Propolis in dentistry and oral cancer management

Molecular Targets of Plant-Derived Bioactive Compounds in Oral Squamous Cell Carcinoma

BACKGROUND

With a significant increase in both incidence and mortality, oral cancer-particularly oral squamous cell carcinoma (OSCC)-is one of the main causes of death in developing countries. Even though there is evidence of advances in surgery, chemotherapy, and radiotherapy, the overall survival rate for patients with OSCC has improved, but by a small percentage. This may be due, on the one hand, to the fact that the disease is diagnosed when it is at a too-advanced stage, when metastases are already present.

METHODS

This review explores the therapeutic potential of natural herbal products and their use as adjuvant therapies in the treatment of oral cancer from online sources in databases (PubMed, Web of Science, Google Scholar, Research Gate, Scopus, Elsevier).

RESULTS

Even if classic therapies are known to be effective, they often produce many serious side effects and can create resistance. Certain natural plant compounds may offer a complementary approach by inducing apoptosis, suppressing tumor growth, and improving chemotherapy effectiveness. The integration of these compounds with conventional treatments to obtain remarkable synergistic effects represents a major point of interest to many authors. This review highlights the study of molecular mechanisms and their efficiency in in vitro and in vivo models, as well as the strategic ways in which drugs can be administered to optimize their use in real contexts.

CONCLUSIONS

This review may have a significant impact on the oncology community, creating new inspirations for the development of more effective, safer cancer therapies with less toxic potential.

Effects of Thai propolis mixed in mineral trioxide aggregate on matrix metalloproteinase-2 expression and activity in inflamed human dental pulp cells

OBJECTIVES

This study sought to determine effects of Thai propolis extract mixed in mineral trioxide aggregate (MTA) on matrix metalloproteinase-2 (MMP-2) expression and its activity in inflamed human dental pulp cells (HDPCs).

MATERIALS AND METHODS

Interleukin-1β-primed HDPCs were treated with either the eluate of MTA mixed with distilled water, of MTA mixed with 0.75 mg/ml of the propolis extract, or of Dycal®, 0.75 mg/ml of the propolis extract, or 0.2% (v/v) of chlorhexidine for 24 or 72 h. The viability of HDPCs was determined by the PrestoBlue® cytotoxic assay. HDPCs' lysates were analyzed for MMP-2 mRNA expression by RT-qPCR, while their supernatants were measured for MMP-2 activity by gelatin zymography.

RESULTS

At 24 and 72 h, a non-toxic dose of the propolis extract at 0.75 mg/ml by itself or mixed in MTA tended to reduce MMP-2 expression upregulated by MTA, while it further decreased the MMP-2 activity as compared to that of MTA mixed with distilled water. The MMP-2 activity of interleukin-1β-primed HDPCs treated with the eluate of the propolis extract mixed in MTA was significantly lower than that of interleukin-1β-primed HDPCs at 24 h (p=0.012). As a control, treatment with chlorhexidine significantly inhibited MMP-2 expression induced by MTA and MMP-2 activity enhanced by interleukin-1β (p<0.05). Treatment with Dycal® caused a significant increase in HDPC's death, resulting in a significant decrease in MMP-2 expression and activity (p<0.05).

CONCLUSIONS

MTA mixed with Thai propolis extract can reduce MMP-2 mRNA expression and activity when compared to MTA mixed with distilled water in inflamed HDPCs.

Cytotoxicity of Propolis Extracts obtained using Dichloromethane and Hexane Solvent on Human Salivary Gland Tumor Cell Line

AIM

This in vitro study aimed to investigate the effect of propolis extracts from two different solvents on human submandibular salivary gland (HSG) tumor cell line.

MATERIALS AND METHODS

Propolis was extracted by dichloromethane (DCM) and hexane (HEX). Crude extracts were prepared from 6.25 to 200 µg/mL in Dulbecco's modified eagle medium without serum. Flavonoid and total phenolic contents of crude extracts were measured using a modified colorimetric method. The cytotoxicity was evaluated by 3-[4, 5-dimethylthiazol-2-yl]-2,5 diphenyl-tetrazolium (MTT) assay and lactate dehydrogenase (LDH) release assay. The statistics were analyzed by independent sample t-test.

RESULTS

Propolis extracts obtained using DCM and HEX exhibited comparable % yield (38.58 and 38.25) and physical characteristics and different amounts of flavonoid (0.439 ± 0.02 and 0.250 ± 0.01 mg catechin/g sample) and total phenolic compounds (3.759 ± 0.03 and 1.618 ± 0.03 mg gallic acid equivalents/g sample). The DCM group at 25, 50, 100, and 200 µg/mL as well as the HEX group at 50, 100, and 200 µg/mL significantly displayed a decrease in % cell viability and an increase in % cytotoxicity, compared with the untreated control group (P < 0.05). The DCM group showed the half-maximal inhibitory concentration (IC50) of MTT (42.93 ± 2.70) and LDH (34.94 ± 0.22). The HEX group showed the IC50 of MTT (61.30 ± 5.39) and LDH (42.32 ± 1.00). Propolis extracts obtained using both DCM and HEX are effective to inhibit HSG viability.

CONCLUSION

Regarding to the cell morphological observation, MTT and LDH assays, propolis extracts obtained using DCM and HEX exhibited the cytotoxic effect on HSG tumor cell line. Based on our knowledge, this research demonstrates the first preliminary result suggesting propolis as a natural product of choice for salivary gland cancer prevention and therapy.

Honeycomb, a New Food Resource with Health Care Functions: The Difference of Volatile Compounds found in Apis cerana and A. mellifera Honeycombs

The honeycomb composition is very complex, containing honey, royal jelly, pollen, and propolis, and thus contains a large number of bioactive ingredients, such as polyphenols and flavonoids. In recent years, honeycomb as a new functional food resource has been favored by many bee product companies, but the basic research on honeycomb is lacking. The aim of this study is to reveal the chemical differences between A. cerana honeycombs (ACC) and A. mellifera honeycombs (AMC). In this paper, we studied the volatile organic components (VOCs) of ACC and AMC by solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME/GC-MS). A total of 114 VOCs were identified in 10 honeycombs. Furthermore, principal component analysis (PCA) revealed that the chemical composition of ACC and AMC were different. Additionally, orthogonal partial least squares discrimination analysis (OPLS-DA) revealed that benzaldehyde, octanal, limonene, ocimene, linalool, α-terpineol, and decanal are the significant VOCs in AMC extracts, which are mainly derived from propolis. OPLS-DA model also identified 2-phenylethanol, phenethyl acetate, isophorone, 4-oxoisophorone, betula, ethyl phenylacetate, ethyl palmitate, and dihydrooxophorone as potential discriminatory markers of ACC, which likely contribute to protecting the hive against microorganisms and keep it clean.

Honey Bee Products: Preclinical and Clinical Studies of Their Anti-inflammatory and Immunomodulatory Properties

Inflammation is a defense process triggered when the body faces assaults from pathogens, toxic substances, microbial infections, or when tissue is damaged. Immune and inflammatory disorders are common pathogenic pathways that lead to the progress of various chronic diseases, such as cancer and diabetes. The overproduction of cytokines, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor-α, is an essential parameter in the clinical diagnosis of auto-inflammatory diseases. In this review, the effects of bee products have on inflammatory and autoimmune diseases are discussed with respect to the current literature. The databases of Google Scholar, PubMed, Science Direct, Sci-Finder and clinical trials were screened using different combinations of the following terms: “immunomodulatory”, “anti-inflammatory”, “bee products”, “honey”, “propolis”, “royal jelly”, “bee venom”, “bee pollen”, “bee bread”, “preclinical trials”, “clinical trials”, and “safety”. Honey bee products, including propolis, royal jelly, honey, bee venom, and bee pollen, or their bioactive chemical constituents like polyphenols, demonstrate interesting therapeutic potential in the regulation of inflammatory mediator production as per the increase of TNF-α, IL-1β, IL-6, Il-2, and Il-7, and the decrease of reactive oxygen species (ROS) production. Additionally, improvement in the immune response via activation of B and T lymphocyte cells, both in in vitro, in vivo and in clinical studies was reported. Thus, the biological properties of bee products as anti-inflammatory, immune protective, antioxidant, anti-apoptotic, and antimicrobial agents have prompted further clinical investigation.

Antibacterial Effect of Pre-constructed 3D Bone Scaffolds before and after Modification with Propolis

AIM: This study was to determine and compare the antibacterial activity of different scaffold materials before and after their modification with ethanolic extract of Egyptian propolis ethanolic extract of propolis (EEP). SETTINGS AND DESIGN: Preparation of the dry mass of propolis, preparation of EEP, preparation of the scaffolds, and antibacterial activity testing. MATERIALS AND METHODS: Four bacterial strains were used to determine the antibacterial activity of two different scaffold materials before and after their modification with EEP (15% and 25% by weight). RESULTS: Tricalcium phosphate + gelatin binder modified by 25% EEP exhibited the highest antibacterial activity against Escherichia coli. While, tricalcium phosphate + (alginate and cellulose nanowhiskers) binder modified by 25% EEP demonstrated the highest antibacterial activity Staphylococcus aureus, Streptococcus mutans, and Lactobacillus casei. CONCLUSIONS: It can be concluded that EEP had a significant effect on the antibacterial activity of both scaffold materials; the antibacterial activity was higher against Gram-positive bacteria.

Combinations of propolis and Ca(OH)2 in dental pulp capping treatment for the stimulation of reparative dentin formation in a rat model

Background: Caries in the dental pulp result in inflammation and damage to the pulp tissue. During inflammation of the pulp, various inflammatory mediators and growth factors are released, including IL-8, IL-10, TLR-2, VEGF and TGF-β through the NF-kB pathway. In the present study, therapy for pulpal caries was performed through pulp capping by giving a combination of propolis and calcium hydroxide (Ca(OH)2). This treatment was expected to stimulate the formation of reparative dentin as an anti-inflammatory material to prevent pulp tissue damage. Methods: 28 Wistar rats were divided into four groups and treated with Ca(OH)2 with or without the addition of propolis for either 7 or 14 days. Immunohistochemical examination was used to determine the expression of IL-8, IL-10, TLR-2, VEGF, TGF-β in the four treatment groups. Results: The group treated with a combination of propolis and Ca(OH)2 for 7 days showed that the expression of IL-10, IL-8, TLR-2, VEGF, TGF-β increased significantly compared to the treatment group treated with only Ca(OH)2. The expression of IL-10, TLR-2, TGF-β, VEGF increased in the treatment group treated with propolis and Ca(OH)2 for 14 days, while the expression of IL-8 in the decreased significantly. Conclusions: Administration of a combination of propolis and Ca(OH)2 has efficacy in the pulp capping treatment process because it has anti-bacterial and immunomodulatory properties. The results show that it is able to stimulate the process of pulp tissue repair through increased expression of IL-10, TGF-β, VEGF, TLR -2 and decreased expression of IL-8.

Iranian propolis efficiently inhibits growth of oral streptococci and cancer cell lines

Background

Propolis is a natural bee product with a wide range of biological activities that are related to its chemical composition. The present study investigated the quantification of quercetin (Q) in Ardabil ethanol extract of propolis (AEEP), and then compared its anti-bacterial, anti- biofilm and cytotoxic effects on cancer and normal cell lines.

Method

In the present study, the chemical composition of AEEP was determined through the high-performance liquid chromatography (HPLC). The AEEP and its main component, quercetin (Q), were evaluated in vitro against 57 oral streptococci by a broth micro-dilution method. The biofilm formation was assessed through the crystal violet staining and MTT assays. The impact of AEEP and Q anti-proliferative effect were evaluated on the fibroblast as normal and cancer cell lines (KB and A431).

Results

The Q concentration in the composition of AEEP was 6.9% of all its components. The findings indicated that the AEEP and Q were efficient against the cariogenic bacteria and were able to inhibit the S.mutans biofilm adherence at a sub-MIC concentration. Moreover, electron micrographs indicated the inhibition of biofilms compared to control biofilms. In addition, the AEEP and Q indicated a dose-dependent cytotoxic effect on A431 and KB cell lines. On the contrary, they had no cytotoxic effect on fibroblast cells.

Conclusion

The results indicated that the synergistic impact of main components of AEEP was related to the inhibition of the cancer cell proliferation, cariogenic bacteria and oral biofilm formation. It may play a promising role in the complementary medicine and, it is suggested to be used as food additives.

A comparative study of the physicochemical properties of hesperidin, MTA-Angelus and calcium hydroxide as pulp capping materials

Aim

This study compared the setting time, radiopacity, solubility and pH changes between Hisperidin cement, MTA-Angelus and Calcium hydroxide cements.

Methods

The study was conducted on 3 equal groups of samples of the evaluated capping materials including; Hisperidin (group I, N = 24), MTA-Angelus (group II, N = 24) and Dycal (group III, N = 24). According to the assessed property, these groups were further subdivided into three equal subgroups (8 samples each) including; subgroup A for assessment of the setting time, subgroup B for assessment of radiopacity and subgroup C for assessment of the solubility of the material and evaluation of pH. All recorded data were tabulated and statistically analyzed.

Results

The highest mean value of setting time was for the MTA-Angelus followed by Hesperidin and Calcium hydroxide with 72.83, 48.26 and 1.58 min, respectively. MTA-Angelus had the highest radiopacity value and followed by Calcium hydroxide then Hesperidin. Hesperidin showed the solubility in distilled water (≈45% mass loss) in relation to Calcium hydroxide (≈19% mass loss). On the other hand, MTA-Angelus showed 9% increase in weight. On contrast to MTA and Calcium hydroxide, Hesperidin showed decrease in pH value throughout the evaluation periods. Higher pH values in MTA-Angelus and Calcium hydroxide were reported in comparison with Hesperidin.

Conclusion

Despite its slight acidic nature, lower radiopacity and longer initial setting time, Hesperidin, as a natural product, is a promising pulp capping material. Further research on Hesperidin powder is recommended to improve its physicochemical properties and to assess its biological actions.

Propolis: A natural biomaterial for dental and oral healthcare

The field of health has always emphasised on the use of natural products for curing diseases. There are varieties of natural products (such as silk, herbal tea, chitosan) used today in the biomedical application in treating a large array of systemic diseases. The natural product "Propolis" is a non-toxic resinous material having beneficial properties such as antimicrobial, anticancer, antifungal, antiviral and anti-inflammatory; hence gain the attention of researchers for its potential for bio-dental applications. The study aims to explore the properties and chemistry of propolis concerning biomedical and dental applications. In addition, status and scope of propolis for current and potential future in bio-dental applications have been discussed. This review gives an insight to the reader about the possible use of propolis in modern-day dentistry.

The Influence of Toothpaste Containing Australian Melaleuca alternifolia Oil and Ethanolic Extract of Polish Propolis on Oral Hygiene and Microbiome in Patients Requiring Conservative Procedures

The study was based on the use of a toothpaste with antiphlogistic activity, containing Australian Melaleuca alternifolia oil (tea tree oil—TTO) and ethanolic extract of Polish propolis (EEP). Fifty-one patients with varying conditions of the gingiva were divided into two groups. The study group received the toothpaste with TTO and EEP, while the control group received the same toothpaste but without TTO and EEP. Approximal plaque index (API), simplified oral hygiene index (OHI-s) and modified sulcus bleeding index (mSBI) were assessed in three subsequent stages. During each examination, swabs were employed for microbiological inoculation. During the period of use of toothpastes with TTO and EEP, a significant reduction of the API was observed, as assessed upon the control visit after 7 days and after 28 days, compared to baseline. A statistically significant reduction of mSBI was observed after 7 and 28 days of using the toothpaste with TTO and EEP, as compared to the value upon the initial visit. Statistically significant differences in the OHI-s value were observed in the study group, which was using the active toothpaste. The use of a toothpaste containing TTO and EEP helps to maintain microbiome balance. The observed stabilisation of bacterial microflora confirms the beneficial activity of toothpaste containing EEP and TTO compared to the control group, where the lack of these substances contributed to the emergence of qualitative and quantitative changes in oral microbiome.

Effects of Brazilian Propolis on Dental Plaque and Gingiva in Patients with Oral Cleft Malformation Treated with Multibracket and Removable Appliances: A Comparative Study

Orthodontic appliances modify the local environment of the oral cavity, increase the accumulation of dental plaque, and affect the condition of the gingiva. The aim of this study is assessment of Brazilian propolis toothpaste's effect on plaque index (PLI) and gingival index (GI) in patients with CL/CLP treated using orthodontic appliances in the 35-day study period. The study population included 96 patients of an Orthodontic Outpatient Clinic, ACSiMS in Bytom. All the patients participated in the active phase of orthodontic treatment using buccal multibracket appliances or removable appliances. During the first examination, each patient was randomly qualified to the propolis group or control group. A statistically significant decrease in GI and PLI in the entire propolis group (P < 0.01) was shown during repeated examination. Insignificant change in GI was in the entire control group during the repeated examination compared to the baseline. Similar result was obtained in patients treated with multibracket and removable appliances. The orthodontic appliance type did not affect the final dental plaque amount and gingival condition in patients using the propolis toothpaste. These results may be clinically useful to improve prevention and control oral infectious diseases during orthodontic treatment patients with oral cleft.

Caffeic Acid phenethyl ester is a potential therapeutic agent for oral cancer

Head and neck cancers, which affect 650,000 people and cause 350,000 deaths per year, is the sixth leading cancer by cancer incidence and eighth by cancer-related death worldwide. Oral cancer is the most common type of head and neck cancer. More than 90% of oral cancers are oral and oropharyngeal squamous cell carcinoma (OSCC). The overall five-year survival rate of OSCC patients is approximately 63%, which is due to the low response rate to current therapeutic drugs. In this review we discuss the possibility of using caffeic acid phenethyl ester (CAPE) as an alternative treatment for oral cancer. CAPE is a strong antioxidant extracted from honeybee hive propolis. Recent studies indicate that CAPE treatment can effectively suppress the proliferation, survival, and metastasis of oral cancer cells. CAPE treatment inhibits Akt signaling, cell cycle regulatory proteins, NF-κB function, as well as activity of matrix metalloproteinase (MMPs), epidermal growth factor receptor (EGFR), and Cyclooxygenase-2 (COX-2). Therefore, CAPE treatment induces cell cycle arrest and apoptosis in oral cancer cells. According to the evidence that aberrations in the EGFR/phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling, NF-κB function, COX-2 activity, and MMPs activity are frequently found in oral cancers, and that the phosphorylation of Akt, EGFR, and COX-2 correlates to oral cancer patient survival and clinical progression, we believe that CAPE treatment will be useful for treatment of advanced oral cancer patients.