Screening of in vitro antioxidant and enzyme inhibitory activities of different extracts from two uninvestigated wild plants: Centranthus longiflorus subsp. longiflorus and Cerinthe minor subsp. auriculata

Introduction The importance of plants products in traditional medicine has been recognized for some time. Two plants of Turkish origin, Centranthus longiflorus subsp. longiflorus and Cerinthe minor subsp. auriculata used as traditional Turkish medicine have remained uninvestigated for Alzheimer diseases and diabetes mellitus for their in vitro biological activity despite their use for sleep disorders. The antioxidant and enzyme inhibitory properties of these plants have not been reported. The aim of this study was to determine the total phenolics, flavonoids, and antioxidant as well as their enzyme inhibitory activity (in aqueous and solvent extracts). Methods Antioxidant assays used standard methods to assess phosphomolybdenum, free radical scavenging activity, reducing power, and metal chelating activity on ferrous ions. Additionally, the extracts were tested also for enzyme inhibitory activity (Cholinesterase, Tyrosinase, α-amylase, and α-glucosidase). Results Organic extracts showed the highest anti-cholinesterase (AChE, and BChE) activity, while aqueous extracts showed valuable Tyrosinase inhibitory activity. Total phenolics (expressed as gallic acid equivalents) in C. longiflorus subsp. longiflorus and C. minor subsp. auriculata were 46.2 and 25.4 mg in methanolic extracts, 27.5 and 26.2 mg in ethyl acetate extracts, and 37.9 and 46.6 mg in aqueous extracts, respectively. Similarly, total flavonoids (expressed as rutin equivalents) in C. longiflorus subsp. longiflorus and C. minor subsp. auriculata were 39.9 and 27.8 mg in methanolic extracts, 17.6 and 52.4 mg in ethyl acetate extracts, and 24.35 and 24.6 mg in aqueous extracts, respectively. Conclusion The reported results may be valuable for preparing new food supplements and can represent a good model for the development of new drug formulations.