| Abstract | U ovom radu ispitan je sadržaj ukupnih fenola i flavonoida te antioksidativni učinak in vitro metanolnih ekstrakata plodova i
listova šest uzoraka vrste Cornus mas L. i jednog uzorka vrste Cornus officinalis Siebold & Zucc., Cornaceae. Uzorci su
osušeni na zraku, samljeveni i ekstrahirani metanolom u ultrazvučnoj kupelji. Nakon filtracije, organsko otapalo je uklonjeno
pomoću vakuumskog uparivača, a upareni ekstrakti su resuspendirani u destiliranoj vodi, zamrznuti i nakon toga liofilizirani.
Sadržaj ukupnih fenola i flavonoida određen je spektrofotometrijski u vodenim otopinama dobivenih liofilizata Folin-Ciocalteu
metodom odnosno AlCl3 metodom. Antioksidativni (antiradikalni) učinak određen je pomoću ABTS i DPPH testa. Pearsonov
koeficijent korelacije (r) korišten je za utvrđivanje odnosa između izmjerenih parametara (ɑ = 0,05). Sadržaj ukupnih fenola
u ekstraktima plodova i listova vrste C. mas kretao se od 9,69 ± 0,58 do 16,63 ± 0,26 mg ekvivalenta galne kiseline (EGK)/g
suhog ekstrakta (SE) odnosno od 195,32 ± 1,59 do 311,21 ± 1,22 mg EGK/g SE. Sadržaj ukupnih fenola u ekstraktima plodova
i listova vrste C. officinalis iznosio je 13,56 ± 0,15 mg EGK/g SE, odnosno 286,70 ± 1,90 mg EGK/g SE. Sadržaj flavonoida
u ekstraktima plodova C. mas kretao se od 0,18 ± 0,04 do 1,07 ± 0,02 mg ekvivalenta kvercetina (EK)/g SE, dok je sadržaj
flavonoida u ekstraktima listova bio u rasponu od 1,20 ± 0,06 do 4,51 ± 0,22 0 mg EK/g SE. Sadržaj flavonoida u ekstraktima
plodova i listova C. officinalis bio je 0,42 ± 0,03 odnosno 3,66 ± 0,03 mg EK/g SE. Uočena je vrlo dobra negativna povezanost
između ukupnog sadržaja fenola u listovima i plodovima vrste C. mas (r = -0,94, P = 0,005), dok je između sadržaja flavonoida
u listovima i plodovima vrste C. mas uočena vrlo dobra pozitivna povezanost (r = 0,90, P = 0,016). Antiradikalna aktivnost
vrste C. mas procijenjena kao IC50 vrijednost u ABTS testu iznosila je između 52,91 i 179,80 μg/mL za ekstrakte plodova
odnosno između 3,32 i 5,51 μg/mL za ekstrakte listova, dok je za ekstrakte plodova i listova vrste C. officinalis iznosila 63,08
μg/mL i 3,97 μg/mL. Antiradikalna aktivnost vrste C. mas procijenjena kao IC50 vrijednost u DPPH testu iznosila je između
68,64 i 259,16 μg/mL za ekstrakte plodova odnosno između 4,53 i 8,25 μg/mL za ekstrakte listova, dok je za ekstrakte plodova
i listova vrste C. officinalis iznosila 141,38 μg/mL i 4,35 μg/mL. Uočena je vrlo dobra negativna povezanost između sadržaja
ukupnih fenola i antiradikalne aktivnosti listova i plodova istraživanih vrsta procijenjene DPPH testom (r = -0,89, P < 0,001)
i ABTS testom (r = -0,80, P < 0,001). Utvrđene vrijednosti za uzorak vrste C. officinalis bile su usporedive s onima uzoraka
vrste C. mas. |
| Abstract (english) | In this study, total phenolic and flavonoid content and antioxidant activity in vitro of methanolic extracts of fruits and leaves
from six samples of Cornus mas L. and one sample of Cornus officinalis Siebold & Zucc., Cornaceae, have been investigated.
Samples were air-dried, milled and extracted with methanol in an ultrasonic bath. After filtration, organic solvent was removed
using a rotary evaporator and the remaining extracts were resuspended in distilled water, frozen and afterward subjected to
lyophilization. Total phenolic content and flavonoid content were evaluated spectrophotometrically in aqueous solutions of
obtained lyophilizates using the Folin-Ciocalteu method and the AlCl3 method, respectively. The antioxidant (antiradical)
activity was determined using the ABTS and DPPH tests. Pearson’s correlation coefficient (r) was used to establish the
relationships between the measured parameters (ɑ = 0.05). Total phenolic content of C. mas fruit and leaf extracts ranged from
9.69 ± 0.58 to 16.63 ± 0.26 mg gallic acid equivalent (GAE)/g dry extract (DE) and from 195.32 ± 1.59 to 311.21 ± 1.22 mg
GAE/g DE, respectively. Total phenolic contents of C. officinalis fruit and leaf extracts were 13.56 ± 0.15 mg GAE/g DE and
286.70 ± 1.90 mg GAE/g DE, respectively. Flavonoid content in fruit extracts of C. mas ranged from 0.18 ± 0.04 to 1.07 ±
0.02 mg quercetin equivalent (QE)/g DE, while flavonoid content in leaf extracts ranged from 1.20 ± 0.06 to 4.51 ± 0.22 mg
QE/g DE. Flavonoid contents of C. officinalis fruit and leaf extracts were 0.42 ± 0.03 and 3.66 ± 0.03 mg QE/g DE,
respectively. Very strong negative correlation was observed between total phenolic contents in leaves and fruits of C. mas
(r = -0.94, P = 0.005), while very strong positive correlation was observed between leaf and fruit flavonoid contents of C. mas
(r = 0.90, P = 0.016). Antiradical activity estimated as IC50 value by the ABTS test of the fruit and leaf extracts of C. mas
ranged from 52.91 to 179.80 μg/mL and from 3.32 to 5.51 μg/mL, respectively. The antiradical activity of the fruit and leaf
extracts of C. officinalis was 63.08 μg/mL and 3.97 μg/mL, respectively. Antiradical activity estimated as IC50 value by the
DPPH test of the fruit and leaf extracts of C. mas ranged from 68.64 to 259.16 μg/mL and from 4.53 to 8.25 μg/mL,
respectively. The antiradical activity of the fruit and leaf extracts of C. officinalis was 141.38 μg/mL and 4.35 μg/mL,
respectively. Very strong negative correlation was observed between total phenolic content and antiradical activity of leaves
and fruits of investigated species evaluated by the DPPH test (r = -0.89, P < 0.001) and the ABTS test (r = -0.80, P < 0.001).
The determined values for the C. officinalis sample were comparable to those of the C. mas samples. |
