Green approach to obtain extracts of seven edible flowers

Abstract

Edible flowers are considered as a valuable source of bioactive compounds and are used as food and medicine with growing interest. Microwave extraction technique was employed as a green approach to obtain water extracts from seven edible flowers including Viola tricolor L., Cucurbita pepo L., Sambucus nigra L., Calendula officinalis L., Hibiscus rosa-sinensis L., Rosa damascena Mill. and Allium ursinum L. They were characterized in terms of total content of phenolics and flavonoids, as well as antioxidant potential. The total phenolic content in the edible flower’s extracts ranged between 12.08 ± 0.09 and 72.66 ± 0.60 mg gallic acid equivalent (GAE)/g dw and the total flavonoid content was established to vary between 2.36 ± 0.09 and 25.91 ± 0.09 mg quercetin equivalents (QE)/g dw. The highest values were reported in the extracts of Viola tricolor and Rosa damascena. Moreover, the same extracts displayed the highest antioxidant activity evaluated by six in vitro assays. The lowest activity was detected in the A. ursinum and C. pepo flowers extracts. In addition, the correlation between the conducted assays was studied. In conclusion, all of the studied edible flowers can be considered as promising sources of natural antioxidants in the food industry.