In vitro and in vivo burn healing study of standardized propolis: Unveiling its antibacterial, antioxidant and anti-inflammatory actions in relation to its phytochemical profiling.

BACKGROUND: Natural propolis has been used since decades owing to its broad-spectrum activities. Burn injuries are a global health problem with negative impacts on communities. Bacterial infections usually accompany burns, which demand implementation of antibiotics. Antibiotics abuse led to emergence of microbial drug resistance resulting in poor treatment outcomes. In such instances, the promising alternative would be natural antimicrobials such as propolis. OBJECTIVE: Full chemical profiling of propolis and evaluation of in vitro antibacterial, antioxidant and anti-inflammatory activities as well as in vivo burn healing properties. METHODS: Chemical profiling of propolis was performed using Liquid chromatography (UHPLC/MS-PDA and HPLC-PDA). In vitro assessment was done using Disc Diffusion susceptibility test against Staphylococcus aureus and infected burn wound mice model was used for in vivo assessment. In vitro antioxidant properties of propolis were assessed using DPPH, ABTS and FRAP techniques. The anti-inflammatory effect of propolis was assessed against lipopolysaccharide/interferon-gamma mediated inflammation. RESULTS: UHPLC/MS-PDA results revealed identification of 71 phytochemicals, mainly flavonoids. Upon flavonoids quantification (HPLC-PDA), Pinocembrin, chrysin and galangin recorded high content 21.58±0.84, 22.73±0.68 and 14.26±0.70 mg/g hydroalcoholic propolis extract, respectively. Propolis showed concentration dependent antibacterial activity in vitro and in vivo burn healing via wound diameter reduction and histopathological analysis without signs of skin irritation in rabbits nor sensitization in guinea pigs. Propolis showed promising antioxidant IC50 values 46.52±1.25 and 11.74±0.26 µg/mL whereas FRAP result was 445.29±29.9 µM TE/mg. Anti-inflammatory experiment results showed significant increase of Toll-like receptor 4 (TLR4), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) mRNA levels. Nitric oxide and iNOS were markedly increased in Griess assay and western blot respectively. However, upon testing propolis against LPS/IFN-γ-mediated inflammation, TLR4, IL-6 and TNF-α expression were downregulated at transcriptional and post-transcriptional levels. CONCLUSION: Propolis proved to be a promising natural burn healing agent through its antibacterial, antioxidant and anti-inflammatory activities.

Electrospinning-netting of spider-inspired polycaprolactone/collagen nanofiber-nets incorporated with Propolis extract for enhanced wound healing applications.

Nanofibers hold significant promise for wound healing applications, but their potential is limited by their large diameter. To overcome this limitation, the development of nanofibrous systems with refined nanonets (approximately 20 nm in diameter) represents a notable improvement. In this study, a composite of polycaprolactone/collagen (PCLC) nano-fiber/nets (NFNs) was fabricated using benign solvents (acetic acid and formic acid) via the electro-spinning/netting (ESN) technique, harnessing the regenerative potential of collagen as a biological macromolecule. Additionally, to enhance the natural attributes of the NFNs structure, Propolis extract, renowned for its wound healing properties, was incorporated. Five ESN solutions were prepared: PCL, PCLC, PCLC/Pro 5 %, PCLC/Pro 10 %, and PCLC/Pro 15 %. NaCl salt was introduced into all ESN solutions to improve nanonets formation. FE-SEM imaging demonstrated successful nano-net formation in all ESN solutions except for the PCL formulation. The fabricated scaffolds exhibited spider-like nanonets with the addition of collagen and further enhanced nano-net formation with Propolis incorporation. Trunk nanofibers showed filamentous structures without any beads, with an average diameter of 164-728 nm, while the diameter of branched fibers (nanonets) was approximately 20 nm. WVTR values of the NFNs were comparable to commercial dressings such as Tegaderm. The results also demonstrated the potent cytoprotective effects of Propolis-loaded NFNs in a dose-dependent manner. Furthermore, the viability of HFF-2 cells after 72 h of culture on PCLC NFNs significantly increased compared to PCL nanofibers. The highest cell viability was observed in PCLC/Pro 15 % nanofibers after 24, 48, and 72 h of cell culture, indicating the proliferative effect of Propolis extract in nanoformulated form. Additionally, the scaffolds exhibited a hemocompatibility of <3 %, further highlighting their potential in wound healing therapeutics.

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

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

Physicochemical Characterization, Antioxidant, and Proliferative Activity of Colombian Propolis Extracts: A Comparative Study.

Propolis extracts have been widely studied due to their popularity in traditional medicine, presenting incredible biodiversity. This study aimed to analyze propolis extracts' phytochemical, physicochemical, and biological activities from four different biogeographic zones of the Huila region (Colombia). The raw material samples were collected by the scraping method and the ethanolic extracts (EEPs) were obtained by cold maceration with ethanol (96%). The physicochemical and sensory characterization was carried out according to the protocols recommended by the Brazilian Ministry of Agriculture and the main components of the EEPs were identified by LC-HRMS analysis. The determination of total phenols and flavonoids was carried out using colorimetric techniques. The antioxidant activity, cytotoxicity, and cell cycle regulation analyses in L929 and HGnF cells were evaluated using DPPH, Alamar Blue, and 7-amino actinomycin D (7-AAD) assays. The propolis samples presented an average yield of 33.1%, humidity between 1.6 and 2.8%, melting point between 54 and 62 °C, ashes between 1.40 and 2.19%, and waxes of 6.6-17.9%, respectively. The sensory characteristics of all samples were heterogeneous, complying with the quality specifications established by international standards. The polyphenolic and total flavonoid content was representative in the samples from Quebradon (255.9 ± 9.2 mg GAE/g, 543.1 ± 8.4 mg QE/g) and Arcadia (543.1 ± 8.4 mg GAE/g, 32.5 ± 1.18 g QE/g) (p < 0.05) that correlated with high antioxidant activity (Quebradon: 37.2 ± 1.2 µmol/g, Arcadia: 38.19 ± 0.7 µmol/g). In the chemical composition analysis, 19 compounds were characterized as phenolic acids and flavonoids, the most representative being chrysoeriol-O-methyl-ether, ellagic acid, and 3,4-O-dimethylcaffeic acid. Regarding biological activity, Quebradon and Arcadia propolis presented low toxicity with IC50 of 2.83 ± 2.3 mg/mL and 4.28 ± 1.4 mg/mL in HGnF cells, respectively, and an arrest of the cell cycle in the G2/M phase of 71.6% and 50.8% compared to the control (11.9%) (p < 0.05). In general, the results of this study contribute to the identification of valid quality criteria to evaluate Colombian propolis, contributing to its study and chemical and biological characterization as a source of raw material for industrial and pharmaceutical use. In addition, Quebradon and Arcadia propolis can be important sources of bioactive molecules for the development of new drugs.

Encapsulation of propolis extracted with methylal in the chitosan nanoparticles and its antibacterial and cell cytotoxicity studies.

In this study we develop novel type of antibacterial chitosan-propolis NPs to improve theantimicrobial activity against various pathogens. To this aim, we primarily extracted propolis with methylal and ethanol as green solvents and its encapsulation with chitosan NPs. The developed propolis loaded chitosan NPs indicated antimicrobial and anti-biofilm properties against various gram positive and negative. FTIR revealed the successful encapsulation of the propolis extract with Ethanol (PE) and Methylal (PM) into the chitosan nano career matrix. HPLC and GC-MASS also confirmed the presence of flavonoids and phenols compounds of propolis extracted with both solvents. In addition, we confirmed the total phenolic and flavonoid compounds in propolis by calorimetric method of Folin-Ciocalteu and aluminum trichloride complex formation assays, respectively. PE-CH and PM-CH were optimized regarding physicochemical properties such as particle size, zeta potential, and poly dispersity index (PDI) index. DLS and SEM micrographs confirmed a spherical morphology in a range of 360-420 nm with Z potential values of 30-48 mV and PDI of 0.105-0.166 for PE-CH and PM-CH, respectively. The encapsulation efficiency was evaluated using colorimetric analysis, with median values ranging from 90 to 92%. The MIC values within the range of 2 to 230 µg/ml and MBC values between 3 to 346 µg/ml against both gram-positive and negative bacteria. While both PE and PM showed a significant reduction in the number of E. coli, S. aureus, and S. epidermidis, the use of PE-CH and PM-CH led to a statistically significant and greater reduction in number of E. coli, S. aureus, and S. epidermidis strains on the biofilm, pre-formed biofilm and planktonic phases. Besides, the DPPH assay showed significant antioxidant activity for these NPs within the range of 36 to 92%. MTT assay for MHFB-1, HFF, L929, MDF, and MCF-7 cells exhibited statistically significant differences in each other that show the IC50 between 60-160 µg/ml for normal cells and 20 for cancer cells. Finally the present study indicated that both PM and PM-CH greater than PE and PE-CH in which contain high flavonoid and phenolic contents with a high antioxidation potential antioxidant properties, which could be beneficial for cell proliferation and antibiotic and anticancer applications.

A self-healing crosslinked-xanthan gum/soy protein based film containing halloysite nanotube and propolis with antibacterial and antioxidant activity for wound healing.

Traumatic multidrug-resistant bacterial infections are the most threat to wound healing. Lower extremity wounds under diabetic conditions display a significant delay during the healing process. To overcome these challenges, the utilization of protein-based nanocomposite dressings is crucial in implementing a successful regenerative medicine approach. These dressings hold significant potential as polymer scaffolds, allowing them to mimic the properties of the extracellular matrix (ECM). So, the objective of this study was to develop a nanocomposite film using dialdehyde-xanthan gum/soy protein isolate incorporated with propolis (PP) and halloysite nanotubes (HNTs) (DXG-SPI/PP/HNTs). In this protein-polysaccharide hybrid system, the self-healing capability was demonstrated through Schiff bonds, providing a favorable environment for cell encapsulation in the field of tissue engineering. To improve the properties of the DXG-SPI film, the incorporation of polyphenols found in PP, particularly flavonoids, is proposed. The synthesized films were subjected to investigations regarding degradation, degree of swelling, and mechanical characteristics. Additionally, halloysite nanotubes (HNTs) were introduced into the DXG-SPI/PP nanocomposite films as a reinforcing filler with varying concentrations of 3 %, 5 %, and 7 % by weight. The scanning electron microscope (SEM) analysis confirmed the proper embedding and dispersion of HNTs onto the DXG-SPI/PP nanocomposite films, leading to functional interfacial interactions. The structure and crystallinity of the synthesized nanocomposite films were characterized using Fourier Transform Infrared Spectrometry (FTIR) and X-ray diffraction (XRD), respectively. Moreover, the developed DXG-SPI/PP/HNTs nanocomposite films significantly improved cell growth of NIH-3T3 fibroblast cells in the presence of PP and HNTs, indicating their cytocompatibility. The antibacterial activity of the nanocomposite was evaluated against Escherichia coli (E. Coli) and Staphylococcus aureus (S. Aureus), which are commonly associated with wound infections. Overall, our findings suggest that the synthesis of DXG-SPI/PP/HNTs nanocomposite scaffolds holds great promise as a clinically relevant biomaterial and exhibits strong potential for numerous challenging biomedical applications.

Interaction of olive oil-based propolis and caffeic acid phenethyl ester with methylprednisolone used in the treatment of human acute myeloid leukemia.

BACKGROUND: Methylprednisolone (MP) is a pharmaceutical agent employed in the management of Leukemia, which is a systemic malignancy that arises from abnormalities in the hematological system. Numerous investigations in the field of cancer research have directed their attention towards propolis, a natural substance with significant potential as a treatment-supportive agent. Its utilization aims to mitigate the potential adverse effects associated with chemotherapy medications. The objective of this study was to examine the impact of olive oil-based propolis (OEP) and caffeic acid phenethyl ester (CAPE) on the treatment of acute myeloid leukemia, as well as to determine if they exhibit a synergistic effect when combined with the therapeutic support product methylprednisolone. METHODS AND RESULTS: The proliferation of HL-60 cells was quantified using the WST-8 kit. The PI Staining technique was employed to do cell cycle analysis of DNA in cells subjected to OEP, CAPE, and MP, with subsequent measurement by flow cytometry. The apoptotic status of cells was determined by analyzing them using flow cytometry after staining with the Annexin V-APC kit. The quantification of apoptotic gene expression levels was conducted in HL-60 cells. In HL-60 cells, the IC50 dosages of CAPE and MP were determined to be 1 × 10- 6 M and 5 × 10- 4 M, respectively. The HL-60 cells were subjected to apoptosis and halted in the G0/G1 and G2/M phases of the cell cycle after being treated with MP, CAPE, and OEP. CONCLUSIONS: Propolis and its constituents have the potential to serve as effective adjunctive therapies in chemotherapy.

Assessment of phenolic and flavonoid contents, antioxidant and antimicrobial activities of Moroccan propolis.

Background: Despite the extensive literature focused on propolis extract, few data exists on the bioactive compounds and biological activities in the Moroccan propolis and its economic value is low. Objective: In this research, the aim was to evaluate the total content of phenols and flavonoids as well as the antioxidant, antibacterial and antifungal activities of Moroccan propolis. Material and Methods: The polyphenol and flavonoid content of the Moroccan propolis from three geographic regions, was quantified in the ethanolic extract by colorimetric methods using folin-ciocalteu and aluminum chloride. The antioxidant activity was evaluated by the DPPH test and expressed as IC50. Disk diffusion and broth microdilution methods were used to examine in vitro antimicrobial activity against known human microorganism pathogens. Results: The obtained data revealed that Moroccan propolis samples presented significant variations in total polyphenols and flavonoids. All samples showed significant antioxidant activity with IC50 values ranging from 4.23±0.5 to 154±0.21 µg/ mL. A strong correlation between total phenolic activity, flavonoids and antioxidant activity was found. The in vitro study of antibacterial activity showed that the propolis samples exhibited a range of growth inhibitory actions against all bacterial strains tested with the highest activity against gram-positive bacteria. Only propolis from the Sidi Bennour region demonstrated an antifungal activity. Conclusion: The study data show that Moroccan propolis extracts have a promising content of antioxidant and antimicrobial compounds that could be exploited to prevent certain diseases linked to oxidative stress and pathogenic infections.

Preventive effect of propolis on cognitive decline in Alzheimer's disease model mice.

Brazilian green propolis (propolis) is a chemically complex resinous substance that is a potentially viable therapeutic agent for Alzheimer's disease. Herein, propolis induced a transient increase in intracellular Ca2+ concentration ([Ca2+]i) in Neuro-2A cells; moreover, propolis-induced [Ca2+]i elevations were suppressed prior to 24-h pretreatment with amyloid-ß. To reveal the effect of [Ca2+]i elevation on impaired cognition, we performed memory-related behavioral tasks in APP-KI mice relative to WT mice at 4 and 12 months of age. Propolis, at 300-1000 mg/kg/d for 8 wk, significantly ameliorated cognitive deficits in APP-KI mice at 4 months, but not at 12 months of age. Consistent with behavioral observations, injured hippocampal long-term potentiation was markedly ameliorated in APP-KI mice at 4 months of age following repeated propolis administration. In addition, repeated administration of propolis significantly activated intracellular calcium signaling pathway in the CA1 region of APP-KI mice. These results suggest a preventive effect of propolis on cognitive decline through the activation of intracellular calcium signaling pathways in CA1 region of AD mice model.

The effects of high-intensity interval training and Iranian propolis extract on serum levels of TRPV4 and CYP2E1 proteins in patients with nonalcoholic fatty liver.

INTRODUCTION: Non-alcoholic fatty liver disease (NAFLD) is the most common cause of liver failure, fibrosis, cirrhosis, and liver cancer, which can eventually lead to death. AIM: To investigate the effects of high-intensity interval training (HIIT) and iranian propolis extract on serum levels of transient receptor potential cation channel subfamily V member 4 (TRPV4) and cytochrome P450 2E1 (CYP2E1) proteins in patients with NAFLD. METHODS: Thirty-two patients with NAFLD (mean±standard deviation of age: 45.1±3.6 years; body mass index: 30.0±3.6 kg/m2) were assigned in a randomized control trial to one of the following groups: HIIT (n=8), propolis supplement (n=8), propolis + HIIT (n=8), and controls (n=8). The subjects participated in eight weeks of HIIT (one bout of 1-min intervals at 80-95% of the maximal heart-rate, interspersed by two min at 50-55% of the reserve heart-rate). The Propolis supplement was taken three times a day by the patients in the form of 50 mg tablet after the main meals. Body composition, liver injury test (eg; Alanine- and Aspartate- aminotransferase levels), liver ultrasound and serum levels of TRPV4 and CYP2E1 were measured before and after intervention. One-way analysis of variance was used to compare post-tests among the groups. RESULTS: HIIT significantly reduced serum levels of TRPV4 protein (p=0.001). The reduction in CYP2E1 was not significant in HIIT group (p=0.075). Propolis consumption had no significant effect on serum levels of CYP2E1 protein (p=0.059), and TRPV4 (p=0.072). There was a significant decrease in TRPV4 and CYP2E1 in the HIIT (p=0.001) and propolis supplement (p=0.032) groups. CONCLUSION: HIIT and propolis supplementation can be used to reduce TRPV4 and CYP2E1, which in turn reduces oxidative stress and inflammation in patients with NAFLD.

Ethanolic Extract of Propolis and CAPE as Cardioprotective Agents against LPS and IFN-α Stressed Cardiovascular Injury.

The inflammatory process is triggered by several factors such as toxins, pathogens, and damaged cells, promoting inflammation in various systems, including the cardiovascular system, leading to heart failure. The link between periodontitis as a chronic inflammatory disease and cardiovascular disease is confirmed. Propolis and its major component, caffeic acid phenethyl ester (CAPE), exhibit protective mechanisms and anti-inflammatory effects on the cardiovascular system. The objective of the conducted study was to assess the anti-inflammatory effects of the Polish ethanolic extract of propolis (EEP) and its major component-CAPE-in interferon-alpha (IFN-α), lipopolysaccharide (LPS), LPS + IFN-α-induced human gingival fibroblasts (HGF-1). EEP and CAPE were used at 10-100 µg/mL. A multiplex assay was used for interleukin and adhesive molecule detection. Our results demonstrate that EEP, at a concentration of 25 µg/mL, decreases pro-inflammatory cytokine IL-6 in LPS-induced HGF-1. At the same concentration, EEP increases the level of anti-inflammatory cytokine IL-10 in LPS + IFN-α-induced HGF-1. In the case of CAPE, IL-6 in LPS and LPS + IFN-α induced HGF-1 was decreased in all concentrations. However, in the case of IL-10, CAPE causes the highest increase at 50 µg/mL in IFN-α induced HGF-1. Regarding the impact of EEP on adhesion molecules, there was a noticeable reduction of E-selectin by EEP at 25, 50, and100 µg/mL in IFN-α -induced HGF-1. In a range of 10-100 µg/mL, EEP decreased endothelin-1 (ET-1) during all stimulations. CAPE statistically significantly decreases the level of ET-1 at 25-100 µg/mL in IFN-α and LPS + IFN-α. In the case of intercellular adhesion molecule-1 (ICAM-1), EEP and CAPE downregulated its expression in a non-statistically significant manner. Based on the obtained results, EEP and CAPE may generate beneficial cardiovascular effects by influencing selected factors. EEP and CAPE exert an impact on cytokines in a dose-dependent manner.

Biological Activity and Chemical Composition of Propolis Extracts with Potential Use in Vulvovaginal Candidiasis Management.

Environmental sustainability is an increasing challenge in the pharmaceutical field, leading to the search for eco-friendly active ingredients. Among natural ingredients, propolis arises as an excellent alternative, being a complex substance with pharmacological properties. This work aims to explore the potential of propolis as a new pharmaceutical ingredient for the replacement of conventional vulvovaginal antifungals. Propolis extracts were obtained by Ultrasound-Assisted Extraction using different solvents (water, water/ethanol (50:50, v/v), and ethanol). Afterwards, the extracts were characterized regarding total phenolic content (TPC), antioxidant/antiradical activities, radical scavenging capacity, antifungal activity against strains of Candida species, and viability effect on two female genital cell lines. The aqueous extract achieved the best TPC result as well as the highest antioxidant/antiradical activities and ability to capture reactive oxygen species. A total of 38 phenolic compounds were identified and quantified by HPLC, among which ferulic acid, phloridzin and myricetin predominated. Regarding the anti-Candida spp. activity, the aqueous and the hydroalcoholic extracts achieved the best outcomes (with MIC values ranging between 128 and 512 µg/mL). The cell viability assays confirmed that the aqueous extract presented mild selectivity, while the hydroalcoholic and alcoholic extracts showed higher toxicities. These results attest that propolis has a deep potential for vulvovaginal candidiasis management, supporting its economic valorization.

Propolis in the management of cardiovascular disease.

BACKGROUND: Propolis is a resinous compound that is obtained from honey bees. It consists of numerous chemical constituents that impart different therapeutic action. The heart is the core of the body and cardiovascular disease (CVD) is a burden for the human being. This article emphasizes how propolis is fruitful in the management of various CVDs. SCOPE AND APPROACH: This review focuses on how various constituents of the propolis (such as terpenes, flavonoids, phenolics, etc.) impart cardio protective actions. KEY FINDING AND CONCLUSION: With the support of various clinical trials and research outcomes, it was concluded that propolis owns niche cardio protective properties that can be a boon for various cardiac problems (both in preventive and therapeutic action) such as atherosclerosis, excessive angiogenesis, hypertension, and many more.

Development of propolis, hyaluronic acid, and vitamin K nano-emulsion for the treatment of second-degree burns in albino rats.

Burns are the fourth most common type of injury worldwide. Many patients also suffer numerous infections and complications that impair the burn healing process, which makes the treatment of burns a challenge. This study aimed to prepare and characterize nano-emulsion (NE) of propolis, hyaluronic acid, and vitamin K for treatment of second-degree burns. High-Pressure Liquid Chromatography (HPLC) was used for the qualitative assessment of the phenolic and flavonoid contents in crude propolis. The structural, optical, and morphological characterization, besides the antimicrobial, antioxidant, cytotoxicity, in-vitro, and in-vivo wound healing activities were evaluated. For in-vivo study, 30 adult male albino rats were divided randomly into control and treated groups, which were treated with normal saline (0.9%), and NE, respectively. The wounds were examined clinicopathologically on the 3rd, 7th, and 14th days. The NE revealed the formation of a mesh-like structure with a size range of 80-180 nm and a 21.6 ± 6.22 mV zeta potential. The IC50 of NE was 22.29 µg/ml. Also, the NE showed antioxidant and antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. The in-vitro investigation of the NE on normal human skin fibroblasts using scratch assay proved an acceleration for wound healing. The treated rats showed improved wound healing clinically and pathologically and wound contraction percent (WC %) was 98.13% at 14th day, also increased epithelization, fibrous tissue formation, collagen deposition, and angiogenesis compared to the control. It could be concluded that the prepared NE possesses antimicrobial, antioxidant, and healing effect in the treatment of second-degree burns.

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

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

Antimicrobial photodynamic therapy with Brazilian green propolis controls intradermal infection induced by methicillin-resistant Staphylococcus aureus and modulates the inflammatory response in a murine model.

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the leading causes of skin and soft tissue infections worldwide. This microorganism has a wide range of antibiotics resistance, a fact that has made the treatment of infections caused by MRSA difficult. In this sense, antimicrobial photodynamic therapy (aPDT) with natural products has emerged as a good alternative in combating infections caused by antibiotic-resistant microorganisms. The objective of the present study was to evaluate the effects of aPDT with Brazilian green propolis against intradermal MRSA infection in a murine model. Initially, 24 Balb/c mice were infected intradermally in the ears with 1.5 × 108 colony-forming units of MRSA 43300. After infection, they were separated into 4 groups (6 animals per group) and treated with the vehicle, only Brazilian green propolis, only blue LED light or with the aPDT protocol (Brazilian green propolis + blue LED light). It was observed in this study that aPDT with Brazilian green propolis reduced the bacterial load at the site of infection. Furthermore, it was able to inhibit weight loss resulting from the infection, as well as modulate the inflammatory response through greater recruitment of polymorphonuclear cells/neutrophils to the infected tissue. Finally, aPDT induced an increase in the cytokines IL-17A and IL-12p70 in the draining retromaxillary lymph node. Thus, aPDT with Brazilian green propolis proved to be effective against intradermal MRSA infection in mice, reducing bacterial load and modulating the immune response in the animals. However, more studies are needed to assess whether such effects are repeated in humans.

Chemical Profile and Biological Potential of Scaptotrigona Bee Products (Hymenoptera, Apidae, Meliponini): An Review.

Stingless bees belong to the Meliponini tribe and are widely distributed in the tropics and subtropics, where they perform important ecological services. Among the best distributed groups of stingless bees is the genus Scaptotrigona, which includes 22 species distributed throughout the neotropical region, including the area from Mexico to Argentina. Bees of this genus are responsible for the production of products such as honey, propolis, geopropolis and fermented pollen ("saburá"). This review aimed to provide an overview of the chemical composition and biological activities associated with derived products from stingless bees of the genus Scaptotrigona. The bibliographic review was carried out through searches in the Scopus, Web of Science, ScienceDirect and PubMed databases, including publications from 2003 to January 2023. The study of the chemodiversity of products derived from Scaptotrigona demonstrated the mainly presence of flavonoids, phenolic acids, terpenoids and alkaloids. It was also demonstrated that products derived from bees of the genus Scaptotrigona exhibit a wide range of biological effects, such as antibacterial, antioxidant, anti-inflammatory and antifungal activities, among other bioactivities. This review provides an overview of phytochemical and pharmacological investigations of the genus Scaptotrigona. However, it is essential to clarify the toxicity and food safety of these products.

Effect of Mexican Propolis on Wound Healing in a Murine Model of Diabetes Mellitus.

Diabetes mellitus (DM) affects the wound healing process, resulting in impaired healing or aberrant scarring. DM increases reactive oxygen species (ROS) production, fibroblast senescence and angiogenesis abnormalities, causing exacerbated inflammation accompanied by low levels of TGF-ß and an increase in Matrix metalloproteinases (MMPs). Propolis has been proposed as a healing alternative for diabetic patients because it has antimicrobial, anti-inflammatory, antioxidant and proliferative effects and important properties in the healing process. An ethanolic extract of Chihuahua propolis (ChEEP) was obtained and fractionated, and the fractions were subjected to High-Performance Liquid Chromatography with diode-array (HPLC-DAD), High-Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS) and Gas Chromatography-Mass Spectrometry (GC-MS) analyses and 46 compounds were detected. Deep wounds were made in a murine DM model induced by streptozotocin, and the speed of closure and the wound tensile strength were evaluated by the tensiometric method, which showed that ChEEP had similar activity to Recoveron, improving the speed of healing and increasing the wound tensile strength needed to open the wound again. A histological analysis of the wounds was performed using H&E staining, and when Matrix metalloproteinase 9 (MMP9) and α-actin were quantified by immunohistochemistry, ChEEP was shown to be associated with improved histological healing, as indicated by the reduced MMP9 and α-actin expression. In conclusion, topical ChEEP application enhances wound healing in diabetic mice.

Antineoplastic Activity Evaluation of Brazilian Brown Propolis and Artepillin C in Colorectal Area of Wistar Rats.

OBJECTIVE: The study's aim was to evaluate Brazilian Brown Propolis (BBP) and Artepillin C (ARC) chemopreventive action in Wistar rats' colons. METHODS: Fifty male Wistar rats were divided into ten experimental groups, including control groups, groups with and without 1,2-dimethylhydrazine (DMH) induction, and BBP, ARC, and ARC enriched fraction (EFR) treatments, for sixteen weeks. Aberrant crypt foci (ACF) were classified as hyperplastic or dysplastic, and proliferating cell nuclear antigen (PCNA) expression was quantified. RESULT: ACF amounts in experimental groups (induced or not) decreased in both colon portions, while the isolated Aberrant Crypt (AC) number increased. Experimental groups of animals showed higher hyperplasia and dysplasia amounts compared with control groups. The ACF dysplastic amount present in groups induced and treated, in both colon portions, had similar values to IDMH (DMH induction group without treatment). In addition, DMH was effective in ACF inducing and there was positive staining for PCNA in basal and upper dysplastic foci portions in all experimental groups, in the mitotic index (MI) evaluation. To conclude, considering all the experimental groups, the one treated with EFR (fraction enriched with ARC) had the lowest rates of cell proliferation. CONCLUSION: BBP and its derivatives prevented crypt cell clonal expansion.

A Novel Ultrafiltrate Extract of Propolis Exerts Anti-inflammatory Activity through Metabolic Rewiring.

Thousands of years ago, humans started to use propolis because of its medicinal properties, and modern science has successfully identified several bioactive molecules within this resinous bee product. However, a natural propolis extract which has been removed the adhesive glue and preserved propolis bioactive compounds is urgently needed to maximise the therapeutic opportunities. In this study, a novel ultrafiltrate fraction from Brazilian green propolis, termed P30K, was demonstrated with anti-inflammatory properties, both in vitro and in vivo. Total flavonoids and total phenolic acids content in P30K were 244.6 mg/g and 275.8 mg/g respectively, while the IC50 value of inhibition of cyclooxygenase-2 (COX-2) was 8.30 µg/mL. The anti-inflammatory activity of P30K was furtherly corroborated in experimental models of lipopolysaccharides (LPS)-induced acute liver and lung injury. Mechanistically, integrated GC-MS and LC-MS based serum metabolomics analysis revealed that P30K modulated citrate cycle (TCA), pyruvate, glyoxylate and dicarboxylate metabolism pathways to inhibit secretion of pro-inflammatory cytokines. Results of network pharmacology and molecular docking suggested that P30K targeted catechol-O-methyltransferases (COMT), 11ß-hydroxysteroid dehydrogenases (HSD11B1), and monoamine oxidases (MAOA and MAOB) to promote cellular metabolomic rewiring. Collectively, our work reveals P30K as an efficient therapeutic agent against inflammatory conditions and its efficacy is related to metabolic rewiring.