Total Phenolics, Flavonoids Contents, Antioxidant Activity and DNA Protective Effect of Lenten Rose (Helleborus orientalis)

The aims of the present study were to evaluate the antioxidant activity and DNA Protective effect of Helleborus orientalis (HO) leaf extract against oxidative damage, and to determine the total phenolic and flavonoid contents of the plant species studied.

Methods: The total phenol content (TPC) of H. orientalis (Ranunculaceae) extract was determined using the Folin-Ciocalteu technique. The aluminum chloride colorimetric assay in the determination of The total flavonoid content (TFC) and was used, Analysis of Phenolic Acids was identified by High-Performance Liquid Chromatography (HPLC). Antioxidant activity was analyzed by the 2,2-Diphenyl-1-picrylhydrazyl (DPPH) Assay. Protective effect of H. orientalis leaf extract against to H2O2 was evaluated by using TAS, TOS methods and Comet assay.

Key Findings: H. orientalis ethanol extracts contain high amounts of antioxidants. The HO leaf methanol extract (LME) decreased the DNA damage at all tested concentrations in a dose-dependent manner (r=0.86 p<0.01) against to H2O2.

Conclusions: The total phenol content in the extracts of different parts of the plant varied from 4.00 mg GAE/1 gr to 19.42 mg GAE/1 gr. The flowers had the highest phenol content (19.42 mg GAE/1 gr sample) and followed by the leaves (17.20 mg GAE/1 gr sample). The total flavonoid content in the extracts from different parts of the plant varied from 2.57 mg QE/1 gr to 11.88 mg QE/1 gr. The flowers had the highest flavonoid content (11.88 mg QE/1 gr sample) and followed by the leaves (10.21 mg QE/1 gr sample).

Antioxidant activity of fractions was explained as a percentage of DPPH radicals’ scavenging and IC50 values (μg/ml). Leaf and flowers of HO are richer in antioxidant than its root and stem. As the concentration of leaf extracts used increased, the DNA protective effect increased and it was statistically significant at overdoses of 2500 μg/mL. Total antioxidant status (TAS) levels were significantly (p <0.05) decreased in the H2O2 group (3.4±0.21) but H. orientalis was significantly (p<0.05) increased TAS levels in this group. When the concentration of leaf extracts used increased, the protective effect has also increased and statistically significant at overdoses of 2500 μg / mL (6.3±0.67). Total oxidant status (TOS) levels were significantly (p <0.05) increased in the H2O2 group (25.3±0.74) and H. orientalis was significantly (p<0.05) decreased TOS levels in groups.