Phytochemical Profile, Antioxidant Potential, Antimicrobial Activity, and Cytotoxicity of Dry Extract from Rosa damascena Mill

Abstract

Dry rose extract (DRE) obtained industrially by aqueous ethanol extraction from R. damascena flowers and its phenolic-enriched fraction, obtained by re-extraction with ethyl acetate (EAE) were the subject of this study. ¹H NMR of DRE allowed the identification and quantitation of fructose and glucose, while the combined use of HPLC-DAD-ESIMS and HPLC-HRMS showed the presence of 14 kaempferol glycosides, 12 quercetin glycosides, 4 phenolic acids and their esters, 4 galloyl glycosides, 7 ellagitannins, and quinic acid. In addition, the structures of 13 of the flavonoid glycosides were further confirmed by NMR. EAE was found to be richer in TPC and TFC and showed better antioxidant activity (DPPH, ABTS, and FRAP) compared to DRE. Both extracts displayed significant activity against Propionibacterium acnes, Staphylococcus aureus, and S. epidermidis, but showed no activity against Candida albicans. Toxicity tests on normal human skin fibroblasts revealed low toxicity for both extracts with stronger effects observed at 24 hours of treatment that were compensated for over the following two days. Human hepatocarcinoma (HepG2) cells exhibited an opposite response after treatment with a concentration above 350 µg/mL for EAE and 500 µg/mL for DRE, showing increased toxicity after the third day of treatment. Lower concentrations were non-toxic and did not significantly affect the cell cycle parameters of either of the cell lines.

Keywords: Rosa damascena Mill; antimicrobial activity; antioxidant activity; cell cycle; cytotoxicity; dry rose extract; phenolics.

Figure 1

¹H NMR spectrum of dry rose extract (DRE) in D₂O/CD₃OD (1:1) buffered with 1 M KH₂PO₄.

Figure 2

HPLC-DAD chromatogram of dry rose extract (DRE) at 280 (green) and 350 (blue) nm. For the peak identification see Table 1.

Figure 3

Inhibition effect of DRE and EAE on test pathogens.

Figure 4

Cytotoxicity of rose extracts tested at 24 (blue bars) and 72 (red bars) hours after treatment of human skin fibroblasts. Data are presented as mean ± SD. *—Statistically different data (p < 0.05).

Figure 5

Cytotoxicity of Rosa damascena extracts on HepG2 human hepatocarcinoma cells after 24 (blue) and 72 (red) hours of treatment. Data are presented as mean ± SD. *—Statistically different data (p < 0.05).

Figure 6

Flow cytometry of HSF cells treated with a low dose (10 µg/mL) and the first effective dose of 100 µg/mL of EAE. Dot plots and histograms of representative experiments are shown. Cell populations included in the analysis are represented by red dots. In the histograms, pink represents the count of cells in G0/G1 phase, green the count of cells in S phase and purple the count of cell in G2/M phase of the cell cycle.

Figure 7

Flow cytometry of HepG2 cells treated with a low dose (10 µg/mL) of DRE. Dot plots and histograms of representative experiments are shown. Cell populations included in the analysis are represented by red dots. In the histograms, pink represents the count of cells in G0/G1 phase, green the count of cells in S phase and purple the count of cell in G2/M phase of the cell cycle.