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.

Antioxidant and Anti-cancer Cell Proliferation Activity of Propolis Extracts from Two Extraction Methods

“…Increasing of ethanol concentration at 30, 40, 50, 70% affected total phenolic compound and DPPH activity due to polyphenolic compound in propolis could easily dissolve in ethanol more than water (Siripatrawan et al, 2013). Similarly to the study of Park et al (1998) and Cvek et al (2007) revealed that the use of ethanol at concentration more than 70% did not assist to extract the phenolic compound in propolis extraction process (Park et al, 1998 andCvek et al, 2007).…”

Desempenho do processo de concentração de extratos de própolis por nanofiltração

“…A avaliação do efeito da pressão, temperatura e velocidade tangencial no fluxo de permeado foi realizada utilizando-se DWYer, 1998). Além disso, Cvek et al (2007) estudaram o processo de extração da própolis em temperatura ambiente, 50, 70 °C e ebulição. Analisando os compostos fenólicos e flavonoides, concluíram que a temperatura ambiente é a que melhor preserva os compostos de interesse.…”

Comprehensive Study of Mediterranean (Croatian) Propolis Peculiarity: Headspace, Volatiles, Anti‐Varroa‐Treatment Residue, Phenolics, and Antioxidant Properties

“…Them ajor compounds identified by headspace solid-phase microextraction (HS-SPME), simultaneous distillation extraction (SDE), and subsequent GC-FID and GC/MSanalyses were a-eudesmol(up to 19.9%), b-eudesmol (upto 12.6%), g-eudesmol(up to 10.5%),benzylb enzoate (upt o2 8.5%),a nd 4-vinyl-2-methoxyphenol(up to 18.1%).V anillin was determined as minorc onstituentb yS DE/GC-FID/MSa nd HPLC-DAD.T he identified acaricide residuet hymol was ca.t hree times more abundantb yHS-SPME/GC-FID/MS than by SDE/GC-FID/MS and was not detected by HPLC-DAD. In addition, UV/VIS assays have been applied, e.g., to monitor the formation of AlCl 3 complexes for the quantitative determination of flavones and flavonols [9], the 2,4-dinitrophenylhydrazinem ethodf or flavanones [9], or the FolinÀCiocalteu method for the quantification of the total phenol (TP) content [10]. Up to now,m ore than 200 compounds have been identified in propolis,with focus on polyphenols (flavonoids,a ccompanied by phenolic acid esters,aldehydes,ketones,and others) [11].Moreover,the following biological activities of different propolis preparations have been reported [12][13]: antioxidant, antihepatotoxic, neuroprotective,a nti-inflammatory,a ntibacterial, antifungal, and antiviral properties.I th as also been demonstrated that propolis and some of its constituents (e.g., caffeic acid phenethyl esterorartepillinC)exhibited ap ronounced cytostatic,a nticarcinogenic, and antitumor effect both in in vitro and in vivo tumor models [14].…”