Edible flowers are receiving renewed interest as rich sources of bioactive compounds. Ethanol extracts of eight edible flowers were phytochemically characterized and investigated for their bioactivity. Rutin, quercetin, luteolin, kaempferol, and myricetin were selected as standards and quantified by HPLC. The fatty acid profile was analyzed by GC and GC-MS. Antioxidant properties were evaluated by using different in vitro tests. The hypoglycemic effects were investigated via the inhibition of α-amylase and α-glucosidase. Sambucus nigra exhibited the highest radical-scavenging activity (IC50 of 1.4 μg/mL), followed by Hedysarum coronarium (IC50 of 1.6 μg/mL). Both species contained high quercetin and rutin contents. S. nigra extract exerted the highest activity in preventing lipid oxidation. Malva sylvestris extract inhibited both α-amylase and α-glucosidase with IC50 values of 7.8 and 11.3 μg/mL, respectively. These findings support the consumption of edible flowers as functional foods and their use as sources of natural antioxidants by the food industry.

This study aims at investigating the contribution of two classes of compounds, flavonoids and iridoids, to the bioactivity of Arbutus unedo L. leaves and fruits. The impact of different extraction procedures on phytochemicals content and hypoglycemic, antioxidant, and nitric oxide (NO) inhibitory activities of A. unedo fresh and dried plant materials was investigated. Ellagic acid 4-O-β-D-glucopyranoside, kaempferol 3-O-glucoside, and norbergenin were identified for the first time in this genus by using liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry (LC-ESI-QTOF-MS). Three iridoids (gardenoside, geniposide, unedoside) are specifically identified in the leaves. Interestingly, asperuloside was extracted only from dried fruits by ethanol with Soxhlet apparatus. Extracts were screened for their potential antioxidant activities by using the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), Ferric Reducing Activity Power (FRAP), and β-carotene bleaching tests. Based on the Global Antioxidant Score (GAS) calculation, the most promising antioxidant extract was obtained by hydroalcoholic maceration of dried leaves that showed half maximal inhibitory concentration (IC50) of 0.42 and 0.98 μg/mL in ABTS and DPPH assays, respectively. The hypoglycaemic activity was investigated by α-amylase and α-glucosidase inhibition tests. Extracts obtained by ethanol ultrasound extraction of fresh leaves and hydroalcoholic maceration of fresh fruits (IC50 of 19.56 and 28.42 μg/mL, respectively) are more active against α-glucosidase than the positive control acarbose (IC50 of 35.50 μg/mL). Fruit extracts exhibited the highest anti-inflammatory activity.

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