Micromorphological Features, DNA Barcoding and Nutraceutical Compounds of Two Edible Flowers: Petunia × Hybrida and Verbena Bonariensis

Petunia × hybrida and Verbena bonariensis are two herbaceous taxa with edible flowers originating from South America. Despite the well-known ornamental value of these taxa, their potential as a food source remains underexplored.

Therefore, in our study, the flowers of P. × hybrida and V. bonariensis obtained from plants grown organically in a greenhouse were identified via DNA barcoding analysis and investigated to characterize the micromorphological features, composition in nutrients, nutraceutical compounds, and spontaneous emission of volatile compounds. P. × hybrida flowers exhibited greater levels of crude proteins, carotenoids, and antioxidant activity. In contrast, V. bonariensis had a higher content of total soluble sugars, total polyphenols, total flavonoids, and ascorbic acid. The DNA sequences obtained from both taxa returned maximum identity and were submitted to GenBank.

Both taxa displayed characteristic anthocyanin patterns and taxon-specific glandular trichomes, rich in secondary compounds such as terpenoids, mucilages, and polyphenols. The fragrance and flavor detected for these edible flowers were also dependent on taxon-specific VOCs patterns: P. × hybrida VOCs were rich in non-terpene compounds, predominantly comprising esters (61.6%), especially methyl nonadecanoate (21.7 ± 0.3%) and methyl benzoate (12.7 ± 0.3%); V. bonariensis was characterized by terpenoids, particularly the monoterpene hydrocarbon (E)-β-Ocimene (47.6 ± 2.0%).

Our interdisciplinary study provides the first data for the authentication of these taxa. These data underline the high nutraceutical value of these edible flowers and will also be useful in the case of commercial exploitation.