Preliminary Observations on Viola calcarata as a Source of Bioactive Compounds: Antioxidant Activity and Phytochemical Profile of Two Alpine Subspecies

Abstract

Viola L. is a botanical genus with approximately 525 to 620 species, spread worldwide. Several violets are traditionally used as edible flowers and have been recently proved to be a source of bioactive compounds, including flavonols, flavanols, benzoic acids, and cinnamic acids. However, no information is available about the phytochemical profile of the Viola calcarata complex, which is found in the Alpine environment. Thus, the present research aimed to assess the antioxidant activity and the presence of bioactive compounds (anthocyanins and phenolic compounds) in V. calcarata subspecies, to promote their biodiversity and use in the agrifood sector. Two V. calcarata subspecies were chosen, with different colors: V. calcarata subspecies calcarata L., with white (CW), yellow (CY), and violet flowers (CV); and V. calcarata subspecies villarsiana (Roem & Schult.) Merxm., with bicolor (violet and yellow—VB) flowers. CY showed a significantly higher phenolic content (1116.43 mg GAE 100 g−1 FW) than the other subspecies, while CV showed higher values in anthocyanins content (44.73 mg C3G 100 g−1 FW). Regarding the antioxidant activity, CW (215.07 mmol Fe2+ kg−1 FW, 99.53 µmol TE g−1 FW, and 32.30 µmol TE g−1 FW for FRAP, DPPH, and ABTS, respectively) and VB (217.33 mmol Fe2+ kg−1 FW, 90.97 µmol TE g−1 FW, and 29.17 µmol TE g−1 FW for FRAP, DPPH, and ABTS, respectively) showed the highest values. Through HPLC, a total of eight phenolic compounds were quantitatively identified among the two subspecies, including flavonols, cinnamic acids, benzoic acids, catechins, and vitamin C. Though different in their composition, the two subspecies are rich in phenolic compounds, highlighting the importance of preserving their biodiversity and their potential use in the agrifood sector.

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

“…Many compounds including aliphatics, shikimic acid derivatives, sesquiterpenes, and monoterpenes have been identified in different relative quantities based on species and its origin. Antibacterial, antifungal, and antiplasmodial properties have been documented with mixed results [10][11][12][13][14][15][16][17].…”

“…Only a recent work has covered these aspects of Viola calcarata L. [16], however, no reports have dealt with documenting the non-volatile chemical composition of V. dubyana Burnat ex Gremli and Viola calcarata L. These are two rare Viola species belonging to the V. calcarata complex in Viola section Melanium (Violaceae) and growing on the Italian Alps and Prealps, linked together by a common aspect and similar ecology, but with constant botanical characteristics well correlated to the geographical distribution [18]. V. calcarata is typical of meadows, pastures, and screes, mostly above 1500 m, while V. dubyana grows on calcareous dry pastures and rocky places between 900 and 2100 m in altitude [19].…”

Editorial: Edible flowers: Understanding the effect of genotype, preharvest, and postharvest on quality, safety, and consumption

“…However, the phenolic composition of edible flowers as well as the presence and concentration of other botanicals vary widely between different tissues, plant parts, different species and cultivars, and based on the growing condition and environment (Demasi et al, 2021a ; Falla et al, 2021 ).…”

From Fresh to Dried Lavender Flower: Changes in Phytochemical Profile According to Drying Method

“…In recent years, knowledge of the beneficial properties of plants, and especially edible flowers, has increased, leading to a rise in their consumption, especially as natural food colorants or additives [1][2][3]. Recent studies highlighted their health benefits [4][5][6][7][8][9] due to their composition rich in vitamins and phytochemicals (carotenoids or phenolics) with antioxidant properties [10][11][12][13][14][15][16][17].…”