GC-MS and SPME-GC/MS Analysis and Bioactive Potential Evaluation of Essential Oils from Two Viola Species Belonging to the V. calcarata Complex

Abstract

Viola calcarata L. and Viola dubyana Burnat ex Gremli belong to the V. calcarata complex in Viola section Melanium (Violaceae family). For the first time, the essential oils (EOS) obtained by hydrodistillation from dried flowers, were analyzed by GC/MS and SPME-GC/MS to describe their volatile chemical profile. Differences in the qualitative and quantitative composition between the two violets have been found. A total of 43 compounds were identified among which methyl salicylate was the most abundant (from 45.5 to 68.0%) both in the vapor and liquid phase. The performed bioactivity tests pointed out the greater effect of V. dubyana EO compared to that obtained from V. calcarata. Nevertheless, both EOs proved to be good scavengers, especially toward the ABTS⋅+ radical. They also showed a dose-dependent phytotoxic action against Sinapis alba and Lolium multiflorum. Their seed germination was inhibited up to 100% and 25%, respectively, in response to the highest used dose (100 μL) of each EO. Furthermore, a significant decrease in root and shoot length was observed. The resulting seedling vigor index was reduced by 15–100% and 8–82% for S. alba and by 11–91% and 4–91% for L. multiflorum by V. dubyana and V. calcarata EOS, respectively.

Viola calcarata L. and Viola dubyana Burnat ex Gremli hydrolates: DI-SPME-GC-MS analysis and biological activity evaluation

“…Data on the hydrolates from this work complemented the previous study both in terms of chemical composition and biological activity of Viola calcarata L. and Viola dubyana Burnat ex Gremli (complex V. calcarata, section Viola Melanium, Violaceae family) (Fig. 1) [Vitalini et al 2022]. These are two indigenous Italian species present in the Alps where bloom between April-May and July-August, above 1000 meters s.l.…”

“…Hydrolate preparation. After the hydrodistillation of the essential oil of V. calcarata and V. dubyana [Vitalini et al 2022], the respective hydrolates were collected and placed in dark vials, then stored at 4 °C until use. Direct Immersion Solid-Phase Microextraction (DI-SMPE) sampling.…”

“…Phytotoxicity assay. A dose-response test was carried out by following S. Vitalini et al [2022], with minor modifications. The phytotoxic potential of hydrolates was assessed at 2, 20, 50, 100 and 200 µL by placing them in a small handmade aluminum container inside the Petri dish (90 mm in diameter) to avoid direct contact with the target seeds (15) of L. multiflorum and S. alba distributed evenly on a filter paper layer moistened with 4 mL of deionized water.…”

Chemical Investigation and Dose-Response Phytotoxic Effect of Essential Oils from Two Gymnosperm Species (Juniperus communis var. saxatilis Pall. and Larix decidua Mill.)

“…In the GC oven was housed a Varian Factor Four VF-1 capillary column and helium was used as carrier gas at a flow rate of 1 mL/min. The adopted chromatographic conditions followed a previous study [ 61 ]. The mass spectra were obtained in the electron impact mode (EI), at 70 eV in scan mode in the range 35–400 m / z .…”

Green natural nail polish modified with essential oils to treat onychomycosis

“…To investigate the volatile chemical composition of nail samples (nail alone, nail with EO and nail with MIX), 2 ml of each sample was individually placed into a 7 ml glass vial with PTFE‐coated silicone septum. The sampling was performed by SPME technique 16 …”