Chemical composition of edible flowers: Worldwide research and case study from the Czech Republic

• Edible flowers are nutritionally and culinary valuable. • Mainly studied species are Rosa sp., Dianthus sp. and Calendula officinalis. • Mostly analyzed compounds include phenols, flavonoids and total antioxidant capacity. • Warmer conditions usually lead to higher antioxidant capacity and phenolic content. • In Czech case study the chemical content of 41 edible flowers is reported. Edible flowers are nutritionally, culinary and aesthetically valuable addition to food and beverages. Chemical composition of edible flowers (phenols, flavonoids, antioxidant activity etc.) has been analyzed in many studies from various parts of the world. Number of papers focused on content analysis of edible flowers markedly increased from year 2019. Species Calendula officinalis and species of genera Rosa, Dianthus , and Allium are most often studied species of edible flowers worldwide. From the comparison of content analysis from Czech Republic and other parts of the world is not possible clearly assess that climate conditions affect content in expected way. Warmer climate conditions do not always lead to higher phenolic content or antioxidant activity compared to plants from mild climate conditions. This review includes the results from extend study of edible flowers from Czech Republic. Mentioned case study include analysis of total phenolic and flavonoid content, antioxidant activity (DPPH), l -ascorbic acid, nitrates and saponins content of 41 species of edible flowers including both, wild and cultivated species. High values of phenolic content in Origanum sp. were confirmed by Czech and Portugal study. Very high content of l -ascorbic acid in species Primula veris (3838±952 mg/kg FW), Viola odorata (1227±212 mg/kg FW), Armoracia rusticana (1739 ± 245 mg/kg FW), Iris domestica (2068 ± 483 mg/kg FW) and Tropaeolum majus was comparable to results of study from Croatia. However, chemical composition of edible flowers is a very complex and variable issue affected by many factors such climate soil condition, or plant health condition.