent decrease in DPSC viability/proliferation with a more prominent effect with EEP at 7 days. Neither AEP nor EEP induced DPSC differentiation into mineralizing cells, but both AEP and EEP (0.03-0.1 mg/ml) induced a dose dependent increase in DPSC migration. In addition, EEP prevents the upregulation of IL1b and IL6 but not IL8 and CCL2 in response to lipopolysaccharide stimulation. AEP has less potent anti-inflammatory effects and prevents only IL1b upregulation.

Conclusion

This study provides new information about the biologic properties of ethanolic and aqueous extracts of propolis and shows that propolis, at doses that do not affect cell viability, induces DPSC migration and has anti-inflammatory properties. These data highlight the potential use of propolis as an alternative intra-canal medicament for regenerative endodontic procedures.

Effect of Propolis on Salivary Glands After Radiotherapy

OBJECTIVES

To investigate the effects of increasing propolis doses on salivary glands exposed to radiotherapy (RT).

METHODS

Thirty-seven rats were divided into 4 groups: The control group (G0, n: 7), G1 group (n: 10), G2 group (n: 10), and G3 group (n: 10). The rats in the G1 group received 15 Gray (Gy) RT only to the head and neck area. The rats in the G2 and G3 groups received 15 Gy RT for the head and neck area along with 100 mg/kg/ml and 200 mg/kg/ml of propolis. The parotid, submandibular, and sublingual glands of rats were immunohistochemically stained with aquaporin-1 (AQP-1) and aquaporin-5 (AQP-5). They were also evaluated for malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPO), total antioxidant (TAS), and total oxidant status (TOS).

RESULTS

AQP-1 and AQP-5 values were highest in G0 group followed by G3, G2, and G1 groups in decreasing order. The MDA and TOS values were highest in G1 group, which was followed by G2, G3, and G0 groups. The highest GPO, SOD, and TAS values were observed in G0 group followed by G3, G2, and G1 groups in decreasing order.

CONCLUSION

It was found that propolis increased antioxidant products and decreased oxidative products in the salivary glands receiving RT in parallel with the dose increase. Similarly, in the groups receiving propolis, an increase in the immune expression of aquaporin molecules was detected in a dose-dependent manner. Based on these data, it could be stated that propolis has a healing effect on the salivary glands exposed to RT.

Ipomoea carnea mitigates ethanol-induced ulcers in irradiated rats via Nrf2/HO-1 pathway: an in vivo and in silico study

The aim of this study was to investigate the potential of Ipomoea carnea flower methanolic extract (ICME) as a natural gastroprotective therapy against ethanol-induced gastric ulcers, particularly in individuals exposed to ionizing radiation (IR). The study focused on the Nrf2/HO-1 signaling pathway, which plays a crucial role in protecting the gastrointestinal mucosa from oxidative stress and inflammation. Male Wistar rats were divided into nine groups, the control group received distilled water orally for one week, while other groups were treated with ethanol to induce stomach ulcers, IR exposure, omeprazole, and different doses of ICME in combination with ethanol and/or IR. The study conducted comprehensive analyses, including LC-HRESI-MS/MS, to characterize the phenolic contents of ICME. Additionally, the Nrf2/HO-1 pathway, oxidative stress parameters, gastric pH, and histopathological changes were examined. The results showed that rats treated with IR and/or ethanol exhibited histopathological alterations, increased lipid peroxidation, decreased antioxidant enzyme activity, and reduced expression levels of Nrf2 and HO-1. However, pretreatment with ICME significantly improved these parameters. Phytochemical analysis identified 39 compounds in ICME, with flavonoids, hydroxybenzoic acids, and fatty acids as the predominant compounds. Virtual screening and molecular dynamics simulations suggested that ICME may protect against gastric ulceration by inhibiting oxidative stress and inflammatory mediators. In conclusion, this study demonstrates the potential of ICME as a natural gastroprotective therapy for preventing gastric ulcers. These findings contribute to the development of novel interventions for gastrointestinal disorders using natural plant extracts particularly in individuals with a history of radiation exposure.

Propolis Protects GC-1spg Spermatogonial Cells against Tert-Butyl Hydroperoxide-Induced Oxidative Damage

Propolis is a natural resin produced by honeybees with plenty of pharmacologic properties, including antioxidant activity. Oxidative stress disrupts germ cell development and sperm function, with demonstrated harmful effects on male reproduction. Several natural antioxidants have been shown to reduce oxidative damage and increase sperm fertility potential; however, little is known about the effects of propolis. This work evaluated the role of propolis in protecting spermatogonial cells from oxidative damage. Propolis' phytochemical composition and antioxidant potential were determined, and mouse GC-1spg spermatogonial cells were treated with 0.1-500 µg/mL propolis (12-48 h) in the presence or absence of an oxidant stimulus (tert-butyl hydroperoxide, TBHP, 0.005-3.6 µg/mL, 12 h). Cytotoxicity was assessed by MTT assays and proliferation by Ki-67 immunocytochemistry. Apoptosis, reactive oxygen species (ROS), and antioxidant defenses were evaluated colorimetrically. Propolis presented high phenolic and flavonoid content and moderate antioxidant activity, increasing the viability of GC-1spg cells and counteracting TBHP's effects on viability and proliferation. Additionally, propolis reduced ROS levels in GC-1spg, regardless of the presence of TBHP. Propolis decreased caspase-3 and increased glutathione peroxidase activity in TBHP-treated GC-1spg cells. The present study shows the protective action of propolis against oxidative damage in spermatogonia, opening the possibility of exploiting its benefits to male fertility.

Radioprotective Effects from Propolis: A Review

Propolis is a natural bee-produced substance with antimicrobial, anti-inflammatory, and wound-healing properties, containing some components from the leaves, buds and resins of plants. It has been used for centuries for various health benefits. In this manuscript, our group reviewed the radioprotective effect of propolis using PubMed and Embase, and our review was conducted according to the PRISMA statement. Finally, 27 articles were included in this review, which includes the radioprotective effect of propolis from cell-based studies (n = 8), animal models (n = 14), and human trials (n = 5). Results reflected that the dosage forms of propolis extracted in the scientific literature were ethanolic extracts of propolis, a water-soluble derivate of propolis, or capsules. The efficacy of the radioprotective properties from propolis is extracted from the bibliography, as several compounds of this resinous mixture individually or synergistically are possible candidates that have the radioprotective effect. In fact, studies prior to 2011 lacked a comprehensive characterization of propolis due to the variability in active compounds among different batches of propolis and were limited to analytical techniques. Furthermore, in this manuscript, we have selected studies to include primarily propolis types from Brazil, Croatia, Egypt, European countries, and those commercialized in Spain. They all contained ethanolic extract of propolis (EEP) and were influenced by different dosage forms. EEP showed a significant presence of lipophilic bioactive compounds like flavones, flavonols, and flavanones.

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.

Propolis-Loaded Chitosan Nanoparticles for the Treatment of Bacterial Diarrhea: In Vitro and In Vivo Evaluation

Diarrhea is a disorder in the gastrointestinal system that is accompanied by cramps, decreased stool’s viscosity, and reduced defecation intervals. In the current study, propolis was loaded into chitosan nanoparticles to develop a potential treatment for gastrointestinal infections. Various In Vitro experiments were performed to characterize the produced nanoparticles. The healing function of propolis-loaded chitosan nanoparticles (ProCHNPs) was evaluated in a rat model of enteropathogenic Escherichia coli-induced diarrhea. In Vitro studies showed that ProCHNPs were not toxic against intestinal epithelial cells and improved their viability. Furthermore, these particles had around 261.49±63.22 nm average particle size and showed significantly higher antibacterial and anti-inflammatory activities than propolis-free chitosan nanoparticles. In Vivo studies showed that ProCHNPs had comparable anti-diarrhea function with norfloxacin as the standard drug. In addition, ProCHNPs increased the number of beneficial bacteria in the intestinal microflora and reduced the level of pro-inflammatory cytokines in the colon tissue. This study suggests potential use of ProCHNPs as an alternative treatment for bacterial diarrhea.

The effect of systemic application of propolis on tongue damage and oral mucositis in rats exposed to radiation

PURPOSE

In this experimental study, the effect of dose-dense systemic application of propolis on oral mucosity, histological changes in papilla, and inflammatory and hypoxic markers in rats exposed to radiation was investigated.

METHODS

Seven rats were in the control and 30 rats in the experimental group. Three experimental groups were formed. In Group 1 RT (15 Gy) was delivered only to the head and neck region. In Group 2, RT (15 Gy) and systemic administration of 100 mg/kg/ml propolis, in Group 3, RT (15 Gy) and systemic administration of 200 mg/kg/ml propolis were applied. Oral mucositis index (OMI) was scored in control and experimental groups. Proinflammatory markers [interleukin-6 (IL-6), myeloperoxidase (MPO), tumor-necrosis factor-α (TNF-α)] hypoxia markers [glucose transporter-1 (GLUT-1), hypoxia-inducible factor 1α (HIF-1α)] were studied histomorphologically.

RESULTS

The significantly highest OMI score was observed in the G1. OMI score was statistically significantly decreased in experimental groups receiving systemic propolis, especially in G3. Proinflammatory markers increased significantly only in the experimental RT group, G1. Serum levels of MPO and TNF-α significantly decreased in the dose-dense systemic propolis arm. The highest levels of hypoxia markers (HIF-1α and GLUT-1) were detected in the RT group, then in G2, G3, and control groups in order of decreasing frequency. However, the difference between the groups did not reach the level of statistical significance.

CONCLUSION

Systemic propolis can be reduced acute mucositis with its anti-inflammatory effect without developing resistance to RT (tumor protection). However, greater number of clinical studies should be designed to arrive at definitive conclusions.

Could Polyphenols Really Be a Good Radioprotective Strategy?

Currently, radiotherapy is one of the most effective strategies to treat cancer. However, deleterious toxicity against normal cells indicate for the need to selectively protect them. Reactive oxygen and nitrogen species reinforce ionizing radiation cytotoxicity, and compounds able to scavenge these species or enhance antioxidant enzymes (e.g., superoxide dismutase, catalase, and glutathione peroxidase) should be properly investigated. Antioxidant plant-derived compounds, such as phenols and polyphenols, could represent a valuable alternative to synthetic compounds to be used as radio-protective agents. In fact, their dose-dependent antioxidant/pro-oxidant efficacy could provide a high degree of protection to normal tissues, with little or no protection to tumor cells. The present review provides an update of the current scientific knowledge of polyphenols in pure forms or in plant extracts with good evidence concerning their possible radiomodulating action. Indeed, with few exceptions, to date, the fragmentary data available mostly derive from in vitro studies, which do not find comfort in preclinical and/or clinical studies. On the contrary, when preclinical studies are reported, especially regarding the bioactivity of a plant extract, its chemical composition is not taken into account, avoiding any standardization and compromising data reproducibility.

Comparison of Ethanolic and Aqueous-Polyethylenglycolic Propolis Extracts: Chemical Composition and Antioxidant Properties

In recent years, particular attention has been paid to the natural antioxidants. Bee products, especially propolis, are characterized by multifunctional (antioxidant, anti-inflammatory, antibacterial, antiviral, and food preservative) effects and can be used for the development of functional food or food preservatives. Propolis extracts that are commonly produced are ethanolic; therefore, to certain groups of consumers, for example, children and alcohol sensitive group, their applicability is limited. The aim of this study was to develop alternative propolis from aqueous-polyethylenglycolic propolis extract (AQUA-PEG) and compare the chemical composition as well as antioxidant (radical-scavenging and reduction properties) activities to those of ethanolic propolis extract (EEP). Polyethylene glycol is quite a good solvent, which can be successfully used for the preparation of NEP. The total quantity of phenolic compounds identified in AQUA-PEG (400.36 µg/mL), prepared according to our technology, is very similar to that of EEP (433.53 µg/mL), whereas the amount of phenolic acids was greater by 1.31-fold in AQUA-PEG and of flavonoids was greater by 2.38-fold in EEP. The antioxidant activity depends on the method used: by applying the ABTS and CUPRAC methods, both extracts demonstrate similar antioxidant (antiradical and reducing) activity, whereas in the case of the DPPH and FRAP method, significantly higher antioxidant activity was detected in EEP. This should be taken by researchers into account especially when interpreting the results and drawing conclusions about the antioxidant activity of propolis extracts. On the basis of the results, AQUA-PEG, prepared by the developed technology, can be used as an alternative form to ethanolic propolis extract, since it contains a large quantity of antioxidants, namely, flavonoids and phenolic acids. We believe that nonethanolic propolis extract has the prospect of being applied for the development of functional foods in order to alleviate certain symptoms of oxidative stress or for the prevention of some oxidative-stress-related diseases.

Research progress on radioprotective effects of bee products

Radiation exposure is an on going and serious threat in military and public health concern. There is an unmet need for effective preventative or mitigative treatments against radiation-induced injuries. The handful of Food and Drug Administration in the US approved radiation protection agents cannot be widely used due to their side effects. Some natural nontoxic compounds such as bee products have been reported to prevent and treat radiation-induced injuries (e.g. scavenging free radicals, inhibiting cell apoptosis and reducing DNA damage), indicating that they may be a potential option as a safe radioprotective agent. Bee products are nontoxic and have no known side effects on the human body, and are effective in the field of radiation protection. They are expected to be interesting drug candidates for preventing and treating radiation-induced injuries. This article reviews the prevention and treatment of bee products on radiation-induced injuries.

Bioactive Polyphenols from Pomegranate Juice Reduce 5-Fluorouracil-Induced Intestinal Mucositis in Intestinal Epithelial Cells

Intestinal epithelial cells (IECs) play a pivotal role in maintaining intestinal homeostasis. Different noxious agents, among them also anticancer therapies, can impair intestinal epithelial integrity triggering inflammation and oxidative stress. A frequent complication of chemotherapy is gastrointestinal mucositis, strongly influencing the effectiveness of therapy, increasing healthcare costs, and impairing patients’ quality of life. Different strategies are used to treat gastrointestinal mucositis, including products from natural sources. Our study focused on the effect of pomegranate (Punica granatum L.) juice extract on IEC-6 cells, both during inflammatory conditions and following treatment with 5-fluorouracil (5-FU). The polyphenolic profile of pomegranate juice was characterized in detail by Online Comprehensive two dimensional Liquid Chromatography-Mass Spectrometry. The evaluation of pomegranate juice extract in IEC-6 indicates a significant inhibition in proinflammatory factors, such as cytokines release, cyclooxygenase-2 and inducible nitric oxide synthase expression, and nitrotyrosine formation. Pomegranate also inhibited oxidative stress and adhesion protein expression. In 5-FU-treated IEC-6, pomegranate also inhibited both inflammatory and oxidative stress parameters and apoptosis. It promoted wound repair and tight junction expression. These results suggest a potential use of pomegranate as an adjuvant in the treatment of intestinal inflammatory and oxidative stress states, which also occur during chemotherapy-induced mucositis.

Antiviral effects of Brazilian green and red propolis extracts on Enterovirus surrogates

Propolis is a natural product of bees with biological activities that are mainly associated with bee type and geographic origin. Propolis extract has been proposed with several applications in environmental health. The ethanol extracts have shown good antimicrobial activity. The association of this technique with ultrasound-assisted extraction has been studied to improve the characteristics of the obtained extracts. Thus, the objective of this work is to verify the antiviral action against two strains of bacteriophages of two extracts of Brazilian propolis (green and red) obtained by conventional extraction and ultrasonic extraction. The activities of the propolis red and green extracts were confirmed by the significant ~3 and ~4.5 Log 10 PFU/mL reduction in the concentrations of the MS2 and Av-08 bacteriophages, respectively. It was found that ultrasound-assisted extraction is comparable to the maceration process and demonstrated the best antiviral activities. Brazilian red propolis was more effective than green propolis in viral reduction in all treatments.

Glycyrrhizin Ameliorates Radiation Enteritis in Mice Accompanied by the Regulation of the HMGB1/TLR4 Pathway

Radiation enteritis is a common side effect of radiotherapy for abdominal and pelvic malignancies, which can lead to a decrease in patients' tolerance to radiotherapy and the quality of life. It has been demonstrated that glycyrrhizin (GL) possesses significant anti-inflammatory activity. However, little is known about its anti-inflammatory effect in radiation enteritis. In the present study, we aimed to investigate the potential anti-inflammatory effects of GL on radiation enteritis and elucidate the possible underlying molecular mechanisms involved. The C57BL/6 mice were subjected to 6.5 Gy abdominal X-ray irradiation to establish a model of radiation enteritis. Hematoxylin and eosin staining was performed to analyze the pathological changes in the jejunum. The expression of TNF-α in the jejunum was analyzed by immunochemistry. The levels of inflammatory cytokines, such as TNF-α, IL-6, IL-1β, and HMGB1 in the serum were determined by enzyme-linked immunosorbent assay. The intestinal absorption capacity was tested using the D-xylose absorption assay. The levels of HMGB1 and TLR4 were analyzed by western blotting and immunofluorescence staining. We found that GL significantly alleviated the intestinal damage and reduced the levels of inflammatory cytokines, such as TNF-α, IL-6, IL-1β, and HMGB1 levels. Furthermore, the HMGB1/TLR4 signaling pathway was significantly downregulated by GL treatment. In conclusion, these findings indicate that GL has a protective effect against radiation enteritis through the inhibition of the intestinal damage and the inflammatory responses, as well as the HMGB1/TLR4 signaling pathway. Thereby, GL might be a potential therapeutic agent for the treatment of radiation enteritis.