Free-radical scavenging capacity and antioxidant activity of Berberis croatica Horvat and B. vulgaris L
Plants of the genus Berberis are commonly used in nutrition and phytomedicine. The purpose of this study was to investigate radical scavenging properties and antioxidant activity of roots, leaves and twigs of Croatian barberry (B. croatica Horvat), an endemic illyric-balcanic species , and compare it to antioxidant activity of common barberry, (B. vulgaris L.). Ethanolic extracts of roots, twigs and leaves of B. croatica and B. vulgaris collected at four locations in Croatia (two locations per species) were investigated. Content of total phenols and flavonols were determined by using Folin Ciocalteu and aluminium chloride method, respectivelly. Antioxidant activity was established using following methods: radical scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical, reducing power and β-carotene-linoleic acid assay as well as electron paramagnetic resonance (EPR) spectroscopy. In all the analyses the leaf extracts were found to possess most marked antioxidant activities, not significantly different from positive control butylated hydroxyanisole (BHA) (ANOVA, p>0.05). Activity of twigs and roots extracts was somewhat less pronounced then the activity of leaves extracts. This investigation revealed no statistically significant differences in antioxidant activities between plant species (p>0.05). With the exception of the β-carotene-linoleic acid assay, antioxidant activity in all the applied assays correlated well with content of total phenols and flavonols (r 2>0.83). That suggests that those compounds play an important role in overall antioxidant activity of investigated plant organs.
References: 1. Kušan, F. (1969) Acta Bot. Croat. 28:423–436.