Comparative assessment of polyphenolic content and antioxidant capacity of Arnica montana samples differentiated on organ types from wild populations in the Romanian Eastern Carpathians

Arnica montana L. flowerheads are mainly used for therapeutic purposes. In the last years a high interest in using the whole plant was observed, both for human and veterinary uses. Considering the conservation status of the species, the use of the whole plant is possible only through development of cultures. Although the anti-inflammatory activity of Arnica extract is mainly associated with the specific action of sesquiterpen-lactones, the phenolic compounds have an important role due to their antioxidant activity.

The aim of our study was the comparative assessment, on organ type (flowerheads, leaves, root and rhizome, respectively) of the total phenolic content (Folin-Ciocalteu method), and antioxidant activity of the methanolic extracts. In vitro antioxidant activity was investigated by DPPH and ABTS assays; caffeic acid was used as positive control. We report for the first time the antioxidant activity for the whole plant harvested from the Romanian Eastern Carpathians.

The highest phenolic content was found in the leaf extract (154.42 ± 1.65 mg gallic acid equivalents (GAE)/g), followed by the root (140.73 ± 0.74 mg GAE/g) and flower extracts (130.43 ± 1.59 mg GAE/g). All extracts showed important antioxidant activities. However, reducing power of the leaf extract (0.776 ± 0.005 at 5 mg/mL) was higher than that of the other Arnica extracts (0.682 ± 0.007 and 0.643 ± 0.005 for the root and flower extracts). At 5 mg/mL, leaf extract displayed DPPH (90.63 ± 0.22%) and ABTS (97.26 ± 0.08%) quenching capacities similar to those of the standard – caffeic acid (DPPH scavenging activity: 97.69 ± 0.03% and ABTS scavenging activity: 100.34 ± 0.03%).

Along with flowers, leaves and underground parts of the plant (root and rhizome) are important sources of phenolic compounds with significant antioxidant activity.

Acknowledgement: The work was sustained through the program Partnership in Priority Areas – PNII, implemented with the support of MEN – UEFISCDI, Romania, project No. 74/2014.