Essential Oil Content, Antioxidative Characteristics and Enzyme Inhibitory Activity of Sideritis akmanii Aytaç, Ekici & Dönmez

Abstract

Objectives: Our research measures the essential oil analysis mineral substance profiles, total phenolic substance content, free radical scavenger properties, antioxidant capacity, and enzyme inhibitory activity of Sideritis akmanii Aytaç, Ekici & Dönmez, 1996.

Materials and methods: A mixture of S. akmanii plant roots and stems were used. Essential fatty acid components of S. akmanii were determined by gas chromatography-mass spectrometry and bioelement concentrations by inductively coupled plasma optical emission spectrometry. The antioxidant activity of extracts was screened by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities, total phenolic content, total antioxidant status (TAS), total oxidant status (TOS) analysis. Cholinesterase (ChE), α-glucosidase, α-amylase, and tyrosinase inhibitory activity was determined.

Results: The results demonstrated that the phenolic substance content was higher in methanol extract (144.08±2.01 μg gallic acid equivalent/mg extract). DPPH scavenging effect of S. akmanii methanol extract (73.2%) was higher than acetone extract (60.1%). TAS values of extract methanol and acetone were 2.32±0.4 and 2.38±0.2 μmol trolox Eq /g, TOS values were 4.88±0.6 and 5.04±0.5 μmol H₂O₂ Eq/g, and oxidative stress index values were 2.1±0.3 and 2.11±0.24 arbitrary units, respectively. Hexadecanoic acid (17.9%) was found as the main component in the plant essential oil. S. akmanii species was prominent with high Mg and Al concentrations. Anti-ChE activity was determined that acetone extract (42.95%±0.90; 217.37±0.81 mg galantamine equivalents [(GALAEs)/g] exhibited higher than methanol (33.33%±1.81; 208.76±1.62 mg GALAE/g). α-Amylase inhibition was high in methanol extract [53.62±1.85 mmol angiotensin converting enzymes (ACEs)/g extract] compared to acetone (47.73±0.92 mmol ACEs/g extract). The tyrosinase inhibitory activity of S. akmanii was determined very low inhibition of the reference compound.

Conclusion: It has been determined that S. akmanii Aytaç, Ekici & Dönmez extracts have antioxidant properties and can inhibit acetylcholinesterase, α-glucosidase, α-amylase enzymes. This study is informative on future studies on S. akmanii a highly bioavailable species and very extensive studies should be carried out.

Keywords: Ekici & Dönmez; Sideritis akmanii Aytaç; antioxidative activity; bioelement; enzyme inhibitory activity; essential oil.

Figure 1

Gallic acid standard curves

Figure 2

DPPH radical scavenging activities of plant extracts in different concentrations (45-135 µg/mL) SAM: Sideritis akmanii methanol extract, SAA: Sideritis akmanii acetone extract, BHT: Butylated hydroxytoluene and α-tocopherol

Figure 3

TAS, TOS and OSI data for Sideritis akmanii. The results are presented as mean ± SD (n=4) SAM: Sideritis akmanii methanol extract, SAA: Sideritis akmanii acetone extract, TAS: Total antioxidant status, TOS: Total oxidant status, OSI: Oxidative stress index, SD: Standard deviation