Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15-18 March 2016.

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

Chemical analysis of Greek pollen - Antioxidant, antimicrobial and proteasome activation properties

<p>Abstract</p> <p>Background</p> <p>Pollen 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.</p> <p>Results</p> <p>Three 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.</p> <p>Conclusions</p> <p>The 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.</p

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

Chemistry and bioactivity of royal jelly from Greece

Twenty-five compounds were identified from the dichloromethane and methanol extracts of royal jelly from Greece. Among them, 16 compounds are reported for the first time as royal jelly constituents, whereas 7 of them are isolated for the first time as natural products. The 7 new compounds were fatty acid derivatives: 10-acetoxydecanoic acid (1), trans-10-acetoxydec-2-enoic acid (2), 11-oxododecanoic acid (3), (11S)-hydroxydodecanoic acid (4), (10R, 11R)-dihydroxydodecanoic acid (5), 3,11-dihydroxydodecanoic acid (6), and (11S), 12-dihydroxydodecanoic acid (7). The structures of the isolated compounds were determined by spectroscopic methods, mainly by the concerted application of 1D and 2D NMR techniques (HMQC, HMBC) and mass spectrometry. The studied sample and the isolated compounds were tested for their antimicrobial activity against Gram-positive and Gram-negative bacteria and fungi and exhibited interesting activities. © 2005 American Chemical Society

Chemical constituents of selected unifloral Greek bee-honeys with antimicrobial activity

(±)-3-Hydroxy-4-phenyl-2-butanone (1) and (+)-8-hydroxylinalool (2) were isolated from Greek honey samples and their structures were determined by spectroscopic and mass spectrometry methods. The enantiomeric ratio of 1 and 2 was determined using chiral GC-MS. Compound 1 has recently been proposed as a possible chemical marker of thyme honey, but although 1, in our hands, was identified only in monofloral thyme honey amongst the honey samples, it was not found in all studied thyme honey samples and additionally its origin was not directly associated with thyme, proving that compound 1 should not be considered as an unambiguous marker of thyme honey. Compound 2 was isolated and identified as the (+)-6S isomer only in monofloral citrus honey. The combination of (+)-8-hydroxylinalool with methyl anthranilate and caffeine could be proposed as a fingerprint marker for the description of citrus honey. All studied honey extracts and the isolated compounds were also tested for their antimicrobial activity. © 2011 Elsevier Ltd. All rights reserved

Chemical analysis and antimicrobial activity of Greek propolis

One new 2,3-dihydroflavone derivative, 7-0-prenylstrobopinin, and 25 known diterpenes and phenolic compounds were identified from the n-butanol extract of Greek propolis. This is the first time that diterpenes have been isolated from propolis of European origin, while six of the known compounds are reported as propolis constituents for the first time. The structures of the isolated compounds were determined by spectroscopic methods, mainly by the concerted application of 1D, 2D NMR techniques (HMQC, HMBC, NOESY) and mass spectrometry. The studied sample and the isolated compounds were tested for their antimicrobial activity against Gram (±) bacteria and fungi and five of them exhibited strong activities

Volatile constituents of propolis from various regions of Greece - Antimicrobial activity

The volatiles of five samples of Greek propolis from various geographic origin (A-E) were analyzed by capillary gas chromatography, using flame ionization GC and mass spectrometric detection. Ninety-four components were identified from the oils. The major components from each sample were found to be: junipene (11.7%), α-pinene (7.9%), manoyl oxide (7.1%) (sample A), α-pinene (45.8%), trans-β-terpineol (6.6%) (sample B), α-pinene (17.7%), α-eudesmol (12.1%), n-decanal (6.2%), guaiol (5.0%) (sample C), α-pinene (18.2%), δ-cadinene (8.4%) and α-muurolene (5.0%) (sample D), α-pinene (10.9%), n-decanal (10.3%), cedrol (6.3%), n-nonanal (5.4%), and manool (5.2%) (sample E). The total profile of the volatile constituents of all samples reveals the predominance of terpenoids, especially of α-pinene. The in vitro antimicrobial activity of the volatiles from all five studied samples against six bacteria and three fungi is also assayed and reported. © 2006 Elsevier Ltd. All rights reserved

Natural and synthetic 2,2-dimethylpyranocoumarins with antibacterial activity

A new efficient synthetic approach to the natural coumarins 5-hydroxyseselin (5), 5-methoxyseselin (3), and (±) cis-grandmarin (9) is described as well as the synthesis of some new derivatives in the 5-methoxyseselin series (10-15). The natural coumarins 7-hydroxyalloxanthyletin (6), alloxanthoxyletin (8), and dipetalolactone (7) have also been obtained as secondary products. The type of fusion of the pyrano ring in all cases has been established by 2D NMR spectroscopy. The compounds have been studied for their in vitro antibacterial activity, which has been compared with that of some previously synthesized seselin derivatives. The most active compounds were 3, 7, 8, 11, and 14. Some structure-activity relationships are discussed