EKSTRAKCIJA I ANALIZA KONDENZIRANIH TANINA CASTANEA SATIVA MIIL.

Proanthocyanidins, also known as condensed tannins are widespread in woody plants, but are also found in certain forages. Castanea sativa Mill. are exploited for various purposes, but a little is known about potential of this species and possible application in diet and therapy. The parts of chestnut such as: seed, peeled seed, brown seed shell, red internal seed shell, leaves, catkin, spiny bur, as well as the new and old chestnut bark were extracted with 50% ethanol as an extragents. Contents of total phenolics and total flavonoids were measured by application of the standard colorimetric assay. The total condensed tannins content estimated was highest in red internal seed shell 15.29%CE (vanillin assay) and 3.12%CT (acid butanol assay). Also high content of total phenolic compounds and condensed tannins had extracts of catkin, brown seed shell of chestnut and new chestnut bark. Extracts of C. sativa Mill. can be a potential resource of natural tannins with possible application in diet and therapy.Proantocijanidini, poznati kao kondenzirani tanini su jako rasprostranjeni u drvenastim biljkama, a pronađeni su i u hrani. Castanea sativa Mill. se dosta koristi za različite namjene, međutim malo je poznat njegov potencijal i moguća primjena u dijeti i terapiji. Dijelovi kestena kao što su; cijeli plod, srž ploda, vanjska smeđa kora ploda, crvena unutrašnja kora ploda, list, resa, ježura, kao i nova i stara kora drveta su ekstrahirani primjenom 50% etanola kao ekstragensa. Sadržaj ukupnih fenola i flavonoida je određen primjenom standardnih kolorimetrijskih testova. Sadržaj ukupnih kondenziranih tanina je najviši u crvenoj unutrašnjoj kori 15,29%CE (vanilin test) i 3,12%CT (kiseli butanolni test). Visok sadržaj ukupnih fenolnih tvari i kondenziranih tanina je određen u ekstraktima rese, vanjske smeđe kore i nove kore drveta. Ekstrakti C. sativa Mill. mogu biti potencijalna sirovina koja sadrži prirodne tanine sa mogućom primjenom u dijeti i terapiji

Isoflavone content and antioxidant properties of soybean seeds

The isoflavone content and antioxidant properties of five Croatian soybean seed cultivars from two locations were analysed. The content of total and individual isofavones was determined by high performance liquid chromatography. For determination of antioxidant properties scavenging capacity on DPPHֹ radicals has been applied. The total phenolic content, oil and protein content in soybean cultivars were also determined. Significant differences in the content of individual isoflavones were observed within the soybean cultivars. The total phenol content in soybean cultivars ranged from 87.2 to 216.3 mg GAE/100g of soybean. The total isoflavone content in soybean seeds ranged from 80.7 to 213.6 mg/100g of soybean. The most abundant isoflavone in soybean seeds was genistein. There was statistically significant difference (p < 0.05) among two locations in total and individual isoflavone contents. The highest contents of total isoflavones were found in cultivar “os55-95”. Conversely, cultivars poor in isoflavones also showed low levels of DPPH-radical scavenging activity

Selenium and Zinc content and radical scavenging capacity of edible mushrooms Armilaria mellea and Lycoperdon saccatum

Armillaria mellea and Lycoperdon saccatum are two delicious mushrooms growing widely trough all Balkan region. Investigation of A. mellea and L. saccatum antioxidant properties includes preparation of mushrooms extracts, determination of Selenium and Zinc content and evaluation of theirs antioxidant activity involving scavenging activity of ˙O2- radicals, DPPH and reducing power assay. Higher extraction yield of 24.48 % has been achieved for L. saccatum, but higher content of Selenium and Zinc was determined in A. mallea extract, 2.359 mg/kg and 50.380 mg/kg, respectively. The radical scavenging activity was found to exhibit 50 % of inhibition value (IC50 value) at the extracts concentration of 0.0161±0.0001 mg/ml for the L. saccatum extract and 0.0108±0.0002 mg/ml for A. mallea extract. The determined relative inhibition of ˙O2- radicals for L. sacatum extract is lower than for A. malea. It was determined that both mushrooms extract posses’ reductive capabilities and thus were capable of reducing iron (III)

KAPACITET EKSTRAKTA PITOMOG KESTENA ZA SUZBIJANJE LIPIDNE PEROKSIDACIJE

Permanent attention of researchers has been focused on the use of natural antioxidants to inhibit lipid peroxidation, or to protect the damage provoked by free radicals. Extracts of sweet chestnut, Lovran’s Marrone cultivar and grafted Italian ″Marrone″ cultivar obtained in two years (2006. and 2007.), were investigated for their capacity to remove lipid peroxidation in liposomes exposed to hydroxyl radical, and for their total phenolics and flavonoids content. Selected tissues of sweet chestnut (Castanea sativa Mill.) fruit, leaf, catkin, spiny burs, young and old bark of chestnut tree have been extracted under the same conditions using 50% ethanol and afterwards dry extracts of examined samples have been gained. All extracts, excluding those with low content of both, total phenolics and flavonoids, showed the ability to protect liposomes from lipid peroxidation. We find practical importance of results in the fact that extract of spiny burs could potentially have beneficial effects in diet of hypertensive patients.Pozornost istraživača plijeni mogućnost korištenja prirodnih antioksidansa u inhibiciji lipidne peroksidacije, ili za zaštitu od oštećenja prouzročenih slobodnim radikalima. U dvogodišnjem razdoblju (2006. i 2007.) istraživan je kapacitet ekstrakta pitomog kestena, kultivara Lovranski marun i cijepljeni Talijanski marun za suzbijanje lipidne peroksidacije na liposomima izloženim hidroksi radikalima, kao i sadržaj fenolnih tvari i flavonoida. Dijelovi ploda kestena (Castanea sativa Mill.), list, resa, ježevica, mlada i stara kora drveta ekstrahirani su pod istim uvjetima korištenjem 50% etanola, a nakon toga je iz istraživanih uzoraka dobiven suhi ekstrakt. Svi ekstrakti, osim onih s malim sadržajem ukupnih fenola i flavonoida, pokazuju sposobnost zaštite liposoma od lipidne peroksidacije. Praktični značaj rezultata istraživanja vidimo u mogućnosti korištenja ekstrakta ježevica u dijeti pacijenata oboljelih od hipertenzije

EPR spin-trapping and spin-probing spectroscopy in assessing antioxidant properties: Example on extracts of catkin, leaves, and spiny burs of castanea sativa

Electron paramagnetic resonance (EPR) spin-trapping and spin-probing techniques were applied to determine antioxidant activity of extracts of catkin, leaves, and spiny burs of Castanea sativa against physiologically relevant reactive species-superoxide and hydroxyl radical generated in simple chemical systems and hydrogen peroxide applied on erythrocytes. Efflux of K + was used as a marker of membrane integrity. Chemical composition of extracts was analyzed using HPLC/DAD and LC/MS. Extracts showed high antioxidative capacity against superoxide but lower activity against hydroxyl radical. They protected fluidity and integrity of membranes of erythrocytes exposed to hydrogen peroxide. Levels of derivatives of ellagitannins showed positive correlation with the antioxidative activity of extracts. Therefore, ellagitannins from chestnut extracts could represent easily accessible natural antioxidants and beneficial component of human diet in pathophysiological conditions related to oxidative stress. In conclusion, EPR spectroscopy represents a valuable tool for evaluation of antioxidant activity in both hydrophilic and lipophilic media

UKLANJANJE RADIKALA, ANTIMIKROBNA AKTIVNOST I SADRŽAJ FENOLNIH MATERIJA CASTANEA SATIVA EKSTRAKATA

Radical Scavenging and antimicrobial activity of extracts of three cultivar of Castanea Sativa Mill. have been examined. Leaf and catkins have been extracted under the same conditions by 50% ethanol as extragens, afterwards dry extracts of examined samples have been gained. Total phenolic content was determined by HPLC, subsequent to preliminary acid hydrolysis of samples. For determination of extract infl uence to creating and transformation of hydroxide (OH) radicals and (DPPH) radicals, extracts have been dissolved in distillated water and added to Fenton’s model system in concentration of 0.2 mg/ml. High value antioxidant activity (AA) in relation to hydroxyl radicals has turned out catkins from Lovran chestnut (59.09%). The greatest antiradical activity in relation to DPPH radicals occurred with extracts of catkins from domestic sweet chestnut (37.50). The antimicrobial tests have showed that ethanol extracts of leaf and catkins inhibited growth of Gram positive bacteria.Ispitivano je uklanjanje radikala i antimikrobna aktivnost ekstrakata, tri kultivara Castanea Sativa Mill. Lišće i rese su ekstrahirane pod istim uvjetima 50%-tnim etanolom kao ekstragensom, a zatim su dobiveni suhi ekstrakti ispitivanih uzoraka. Nakon izvršene kisele hidrolize uzoraka ukupne fenolne tvari su ordređene HPLC-om. Radi određivanja efekta ekstrakata na stvaranje i transformiranje hidroksil (OH) radikala i (DPPH) radikala, ekstrakti su rastvoreni u destiliranoj vodi i dodani u Fenton-ov model sistem, do fi nalne koncentracije od 0,2 mg/ml. Visoka vrijednost antioksidativne aktivnosti (AA) u odnosu na hidroksil radikale određena je za resu Lovranskog kestena (59,09%). Najveća antiradikalna aktivnost u odnosu na DPPH radikale je utvrđena kod ekstrakta rese domaćeg pitomog kestena (37,50). Antimikrobni test je pokazao da etanolni ekstrakti rese i lista inhibiraju rast Gram pozitivnih bakterija

Antioxidant Properties of Phenolics in Castanea sativa Mill. Extracts

Using electron paramagnetic resonance (EPR) spectroscopy, antioxidant properties of chestnut extracts have been investigated as a source of phenolic compounds. In addition to their high antioxidant activities against hydroxyl and organic free (DPPH) radicals, phenolics showed to be potent protectors of membranes from lipid peroxidation To the best Of Our knowledge, the ability of an antioxidant to overcome body's refractory response towards antioxidant supplementation has been examined for the first time. The water soluble extracts obtained from leaves, catkins, and outer brown peel of Castanea sativa Mill. showed high antioxidant activity in scavenging OH and DPPH radical All extracts, except for sweet chestnut catkins, showed the ability to protect liposomes from peroxidation Phenolic compounds, as active antioxidants, have the ability to enter and protect cell membranes from lipid peroxidation, thus overcoming the body's refractory response to the antioxidant supplements In the diet. It is shown that phenolics are easily accessible natural antioxidants that can be Used as food supplements or for the treatment of pathophysiological conditions related to oxidative stress

The impact of some parameters on volatile compounds in hard type cheeses

Volatile compounds (VCs) analysis was performed by solid-phase microextraction-gas chromatography-mass spectrometry. Main groups that define typical cheese flavour formed as a result of the addition of a starter culture (SC). The cheesemaking environment, the type of milk (cow, ewe, goat), and the heat treatment of milk were observed. The SC had influenced the total amount of some fatty acids and ketones. Compared to cow and ewe cheeses, goat cheese had higher values of hexanoic and octanoic acids, however, two alcohols, 1-hexanol, 2-ethyl- and hexanol, were only present in cow cheeses. We confirmed that the cheesemaking environment is also an important parameter influencing VC profiles of cheese. Higher amount of esters and the absence of 2-phenylethanol were observed in raw milk cheese, compared to thermised milk cheese where δ-octalactone was present