Propolis Extract Regulates microRNA Expression in Glioblastoma and Brain Cancer Stem Cells.

BACKGROUND: Grade IV gliomas are classified as glioblastoma (GBM), which is the most malignant brain cancer type. Various genetic and epigenetic mechanisms play a role in the initiation and progression of GBM. MicroRNAs (miRNAs) are small, non-coding RNA molecules that belong to the main epigenetic regulatory RNA class that plays different roles in either physiological or pathological conditions, including GBM pathogenesis regulating expression levels of the target genes. Brain Cancer Stem Cells (BCSCs) are responsible for poor prognosis, including therapy resistance and relapse. Epigenetic regulation mediated by miRNAs is also a critical component of BCSC selfrenewal and differentiation properties. Propolis is a resinous substance collected by honey bees from various plant sources. The flavonoid content of propolis varies depending on the collection region and the extraction method. Although there are studies that include the effects of different originated-propolis on the miRNA expression levels of the glioblastoma cells, the impact on the BCSCs has not been studied yet. OBJECTIVE: This study aims to evaluate the effects of propolis obtained from Aydin, a city in western Turkey, on miRNA expression levels of BCSCs and GBM cells. METHODS: Aydin propolis was dissolved in 60% ethanol, and after evaporation, distilled water was added to prepare the propolis stock solution. The flavonoids content of the Aydin propolis was determined by MS Q-TOF analysis. Commercially obtained U87MG and BCSCs were used as in-vitro brain cancer models. Cytotoxic and apoptotic effects of Aydin propolis were determined via WST-1 assay and Annexin V test, respectively. The miRNA expression profile was investigated using the real-time qRT-PCR method. The fold changes were calculated by the2-ΔΔCt method. The miRNA-mRNA-pathway interactions, including significantly altered miRNAs, were determined using different bioinformatics tools and databases. RESULTS: Quercetin 3-methyl ether was the main component of the Aydin propolis. Aydin propolis did not show significant cytotoxic and apoptotic effects on both GBM and BCSCs up to 2mg/ml concentration. Aydin propolis treatment decreased the expression of nine miRNAs in the U87MG and five miRNAs in the BCSCs. Moreover, ten miRNAs have upregulated from 2.22 to 10.56 folds in propolis treated GBM cells compared to the control group significantly (p<0.05). In the study, the potential roles of two new miRNAs, whose regulations in glioma were not previously defined, were identified. One of them was miR-30d-5p, a novel potential oncomiR in GBM, which was 2.46 folds downregulated in Aydin propolis treated GBM cells. The other one is miR-335-5p, which is a potential tumor suppressor miR in GBM, that was 5.66 folds upregulated in Aydin propolis treated GBM cells. FOXO pathway, its upstream and downstream regulators, and critically neuronal developmental regulators, NOTCH and WNT pathways, were determined as the most deregulated pathways in Aydin propolis treated cells. CONCLUSION: The determination of the anti-cancer effect of Aydin propolis on the miRNA expression of GBM, especially on cancer stem cells, may contribute to the elucidation of brain cancer genetics by supporting further analyses.

Brazilian Red Propolis shows antifungal and immunomodulatory activities against Paracoccidioides brasiliensis.

ETHNOPHARMACOLOGICAL RELEVANCE: Paracoccidioidomycosis (PCM) is a systemic mycosis with high prevalence in South America and especially in Brazil with severe clinical consequences that need broadened therapeutic options. Propolis is a natural resin from bees used in folk medicine for centuries with the first report in the ancient history of Egypt by Eberly papyrus, in Middle-Ages used to wash the newborn's umbilical cord and World War II as antiseptic or antibiotics. Nowadays it is a natural product worldwide consumed as food and traditionally used for oral and systemic diseases as an anti-inflammatory, antimicrobial, antifungal, and other diseases. Brazilian red propolis (BRP) is a new type of propolis with a distinguished chemical profile and biological activities from propolis (green) with pharmacological properties such as antimicrobial, anti-inflammatory, antioxidant, and others. AIM OF STUDY: Thus, the main purpose of this study was to investigate the direct in vitro and ex vivo effect of BRP on Paracoccidioides brasiliensis. MATERIAL AND METHODS: Antifungal activity of different concentrations of BRP on a virulent P. brasiliensis isolate (Pb18) was evaluated using the microdilution technique. Also, mice splenic cells co-cultured with Pb18 were treated with BRP at different times and concentrations (only Pb18 = negative control). Mice were inoculated with Pb18 and treated with different concentrations of BRP (50-500 mg/mL) in a subcutaneous air pouch. In this later experimental model, macroscopic characteristics of the air pouch were evaluated, and cellular exudate was collected and analyzed for cellular composition, mitochondrial activity, total protein reactive oxygen specimens (ROS), and nitric oxide production, as well as the number of viable fungal cells. RESULTS: The in vitro experiments showed remarkable direct antifungal activity of BRP, mainly with the highest concentration employed (500 mg/mL), reducing the number of viable cells to 10% of the original inoculum after 72 h incubation. The splenocytes co-cultivation assays showed that BRP had no cytotoxic effect on these cells, on the contrary, exerted a stimulatory effect. This stimulation was also observed on the PMNs at the air pouch, as verified by production of ROS and total proteins and mitochondrial activity. This activation resulted in enhanced fungicidal activity, mainly with the 500 mg/mL concentration of BRP. An anti-inflammatory effect was also detected, as verified by the smaller volume of the BRP-treated air pouch as well as by an earlier shift from neutrophils to mononuclear cells present in the infection site. CONCLUSION: Our results strongly suggest, for the first time in the literature, that Brazilian Red propolis has four protective mechanisms in experimental paracoccidioidomycosis: activating neutrophils, exerting a direct antifungal effect, preventing fungal dissemination, and controlling excessive inflammation process.

Nonclinical Toxicological Studies of Brazilian Red Propolis and Its Primary Botanical Source Dalbergia ecastaphyllum.

Propolis is one of the most widely used products in traditional medicine. One of the most prominent types of Brazilian propolis is the red one, whose primary botanical source is Dalbergia ecastaphyllum (L.) Taub. Despite the potential of Brazilian red propolis for developing new products with pharmacological activity, few studies guarantee safety in its use. The objective of this study was the evaluation of the possible toxic effects of Brazilian red propolis and D. ecastaphyllum, as well as the cytotoxicity assessment of the main compounds of red propolis on tumoral cell lines. Hydroalcoholic extracts of the Brazilian red propolis (BRPE) and D. ecastaphyllum stems (DSE) and leaves (DLE) were prepared and chromatographed for isolation of the major compounds. RP-HPLC-DAD was used to quantify the major compounds in the obtained extracts. The XTT assay was used to evaluate the cytotoxic activity of the extracts in the human fibroblast cell line (GM07492A). The results revealed IC50 values of 102.7, 143.4, and 253.1 µg/mL for BRPE, DSE, and DLE, respectively. The extracts were also evaluated for their genotoxic potential in the micronucleus assay in Chinese hamster lung fibroblasts cells (V79), showing the absence of genotoxicity. The BRPE was investigated for its potential in vivo toxicity in the zebrafish model. Concentrations of 0.8-6.3 mg/L were safe for the animals, with a LC50 of 9.37 mg/L. Of the 11 compounds isolated from BRPE, medicarpin showed a selective cytotoxic effect against the HeLa cell line. These are the initial steps to determine the toxicological potential of Brazilian red propolis.

Molecular Insights into the Antistress Potentials of Brazilian Green Propolis Extract and Its Constituent Artepillin C.

Propolis, also known as bee-glue, is a resinous substance produced by honeybees from materials collected from plants they visit. It contains mixtures of wax and bee enzymes and is used by bees as a building material in their hives and by humans for different purposes in traditional healthcare practices. Although the composition of propolis has been shown to depend on its geographic location, climatic zone, and local flora; two largely studied types of propolis: (i) New Zealand and (ii) Brazilian green propolis have been shown to possess Caffeic Acid Phenethyl Ester (CAPE) and Artepillin C (ARC) as the main bioactive constituents, respectively. We have earlier reported that CAPE and ARC possess anticancer activities, mediated by abrogation of mortalin-p53 complex and reactivation of p53 tumor suppressor function. Like CAPE, Artepillin C (ARC) and the supercritical extract of green propolis (GPSE) showed potent anticancer activity. In this study, we recruited low doses of GPSE and ARC (that did not affect either cancer cell proliferation or migration) to investigate their antistress potential using in vitro cell based assays. We report that both GPSE and ARC have the capability to disaggregate metal- and heat-induced aggregated proteins. Metal-induced aggregation of GFP was reduced by fourfold in GPSE- as well as ARC-treated cells. Similarly, whereas heat-induced misfolding of luciferase protein showed 80% loss of activity, the cells treated with either GPSE or ARC showed 60-80% recovery. Furthermore, we demonstrate their pro-hypoxia (marked by the upregulation of HIF-1α) and neuro-differentiation (marked by differentiation morphology and upregulation of expression of GFAP, ß-tubulin III, and MAP2). Both GPSE and ARC also offered significant protection against oxidative stress and, hence, may be useful in the treatment of old age-related brain pathologies.

Chemical composition, cytotoxicity, and antibacterial activity of propolis from Africanized honeybees and three different Meliponini species.

ETHNOPHARMACOLOGICAL RELEVANCE: Propolis extracts are widely used in traditional folk medicine and exhibit several properties such as antitumor, anti-inflammatory, and antimicrobial. However, these products have not been investigated in combination with medicines used in clinical practice. AIM OF THE STUDY: This study aimed to evaluate the chemical composition of propolis extracts from Apis mellifera scutellata and different Meliponini species and characterize their cytotoxicity against tumor cells, antibacterial effects, and interference with the actions of doxorubicin and gentamicin. MATERIALS AND METHODS: Chromatographic and spectrometric analyses were performed using ultra-high-performance liquid chromatography (UPLC)-tandem mass spectrometry (MS/MS). Propolis extracts were evaluated for cytotoxicity and synergism using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the antimicrobial activity was examined using the broth microdilution technique and synergism was investigated using checkerboard and time-kill assays. RESULTS: The chemical characterization revealed the presence of 63 compounds, and the extracts showed selective cytotoxicity against tumor cell lines. Propolis extracts of mandaçaia and mirim exerted selective synergistic cytotoxicity in combination with doxorubicin. Except for the tubuna extract, all evaluated extracts exhibited antibacterial effects on gram-positive strains. Mandaçaia and mirim extracts exerted a synergistic effect with gentamicin; however, only mandaçaia extract exerted a selective effect. CONCLUSION: Propolis could be a source of antineoplastics and antibiotics. These natural products may reduce the occurrence of doxorubicin and gentamicin related adverse effects, resistance, or both.

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.

Comparative Analysis of the Antibacterial Activity and HPLC Phytochemical Screening of the Brazilian Red Propolis and the Resin of Dalbergia ecastaphyllum.

The aim of this study was to investigate the antibacterial activity of red propolis and resin and their association with standard antibiotics to evaluate possible differences of activity. We also submitted red propolis and the resin to a HPLC analysis to confirm the botanical origin. The extracts were tested against P. aeruginosa and S. aureus alone and in association with gentamicin and imipenem. The HPLC analysis identified seven compounds with six of them present in both substances. The lowest MIC values obtained in this study were observed against S. aureus. In general, MIC values showed to be lower for red propolis against all species tested in comparison to resin. Despite the synergistic behavior to be similar for both substances, we observed that inhibitory concentrations of drugs were lower when associated with red propolis in comparison to resin.

Indian propolis ameliorates the mitomycin C-induced testicular toxicity by reducing DNA damage and elevating the antioxidant activity.

Development of excellent curative therapy for most of the malignancies has resulted in a growing population of cancer survivors who are at increased risk for a variety of health problems including infertility. Therefore, fertility preservation has become an important issue during cancer treatment in recent years. Combination therapy with natural agents such as vitamins, antioxidants, dietary supplements, and plant products are considered as an attractive option to mitigate normal tissue toxicity imparted by chemotherapy. The aim of the present study was to explore the beneficial effect of hydroethanolic extract of Indian propolis (HEIP) on mitigating mitomycin C (MMC)-induced testicular damage and its mechanism of action. Healthy adult male mice were injected intraperitoneally with saline, MMC, HEIP and HEIP followed by MMC after 1h. The animals were dissected at 35days after various treatments to analyze testicular function. MMC administration resulted in significant reduction in testicular function in a dose-dependent manner at 35days after treatment which significantly improved by HEIP pre-treatment. At 24h after treatment, MMC induced significant increase in oxidative stress, γ-H2AX foci and expression of RAD51 and KU80 in testicular cells. Prior treatment with HEIP decreased the oxidative stress, reduced DNA damage and restored the testicular testosterone and inhibin B level. In conclusion, co-administration of Indian propolis extract may play a promising beneficial role in fertility preservation of males undergoing chemotherapy.

Chemopreventive Action by Ethanol-extracted Brazilian Green Propolis on Post-initiation Phase of Inflammation-associated Rat Colon Tumorigenesis.

BACKGROUND/AIM: Propolis has since long been utilized in numerous folk medicines with a variety of medicinal properties. In this study, the effects of ethanol-extracted (EEP) and water-extracted (WEP) Brazilian green propolis on the post-initiation phase of inflammation-associated rat colon tumorigenesis were directly compared. MATERIALS AND METHODS: Male F344 rats at 6 weeks of age were subcutaneously injected with 1,2-dimethylhydrazine (DMH) at 40 mg/kg body weight twice during the first week, followed by 1% dextran sodium sulfate (DSS) in drinking water for one week. After a 1-week no-treatment period, animals were administered either basal Oriental MF powdered diet, or 1% EEP or 1% WEP in the basal diet until week 32. RESULTS: Post-initiation treatment with EEP significantly reduced the multiplicity of colorectal carcinomas compared to the control (0.40±0.13/rat vs. 2.29±0.84/rat, respectively, p<0.05), and EEP also reduced the tumor volume. Immunohistochemically, expression of inflammation-associated proteins inducible nitric oxide synthase, tumor necrotic factor alpha, nuclear factor kappa B and glutathione peroxidase-2 were significantly diminished in colorectal tumors from EEP-treated rats. CONCLUSION: Suppression of inflammation and oxidative stress, which had been triggered by DMH and promoted by DSS, was a primary mechanism by which EEP suppressed carcinogenesis.

Selective treatment to reduce contamination of propolis by polycyclic aromatic hydrocarbons (PAHs) still preserving its active polyphenol component and antioxidant activity.

The adverse effects on health and environment caused by polycyclic aromatic hydrocarbons (PAHs) are critical problems. EFSA has defined 16 priority PAHs that are both genotoxic and carcinogenic, and identified eight (PAH8) priority PAHs as good indicators of the toxicity and occurrence in food. Food supplements containing propolis were also found to contain relatively high quantities of PAHs. We report about an extractive procedure which is able to purify propolis from a high content of PAHs using a balanced mixture of ethanol and water solvents. Extracts were characterised for total content of polyphenols, for in vitro antioxidant activity, and single classes of polyphenols evaluated by HPLC-ESI-MS. Obtained propolis extracts were found to have PAH8 and specific benzo[a]pyrene content below limits recommended by EFSA. The reported extractive procedure is easily applicable for possible industrial productions and may also be adopted to the purification of polyphenols from other plant extracts and natural sources.

Anti-inflammatory effects of ethanol extracts of Chinese propolis and buds from poplar (Populus×canadensis).

ETHNOPHARMACOLOGICAL RELEVANCE: Propolis is used widely in a number of cultures as a folk medicine and is gaining wider recognition for its potential therapeutic use, due to its wide range of biological properties and pharmacological activities, especially its anti-inflammatory effects. Despite an increasing number of studies focused on the biological activities of propolis together with its botanical sources, studies on Chinese propolis are insufficient. This study was designed to investigate the anti-inflammatory properties of ethanol extracts from Chinese propolis (EECP) and poplar buds (EEPB) from Populus×canadensis Moench (Salicaceae family). MATERIALS AND METHODS: Phytochemical analysis of EECP and EEPB was performed via total phenolic and flavonoid content measurements followed by high-performance liquid chromatography (HPLC) analysis. DPPH and ABTS free-radical scavenging methods were used to evaluate their anti-oxidant properties. The anti-inflammatory effects of EECP and EEPB were investigated in vitro by evaluating their modulating effects on the key inflammatory cytokines and mediators in LPS/IFN-γ co-stimulated RAW 264.7 cells and by measuring nuclear factor (NF)-κB activation in TNF-α or IL-1ß stimulation HEK 293 cells using reporter gene assays. Their effects on acute inflammatory symptoms (LPS-induced endotoxemia and acute pulmonary damage) were also examined in mice. RESULTS: EECP and EEPB exhibited strong free-radical scavenging activity and significant in vitro anti-inflammatory effects by modulating key inflammatory mediators of mRNA transcription, inhibiting the production of specific inflammatory cytokines, and blocking the activation of nuclear factor (NF)-κB. The administration of EECP and EEPB (25 and 100 mg/kg) provided significant protective effects by attenuating lung histopathological changes and suppressing the secretion of LPS-stimulated inflammatory cytokines, such as interleukin-6 (IL-6), IL-10, MCP-1, TNF-α and IL-12p70 production in endotoxemic mice. CONCLUSIONS: The results presented here reveal the potent anti-inflammatory properties of Chinese propolis and poplar buds, and provide biological information for developing suitable substitute(s) for propolis in the prevention and treatment of inflammatory diseases.

Propolis cinnamic acid derivatives induce apoptosis through both extrinsic and intrinsic apoptosis signaling pathways and modulate of miRNA expression.

Propolis cinnamic acid derivatives have a number of biological activities including anti-oxidant and anti-cancer ones. In this study, we aimed to elucidate the mechanism of the anti-cancer activity of 3 representative propolis cinnamic acid derivatives, i.e., Artepilin C, Baccharin and Drupanin in human colon cancer cell lines. Our study demonstrated that these compounds had a potent apoptosis-inductive effect even on drug-resistant colon cancer cells. Combination treatment of human colon cancer DLD-1 cells with 2 of these compounds, each at its IC20 concentration, induced apoptosis by stimulating both intrinsic and extrinsic apoptosis signaling pathways. Especially, Baccharin plus Drupanin exhibited a synergistic growth-inhibitory effect by strengthening both intrinsic and extrinsic apoptotic signaling transduction through TRAIL/DR4/5 and/or FasL/Fas death-signaling loops and by increasing the expression level of miR-143, resulting in decreased expression levels of the target gene MAPK/Erk5 and its downstream target c-Myc. These data suggest that the supplemental intake of these compounds found in propolis has enormous significance with respect to cancer prevention.

Potential effects of Trachyspermum copticum essential oil and propolis alcoholic extract on Mep3 gene expression of Microsporum canis isolates.

OBJECTIVE: The purpose of this study was to evaluate the effects of Trachyspermum copticum (T. copticum) essential oil and propolis alcoholic extract on growth and transcription of Mep3 gene of Microsporum canis (M. canis) strains. METHODS: The antifungal activity was assayed by broth macrodilution method. Fungal isolates were grown in soy peptone liquid medium and treated with T. copticum oil and propolis extract. Total RNAs of M. canis were subjected to reverse transcription-polymerase chain reaction (RT-PCR). Specific primers of Actin and Mep3 genes were used. RESULTS: The results revealed that MIC values of T. copticum oil against M. canis strains were ranged from 0.2-30.5 µg/mL, with 42.3% of the strains inhibited at 0.9 µg/mL. In addition, MIC values of propolis extract against M. canis strains were ranged from 0.2-488.2 µg/mL, with 34.6% of the strains inhibited at 0.9 µg/mL. RT-PCR analysis of Mep3 and Actin expression showed DNA fragments of 661 and 690 bp amplified in all isolates before treatments with T. copticum essential oil and propolis extract. Both T. copticum and propolis completely inhibited the expression of Mep3 gene. CONCLUSION: We reported for the first time that T. copticum and propolis inhibits the expression of Mep3 gene in M. canis strains in relation to a remarkable inhibition in protease production by the fungus.

[Advance in studies on antioxidant activity of propolis and its molecular mechanism].

Propolis is an adhesive substance mixed with plant resins collected by honeybees (Apis mellifera) and secretions from their mandibular gland and wax gland, with wide pharmacological activity and healthcare functions. Its antioxidant activity has long been regarded as one of the most important biological activities of propolis. This article summarizes studies on the antioxidant activity of propolis extracts from different geographic origins and with different extraction methods, as well as several important monomer active ingredients in propolis, and concludes the potential molecular mechanism of antioxidant activity of propolis and its monomer ingredients, with the aim of providing ideas for further studies on pharmacological activity of propolis, as well as reference for in-depth development of propolis products.

Chemical and functional characterization of Italian propolis obtained by different harvesting methods.

The composition and antioxidant activity of Italian poplar propolis obtained using three harvesting methods and extracted with different solvents were evaluated. Waxes, balsams, and resins contents were determined. Flavones and flavonols, flavanones and dihydroflavonols, and total phenolics were also analyzed. To characterize the phenolic composition, the presence of 15 compounds was verified through HPLC-MS/MS. The antioxidant activity was evaluated through 1,1-diphenyl-2-picrylhydrazyl radical and reducing power assays. The ability of propolis to inhibit lipid oxidation was monitored by analyzing hydroperoxide and TBARS formation in lipids incorporated into an oil-in-water (O/W) emulsion. Acetone shows the highest extraction capacity. Wedge propolis has the highest concentration of active phenolic compounds (TP = 359.1 ± 16.3 GAEs/g; TFF = 5.83 ± 0.42%; TFD = 7.34 ± 1.8%) and seems to be the most promising for obtaining high-value propolis more suitable to prepare high-quality dietary supplements (TBARS = 0.012 ± 0.009 mmol std/g; RP = 0.77 ± 0.07 TEs/g).

¹H-NMR simultaneous identification of health-relevant compounds in propolis extracts.

INTRODUCTION: Propolis is a resinous substance collected by bees from exudates of different plants that is rich in well-known health-relevant phenolic compounds such as flavonoids and phenolic acids. Propolis extracts are very complex matrices difficult to study. Different analytical methods are usable to analyse propolis extracts and to obtain chemical fingerprint but to our knowledge NMR has not previously been used for this purpose. OBJECTIVE: This study aims to demonstrate that it is possible to use ¹H-NMR for the simultaneous recognition of phenolic compounds in complex matrices, such as propolis extracts, using appropriate tools for spectra pre-treatment and analysis. METHODOLOGY: In this work 12 typical phenolic propolis compounds (apigenin, chrysin, galangin, kaempferol, quercetin, naringenin, pinocembrin, pinostrobin, caffeic acid, cinnamic acid, p-coumaric acid and ferulic acid) were considered as reference compounds and their presence in samples was verified by HPLC-MS. A simple ¹H-NMR sequence was used to obtain spectra of samples. Spectra were pre-treated by using an appropriate tool for spectra alignment and analysed by using software for the study of spectra originated from complex matrices. Sixty-five propolis samples were used to test the proposed identification procedure. RESULTS: Ten out of 12 considered compounds were identified as statistically significant in most of the samples. CONCLUSION: This work suggests that it is possible to efficiently use ¹H-NMR, coupled with appropriate spectral analytical tools, for the simultaneous detection of phenolic compounds in complex matrices.

Evaluation of the in vitro antimicrobial activity of an ethanol extract of Brazilian classified propolis on strains of Staphylococcus aureus

Staphylococcus aureus (S. aureus) is one of the most frequent causes of hospital acquired infections. With the increase in multiple drug resistant strains, natural products such as propolis are a stratagem for new product discovery. The aims of this study were: to determine the in vitro antimicrobial activity of an ethanol extract of propolis; to define the MIC50 and MIC90 (Minimal Inhibitory Concentration - MIC) against 210 strains of S. aureus; to characterize a crude sample of propolis and the respective ethanol extract as to the presence of predetermined chemical markers. The agar dilution method was used to define the MIC and the high performance liquid chromatography (HPLC) method was used to characterize the samples of propolis. MIC results ranged from 710 to 2,850 µg/mL. The MIC50 and MIC90 for the 210 strains as well as the individual analysis of American Type Culture Collection (ATCC) strains of Methicillin-susceptible Staphylococcus aureus (MSSA) and Methicillin-resistant Staphylococcus aureus (MRSA) were both 1,420 µg/mL. Based on the chromatographic analysis of the crude sample and ethanol extracted propolis, it was concluded that propolis was a mixture of the BRP (SP/MG) and BRP (PR) types. The results obtained confirm an antimicrobial activity in relation to the strains of the S. aureus tested.

Alternative medicine safety: Agaricus blazei and propolis.

All medicines pose a potential health risk, be they Eastern or Western medicines. Newly developed Western drugs must undergo rigorous testing to ensure their efficacy and safety, while with Eastern drugs, safety has generally been established because of their long histories of safe usage as traditional medicines. The regulation of Western medicines is much stronger than that of Eastern medicines, partly as pure chemicals are used and their effects and side effects are more likely to be acute. Eastern medicines consist of multiple components, generally extracted from a single or several plants or other natural sources, and their effects are not so acute, with delayed onset of side effects. However, the chronic usage of many Eastern medicines may result in the gradual accumulation of toxic compounds in the body. For example, Agaricus blazei extracts have been used as alternative medicines for cancer, but contain the known carcinogen agaritine (this carcinogen is also present in Agaricus bisporus). To ensure the safety of this alternative medicine, agaritine should be removed or its content reduced if the extract is to be taken chronically. Clearly, the safety of not only pure medicines, but also alternative medicines and daily foods, should be carefully controlled.

Antimethicillin-resistant Staphylococcus aureus (MRSA) activity of 'pacific propolis' and isolated prenylflavanones.

The need to discover and develop alternative therapies to treat methicillin-resistant Staphylococcus aureus (MRSA) infections is timely. This study was undertaken to purify and identify some anti-MRSA constituents from propolis, a natural product from the beehive traditionally used in folk medicine for its antimicrobial properties. A crude extract of propolis originating from the Solomon Islands ('Pacific propolis') was screened, using an agar dilution assay, in vitro against 15 MRSA clinical isolates. Results revealed activity worthy of further investigation, and subsequent purification work on this crude extract afforded 23 fractions. Further purification of active fractions led to the isolation of compounds 1-4, characterized upon analysis of their spectroscopic data (1D- and 2D-NMR, MS) and by comparison with the literature, as the prenylflavanones propolin H (1), propolin G (2), propolin D (3), and propolin C (4). This study is the first to report the anti-MRSA activity of 'Pacific propolis' and the presence of prenylflavanones in the propolis sample selected. The anti-MRSA activity of propolin D (3) (MIC 8-16 mg/L) and propolin C (4) (MIC 8-32 mg/L) is reported for the first time.