Biochemical activities of propolis extracts. II. Photodynamic activities

Analysis of antimicrobial activity of Karnataka propolis against oral pathogens – An in vitro study

Background:

Propolis, a natural antibiotic, which is in high demand in dentistry is a resinous substance. The main ingredient of propolis that is required for antibiotic effect is flavonoids and phenolic acids. Although propolis is a promising option for the control of oral microbes with lower related hazards and a good immunomodulator effect, its composition differs considerably depending on its botanical origin, the site and the season of collection. This original research aims to find the chemical composition and minimum inhibitory concentration (MIC) of propolis procured from different places of Karnataka state. The results would help the dentist and the pharmacist to select the best propolis to use as antibiotics in treating oral disease.

Materials and Methods:

Propolis sample from 5 different locations of Karnataka was procured from single apiary in Bangalore. Extraction of propolis using two different extracting solvents was carried out. The total phenolic content, total flavonoid content and MIC of each sample were analyzed.

Results:

Water extract propolis of Sullia and Hubli was highly active against tested organism with the MIC <0.312; alcohol extract of Sullia, Hubli and Chitradurga was moderately active with the MIC between 0.312 and 5 mg/ml. Vijayapura and Bagalkot were least active with the MIC >5 mg/ml at tested concentration.

Conclusion:

Propolis procured from different locations of Karnataka can be used as an antimicrobial agent with varying concentrations. However, when propolis is procured for therapeutic purpose, then it needs to be tested for its chemical composition before being utilized.

Propolis Reduces the Expression of Autophagy-Related Proteins in Chondrocytes under Interleukin-1β Stimulus

Background: Osteoarthritis (OA) is a progressive and multifactorial disease that is associated with aging. A number of changes occur in aged cartilage, such as increased oxidative stress, decreased markers of healthy cartilage, and alterations in the autophagy pathway. Propolis extracts contain a mixture of polyphenols and it has been proved that they have high antioxidant capacity and could regulate the autophagic pathway. Our objective was to evaluate the effect of ethanolic extract of propolis (EEP) on chondrocytes that were stimulated with IL-1β. Methods: Rabbit chondrocytes were isolated and stimulated with IL-1β and treated with EEP. We evaluated cell viability, nitric oxide production, healthy cartilage, and OA markers, and the expression of three proteins associated with the autophagy pathway LC3, ATG5, and AKT1. Results: The EEP treatment reduces the expression of LC3, ATG5, and AKT1, reduces the production of nitric oxide, increases the expression of healthy markers, and reduces OA markers. Conclusions: These results suggest that treatment with EEP in chondrocytes that were stimulated with IL-1β has beneficial effects, such as a decrease in the expression of proteins associated with autophagy, MMP13, and production of nitric oxide, and also increased collagen II.

Propolis Protects Endotoxin Induced Acute Lung and Liver Inflammation Through Attenuating Inflammatory Responses and Oxidative Stress

Propolis is a natural bee product, and it has many effects, including antioxidant, anti-inflammatory, antihepatotoxic, and anticancer activity. In this study, we aimed to explore the potential in vivo anti-inflammatory, antioxidant, and antiapoptotic properties of propolis extract on lipopolysaccharide (LPS)-induced inflammation in rats. Forty-two, 3- to 4-month-old male Sprague Dawley rats were used in six groups. LPS (1 mg/kg) was administered intraperitoneally to rats in inflammation, inflammation + propolis30, and inflammation+propolis90 groups. Thirty milligram/kilogram and 90 mg/kg of propolis were given orally 24 h after LPS injection. After the determination of the inflammation in lung and liver tissues by ¹⁸F-fluoro-deoxy-d-glucose-positron emission tomography (¹⁸FDG-PET), samples were collected. The levels of malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), nitric oxide (NO), and DNA fragmentation were determined. The decrease of MDA levels in inflammation + propolis30 and inflammation + propolis90 groups was determined compared to the inflammation group in lung and liver tissues. The increase of SOD% inhibition in inflammation + propolis90 group was determined in liver, lung, and hemolysate compared to the inflammation group. Increased CAT activities in inflammation + propolis30 and inflammation + propolis90 groups were observed in liver tissue and hemolysate compared to inflammation group. In lung tissue, NO levels were lower in inflammation group compared to the control group, but DNA fragmentation levels were higher. ¹⁸F-FDG uptake of tissues in inflammation + propolis30 and inflammation + propolis90 groups was decreased compared to the inflammation group. In conclusion, the data of this study indicate that the propolis application may serve as a potential approach for treating inflammatory diseases through the effect of reducing inflammation and free oxygen radical production.

Alternative preparation of propolis extracts: comparison of their composition and biological activities

Background

Propolis is the bee product noted for multiple biological effects, and therefore it is widely used for the prevention and treatment of a variety of diseases. The active substances of propolis are easily soluble in ethanol. However ethanolic extracts cannot be used in treatment of certain diseases encountered in ophthalmology, pediatrics, etc. Unfortunately, the main biologically active substances of propolis are scarcely soluble in water, oil and other solvents usually used in pharmaceutical industry. The aim of this study was to investigate chemical composition, radical scavenging and antimicrobial activity of propolis extracts differently made in nonethanolic solvents.

Methods

Total content of phenolic compounds in extracts was determined using Folin-Ciocalteu method. Chemical composition and radical scavenging activity of extracts were determined using HPLC system with free radical reaction detector. Antimicrobial activity of examined preparations was evaluated using the agar-well diffusion assay.

Results

Total amount of phenolic compounds in extracts made in polyethylene glycol 400 (PEG) and water mixture or in PEG, olive oil and water mixture at 70 °C was comparable to that of ethanolic extract. Predominantly identified compounds were phenolic acids, which contribute ca. 40 % of total radical scavenging activity.

Investigated nonethanolic extracts inhibited the growth and reproduction of all tested microrganisms. Antimicrobial activity of some extracts was equal or exceeded the antimicrobial effect of ethanolic extract. Extracts made in pure water or oil only at room temperature, contained more than 5 – 10-fold lower amount of phenolic compounds, and demonstrated no antimicrobial activity.

Conclusions

Nonethanolic solvent complex and the effect of higher temperature allows more effective extraction of active compounds from propolis. Concentration of total phenolic compounds in these extracts does not differ significantly from the concentration found in ethanolic extract. Propolis nonethanolic extracts have radical scavenging and antimicrobial activity.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-015-0677-5) contains supplementary material, which is available to authorized users.

Assessment of the antioxidant activities of Brazilian extracts of propolis alone and in topical pharmaceutical formulations

The antioxidant activity of extracts of propolis and of formulations added with these extracts were measured by scavenging different radicals in different systems. For the ethanolic extract of propolis (EEP) and the glycolic extract of propolis (GEP) the IC50 observed were respectively of 0.024 and 0.035 microL/mL in scavenging hydroxyl radical, 0.016 and 0.012 microL/mL in inhibiting lipid peroxidation, 0.22 and 0.24 microL/mL in inhibiting chemiluminescence produced in the H2O2/luminol/horseradish peroxide (HRP) system and about 0.005 microL/mL for both extracts in inhibiting chemiluminescence produced in the xanthine/luminol/xanthine oxidase (XOD) system. The antioxidant activity of extracts of propolis in the formulations was not able to be assessed neither using the deoxyribose assay, since the formulation components interfered in the assay measurements, nor using chemiluminescence in the H2O2/luminol/HRP system, since this method did not show to be sensitive for the extract of propolis evaluation. However, the antioxidant activity of extracts of propolis could be successfully evaluated in the formulations using both lipid peroxidation and chemiluminescence generated in the xanthine/luminol/XOD system inhibitions.

Antimicrobial activity of propolis samples from two different regions of Anatolia

Antimicrobial activity of two propolis samples from Kazan and Marmaris regions in Turkey were investigated by the disc diffusion method. Antimicrobial activity was tested with four different ethanolic extracts (30, 50, 70, and 96% ethanol) of each sample against seven Gram positive, four Gram negative bacteria and one fungus culture. The activity was found to be mainly due to caffeic acid and its esters. An isomeric mixture containing 3,3-dimethylallyl caffeate, and isopent-3-enyl caffeate was isolated from Kazan propolis samples.

Activation of murine macrophage cell line RAW 264.7 by Korean propolis

Monocytes and macrophages play a major role in defense mechanism of the host response to tumor, in part through the secretion of several potent products and macrophage cytokines. Monocytes and tissue macrophages produce at least two groups of protein mediators of inflammation, interleukin 1 (IL-1) and tumor necrosis factor (TNF). Recent studies emphasizes that TNF and IL-1 modulate the inflammatory function of endothelial cells, leukocytes, and fibroblasts. In this study, our work is directed toward studying the in vitro effects of Korean propolis on the ability to induce cellular and secretory responses in murine macrophage cell line, RAW 264.7. It was found that Water Extract of Korean Propolis (WEP) could activate macrophages by producing cytokines. The production of the macrophage cytokines, IL-1 and TNF-alpha, by RAW 264.7 treated with WEP was examined from 2.5 microg/ml up to 25 microg/ml with dose dependent manner. Nitric oxide (NO) production was also increased when cells were exposed to combination of LPS and WEP from 2.5 microg/ml up to 25 microg/ml. At high dose of WEP (50 to 100 microg/ml) used to prescribe for anti-inflammatory and analgesic medicine showed inhibition of NO production in LPS-stimulated macrophage. Besides cytokine production, NO release, surface molecule expression and cell morphologic antigen expression were increased in response to the stimulation by WEP. These results suggested WEP may function through macrophage activation.

Apoptosis and suppression of tumor growth by artepillin C extracted from Brazilian propolis

Artepillin C was extracted from Brazilian propolis. Artepillin C (3,5-diprenyl-4-hydroxycinnamic acid) has a molecular weight of 300.40 and possesses antibacterial activity. When artepillin C was applied to human and murine malignant tumor cells in vitro and in vivo, artepillin C exhibited a cytotoxic effect and the growth of tumor cells was clearly inhibited. The artepillin C was found to cause significant damage to solid tumor and leukemic cells by the MTT assay, DNA synthesis assay, and morphological observation in vitro. When xenografts of human tumor cells were transplanted into nude mice, the cytotoxic effects of artepillin C were most noticeable in carcinoma and malignant melanoma. Apoptosis, abortive mitosis, and massive necrosis combined were identified by histological observation after intratumor injection of 500 microg of artepillin C three times a week. In addition to suppression of tumor growth, there was an increase in the ratio of CD4/CD8 T cells, and in the total number of helper T cells. These findings indicate that artepillin C activates the immune system, and possesses direct antitumor activity.

Effect of different formulations of propolis on mice infected with Trypanosoma cruzi

Propolis, a bee product, can be regarded as one of the potential natural sources in folk medicine, displaying strong antimicrobial activity. Previous work showed that propolis extracts exhibited in vitro activity against Trypanosoma cruzi (Higashi and de Castro, 1994). Different formulations of propolis were administered to experimentally Trypanosoma cruzi-infected mice and the parasitemia kinetics and survival rate were monitored. The oral administration of ethanolic extracts up to 1.2 g propolis/kg per day or propolis offered ad libitum in the drinking water (up to 4 g/kg per day) or added to the food (up to 5 g/kg per day) did not interfere with both parameters. The differences between in vitro and in vivo trypanocidal activity of propolis and future perspectives are discussed.