Centaurea hypoleuca DC: Phenolic content, antimicrobial, antioxidant and enzyme inhibitory activities

Centaurea hypoleuca is one of the plants have been traditionally used in treatments of many diseases in folk medicine in Turkey. In the present study, ethanol, methanol, and ethyl acetate extracts of the plant's aerial parts were examined and their antioxidant, antimicrobial, and enzyme inhibition activities were determined for the first time. The antioxidant assays were performed in vitro using ABTS and DPPH methods, whereas the antimicrobial efficiency was determined using disc diffusion and microdilution methods. Moreover, the enzyme inhibition activity was analyzed using calorimetric methods targeting the key enzymes used in the treatment of Alzheimer's disease (cholinesterase) and diabetes (glucosidase and amylase). Also, the phenolic contents were analyzed using HPLC. The biological activity of flower ethyl acetate extract was found to be significantly higher than those of other extracts. This extract was more prominent because of its strong antimicrobial activity with the MIC value of 8 µg mL−1 against MRSA. Moreover, the main components of the extract were determined to be catechin and chlorogenic acid. In conclusion, these results indicate that C. hypoleuca can be pharmaceutically used as herbal remedies for its antioxidant, antimicrobial, and enzyme inhibitor effects.