Influence of caffeic acid phenethyl ester on bone healing in a rat model

Caffeic acid derivative MPMCA suppresses osteoclastogenesis and facilitates osteoclast apoptosis: implications for the treatment of bone loss disorders

Osteoclast activity plays a crucial role in the pathological mechanisms of osteoporosis and bone remodeling. The treatment of these disorders involves the use of pharmacological medicines that work by inhibiting the activity of osteoclasts. Nevertheless, the prevalent and infrequent negative consequences of current antiresorptive and bone anabolic treatments pose significant drawbacks, hence restricting their prolonged administration in patients, particularly those who are elderly and/or suffer from many medical conditions. We are currently in the process of creating a new molecule called N-(4-methoxyphen) methyl caffeamide (MPMCA), which is a derivative of caffeic acid. This compound has shown potential in preventing the production of osteoclasts and causing existing osteoclasts to undergo cell apoptosis. Our investigation discovered that MPMCA hinders osteoclast function via suppressing the MAPK pathways. The expectation is that the findings of this study will stimulate the advancement of a novel approach to treating anti-resorption.

Applications of honeybee-derived products in bone tissue engineering

Nowadays, there is an increasing prevalence of bone diseases and defects caused by trauma, cancers, infections, and degenerative and inflammatory conditions. The restoration of bone tissue lost due to trauma, fractures, or surgical removal resulting from locally invasive pathologies requires bone regeneration. As an alternative to conventional treatments, sustainable materials based on natural products, such as honeybee-derived products (honey, propolis, royal jelly, bee pollen, beeswax, and bee venom), could be considered. Honeybee-derived products, particularly honey, have long been recognized for their healing properties. There are a mixture of phytochemicals that offer bone protection through their antimicrobial, antioxidant, and anti-inflammatory properties. This review aims to summarize the current evidence regarding the effects of honeybee-derived products on bone regeneration. In conclusion, honey, propolis, royal jelly, beeswax, and bee venom can potentially serve as natural products for promoting bone health.

Caffeic acid phenethyl ester ameliorates titanium particle-induced bone loss and inflammatory reaction in a mouse acute model

With the increasing clinical application of dental and orthopedic implants, the problem of peri-implant osteolysis has attracted attention. The inflammatory response and osteoclast differentiation induced by wear particles play an important role in peri-implant bone loss. However, the treatment of peri-implant osteolysis is still lacking. In the present study, we investigated the effect of caffeic acid phenethyl ester (CAPE) on titanium particles induced bone loss in a mouse model. We found that CAPE significantly suppressed titanium particle-induced bone loss in vivo. CAPE treatment decreased ratio of nuclear factor kappa B receptor activator ligand (RANKL)/osteoprotegerin (OPG) and subsequently reduced osteoclastogenesis in the mouse model. In addition, CAPE downregulated the expression and secretion of interleukin-6 (IL-6), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) stimulated by titanium particles in vivo. In summary, we conclude that CAPE prevent the titanium particles-induced bone loss.

Effects of systemic Anatolian propolis administration on a rat-irradiated osteoradionecrosis model

OBJECTIVE

Radiotherapy after head and neck cancer is associated with the risk of osteonecrosis development. This study aims to investigate the effectiveness of systemic propolis application to prevent the disease as it has no definite treatment protocol despite the proposed treatment methods and significantly decreases individuals' quality of life.

METHODOLOGY

In total, 29 male Wistar-Albino rats were divided into control, 35 Gy irradiation (Group 1), 35 Gy irradiation+100 mg/kg/ml propolis administration (Group 2), and 35 Gy irradiation+200 mg/kg/ml propolis administration groups (Group 3). Propolis was first applied on the day after radiotherapy, except for the control group. Right first and second molars were extracted from all rats three weeks following radiotherapy. Samples were collected seven weeks after radiotherapy. Osteoblast and osteoclast counts were calculated by histomorphometric analysis. Immunohistochemical analysis determined bone morphogenic protein-2 (BMP-2) and transforming growth factor beta-3 (TGFβ-3).

RESULTS

Group comparison found non-significant differences regarding osteoblast (p=0.130) and osteoclast (p=0.063) counts. However, Group 1 showed the lowest mean osteoblast (OBL: 82.63 [±13.10]) and highest mean osteoclast counts (OCL: 12.63 [±5.55]). OBL/OCL ratio showed significant differences between groups (p=0.011). Despite the significant difference between the Control and Groups 1 (p=0.006) and 2 (p=0.029), Group 3 showed a non-significant difference (p=0.091). For BMP-2 and TGFB3, the control group showed significant differences with the other two groups (p<0.001), except for Group 3.

CONCLUSION

Anatolian propolis showed beneficial effects in a radiotherapy-mediated osteonecrosis model, highlighting its potential as a promising intervention.

Synthetic Calcium-Phosphate Materials for Bone Grafting

Synthetic bone grafting materials play a significant role in various medical applications involving bone regeneration and repair. Their ability to mimic the properties of natural bone and promote the healing process has contributed to their growing relevance. While calcium-phosphates and their composites with various polymers and biopolymers are widely used in clinical and experimental research, the diverse range of available polymer-based materials poses challenges in selecting the most suitable grafts for successful bone repair. This review aims to address the fundamental issues of bone biology and regeneration while providing a clear perspective on the principles guiding the development of synthetic materials. In this study, we delve into the basic principles underlying the creation of synthetic bone composites and explore the mechanisms of formation for biologically important complexes and structures associated with the various constituent parts of these materials. Additionally, we offer comprehensive information on the application of biologically active substances to enhance the properties and bioactivity of synthetic bone grafting materials. By presenting these insights, our review enables a deeper understanding of the regeneration processes facilitated by the application of synthetic bone composites.

Protective effects of caffeic acid phenethyl ester (CAPE) and thymoquinone against cigarette smoke in experimental bone fracture healing

This study investigated the protective characteristics of caffeic acid phenethyl ester (CAPE) and thymoquinone (TMQ) against the effects of cigarette smoke in recovery from bone fractures. Sixty Wistar albino rats were divided into six groups (n = 10). The rats' femur bones were fractured and then fixed with microplates and microscrews. In the CAPE group, CAPE was given by intraperitoneal injection for 30 days at a dose of 10 μmol/kg once a day. In the TMQ group, TMQ was given orogastrically for 30 days at a dose of 10 mg/kg once a day. In the cigarette groups, CAPE was given by intraperitoneal injection for 30 days at a dose of 10 μmol/kg once a day (CAPE-CG), TMQ was given orogastrically for 30 days at a dose of 10 mg/kg once a day (TMQ-CG), and controls were exposed to cigarette smoke three times a day for 8 min each time for 30 days. The controls received no postoperative treatment. The rats were sacrificed on the 30th day following surgery. According to the histopathological and immunohistochemical results, cigarette smoke had a negative impact on bone healing. TMQ and CAPE increased bone formation and reduced bone destruction. Therefore, TMQ and CAPE were found to be partially protective against the adverse effects of smoking on bone tissue.

Comparative effects of systemic administration of levofloxacin and cephalexin on fracture healing in rats

Objectives

This study aimed to compare the effects of systemic administration of levofloxacin or cephalexin on fracture healing in rats.

Materials and Methods

In this animal study, tibial fractures not requiring fixation were artificially induced in 30 male Wistar albino rats using a 1.1 mm surgical bur. The rats were randomly divided into 6 groups (n=5). Groups 1 and 2 received daily subcutaneous saline injections. Groups 3 and 4 received subcutaneous injections of 25 mg/kg levofloxacin twice daily. Groups 5 and 6 received daily subcutaneous injections of 20 mg/kg cephalexin. The rats in Groups 1, 3, and 5 were sacrificed after 1 week, while the rats in Groups 2, 4, and 6 were sacrificed after 4 weeks. The score of fracture healing was determined through histological assessment of sections from the fracture site according to Perry and colleagues. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests.

Results

The mean score of fracture healing at 4 weeks was significantly higher than that at 1 week in the saline, levofloxacin, and cephalexin groups (P<0.001). At 1 week, no significant difference was noted among the three groups of saline, levofloxacin, and cephalexin in the mean score of fracture healing (P=0.360). However, this difference was significant at 4 weeks (P=0.018), and the mean score in the saline group was significantly higher compared to that in the levofloxacin group (P=0.015).

Conclusion

It is recommended not to prescribe levofloxacin for more than 1 week after surgical management of bone fractures due to its possible adverse effects on fracture healing.

Effects of low dose doxycycline and caffeic acid phenethyl ester on sclerostin and bone morphogenic protein-2 expressions in experimental periodontitis

We investigated the effects of caffeic acid phenethyl ester (CAPE) and low-dose doxycycline (LDD) on sclerostin and bone morphogenic protein (BMP)-2 expression in experimental periodontitis. We used male rats in groups as follows: control group (C), periodontitis + CAPE group (PC), periodontitis + LDD group (PD), periodontitis + LDD + CAPE group (PCD) and periodontitis group (P). We administered 10 µmol/kg/day CAPE by an intraperitoneal (i.p.) injection and 10 mg/kg/day LDD by oral gavage. Histopathological changes among groups were evaluated and compared. Sclerostin and BMP-2 expression was analyzed using immunohistochemistry. LDD and/or CAPE treatment ameliorated pathology. The highest sclerostin and lowest BMP-2 expressions were found in P group. Group PC exhibited the highest BMP-2 expression scores and the most significant improvement among the treatment groups. The lowest sclerostin expression was observed in the PD group. We found that preventing sclerostin activity may be a useful treatment alternative for bone resorption, especially in cases of periodontitis and peri-implantitis. We found that CAPE and/or LDD may act as anti-sclerostin agents.

Low concentrations of caffeic acid phenethyl ester stimulate osteogenesis in vitro

OBJECTIVE

The aim of this study was to evaluate the effects of caffeic acid phenethyl ester (CAPE) on osteoblast-like cell cultures (SAOS-2).

METHODS

SAOS-2 were exposed to CAPE at 1 nM, 10 nM, 100 nM, 1 μM, and 10 μM. Non-exposed cultures were used as control. The following parameters were assayed: 1) cell viability at 1, 3, and 7 days; 2) alkaline phosphatase (ALP) activity at 5 and 10 days; 3) matrix mineralization at 14 days; and 4) Runt-related transcription factor 2 (RUNX2), ALP, osteopontin (SPP1), and osteocalcin (BGLAP) gene expression at 5 and 10 days. The data were analyzed by ANOVA two-way or Kruskal-Wallis (α = 5%).

RESULTS

At day 1, cell viability was similar among all groups (p > 0.05). At days 3 and 7, cultures exposed to CAPE at 10 μM exhibited a significant reduction in cell viability compared with the others groups (p < 0.05). At day 5, ALP activity was similar among all experimental groups; at day 10, however, the stain intensity was higher in cultures exposed to CAPE at 100 nM and 10 nM in comparison with the other groups (p < 0.05). At days 5 and 10, RUNX2, ALP, SPP1, and BGLAP gene expression was greater in cultures exposed to CAPE in comparison with the control (p < 0.05). At day 14, matrix mineralization was similar in cultures exposed to CAPE at 1 nM and 10 nM (p > 0.05), but superior to those ones observed in the other experimental groups (p < 0.05).

CONCLUSION

CAPE at low concentrations can positively module the osteogenesis in vitro.

Recent progresses in the pharmacological activities of caffeic acid phenethyl ester

The past decades have seen a growing interest in natural products. Caffeic acid phenethyl ester (CAPE), a flavonoid isolated from honeybee propolis, has shown multiple pharmacological potentials, including anti-cancer, anti-inflammatory, antioxidant, antibacterial, antifungal, and protective effects on nervous systems and multiple organs, since it was found as a potent nuclear factor κB (NF-κB) inhibitor. This review summarizes the advances in these beneficial effects of CAPE, as well as the underlying mechanisms, and proposes that CAPE offers an opportunity for developing therapeutics in multiple diseases. However, clinical trials on CAPE are necessary and encouraged to obtain certain clinically relevant conclusions.

Effect of Caffeic Acid Phenethyl Ester Provision on Fibroblast Growth Factor-2, Matrix Metalloproteinase-9 Expression, Osteoclast and Osteoblast Numbers during Experimental Tooth Movement in Wistar Rats (Rattus norvegicus)

Objectives  To investigate the effect of caffeic acid phenethyl ester (CAPE) provision on matrix metalloproteinase-9 (MMP-9), fibroblast growth factor-2 (FGF-2) expression, osteoclast and osteoblast numbers during experimental orthodontic tooth movement (OTM) in male Wistar rats ( Rattus norvegicus ).

Materials and Methods  Forty-eight healthy male Wistar rats ( R. norvegicus ), 16 to 20 weeks old with 200 to 250 g body weight (bw) were divided into several groups as follows: K1: OTM for 3 days; K2: OTM for 7 days; K3: OTM for 14 days; KP1: OTM and CAPE for 3 days; KP2: OTM and CAPE for 7 days; and KP3: OTM and CAPE for 14 days. A nickel titanium closed coil spring 8.0 mm long with 10 g/mm ² was installed between the upper left first molar and upper central incisor to move molar mesially. CAPE provision with a dose of 20 mg/kg bw of animal studies was done per orally. Immunohistochemistry was done to examine MMP-9 expression and osteoclast number in compression side as well as FGF-2 expression and osteoblast number in tensile side of the OTM.

Statistical Analysis  One-way analysis of variance test and Tukey’s honest significant difference test were performed to determine the difference between the groups ( p < 0.05).

Results  MMP-9 expression and osteoclast numbers in the compression side were significantly different between the groups. Similarly, FGF-2 expression and osteoclast numbers in the tensile side were significantly different between the groups.

Conclusions  CAPE provision during OTM increases the number of osteoblasts and the FGF-2 expression significantly in the tensile side. Osteoclast numbers and MMP-9 expression significantly decrease in the compression side.

Effects of Caffeic Acid and Its Derivatives on Bone: A Systematic Review

PURPOSE

Caffeic acid is a metabolite of hydroxycinnamate and phenylpropanoid, which are commonly synthesized by all plant species. It is present in various food sources that are known for their antioxidant properties. As an antioxidant, caffeic acid ameliorates reactive oxygen species, which have been reported to cause bone loss. Some studies have highlighted the effects of caffeic acid against bone resorption.

METHODS

A systematic review of the literature was conducted to identify relevant studies on the effects of caffeic acid on bone. A comprehensive search was conducted from July to November 2020 using PubMed, Scopus, Cochrane Library and Web of Science databases. Cellular, animal and human studies reporting the effects of caffeic acid, as a single compound, on bone cells or bone were considered.

RESULTS

The literature search found 226 articles on this topic, but only 24 articles met the inclusion criteria and were included in this review. The results showed that caffeic acid supplementation reduced osteoclastogenesis and bone resorption, possibly through its antioxidant potential and increased expression of osteoblast markers. However, some studies showed that caffeic acid did not affect bone resorption in ovariectomized rats and might impair bone mechanical properties in normal rats.

CONCLUSION

Caffeic acid potentially regulates the bone remodelling process by inhibiting osteoclastogenesis and bone resorption, as well as osteoblast apoptosis. Thus, it has medicinal values against bone diseases.

Historical and modern research on propolis and its application in wound healing and other fields of medicine and contributions by Polish studies

ETHNOPHARMACOLOGICAL RELEVANCE

The history of medical application of propolis (also known as bee glue) dates back to the times of ancient Greeks, Romans, Persians and Egyptians. Honey and other bee products, including propolis, occupy an important place in Polish folk medicine. Scientific research on propolis in Poland began in the early 1960s in Zabrze and continues until now.

AIM OF THE REVIEW

The aim of this review is to provide an overview of information on Polish research on propolis and its medical application with particular emphasis on studies concerning wound healing. Consequently, our goal is also to shed a new light on therapeutic potential of Polish propolis in order to support future research in the field.

MATERIALS AND METHODS

A systematic review of scientific literature on propolis and its medical application was performed by using the literature databases (PubMed, Web of Science, Google Scholar). We paid special attention to papers describing the effect of propolis on skin wound healing as well as to Polish contribution to research on propolis.

RESULTS

Professor Stan Scheller was the first Polish scientist dealing with propolis and its medical potential. His legacy was continued by several research teams that studied the topic in various aspects. They analyzed propolis composition, its antioxidant, anti-inflammatory, antimicrobial, antiapoptotic and anticancer properties as well as its application in dentistry and wound treatment. Burn wound healing physiology after propolis administration was thoroughly studied on pig model, whereas research on patients proved the efficacy of propolis in chronic venous leg ulcer treatment.

CONCLUSION

Polish scientists have made a significant contribution to the research on propolis, its biological properties and influence on wound healing. Propolis ointments can effectively accelerate the healing process and improve healing physiology, so they can be recommended as a promising topical medication for wound treatment in the future clinical and preclinical trials.

The effect of two phosphodiesterase inhibitors on bone healing in mandibular fractures (animal study in rats)

OBJECTIVES

Despite advances in maxillofacial surgery, impaired bone healing remains a concern for surgical teams. Many studies have evaluated the effects of sildenafil and pentoxifylline on bone healing. However, their effects on healing of bone fractures have not been well investigated. This study aimed to assess the effects of the phosphodiesterase inhibitors sildenafil and pentoxifylline on healing of mandibular fractures in rats.

MATERIALS AND METHODS

A total of 60 rats were randomly divided into six groups of 10. Mandibular fracture was induced in all rats. After the surgical procedure, group C1 received saline, group S1 received 10 mg/kg sildenafil and group P1 received 50 mg/kg pentoxifylline. The rats were sacrificed after 1 week. Groups C4, S4, and P4 received pharmaceutical therapy as in groups C1, S1, and P1 but were sacrificed after 4 weeks. The samples then underwent histological analysis.

RESULTS

The mean rate of bone healing of mandibular fractures in groups S1 and P1 was significantly higher than in group C1 at 1 week (P<0.001). The mean rate of bone healing of mandibular fractures in group P1 was higher than in group S1 at 1 week (P=0.04). The mean rate of bone healing of mandibular fractures in groups S4 (P=0.001) and P4 (P=0.004) was significantly higher than in group C4 at 4 weeks, but no significant difference was noted in the rate of healing between groups P4 and S4 (P=0.53).

CONCLUSION

Sildenafil and pentoxifylline can be used as adjuncts to enhance bone healing in rats.

A biochemical and immunohistochemical study of the effects of caffeic acid phenethyl ester on alveolar bone loss and oxidative stress in diabetic rats with experimental periodontitis

Caffeic acid phenethyl ester (CAPE) is used as a therapeutic agent to prevent bone loss. We determined the effects of systemically administered CAPE on alveolar bone loss and oxidative stress in diabetic rats with experimental periodontitis. Forty male rats were divided into four equal groups: control, experimental periodontitis (EP), EP-diabetes mellitus (EP-DM) and EP-DM-CAPE. DM was induced by streptozotocin, then lipopolysaccharide was injected to induce periodontitis. CAPE was administered to the EP-DM-CAPE group daily for 15 days. Then, serum samples were taken and the rats were sacrificed for histological analyses. Serum interleukin (IL-1β) and oxidative stress also were evaluated. Alveolar bone loss was assessed histomorphometrically. Alveolar bone loss and IL-1β levels were significantly less in the EP-DM-CAPE and EP groups compared to the EP-DM group. Oxidative stress was significantly less in the EP-DM-CAPE group compared to the EP and EP-DM groups. Receptor activator of nuclear factor kappa-B ligand (RANKL) levels were significantly higher in the EP-DM group compared to the disease groups. CAPE significantly reduced RANKL levels in the EP-DM-CAPE group compared to the EP-DM group. We found that CAPE treatment significantly inhibited DM induced oxidative stress and RANKL induced osteoclastogenesis and alveolar bone loss in diabetic rats with periodontitis.

Caffeic Acid Phenethyl Ester (CAPE) Induces VEGF Expression and Production in Rat Odontoblastic Cells

Caffeic acid phenethyl ester (CAPE), the main component of propolis, has various biological activities including anti-inflammatory effect and wound healing promotion. Odontoblasts located in the outermost layer of dental pulp play crucial roles such as production of growth factors and formation of hard tissue termed reparative dentin in host defense against dental caries. In this study, we investigated the effects of CAPE on the upregulation of vascular endothelial growth factor (VEGF) and calcification activities of odontoblasts, leading to development of novel therapy for dental pulp inflammation caused by dental caries. CAPE significantly induced mRNA expression and production of VEGF in rat clonal odontoblast-like KN-3 cells cultured in normal medium or osteogenic induction medium. CAPE treatment enhanced nuclear factor-kappa B (NF-κB) transcription factor activation, and furthermore, the specific inhibitor of NF-κB significantly reduced VEGF production. The expression of VEGF receptor- (VEGFR-) 2, not VEGFR-1, was up regulated in KN-3 cells treated with CAPE. In addition, VEGF significantly increased mineralization activity in KN-3 cells. These findings suggest that CAPE might be useful as a novel biological material for the dental pulp conservative therapy.

Therapeutic effects of caffeic acid phenethyl ester on alveolar bone loss in rats with endotoxin-induced periodontitis

Background/purpose

Caffeic acid phenethyl ester (CAPE) is an antioxidant which is decreases the bone resorption and enhances the bone healing. The aim of this study was to investigate the effects of administering systemic CAPE on alveolar bone loss in rats with experimental periodontitis.

Materials and methods

Thirty male Sprague Dawley rats were divided into three groups: control, endotoxin-induced periodontitis (EP), and EP treated with CAPE (EP-CAPE). Endotoxin was injected into the gingiva of test rats on days 1, 3, and 5, whereas saline was injected into the control rats. The EP-CAPE group received 10 mmol/kg/day CAPE intraperitoneally for 28 consecutive days. Saline was given in the control and EP groups in the same manner. At the end of the study, intracardiac blood samples were obtained, and the rats were sacrificed. Alveolar bone loss was analyzed with histometric measurements. The oxidative stress index (OSI) was used to evaluate the oxidative stress. The receptor activator of the nuclear factor kappa B ligand (RANKL) level was analyzed stereologically.

Results

CAPE administration significantly decreased the serum OSI and interleukin-1β levels. Alveolar bone loss was statistically higher in the EP group compared with the EP-CAPE group (P < 0.05). Immunohistochemical analyses of the RANKL were significantly lower in the EP-CAPE group than in the EP group (P < 0.05).

Conclusion

This experimental study revealed that CAPE administration significantly prevented alveolar bone loss and stimulated periodontal tissue healing.

Green propolis extract promotes in vitro proliferation, differentiation, and migration of bone marrow stromal cells

BACKGROUND

Propolis is a resinous material extracted from bee glue with a complex chemical composition. The unique biological properties of propolis have led to its use in alternative medicine and as a nutritional supplement. Recent research shows that propolis could affect the immune system by decreasing the production of inflammatory cytokines and potentiating an effect on resident stem cells. The exact mechanism, however, is unknown. The goal of this study was to demonstrate whether green propolis extract affects any characteristic properties of mesenchymal stromal cells (MSCs)in vitro.

METHODS

The cytocompatibility of propolis extract and the proliferation of bone marrow mesenchymal stromal cells (BMMSCs) in the presence of propolis was evaluated by live/dead cell staining and MTS viability assay over a period of 3 days. Also, we evaluated the effect of propolis extract on trilineage differentiation and migration capacity of undifferentiated and differentiated BMMSCs.

RESULTS

Relative to the control, propolis extract resulted in a significant and linear increase in the proliferation of MSCs and inhibited the osteogenic differentiation of BMMSCs, while there was a potentiation of chondrogenesis and adipogenesis. Finally, in relevance to wound healing, an in vitro scratch assay demonstrated that the migratory potential of differentiated BMMSCs was enhanced in the presence of propolis.

CONCLUSION

We have demonstrated that propolis extract was not toxic to BMMSCs (<400 μg/ml), supported their proliferation, potentiated chondrogenic and adipogenic differentiation processes, and supported cell migrationin vitro. Most interestingly, there was a down-regulation of osteogenesis. These data support the use of propolis extract for enhanced cell proliferation and tissue regeneration; however, it warrants further investigation.

Caffeic acid phenethyl ester protects against oxidative stress and dampens inflammation via heme oxygenase 1

Periodontal disease is associated with chronic oxidative stress and inflammation. Caffeic acid phenethyl ester (CAPE), which is a potent inducer of heme oxygenase 1 (HO1), is a central active component of propolis, and the application of propolis improves periodontal status in diabetic patients. Here, primary murine macrophages were exposed to CAPE. Target gene expression was assessed by whole-genome microarray, RT-PCR and Western blotting. The antioxidative and anti-inflammatory activities of CAPE were examined by exposure of the cells to hydrogen peroxide, saliva and periodontal pathogens. The involvement of HO1 was investigated with the HO1 inhibitor tin protoporphyrin (SnPP) and knockout mice for Nrf2, which is a transcription factor for detoxifying enzymes. CAPE increased HO1 and other heat shock proteins in murine macrophages. A p38 MAPK inhibitor and Nrf2 knockout attenuated CAPE-induced HO1 expression in macrophages. CAPE exerted strong antioxidative activity. Additionally, CAPE reduced the inflammatory response to saliva and periodontal pathogens. Blocking HO1 decreased the antioxidative activity and attenuated the anti-inflammatory activity of CAPE. In conclusion, CAPE exerted its antioxidative effects through the Nrf2-mediated HO1 pathway and its anti-inflammatory effects through NF-κB inhibition. However, preclinical models evaluating the use of CAPE in periodontal inflammation are necessary in future studies.

Propolis, also known as ‘honeybee glue,’ may protect teeth and gums against periodontal disease. In periodontal disease, chronic inflammation and oxidative damage harm gum tissue and lead to tooth loss; propolis has been shown to improve periodontal health for patients with diabetes. Bees make propolis by mixing beeswax, honey, plant resins and their own saliva, and use it to patch honeycomb and prevent growth of microbes in the hive. Reinhard Gruber of the Department of Oral Biology at the Medical University of Vienna and of the Department of Periodontology, University of Bern and co-workers investigated the effects of one of propolis’ active ingredients, caffeic acid phenethyl ester (CAPE), on oxidative stress and inflammation. They found that CAPE reduced oxidative damage and dampened inflammation; further investigation revealed the genetic basis of the beneficial effects, paving the way for future clinical studies. These results may help identify alternative treatments for periodontal disease.

Propolis extract a new reinforcement material in improving bone healing: An in vivo study

BACKGROUND

Propolis is known for its antioxidant, immune response modulating, and wound healing effects. In the present study in order to determine the bone healing capacity of the propolis extract, a critical sized, nonunion, radial bone defect model was repaired in rat, using chitosan and demineralized bone matrix (DBM) scaffolds along with propolis extract.

MATERIALS AND METHODS

Seventy-two radial bone defects in 36 healthy male rats were randomly divided into 6 groups (n = 12/group). The groups included autograft, defect or untreated group, chitosan, DBM, chitosan and propolis (chitosan-propolis), and DBM and propolis (DBM-propolis). The bone repairing capability was characterized using radiography at 28th, 42nd and 56th postoperative days. Gross morphologic, histopathologic, histomorphometric and biomechanical examinations were performed following euthanasia at the 56th post-operative day.

RESULTS

The DBM-propolis group, showed better structural and biomechanical properties compared to the untreated, DBM, chitosan and chitosan-propolis groups. The defect site in the chitosan and untreated groups were mainly restored by fibrous connective tissue while the lesions in the autograft group were mostly filled by cartilage and a lesser amount of woven bone. The woven bone, and the hyaline cartilage were the main constituents of the newly formed tissues in the DBM-propolis group, at the 56th day after injury.

CONCLUSION

The results of this study showed that percutaneous injection of diluted aqueous propolis extract in the bone defect (25 mg/defect) can improve bone formation in the critical radial bone defect in rat. Since there was no significant difference between the autograft and DBM-propolis group, probably this therapeutic strategy has high potential in augmentation of autologous bone grafting.

Is caffeic acid phenethyl ester more protective than doxycycline in experimental periodontitis?

BACKGROUND AND OBJECTIVES

Host modulation therapies (anti-inflammatory drugs, bone-stimulating agents, anti-proteinase etc.) target the inhibition or stabilization of tissue breakdown. The aim of the present study was to evaluate the effects of caffeic acid phenethyl ester (CAPE) and/or low dose doxycycline (LDD) administrations on alveolar bone loss (ABL), serum cytokines and gingival apoptosis, as well as the levels of oxidants and anti-oxidants in rats with ligature-induced periodontitis.

MATERIAL AND METHODS

The animals were randomly divided into five groups: Group C (periodontally healthy), Group PC (Periodontitis+CAPE), Group PD (Periodontitis+LDD), Group PCD (Periodontitis+CAPE+LDD), Group P (Periodontitis). Experimental periodontitis was induced for 14days. Levels of ABL, and the serum cytokines, interleukin (IL)-1 β, IL-6, tumor necrosis factor-α (TNF-α) and IL-10 were assessed as were the levels of the oxidants and anti-oxidants, malondialdehyde (MDA), glutathione (GSH) and glutathione peroxidase (GSH-Px), and levels of gingival apoptosis.

RESULTS

The lowest ABL levels was evident in the PC group, among the experimental groups. There was also less inflammatory infiltration in the PC group than the PD group. IL-1β, IL-6, and IL-10 were lower in the PC group and higher in the P group in comparison to the levels in the other experiment groups. TNF-α levels in the PD group were higher than levels in the PC and PCD groups. The PC and PCD groups did not differ from the C group in regard to MDA levels. The highest GSH-Px level was found in the PC group. Gingival apoptosis in the PC group was not only lower than the PD and PCD groups, but also lower than in the C group.

CONCLUSION

The present study suggests that CAPE has more anti-inflammatory, anti-oxidant and anti-apoptotic effects than LDD, with no additive benefits of a CAPE+LDD combination being evident in rats with periodontitis.

Caffeic acid phenethyl ester protects against glucocorticoid-induced osteoporosis in vivo: Impact on oxidative stress and RANKL/OPG signals

Glucocorticoid-induced osteoporosis (GIO) is one of the most common causes of secondary osteoporosis. Given that glucocorticoids are considered as a main component of the treatment protocols for a variety of inflammation and immune-mediated diseases besides its use as adjuvant to several chemotherapeutic agents, it is crucial to find ways to overcome this critical adverse effect. Caffeic acid phenethyl ester (CAPE), which is a natural compound derived from honeybee propolis displayed promising antiosteoporotic effects against mechanical bone injury in various studies. The current work aimed at investigating the potential protective effect of CAPE against GIO in vivo with emphasis on the modulation of oxidative status and receptor activator of NF-kB ligand (RANKL)/osteoprotegrin (OPG) signaling. The results showed that CAPE opposed dexamethasone (DEX)-mediated alterations in bone histology and tartarate-resistant acid phosphatase (TRAP) activity. In addition, CAPE restored oxidative balance, Runt-related transcription factor 2 (RunX2) expression and reduced caspase-3 activity in femur tissues. Co-administration of CAPE with DEX normalized RANKL/OPG ratio and Akt activation indicating a reduction in DEX-osteoclastogenesis. In conclusion, concurrent treatment of CAPE with DEX exhibited promising effects in the protection against DEX-induced osteoporosis through opposing osteoclastogenesis and protecting osteoblasts. The potent antioxidant activity of CAPE is, at least in part, involved in its anti-apoptotic effects and modulation of RunX2 and RANKL/OPG signals. The use of CAPE-enriched propolis formulas is strongly recommended for patients on chronic glucocorticoid therapy to help in the attenuation of GIO.

In vitro effects of caffeic acid, nortriptyline, precocene I and quercetin against Rhipicephalus annulatus (Acari: Ixodidae)

In the present study, the acaricidal effects of caffeic acid, nortriptyline, precocene I and quercetin against Rhipicephalus annulatus (syn. Boophilus annulatus) Say (Acari: Ixodidae) were evaluated. Adult immersion technique (24 ticks immersed for 2 min in one dilution of the compound) was used for the assessment of the effects of caffeic acid (0.39-100 mg/mL), nortriptyline (0.625-50 mg/L), precocene I (0.004488-5 mg/mL) and quercetin (6.25-100 mg/mL) against R. annulatus. Adult tick mortality, reproductive index, inhibition of fecundity and hatching were calculated. Caffeic acid, nortriptyline, precocene I and quercetin revealed very low adult mortality and inhibition of fecundity, even at the highest concentration tested. Quercetin (>50 mg/mL) caused blocking of hatching of eggs.

Pentoxifylline and electromagnetic field improved bone fracture healing in rats

Background

The aim of this study was to evaluate the effects of a phosphodiesterase inhibitor pentoxifylline (PTX), electromagnetic fields (EMFs), and a mixture of both materials on bone fracture healing in a rat model.

Materials and methods

Eighty male Wistar rats were randomly divided into four groups: Group A, femur fracture model with no treatment; Group B, femur fracture model treated with PTX 50 mg/kg/day intraperitoneal injection; Group C, femur fracture model treated with EMF 1.5±0.2 Mt/50 Hz/6 hours/day; and Group D, femur fracture model treated with PTX 50 mg/kg/day intraperitoneal injection and EMF 1.5±0.2 Mt/50 Hz/6 hours/day.

Results

Bone fracture healing was significantly better in Group B and Group C compared to Group A (P<0.05), but Group D did not show better bone fracture healing than Group A (P>0.05).

Conclusion

It can be concluded that both a specific EMF and PTX had a positive effect on bone fracture healing but when used in combination, may not be beneficial.

Effects of caffeic acid phenethyl ester on palatal mucosal defects and tooth extraction sockets

Aim

The purpose of this study was to evaluate the effects of caffeic acid phenethyl ester (CAPE) on palatal mucosal defects and tooth extraction sockets in an experimental model.

Materials and methods

Forty-two male Sprague-Dawley rats with a mean age of 7 weeks and weighing 280–490 g were used in this study. The rats were randomly divided into two groups: group A (the control group, n=21) and group B (the experimental group, n=21). Under anesthesia with ketamine (8 mg/100 g, intraperitoneally), palatal mucosal defects were created and tooth extraction was performed in the rats in groups A and B. Group A received no treatment, whereas group B received CAPE. CAPE was injected daily (10 μmol/kg, intraperitoneally). The rats were killed on days 7, 14, and 30 after the procedures. Palatal mucosa healing and changes in bone tissue and fibrous tissue were evaluated histopathologically.

Result

Pairwise comparisons showed no statistically significant difference between days 7 and 14 in either group (P>0.05). At day 30, bone healing was significantly better in group B (CAPE) than in group A (control) (P<0.05). Fibrinogen levels at day 30 were significantly higher in group A (control) than in group B (CAPE) (P<0.05). Pairwise comparisons showed no statistically significant difference in palatal mucosa healing levels between days 7 and 14 in both groups (P>0.05).

Conclusion

In conclusion, the findings of this study suggest that CAPE can significantly improve tooth socket healing.

Caffeic acid phenethyl ester and therapeutic potentials

Caffeic acid phenethyl ester (CAPE) is a bioactive compound of propolis extract. The literature search elaborates that CAPE possesses antimicrobial, antioxidant, anti-inflammatory, and cytotoxic properties. The principal objective of this review article is to sum up and critically assess the existing data about therapeutic effects of CAPE in different disorders. The findings elaborate that CAPE is a versatile therapeutically active polyphenol and an effective adjuvant of chemotherapy for enhancing therapeutic efficacy and diminishing chemotherapy-induced toxicities.