Optimisation of an extraction procedure and chemical characterisation of Croatian propolis tinctures.
ABSTRACT Three spectrophotometric methods for the quantitative determination of different flavonoid groups and total phenolics in Croatian propolis samples were optimised and validated. The assay based on the formation of aluminium chloride complex (with galangin as a standard) was applied to the quantification of flavones and flavonols, while the 2,4-dinitrophenylhydrazine method (with pinocembrine as a reference) was used for the quantification of flavanones. Total phenolic content was measured by the Folin-Ciocalteau method using reference solution of caffeic acid:galangin:pinocembrine (1:1:1). Through analytical validation, the most suitable extraction conditions (with respect to time, temperature and concentration of extraction solvent) were determined, and final conditions for the extraction were established (80% ethanol, 1 h at the room temperature). The appropriate ratio between the mass of raw propolis and the extraction solvent volume was also established. By the application of the optimised method of extraction, 10 propolis tinctures were prepared and subjected to the analysis of general pharmacopoeial parameters, which are fundamental for the creation of quality specification (relative density, dry residue of extract, content of ethanol, methanol and 2-propanol). Additionally, the content of waxes as the main inactive constituents was determined in order to observe the level of their migration from crude propolis to the prepared tinctures.
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ABSTRACT: Propolis is a sticky material mixed by honeybees to utilize it in protecting their hives from infection by bacteria and fungi. The therapeutic properties of propolis are due to its chemical composition with bio-active compounds; therefore, researchers are interested in studying its chemical constituents and biological properties. The main objective of this study is to determine the chemical compositions, characteristics and relative concentrations of organic compounds in the extractable organic matter of propolis samples collected from four different areas in Ethiopia.SpringerPlus 01/2014; 3:253.
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ABSTRACT: Propolis is a complex resinous product gathered by honeybees whose chemical composition is highly variable, depending strongly on the plant sources available to the bees at the site of collection. Propolis from several locations in Portugal, including islands, was fully characterized in terms of physicochemical properties, phenolic composition and antioxidant activity, enabling the establishment of quality standards. Color, frequently used as a commercial parameter, was accessed by the first time in propolis with the CIELAB system, and proposed as a quick and reliable method for quality recognition. The results attested the existence of two different types of propolis within the six regions under study. One, the poplar propolis most common in temperate regions, revealed a high content in phenolics and show high bioactivity. The other, with darker green color is less rich in phenolics and generally less bioactive.Journal of Oil & Fat Industries 11/2013; 90(11). · 1.62 Impact Factor
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ABSTRACT: Antioxidant activity, total phenolic, total flavonoid compounds and cytotoxicity to cancer cell lines of propolis extracts from two extraction methods were investigated in this study. Propolis was collected from Phayao province and extracted with 70% ethanol using maceration and sonication techniques. The antioxidant activity was evaluated by DPPH assay. Total phenolic and flavonoid compounds were also determined. Moreover, the cytotoxicity of propolis was evaluated using MTT assay. The percentage propolis yield after extraction using maceration (18.1%) was higher than using sonication (15.7%). Nevertheless, antioxidant and flavonoid compounds of the sonication propolis extract were significant greater than using maceration. Propolis extract from sonication showed antioxidant activity by 3.30±0.15 mg gallic acid equivalents/g extract. Total phenolic compound was 18.3±3.30 mg gallic acid equivalents/g extract and flavonoid compound was 20.49±0.62 mg quercetin/g extract. Additionally, propolis extracts from two extraction methods demonstrated the inhibitory effect on proliferation of A549 and HeLa cancer cell lines at 24, 48 and 72 hours in a dose-dependent manner. These results are of interest for the selection of the most appropriate method for preparation of propolis extracts as potential antioxidant and anticancer agents.Asian Pacific journal of cancer prevention: APJCP 01/2013; 14(11):6991-5. · 1.50 Impact Factor