In Vitro α-Amylase and α-Glucosidase Inhibitory Activity and Chemical Profiling of Different Centaurea L. Taxa Growing in Türkiye and North Cyprus

Background and Aims: Centaurea is an extensive genus of flowering plants from the Asteraceae family, widely distributed across the Northern Hemisphere's temperate regions, with a notable presence in the Irano-Turanian and Mediterranean geographical regions. In Türkiye, the Centaurea genus encompasses 209 taxa, while Cyprus is home to 6 taxa within this genus. In this study, the antidiabetic activities and phytochemical content of nine Centaurea taxa, which grow in Türkiye and North Cyprus, C. aegialophila, C. calcitrapa subsp. angusticeps, C. calcitrapa subsp. calcitrapa, C. drabifolia subsp. cappadocica, C. ensiformis, C. glastifolia, C. hyalolepis, C. iberica, and C. virgata were evaluated.Methods: Hydroethanolic extracts (70:30 ethanol-water) of the aerial parts of the plants were prepared using sonication-assisted maceration as the extraction method. To evaluate antidiabetic activity, in vitro assays were performed to measure α-amylase and α-glucosidase inhibition. The phytochemical content of these plants was analysed using HPLC. A total of 17 reference standards were employed, and both qualitative and quantitative determination of phenolic compounds were carried out.Results: Among the tested taxa, C. hyalolepis exhibited the most substantial α-amylase (IC50 = 54.94±2.49 μg/mL) and α-glucosidase (IC50 = 8.78±0.33 μg/mL) inhibitory activities. The phytochemical profile of the investigated taxa was revealed. Chlorogenic acid was the most abundant compound and was detected in all taxa, whereas protocatechuic acid was determined in only some of them. Among all tested, flavonoid and phenolic acid derivatives were detected in the investigated Centaurea taxa.Conclusion: The findings demonstrate that certain Centaurea taxa possess notable in vitro antidiabetic activity, particularly through α-glucosidase inhibition. The phytochemical analysis indicates that phenolic acid derivatives, particularly chlorogenic acid and related compounds, may contribute to the observed bioactivity through synergistic interactions with other secondary metabolites. Therefore, this study highlights the antidiabetic potential and phytochemical composition of these Centaurea taxa. However, further bioassay-guided fractionation and mechanistic studies are required to identify the specific active compound(s) responsible for the observed enzyme inhibitory effects.