Antimicrobial activity of secondary metabolites isolated from Centaurea spruneri Boiss. & Heldr.

Two coumarins, scopoletin (1) and isoscopoletin (2), two simple phenolic acids, protocatechuic acid (3) and isovanillic acid (4) and one flavonoid, eriodictyol (5) were isolated from the aerial parts of Centaurea spruneri. The structure of the compounds was established by spectroscopic methods. The in vitro antimicrobial activity of the isolated compounds was tested against eight bacteria and eight fungal species, using a microdilution method. All compounds tested showed moderate antibacterial and antifungal activities. Their minimum inhibitory concentrations were in the range 0.655-2.38 µmol ml-1 and their minimal bactericidal concentrations ranged from 0.694 to 4.15 µmol ml-1 against the tested bacterial species. All compounds showed fungistatic activity at 0.259-2.38 µmol ml-1 and fungicidal at 0.69-2.6 µmol ml-1 against all fungi tested.Iz nadzemnog dela Centaurea spruneri izolovana su dva kumarina skopoletin (1) i izoskopoletin (2), dve proste fenolske kiseline protokatehuinska kiselina (3) i izovanilinska kiselina (4) i flavonoid eriodiktiol. Hemijske strukture poznatih jedinjenja su utvrđene korišćenjem 1D i 2D NMR, MS i UV spektroskopskih analiza. U in vitro testu za određivanje antimikrobne aktivnosti izolovanih jedinjenja korišćena je mikrodiluciona metoda. Dobijena jedinjenja testirana su na po osam bakterijskih i gljivičnih vrsta. Sva jedinjenja su imala umerenu antibakterijsku i antifungalnu aktivnost. Minimalna inhibitorna koncentracija testiranih jedinjenja se kretala od 0,655 do 2,38 µmol ml-1, a minimalna baktericidna koncentracija 0,694-4,15 µmol ml-1. Testirana jedinjenja su pokazala fungicidnu aktivnost od 0,259-2,38 µmol ml-1 i fungistatičku 0,694-2,60 µmol ml-1, na sve testirane gljive.Projekat ministarstva br. 14304

HPLC/DAD/ESI-MS Analysis of Non-volatile Constituents of Three Brazilian Chemotypes of Lippia alba (Mill.) N. E. Brown:

Aqueous preparations and ethanolic extracts of three Brazilian chemotypes of Lippia alba (Mill.) N.E. Brown (Verbenaceae) were investigated for the chemical variability of their non volatile constituents by HPLC/DAD/ESI-MS analysis. The main class of compounds in all the extracts investigated was phenylpropanoids, mainly verbascoside, followed by the flavonoids tricin-7- O-diglucuronide (present in Lippia alba chemotypes 2 and 3), luteolin-7- O-glucuronide (present in L. alba chemotype 1) and mono-and di- O-glucuronic derivatives of apigenin and tricin. Four iridoids, geniposidic acid, theveside, 8- epi-loganin and mussaenoside were also identified

Antimicrobial activity of secondary metabolites isolated from Centaurea spruneri Boiss. & Heldr.

Two coumarins, scopoletin (1) and isoscopoletin (2), two simple phenolic acids, protocatechuic acid (3) and isovanillic acid (4) and one flavonoid, eriodictyol (5) were isolated from the aerial parts of Centaurea spruneri. The structure of the compounds was established by spectroscopic methods. The in vitro antimicrobial activity of the isolated compounds was tested against eight bacteria and eight fungal species, using a microdilution method. All compounds tested showed moderate antibacterial and antifungal activities. Their minimum inhibitory concentrations were in the range 0.655-2.38 µmol ml-1 and their minimal bactericidal concentrations ranged from 0.694 to 4.15 µmol ml-1 against the tested bacterial species. All compounds showed fungistatic activity at 0.259-2.38 µmol ml-1 and fungicidal at 0.69-2.6 µmol ml-1 against all fungi tested.Iz nadzemnog dela Centaurea spruneri izolovana su dva kumarina skopoletin (1) i izoskopoletin (2), dve proste fenolske kiseline protokatehuinska kiselina (3) i izovanilinska kiselina (4) i flavonoid eriodiktiol. Hemijske strukture poznatih jedinjenja su utvrđene korišćenjem 1D i 2D NMR, MS i UV spektroskopskih analiza. U in vitro testu za određivanje antimikrobne aktivnosti izolovanih jedinjenja korišćena je mikrodiluciona metoda. Dobijena jedinjenja testirana su na po osam bakterijskih i gljivičnih vrsta. Sva jedinjenja su imala umerenu antibakterijsku i antifungalnu aktivnost. Minimalna inhibitorna koncentracija testiranih jedinjenja se kretala od 0,655 do 2,38 µmol ml-1, a minimalna baktericidna koncentracija 0,694-4,15 µmol ml-1. Testirana jedinjenja su pokazala fungicidnu aktivnost od 0,259-2,38 µmol ml-1 i fungistatičku 0,694-2,60 µmol ml-1, na sve testirane gljive.Projekat ministarstva br. 14304

Hypericins as Potential Leads for New Therapeutics

70 years have passed since the first isolation of the naphthodianthrones hypericin and pseudohypericin from Hypericum perforatum L. Today, they continue to be one of the most promising group of polyphenols, as they fascinate with their physical, chemical and important biological properties which derive from their unique chemical structure. Hypericins and their derivatives have been extensively studied mainly for their antitumor, antiviral and antidepressant properties. Notably, hypericin is one of the most potent naturally occurring photodynamic agents. It is able to generate the superoxide anion and a high quantum yield of singlet oxygen that are considered to be primarily responsible for its biological effects. The prooxidant photodynamic properties of hypericin have been exploited for the photodynamic therapy of cancer (PDT), as hypericin, in combination with light, very effectively induces apoptosis and/or necrosis of cancer cells. The mechanism by which these activities are expressed continues to be a main topic of discussion, but according to scientific data, different modes of action (generation of ROS & singlet oxygen species, antiangiogenesis, immune responces) and multiple molecular pathways (intrinsic/extrinsic apoptotic pathway, ERK inhibition) possibly interrelating are implicated. The aim of this review is to analyse the most recent advances (from 2005 and thereof) in the chemistry and biological activities (in vitro and in vivo) of the pure naphthodianthrones, hypericin and pseudohypericin from H. perforatum. Extracts from H. perforatum were not considered, nor pharmakokinetic or clinical data. Computerised literature searches were performed using the Medline (PubMed), ChemSciFinder and Scirus Library databases. No language restrictions were imposed

A Validated Method for the Determination of Carnosic Acid and Carnosol in the Fresh Foliage of Salvia rosmarinus and Salvia officinalis from Greece

In the framework of a project aiming at identifying genotypes of Greek rosemary and sage producing high amounts of carnosic acid, an HPLC-PDA method was developed for the determination of the main antioxidant in the fresh leaves. To this end, an effective and repeatable extraction process of the labile diterpene was developed to ensure a good extraction yield. A fast RP-HPLC protocol was developed and optimized to allow for a short and reliable analysis of the unstable target constituent. The HPLC-PDA method was validated for precision and accuracy according to ICH guidelines. Finally, the overall method was validated for precision and accuracy at three concentration levels. The precision was acceptable with % RSD values ranging between 1.42 and 4.35. The recovery ranged between 85.1% and 104.6% with RSD values < 5%, within the acceptable limits. The developed assay was fast and simple and allowed for the fast and accurate determination of carnosic acid and carnosol in the fresh herbs. The methodology was applied to the quantitative analysis of several cultivated samples of S. rosmarinus and S. officinalis, and some of them were revealed to be promising starting materials for the development of Greek genotypes rich in carnosic acid

Labdane diterpenes from Marrubium velutinum and Marrubium cylleneum

From the aerial parts of Marrubium velutinum and Marrubium cylleneum, seven labdane diterpenes, velutine A, 15-epi-velutine A, velutine B, 15-epi-velutine B, velutine C, cyllenine A and 15-epi-cyllenine A, have been isolated together with five known diterpenes and four known flavones. The structures of the isolated compds. were established by means of NMR [1H-1H-COSY, 1H-13C-HMQC, HMBC, HMQC-TOCSY, NOESY] and MS spectral analyses. Complete NMR assignments are reported for known compds

Secondary metabolites from Marrubium velutinum, growing wild in Greece

From the aerial parts of Marrubium velutinum, two new phenylethanoid glycosides, velutinosides III and IV have been isolated together with four known phenylethanoid glycosides, as well as one new acylated flavone and five known flavonoids. The structures of the isolated compds. were established by means of NMR, MS, and UV spectral analyses