Endemic Veronica saturejoides Vis. ssp. saturejoides–Chemical Composition and Antioxidant Activity of Free Volatile Compounds

Abstract

Chemical profile and antioxidant activity of the species Veronica saturejoides Vis. ssp. saturejoides (Plantaginaceae)—which is endemic to Croatia, Bosnia and Herzegovina and Montenegro —were investigated. Volatile compounds produced by glandular trichomes (composed of one stalk cell and two elliptically formed head cells according to scanning electron microscope investigation) were isolated from the plants collected in two locations. Additionally, as a part of specialized metabolites, total polyphenols, total tannins, total flavonoids and total phenolic acids were determined spectrophotometrically. In the lipophilic volatile fractions-essential oils, the most abundant compounds identified were hexahydrofarnesyl acetone, caryophyllene oxide and hexadecanoic acid. In total, the class of oxygenated sesquiterpenes and the group of fatty aldehydes, acids and alcoholic compounds dominated in the essential oils. In the hydrophilic volatile fractions-hydrosols, the most abundant compounds identified were trans-p-mentha-1(7),8-dien-2-ol, allo-aromadendrene and (E)-caryophyllene. A group of oxygenated monoterpenes and the sesquiterpene hydrocarbons dominated in the hydrosols. Antioxidant activity of essential oils and hydrosols was tested with two methods: 2,2′-diphenyl-1-picrylhydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC). Essential oils showed higher antioxidant activity than hydrosols and showed similar antioxidant activity to Rosmarinus officinalis essential oil. Obtained results demonstrate that this genus is a potential source of volatiles with antioxidant activity.

Phytochemical Characterization and Screening of Antioxidant, Antimicrobial and Antiproliferative Properties of Allium × cornutum Clementi and Two Varieties of Allium cepa L. Peel Extracts

“…The antioxidant capacity of the extracts was determined by the DPPH method previously used by Nazlić et al [ 85 ]. This method uses 96-well microtiter plates for the reduction reaction of alcoholic DPPH (2,2-diphenyl-1-picrylhydrazyl) solution (Sigma–Aldrich) in the presence of a hydrogen-donating antioxidant.…”

Chemical Composition and New Biological Activities of Essential Oil and Hydrosol of Hypericum perforatum L. ssp. veronense (Schrank) H. Lindb

“…The assay was performed on a LS55 spectrofluorimeter (Perkin-Elmer, Leatherhead, UK) using 96-well white polystyrene microtiter plates (Porvair Sciences, Leatherhead, UK) according to a method described by Fredotovic et al [73] and Nazlić et al [74]. Each reaction contained 180 µL of fluorescein (1 µM), 70 µL 2,2 -Azobis(2-methyl-propionamidine) dihydrochloride (AAPH, Acros Organics, Fair Lawn, NJ, USA) (300 mM), and 30 µL of plant extract or reference standard Trolox (6.25-50 µM) (Sigma-Aldrich, St. Louis, MO, USA).…”

Wild Species Veronica officinalis L. and Veronica saturejoides Vis. ssp. saturejoides—Biological Potential of Free Volatiles

“…After three days, the samples were transferred to 70% ethanol and stored in the refrigerator. The study of the trichomes for V. saturejoides was carried out in the previous work [28].…”

“…The MS conditions were: ion source temperature 200 • C, ionization voltage 70 eV, mass scan range 40-350 mass units [9,28]. The individual peaks for all samples were identified by comparison of their retention indices of n-alkanes to those of authentic samples and literature [29,30], comparing it to our libraries from previous work [9,28] and to other previously published material for Veronica species [10,12,31,32]. The results are given as the mean of three extractions with standard deviation.…”

“…For the hydrosol assays total undiluted hydrosols were used. All measurements were performed in triplicate according to the method described in Nazlić et al [28].…”