Black and bristly locust flowers are an excellent source of polyphenols, including flavonols, phenolic acids, and anthocyanins. In the present literature, there is a lack of studies showing the quantity and quality of phenolic compounds from different locust flowers. There are a few studies on the status of polyphenols in black locust flowers and their products but not bristly locusts. The aims of this study were to analyze and compare the concentrations of bioactive compounds from Robinia pseudoacacia and Robinia hispida flowers over two years. These two species of plants from six independent locations (parks and green areas) located in Warsaw were assessed in this study. The dry matter and polyphenol contents of the flowers were determined. Black locust flower samples contained significantly more myricetin and luteolin. Only bristly locust flowers contained anthocyanins. Five individual anthocyanins were identified in the pink-colored bristly locust flowers. Pelargonidin-3-O-glucoside and cyanidin-3-O-glucoside were the predominant forms in the pool of total anthocyanins.
Keywords: antioxidant activity; black locust; bristly locust; flower; polyphenols.