Comparative Assessment of the Nutritional, Phenolic, and Amino Acid Profiles, INFOGEST-Based Gastrointestinal Bioaccessibility, and Biological Activities of Althaea officinalis, Jasminum officinale, and Viola odorata

Edible flowers are increasingly recognized as sources of bioactive compounds; however, comparative evidence on their nutritional composition, gastrointestinal bioaccessibility, and biological activities remains limited. This study aimed to comprehensively evaluate the proximate and mineral composition, total and individual phenolic profiles, antioxidant capacity, and amino acid composition of Jasminum officinale, Althaea officinalis, and Viola odorata flowers before and after simulated gastrointestinal digestion, with particular emphasis on the bioaccessibility of phenolic compounds and amino acids. In addition, the enzyme inhibitory activities and in vitro effects of the flower extracts on the viability of HEK-293, Caco-2, and MiaPaCa-2 cells were investigated. The proximate composition varied among the edible flowers, with dry matter, crude protein, crude fat, ash, and carbohydrate contents ranging from 8.35 to 11.43%, 3.80 to 4.74%, 2.55 to 4.35%, 9.57 to 11.88%, and 69.40 to 79.94%, respectively. The mineral composition also varied considerably among the edible flowers, with calcium (936.32–1463.23 mg/100 g dw) and potassium (1637.74–1857.46 mg/100 g dw) being the predominant minerals. J. officinale was particularly rich in magnesium (342.45 mg/100 g dw), A. officinalis in calcium and zinc (1463.23 and 4.62 mg/100 g dw, respectively), and V. odorata in phosphorus, iron, and manganese (253.56, 18.39, and 5.78 mg/100 g dw, respectively). Before digestion, J. officinale exhibited the highest total phenolic content (884.00 mg GAE/100 g) and antioxidant capacity, with a phenolic bioaccessibility index of 60.89%. Simulated digestion generally reduced the phenolic content and antioxidant activity. V. odorata was particularly rich in protocatechuic acid, catechin, chlorogenic acid, ferulic acid, and ellagic acid. A. officinalis showed the strongest in vitro inhibitory activity against α-glucosidase, α-amylase, acetylcholinesterase, and lipoxygenase, whereas J. officinale exhibited the strongest butyrylcholinesterase inhibition. Extracts displayed differential cytotoxic effects against Caco-2 and MiaPaCa-2 cells, while effects on HEK-293 cells were comparatively weaker. Overall, these findings demonstrate species-specific nutritional and bioactive profiles and support further investigation of edible flowers as multifunctional food ingredients.