Redox-Modulating Capacity and Antineoplastic Activity of Wastewater Obtained from the Distillation of the Essential Oils of Four Bulgarian Oil-Bearing Roses

Abstract

The wastewater from the distillation of rose oils is discharged directly into the soil because it has a limited potential for future applications. The aim of the present study was to determine in vitro the chromatographic profile, redox-modulating capacity, and antineoplastic activity of wastewater obtained by distillation of essential oils from the Bulgarian Rosa alba L., Rosa damascena Mill., Rosa gallica L., and Rosa centifolia L. We applied UHPLC-HRMS for chromatographic analysis of rose wastewaters, studied their metal-chelating and Fe(III)-reducing ability, and performed MTT assay for the evaluation of cytotoxic potential against three tumorigenic (HEPG2—hepatocellular adenocarcinoma, A-375—malignant melanoma, A-431—non-melanoma epidermoid squamous skin carcinoma) and one non-tumorigenic human cell lines (HaCaT—immortalized keratinocytes). The median inhibitory concentrations (IC50) were calculated with nonlinear modeling using the MAPLE® platform. The potential of the wastewaters to induce apoptosis was also examined. Mono-, di-, and acylated glycosides of quercetin and kaempferol, ellagic acid and its derivatives as main chemical components, and gallic acid and its derivatives—such as catechin and epicatechin—were identified. The redox-modulating capacity of the samples (TPTZ test) showed that all four wastewaters exhibited the properties of excellent heavy metal cleaners, but did not exert very strong cytotoxic effects. The lowest IC50 rate was provided in wastewater from R. centifolia (34–35 µg/mL of gallic acid equivalents after a 72 h period for all cell lines). At 24 and 48 hours, the most resistant cell line was HEPG2, followed by HaCaT. After 72 h of exposure, the IC50 values were similar for tumor and normal cells. Still, R. damascena had a selectivity index over 2.0 regarding A-431 non-melanoma skin cancer cells, showing a good toxicological safety profile in addition to moderate activity—IC50 of 35 µg/mL polyphenols. The obtained results related to wastewaters acquired after the distillation of essential oils from the Bulgarian R. alba, R. damascena, R. gallica, and R. centifolia direct our attention to further studies for in-depth elucidation of their application as detoxifying agents under oxidative damage conditions in other experimental datasets.

The Anti-Genotoxic Activity of Wastewaters Produced after Water-Steam Distillation of Bulgarian Rosa damascena Mill. and Rosa alba L. Essential Oils

“…The by-product from R. damascena oil distillation contains kaempferol, quercetin, ellagic acid and their glycoside derivatives [ 19 , 22 , 23 ]. The chromatographic analysis of the present wastewater from water steam distillation of essential oils of Bulgarian R. damascena and R. alba [ 37 ], detected various mono-, di-, and acylated glycosides of polyphenolic compounds quercetin and kaempferol, ellagic acid, as well as many of their derivatives, gallic acid and its derivatives—catechin and epicatechin. ( Figure 13 ).…”

“…Gallic acid is about two times more in R. alba L. than in R. damascena ; ellagic acid is also present in a larger amount in R. alba than in R. damascena. Hyperoside and isoquercitrin are present more than twice higher in R. damascena than in R. alba The quantities of kaempherol-3-O-glucoside, kaempherol-3-O-arabinoside and kaempherol-p-coumarouyl-hexoside are more than 2.5 times higher in R. damascena than in R. alba [ 37 ]. This suggests some differences in the biological activity of the wastewater.…”

“…Georgieva et al have found that wastewater from R. damascena Mill. and of R. alba L. did not exert very strong cytotoxic effect on some human cancer and normal cell lines in the MTT assay, but different type of cells showed different sensitivity to the tested substances [ 37 ]. The cells differ in their sensitivity to the tested substances.…”

“…In our previous study we analyzed the chromatographic profile of the waste waters obtained from the water steam distillation of the essential oils of R. damascena Mill. and R. a lba [ 37 ]. There we identified 52 chemical compounds in the waste from R. damascena Mill.…”

“…The most non-volatile polyphenolic compounds, including flavonoids remain in the waste. According to [ 37 ] the total polyphenolic content in the wastewater of R. alba L. oil production was 7.6 ± 0.3 mg GAE/mL, and in R. damascena , it was 7.2 ± 0.2 mg GAE/mL, respectively. The total flavonoid content in the waste from R. alba L. was 1.00 ± 0.01 mg/mL and in R. damascena wastewater it was 1.14 ± 0.01 mg/mL, respectively.…”