Tyrimo objektas ir metodai: Thymus spp. genties augalų žolė. Fenoliniai junginiai nustatyti spektrofotometrijos metodais, timolis – efektyviosios skysčių chromatografijos metodu. Darbo tikslas: ištirti čiobrelio žolėje esančių fenolinių junginių kiekio ir laisvųjų radikalų surišimo gebos įvairavimą Lietuvos klimato sąlygomis augančių čiobrelių žolės mėginiuose. Darbo uždaviniai: surinkti čiobrelių žolės žaliavų mėginius skirtinguose Lietuvos regionuose; spektrofotometrijos metodu nustatyti ir įvertinti suminį fenolinių junginių kiekį čiobrelio žolės mėginiuose; spektrofotometrijos metodu nustatyti ir įvertinti čiobrelio genties augalų žolės mėginių antioksidantinį aktyvumą ir jo įvairavimą; ESC metodu nustatyti fitocheminius žymenis, būdingus čiobrelio genties augalams; dendrograminiu modeliu įvertinti čiobrelių genties žaliavų mėginių rezultatus; sugrupuoti individų, rinktų skirtingose augavietėse žaliavų mėginius pasižyminčius fenolinių junginių kiekybiniais skirtumais ir antioksidantinio aktyvumo skirtumais; įvertinti fenolinių junginių kiekybinės sudėties ir laisvųjų radikalų surišimo gebos koreliacinius ryšius Lietuvos klimato sąlygomis augančių čiobrelių žolės mėginiuose. Išvados: Didžiausias suminis fenolinių junginių kiekis nustatytas T. serpyllum žolės mėginiuose rinktuose Molėtuose, Antalieptėje ir Ignalinoje. Mažiausias fenolinių junginių kiekis nustatytas T. serpyllum mėginio rinkto Lazdijų rajone ir T. pulegioides mėginio rinkto Zarasuose. Didžiausia... [toliau žr. visą tekstą] / Object and methods of assay: the object of this assay is Thymus spp. generic herb. Phenolic compounds were estimated by methods of spectrophotometry, where as thymol – by method of effective liquid chromatography. The aim of the work: to estimate variability of the quantity of phenolic compounds and free radical binding activity of thymus herb samples taken from various places in Lithuania with different climatic conditions. The goals of this work: to collect thyme herb samples from various regions in Lithuania; to estimate and evaluate the total amount of phenolic compounds in thyme herb samples by spectrophotometry method; to estimate and evaluate thyme generic herb antioxidant activity and variety in samples by spectrophotometry method; to estimate phytochemical marks, specific for thyme generic herbs by ESC method; to estimate thyme generic herb samples by dendrogram method; to group raw material samples of different individuals from different growing places that have differences in quantity of phenolic compounds and antioxidant activity; to evaluate correlation between structure of quantitative phenolic compounds and free radical binding activity in thyme samples taken from various places in Lithuania with different climatic conditions. Conclusions: The biggest total amount of phenolic compounds was estimated in T. serpyllum herb samples gathered in Moletai, Antaliepte and Ignalina. The smallest amount of phenolic compounds was estimated in T. serpyllum sample... [to full text]

Fenoliniai junginiai yra vieni iš daugelio obelų lapuose sutinkamų junginių. Dažniausiai sutinkami fenoliniai junginiai yra flavonoidai (floridzinas, epikatechinas, katechinas ir kiti) ir fenolinės rūgštys (kavos rūgštis, chlorogeno rūgštis). Fenoliniai junginiai apsaugoaugalus nuo oksidacinės pažaidos ir kitų nepalankių aplinkos sąlygų. Medicinoje vienas iš svarbiausių flavonoidų pritaikymo būdas, paremtas jų antioksidantiniu poveikiu. Jie vartojami mažinant oksidacinį stresą. Kiti naudingi poveikiai: antiuždegiminis, antivėžinis, antimikrobinis bei teigiamas poveikis širdies ir kraujagyslių sistemai. Tyrimo tikslas: Lietuvoje auginamų skirtingų veislių obelų lapuose nustatyti bendrą fenolinių junginių ir flavonoidų kiekius bei jų antioksidantinį aktyvumą spektrofotometriniu ir ESC metodais. Metodai:liofilizuoti obelų lapai ekstrahuoti ultragarso vonelėje. Ekstrahentas- 70proc. etanolis, ekstrakcijos laikas – 40min, ekstrakcijos temperatūra – 60˚C. Nustatant bendrą fenolinių junginių kiekį tiriamuosiuose ekstraktuose taikytas spektrofotometrinis Folin-Ciocalteu metodas, o rezultatai išreikšti galo rūgšties ekvivalentu (mg/g). Nustatant bendrą flavonoidų kiekį ekstraktuose buvo taikyta reakcija su AlCl3, rezultatai išreikšti rutino ekvivalentu (mg/g).Spektrofotometriniai metodai (DPPH ir FRAP) naudoti nustatant ekstraktų antioksidantinį aktyvumą, kuris išreikštas trolokso ekvivalentu (TEAC μmol/g). ESC metodas taikytas identifikuoti fenolinius junginius ir nustatyti jų... [toliau žr. visą tekstą] / Phenolic compounds are commonly found in apple leaves as secondary plant metabolites. Most common phenolic compounds are flavonoids (phloridzin, epicatechin, catechin and others) and phenolic acids (caffeic acid, chlorogenic acid). For plants phenolics act as antioxidants, protective agents against harsh conditions. For human use phenolics are used as natural antioxidants due to their ability to scavenge free radicals, inhibit their formation processes and induce response to oxidative stress. Other beneficial effects are antimicrobial, anti-cancerogenic, anti-inflammatory and cardiovascular protective effect. The aim of this research was to evaluate total content of phenolic compounds, total content of flavonoid compounds and antioxidant activity of different apple cultivars (Ligol, Aldas, Lodel, Auksis) using spectrophotometry and HPLC. Methods: Apple leaf samples were lyophilised and extracted using ultrasonic sound assisted extraction. 70% ethanol was used as extractant, extraction time was 40 min and temperature – 60˚C. To determine total content of phenolic compounds expressed as gallic acid equivalent (mg/g) for absolutely dried lyophilisate in apple leaf extracts spectrophotometric Folin-Ciocalteu method was used. To identify total content of flavonoids expressed as rutin equivalent (mg/g) for absolutely dried lyophilisate more specific reaction with AlCl3 was used. Two spectrophotometric methods FRAP and DPPH were used to determine total antioxidant activity expressed... [to full text]

ABSTRACT PRODUCTION AND CHARACTERIZATION OF RESOL TYPE PHENOLIC RESIN / LAYERED SILICATE NANOCOMPOSITES TaSan, Cemal Cem M.S., Department of Metallurgical and Materials Engineering Supervisor: Assoc.Prof. Cevdet Kaynak April 2005 133 Pages Polymer / layered silicate (P/LS) nanocomposites belong to one of the most promising group of materials of the past few decades and most probably for the near future. Combining two of the most widely studied topics of material science: composite materials and nanotechnology / P/LS research have drawn great attention starting with the pioneering works of Toyota Research Group in 1980&rsquo / s. The research is now being carried out world wide / since the excellent properties of these new materials, which is achieved by using very low amounts of a cheap reinforcement material (clay), increases the interest on these materials everyday after. In this present study, the object was to investigate the production parameters of phenol formaldehyde based layered silicate nanocomposites. For this purpose, 14 different specimen groups were produced / using two different resol type phenolic resins (PF76 and PF76TD) as the matrix / and 9 different montmorillonite clays (Rheospan, Resadiye, Cloisite Na+, 10A, 15A, 20A, 25A, 30B, 94A) as the reinforcement phase. Initially the curing schedules for the available resins were experimentally determined. Then, a short and effective mixing procedure for the thermosetting resin and the montmorillonite clay was developed. The effects of several processing parameters / such as clay type, clay source, clay content, clay modification, resin type, resin cure type, cure cycle and mixing cycle were determined by X-ray Diffraction, Scanning Electron Microscopy and Mechanical Tests. Then, Transmission Electron Microscopy was used to investigate the level of intercalation and/or exfoliation of the layered silicates. Finally, Differential Scanning Calorimetry was also carried out to analyse thermal properties of the specimens. It was concluded that, a partially intercalated and/or exfoliated structure could be obtained in resol type phenolic resin based systems at very low clay contents (such as 0,5%) leading to remarkable increases in mechanical properties (e.g. 66% increase in fracture toughness).

SCREENING FOR ANTIOXIDANT ACTIVITIES OF SEVERAL MEDICINAL PLANT EXTRACTS AND THEIR EFFECTS ON GLUTATHIONE-S-TRANSFERASE ACTIVITY ABSTRACT Sagdi&ccedil / oglu Celep, A. G&uuml / l&ccedil / in Ph.D., Department of Biochemistry Supervisor: Assoc. Prof. Nursen &Ccedil / oruh May 2005, 154 pages The consumption of fresh fruits, vegetables, and medicinal plants are known to be associated with a long life span and low incidence of oxidative stress related diseases such as Alzheimer&amp / #8217 / s, Parkinson&amp / #8217 / s, cancer, aging and cardiovascular diseases. Fitotherapeutic effects of medicinal plants is virtually attributable to their phenolic compounds with low cytotoxicity. In this study, plants used in Anatolian folk medicine for their effects such as antiinflammatory, antiulcer, antipyretic, fertility, analgesic and aphrodisiac, namely Aesculus hippocastanum L., Papaver bracteatum L., Urtica urens L., Gundelia tournefortii L., Prangos ferulacea L., Chaerophyllum macropodum Boiss., Heracleum persicum Desf., Allium vineale L., Aconitum cochleare Woroschin, Rheum ribes L., Ferula rigidula DC., Rosa heckeliana Tratt, were screened for their antioxidative effects. Antioxidant characteristics of the specified plants were studied using lipid peroxidation inhibiton and DPPH radical scavenging methods. Total phenolics content and their effects on glutathione-S-transferase activity of the plants were further investigated. Rheum ribes L, Ferula rigidula DC, Rosa heckeliana Tratt., Prangos ferulacea L. were found to be very effective antioxidants and also effective inhibitors for glutathione-S-transferase activities among the plants. Rosa heckeliana Tratt. root extracts exhibited very high total phenolics content (0.7 mg/mg of extract) and antioxidant activity with IC50 values of 11.2 &micro / g/mL and 5.1 &micro / g/mL for DPPH scavenging and lipid peroxidation inhibition, respectively. Ferula rigidula DC was identified as the most potent inhibitor for glutathione-S-transferase activity, with IC50 values of 49 &micro / g/mL.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2008. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 5 uppsatser.

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Diss. (sammanfattning). Umeå : Sveriges lantbruksuniv., 2003. / Härtill 5 uppsatser.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.

Lic.-avh. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2004. / Härtill 3 uppsatser.