Mineral Composition, Bioactive Compounds, and Antioxidant Capacity of Sweet Potato Leaves, Water Spinach, and Perilla

The introduction of less common leafy vegetables in the human diet is a priority due to their antioxidant capacity and mineral, flavonoid, and vitamin content. The current article presents a comparative study of the minerals, bioactive compounds, and antioxidant activity in the leaves of less commonly cultivated vegetable species in Romania, specifically sweet potato, three varieties of perilla, and water spinach. The results obtained indicate high variability in minerals and nutrients across these vegetable species. Higher values were identified in red-leaf perilla for P (2694.1 mg kg−1dw), Ca (43,990.0 mg kg−1 dw), Mg (16,696.0 mg kg−1 dw), Na (523.0 mg kg−1 dw), and Zn (43.9 mg kg−1 dw); for K (31,971.0 mg kg−1 dw) in sweet potato; for Cu (17.9 mg kg−1 dw) and Fe (110.0 mg kg−1 dw) in marmorated-leaf perilla; and for Mn (101.0 mg kg−1 dw) in water spinach. The total polyphenol content and high antioxidant activity were 5656 mg GAE g−1 dw and 27.66 µM TE g−1 dw, respectively, in green-leaf perilla. Nineteen bioactive compounds identified within the three species studied varied greatly by species and variety. These results demonstrate that the mineral composition and bioactive compounds of the leafy vegetables studied vary greatly, suggesting that a combination of them may contribute to a diversified human diet with a wider range of nutrients. The mineral composition of the studied species may also contribute to the development of functional foods.