Phenolic compounds and antioxidative potential of Slovenian bee pollen

V okviru magistrske naloge smo določali vsebnost skupnih fenolnih spojin in posameznih podskupin fenolnih spojin ter ugotavljali antioksidativni potencial (AOP) slovenskega cvetnega prahu osmukanca. Ugotavljali smo, ali izbira ekstrakcijskega topila, toplotna obdelava in shranjevanje cvetnega prahu vplivajo na vsebnost fenolnih spojin in AOP. Za pripravo izvlečkov fenolnih spojin smo uporabili različna ekstrakcijska topila: 50 %, 70 % in 96 % etanol, 70 % metanol, 70 % aceton in etil acetat. V izvlečkih smo spektrofotometrično določili vsebnost skupnih fenolnih spojin s Folin-Ciocalteu metodo in vsebnost skupnih flavonoidov ter vsebnost flavonov in flavonolov na podlagi tvorbe kompleksa z Al ionom. Z metodo lovljenja prostega radikala DPPH• in z metodo beljenja β-karotena smo določili AOP. Obdobje zbiranja cvetnega prahu vpliva na vsebnost skupnih fenolnih spojin in na vsebnost posameznih podskupin. Določili smo, da je etil acetat najmanj primerno topilo za ekstrakcijo fenolnih spojin iz cvetnega prahu, medtem ko je najučinkovitejše topilo 70 % aceton. Izvlečki z acetonom imajo tudi najboljšo sposobnost lovljenja radikala DPPH•. Med toplotno obdelavo pri 90 ºC se zmanjša vsebnost fenolnih spojin in pride do poslabšanja AOP. Skladiščenje vzorcev spomladanskega cvetnega prahu v hladilniku ni imelo velikega vpliva na skupne fenolne spojine in AOP, v vzorcu jesenskega cvetnega prahu pa smo po skladiščenju določili manjšo vsebnost fenolnih spojin in slabši AOP.The purpose of this MSc thesis was to determine the content of total phenolic compounds and the content of individual subgroups of phenolic compounds as well as antioxidative potential (AOP) of Slovenian bee pollen. We investigated the effect of extraction solvent, thermal treatment and storage of bee pollen on the content of phenolic compounds and AOP. The extracts of phenolic compounds were prepared by different extraction solvents: 50%, 70% and 96% ethanol, 70% methanol, 70% acetone and ethyl acetate. Total phenolic content of extracts was determined spectrophotometrically with Folin-Ciocalteu method. The determination of total flavonoid content and flavone and flavonole content was based on the formation of complex with Al ion. AOP was determined with DPPH• radical scavenging method and the method of β-carotene bleaching. The harvest time of bee pollen affected the total phenolic content and the content of individual subgroups. We have determined that ethyl acetate is the least suitable solvent for the extraction of phenolic compounds from bee pollen, while the most effective solvent is 70% acetone. The extracts obtained with acetone have the best ability to scavenge DPPH• radical. During thermal treatment at 90ºC the content of phenolic compounds and AOP of bee pollen decreased. The storage of spring bee pollen samples in refrigerator did not have any significant effect on the total phenolic compounds content and AOP, but in autumn bee pollen sample lower content of phenolic compounds and lower AOP was determined after storage