Sage, Salvia officinalis L., Constituents, Hepatoprotective Activity, and Cytotoxicity Evaluations of the Essential Oils Obtained from Fresh and Differently Timed Dried Herbs: A Comparative Analysis

Abstract

Sage, Salvia officinalis L., is used worldwide as an aromatic herb for culinary purposes as well as a traditional medicinal agent for various ailments. Current investigations exhibited the effects of extended dryings of the herb on the yields, composition, oil quality, and hepatoprotective as well as anti-cancer biological activities of the hydrodistillation-obtained essential oils from the aerial parts of the plant. The essential oils' yields, compositions, and biological activities levels of the fresh and differently timed and room-temperature dried herbs differed significantly. The lowest yields of the essential oil were obtained from the fresh herbs (FH, 631 mg, 0.16%), while the highest yield was obtained from the two-week dried herbs (2WDH, 1102 mg, 0.28%). A notable decrease in monoterpenes, with increment in the sesquiterpene constituents, was observed for the FH-based essential oil as compared to all the other batches of the essential oils obtained from the different-timed dried herbs. Additionally, characteristic chemotypic constituents of sage, i.e., α-pinene, camphene, β-pinene, myrcene, 1, 8-cineole, α-thujone, and camphor, were present in significantly higher proportions in all the dried herbs' essential oils as compared to the FH-based essential oil. The in vivo hepatoprotective activity demonstrated significant reductions in the levels of AST, ALT, and ALP, as well as a significant increase in the total protein (p < 0.05) contents level, as compared to the acetaminophen (AAP) administered experimental group of rats. A significant reduction (p < 0.05) in the ALT level was demonstrated by the 4WDH-based essential oil in comparison to the FH-based essential oil. The levels of creatinine, cholesterol, and triglycerides were reduced (p < 0.05) in the pre-treated rats by the essential oil batches, with non-significant differences found among them as a result of the herbs dryings based oils. A notable increase in the viability of the cells, and total antioxidant capacity (TAOxC) levels, together with the reduction in malondialdehyde (MDA) levels were observed by the essential oils obtained from all the batches as compared with the AAP-treated cell-lines, HepG-2, HeLa, and MCF-7, that indicated the in vitro hepatoprotective effects of the sage essential oils. However, significant improvements in the in vivo and in vitro hepatoprotective activities with the 4WDH-based oil, as compared to all other essential oil-batches and silymarin standard demonstrated the beneficial effects of the drying protocol for the herb for its medicinal purposes.

Keywords: HeLA cells; HepG-2 cells; MCF-7; MDA; Sage; Salvia officinalis; TAOxC; cytotoxicity; hepatoprotection.

Figure 1

A heat-map comparison based on the abundance of an individual component of sage’s essential oils from different batches; gray color indicates un-detected from the identified component.

Figure 2

Hepatoprotective effects of sage essential oils against damage induced by 4 mM acetaminophen (AAP) in HepG-2 cells for 24 h in comparison to silymarin. The cytotoxicity of AAP with and without selected dose (100 μg/mL < IC₅₀ values) of sage essential oils and silymarin (SLY) on hepatic cell lines (HepG-2) (A) for hepatoprotective activity tests MDA levels (μM) (B), and TAOxC levels (mM) (C) in HepG-2 cells after exposure to 4 mM AAP and pretreated with sage essential oils or silymarin. Controls: supplemented media (CT); AAP 4 mM (AAP), silymarin (100 μg/mL) (SLY). Values are the mean  ± SD of three independent experiments performed in triplicate. * For p < 0.05, ** for p < 0.01, and *** for p < 0.001.

Figure 3

Dose-response curve of cytotoxicity of doxorubicin as a positive control (A), sage essential oils (1–500 μg/mL) of FH (B), 1WDH (C), 2WDH (D), 3WDH (E), and 4WDH (F) on cancer cell lines breast (MCF-7), hepatic (HepG-2), and cervical (HeLa) in comparison to normal cells (MRC-5).

Figure 4

The cytotoxicity IC₅₀ values of the sage essential oils (μg/mL) on cancer cell lines breast (MCF-7), hepatic (HepG-2), and cervical (HeLa) in comparison to the normal cells (MRC-5). Doxorubicin was used as a cytotoxic drug (positive control).