| Abstract | Polifenolni spojevi najpoznatiji su antioksidansi, kao i dominanti bioaktivni sastojci ljekovitog bilja. Ljekovito bilje od davnina je poznato u narodnoj medicini u liječenju raznih bolesti i zdravstvenih tegoba, što se pripisuje antiseptičkim, antibakterijskim, protuupalnim i ostalim ljekovitim svojstvima bilja. Stoga, unos antioksidansa i ne manje značajnih prehrambenih vlakana igra veliku ulogu u zaštiti ljudskog organizma od štetnog oksidacijskog djelovanja slobodnih radikala. Cilj ovog rada bio je odrediti udjel polifenolnih spojeva (ukupnih fenola, ukupnih neflavonoida i flavonoida, flavan-3-ola, flavona i flavonola, ukupnih proantocijanidina, hidroksicimetnih kiselina, ukupnih tanina), udjel topljivih polisaharida i celuloze u sedam biljnih ekstrakata, kao i antioksidacijski kapacitet istih. Udjeli polifenolnih spojeva određeni su spektrofotometrijskim metodama kao i antioksidacijski kapacitet koji je određen reakcijama s željezo(III)-tripiridiltriazinom (FRAP) te radikalima 2,2′-azino-bis(3-etilbenzotiazolin-6-sulfonskom kiselinom) (ABTS) i 2,2′-difenil-1-pikrilhidrazilom (DPPH). Praćena je i kinetika inhibicije DPPH radikala antioksidansima iz biljnih ekstrakata. Određivanje polisaharida bazira se na ekstrakciji polisaharida vodom te precipitaciji etanolom, dok određivanju celuloze prethodi razaranje biljnog tkiva octenom i dušičnom kiselinom. Najveći udjel ukupnih fenola, ukupnih flavonoida, flavona i flavonola, tanina i hidroksicimetnih kiselina određen je u ekstraktu majčine dušice, a ukupnih proantocijanidina u ekstraktu lista maline. Najveći udjel flavan-3-ola, u reakciji s vanilinom određen je u ekstraktu gloga, a u reakciji s p-DAC reagensom u ekstraktu lista maline. Najveći udjel polisaharida karakterizira ekstrakt koprive, a celuloze ekstrakt majčine dušice. Najveći antioksidacijski kapacitet, određen ABTS i FRAP metodom, određen je u ekstraktu majčine dušice, dok je primjenom DPPH metode najveći antioksidacijski kapacitet određen u ekstraktu lista maline. |
| Abstract (english) | Polyphenolic compounds are well-known antioxidants, as well as the dominant bioactive constituents of medicinal plants. Medicinal plants have a long history in traditional medicine in the treatment of various diseases and health problems, which is attributed to antiseptic, antibacterial, anti-inflammatory and other healing properties of herbs. Therefore, intake of antioxidants and no less important dietary fiber plays an important role in protecting human body against harmful oxidative effects of free radicals. The aim of this study was to determine the proportion of polyphenolic compounds (total phenolics, nonflavonoids and flavonoids, flavan-3-ols, flavones and flavonols, total proantocyanidins, hydroxicinnamics acid, total tannins), the proportion of soluble polysaccharides and cellulose in seven herbal extracts and antioxidant capacity. Shares of polyphenolic compounds were determinated by spectrophotometric methods, as well as antioxidant capacity was determined by reactions with Fe (III)-3-pyridyl-triazine (FRAP) and the radicals 2, 2 '-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2, 2' -diphenyl-1-picrylhydrazyl (DPPH). Kinetics of DPPH radical scavenging with antioxidants from herbal extracts was accompanied. Determination of soluble polysaccharides is based on the extraction of polysaccharides with water and precipitation with ethanol, while determination of cellulose antecede destruction of the plant tissue with acetic and nitric acid. The largest share of total phenol, total flavonoids, flavones and flavonols, tannins and hydroxicinnamics acid was determined in the extract of thyme, while the largest share of proantocyanidins was present in the extract of raspberry leaf. The highest proportion of flavan-3-ols, in reaction with vanillin was determined in the extract of hawthorn and with p-DAC reagent in the raspberry leaf extract. The largest share of the polysaccharides was characterized by an extract of nettle, and cellulose in the extract of thyme. The highest antioxidant capacities, determined by ABTS and FRAP methods, were determinated in the extract of thyme, while using the DPPH method the highest antioxidant capacity was determined in the raspberry leaf extract. |
