Optimisation of an extraction procedure and chemical characterisation of Croatian propolis tinctures

Agency for Medicinal Products and Medical Devices, Ksaverska cesta 4, 10000 Zagreb, Croatia.
Phytochemical Analysis (Impact Factor: 2.34). 09/2007; 18(5):451-9. DOI: 10.1002/pca.1001
Source: PubMed


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.

15 Reads
  • Source
    • "Phenol content was estimated from a standard curve of gallic acid and results expressed as mg of gallic acid equivalents (GAE) 100 g −1 f.w. Total flavonoids content was determined following the method suggested by Cvek et al. (2007) "

  • Source
    • "Phenol content was estimated from a standard curve of gallic acid and results expressed as mg of gallic acid equivalents (GAE) 100 g −1 f.w. Total flavonoids content was determined following the method suggested by Cvek et al. (2007) "
    [Show abstract] [Hide abstract]
    ABSTRACT: The effect of gaseous ozone exposure on the development of stem-end rot disease, caused by Botrytis cinerea, on kiwifruit (Actinidia deliciosa, cv. Hayward) was investigated. Artificially inoculated kiwifruit were subjected for 4 months to conventional cold storage (0 ◦ C, RH 95%) where catalytic oxidation of ethy- lene was applied (control) and to conventional cold storage with continuous supply of ozone (0.3 􏰀L L−1 ) or in a conventional kiwifruit cold storage room, where catalytic oxidation of ethylene was applied. Ozone treatment delayed and simultaneously decreased disease incidence by 56%, while disease sever- ity on infected fruit remained unaffected. Infected fruit formed sclerotia, while no sporulation of the pathogen occurred in the presence of ozone. To elucidate whether the observed disease suppression was mediated by a direct effect of ozone on the fungal pathogen per se or by the induction of a resistance mechanism in the fruit, two additional sets of experiments were conducted. Kiwifruit were exposed to ozone (0.3 􏰀L L−1 ) for 0, 2, 8, 24, 72 and 144 h in a conventional cold storage room either before or after the artificial inoculation with the pathogen and its efficacy on disease incidence and severity was moni- tored. Pre-inoculation exposure of fruit to ozone, at increasing exposure time intervals led to significant suppression of disease incidence, while post-inoculation exposure did not affect it. The observed disease suppression, provided by the pre-inoculation exposure, strongly suggests that ozone treatments induce resistance of kiwifruit to the pathogen. Measurements of antioxidant substances and antioxidant activity on fruit exposed to ozone for the same time intervals showed a strong negative correlation between disease incidence or severity and phenol content.
    Postharvest Biology and Technology 12/2010; 58(3):203-210. DOI:10.1016/j.postharvbio.2010.07.002 · 2.22 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Propolis is the generic name for the resinous substance collected by honeybees (Apis mellifera L.) from a variety of plant sources. Because of its popularity in folk medicine, it has become the subject of intense pharmacological and chemical studies over the last 30 years. Increased use of propolis preparations necessitates analysis of its composition and identification of its pharmacologically active constituents. In this paper a simple, selective, and sensitive HPTLC method is reported for determination and quantification of three phenolic acids (caffeic acid, p-coumaric acid, and isoferulic acid) and four flavonoids (pinocembrin, pinocembrin-7-methyl ether, chrysin, and tectochrysin) in seven propolis samples collected from different parts of Croatia. Chromatographic analysis was performed on 20 cm x 10 cm glass-backed silica gel F-254s HPTLC plates with chloroform-methanol-formic acid, 44:3.5:2.5 (v/v) as mobile phase. Quantification was performed by scanning densitometry at the UV absorption maximum of each compound. The method was found to be simple, reliable, and convenient for analysis of these phenolic compounds in Croatian propolis samples. Its analytical performance (precision, accuracy and robustness) fulfilled the acceptance criteria established for TLC methods in the official literature. The method was also shown to be selective and linear.
    JPC - Journal of Planar Chromatography - Modern TLC 12/2007; 20(6):429-435. DOI:10.1556/JPC.20.2007.6.7 · 0.67 Impact Factor
Show more