Morphogenetic, Ontogenetic and Diurnal Variability in Antioxidant Activity, Total Phenol and Flavonoids of Foeniculum vulgare Miller var. vulgare Extracts

Abstract

Bioactive compounds, appearing at varying quantities and constituents in medicinal plants, act asnatural antioxidants. The aim of this study was to monitor morphogenetic, ontogenetic and diurnal variability inantioxidant activity, total phenols and total flavonoids of bitter fennel extracts. Morphogenetic variability wasassessed using leaf and root-bulb-stem samples of pre-, full- and post-flowering stages, flower samples of fullflowering and seed samples of seed formation and harvest maturity. To monitor diurnal (3 times a day) andontogenetic variability, whole plant samples were taken at pre-, full- and post-flowering. The plant extracts wereobtained by methanol solution and radical scavenging effect of the extracts were determinedspectrophotometrically. The root-bulb-stem extract produced the highest total phenol content. The highestradical-scavenging activity, with the lowest IC50 = 24.17 μg ml –1, was obtained from the seed extract. Totalphenols and flavonoids increased with the order of pre-flowering, full-flowering and post-flowering. Dailyharvesting time (diurnal variability) caused no effect on antioxidant activity, total phenols and flavonoids. Inconclusion, antioxidant activity of bitter fennel extracts significantly differs according to plant organs andgrowing stages.