BackgroundPollen is a bee-product known for its medical properties from ancient times. In our days is increasingly used as health food supplement and especially as a tonic primarily with appeal to the elderly to ameliorate the effects of ageing. In order to evaluate the chemical composition and the biological activity of Greek pollen which has never been studied before, one sample with identified botanical origin from sixteen different common plant taxa of Greece has been evaluated.ResultsThree different extracts of the studied sample of Greek pollen, have been tested, in whether could induce proteasome activities in human fibroblasts. The water extract was found to induce a highly proteasome activity, showing interesting antioxidant properties. Due to this activity the aqueous extract was further subjected to chemical analysis and seven flavonoids have been isolated and identified by modern spectral means. From the methanolic extract, sugars, lipid acids, phenolic acids and their esters have been also identified, which mainly participate to the biosynthetic pathway of pollen phenolics. The total phenolics were estimated with the Folin-Ciocalteau reagent and the total antioxidant activity was determined by the DPPH method while the extracts and the isolated compounds were also tested for their antimicrobial activity by the dilution technique.ConclusionsThe Greek pollen is rich in flavonoids and phenolic acids which indicate the observed free radical scavenging activity, the effects of pollen on human fibroblasts and the interesting antimicrobial profile.

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Stable virgin olive oil-in-water emulsions were prepared using total endogenous surface-active components derived from oil as emulsifying agents, and the interfacial properties of the emulsion droplets were examined. The amount of oil extracted into the aqueous buffer increased with buffer pH, with the most stable emulsions being formed at pH 7.5. Light microscopy of the emulsions revealed the presence of spherical droplets with diameters ranging from 1.5 to 3 µm. Their surface was negatively charged at pH 7.5, as confirmed by the effect of ions and polycations. Potassium chloride, Ca 2+ , and spermine induced rapid aggregation (as monitored by the turbidity change and by light microscopy), showing their maximal effect at 1 M, 4 mM, and 60 µM, respectively. Papain treatment of the emulsion particles rapidly induced particle aggregation, suggesting the destruction of stabilizing structural olive oil proteins. Unlike papain, treatment with phospholipase C did not result in an appreciable turbidity change. Treatment with soybean lipoxygenase slightly increased the turbidity of the emulsion. The interaction of linoleate-Tween 20 mixed micelles with emulsion droplets produced turbidity, which was maximal at a neutral pH, whereas interaction with proteolyzed and lipoxygenase-treated droplets induced both a significant increase in turbidity and a red shift to a different absorption maximum of the system as compared with those of the untreated emulsion.Paper no. J11056 in JAOCS 82, 415-420 (June 2005).

In the present study we report the chemical composition of the Cretan Phoenix theophrasti Gr. fruits, in comparison with dates, from its close relative Phoenix dactylifera L. for their nutritional value and their potential exploitation as a source of bioactive components such as phytosterols, lipids and polyphenols. The non polar dichloromethane (CH2Cl2) extract of the fruits was analysed by several techniques (TLC, CC, GC and GC-MS) and was found to consist mainly from fatty acids, hydrocarbons and phytosterols. Palmitic acid was the most abundant fatty acid, 12.49% of total saponifiables, while beta-sitosterol was the most prevalent phytosterol, 29.46% of total unsaponifiable lipid fraction. The polar methanolic extract was examined for its total phenolic content, by the Folin-Ciocalteu assay, as well as for its antioxidant activity through DPPH assay, in comparison with previous studies on the fruits of several Phoenix dactylifera varieties. This fraction was found to possess strong antioxidant activity despite its lower content of phenolic compounds in comparison with previously studied Phoenix dactylifera specimens.

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