Changes in cytotoxic capacity, phenolic profile, total phenols and flavonoids of Nigella damascena L. seed extracts under different liquid fertilization

Abstract

Nigella damascena L. is an annual herbaceous valuable medicinal and aromatic plant in the Ranunculaceae family. For the first time with this study, the effects of different fertilizer treatments on the total phenolic-flavonoid content and phenolic compound profile in N. damascena seeds were investigated. Also, cytotoxic activities of n-hexane and methanol extracts (0–300 μg/mL) from fertilized seeds against breast (MCF-7) and pancreatic (MIA PaCa-2) cancer and embryonic kidney (HEK 293) cell lines were determined. The highest total phenolic and flavonoid contents in the methanol extract of seeds were obtained from chemical-3 L/da (0.196 ± 0.03 mg GAE/g) and organic- 1200 mL/da (3.85 ± 0.04 mg QE/g) fertilizer treatments, respectively. Phenolic compounds identified qualitatively by HPLC-PDA in the seeds were epicatechin, p-coumaric acid, ferulic acid, rutin hydrate, apigenin and naringenin. Fertilized seed n-hexane extracts caused greater cell inhibition compared to control and showed remarkable selective cytotoxicity against the two cancer cell lines investigated in vitro. However, even at the highest concentration (300 μg/mL) of all seed methanol extracts, 50% cell inhibition did not occur in both cancer and healthy cell lines. Results show that N. damascena seed extracts can be studied further in terms of having an anticancer agent potential.