Investigation of the composition and antioxidant activity of acetone and methanol extracts of Daphne sericea L. and Daphne gnidioides L.

The compositions of methanol and acetone extracts obtained from Daphne sericea L. and Daphne gnidioides L. were investigated. The antioxidant activities of each extract were determined by various test methods. Phenolic composition profile analysis by HPLC–DAD showed that D. gnidioides extracts contain more phenolic compounds than D. sericea extracts. Among the components, syringic acid was found to be the most abundant one in D. gnidioides extracts (42.8 and 38.4 mg per g dry extract of methanol and acetone, respectively). Total flavonoid, total phenolic and total carotenoid contents of methanolic D. gnidioides extracts were found to be 244.5 mg rutin/g dry weight of extract, 1219.3 mg GAE/g dry weight of extract and 11.9 mg/g dry weight of extract, respectively. DPPH·, ABTS·+ and O2·− assays were applied to plant extracts as radical scavenging activity tests. Methanolic extracts of D. sericea and D. gnidioides showed the highest radical scavenging activities according to DPPH· and ABTS·+ tests (61.6 and 147.2 in terms of IC50, respectively). Antioxidant activity tests for measuring lipid oxidation inhibiting capacity were carried in low density lipoprotein (LDL) and bovine brain extract (BBE). Methanolic extracts of D. gnidioides and D. sericea demonstrated remarkable lipid oxidation inhibiting capacity in LDL and BBE tests.