Phytochemical Profile, Antioxidant Capacity, Acetylcholinesterase, and Butyrylcholinesterase Enzyme Inhibition Properties of Myosotis amoena Boiss.

Abstract

Myosotis amoena Boiss. (Turkish name: "Hoş boncukotu") is a perennial herbaceous plant that produces blue flowers during the spring. Phytochemicals, which are secondary metabolites distributed across plants, fungi, microorganisms, and even animal tissues, play crucial roles in health through their antioxidant and bioactive properties. Their antioxidant capacity largely arises from hydroxyl groups and aromatic ring structures that stabilize free radicals via electron delocalization. Enzyme inhibition is a therapeutic strategy in several diseases, including Alzheimer's disease (AD), where acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitors are employed to manage symptoms. This study investigated the phytochemical composition (via LC-MS/MS), total phenolic content, antioxidant capacity, and AChE/BChE inhibitory effects of the ethanol extract of M. amoena using four in vitro methods. The CUPRAC assay demonstrated that M. amoena (1.070) exhibited higher antioxidant activity than Trolox (0.894), although its activity in FRAP, ABTS, and Fe³⁺ reduction assays was lower compared to standard antioxidants. The extract contained 53.03 mg GAE/g extract of total phenolics, with rosmarinic acid being the predominant compound (15.27 mg/g). Furthermore, the extract strongly inhibited AChE and BChE, with IC₅₀ values of 3.9 and 19.8 µg/mL, respectively. These findings highlight, for the first time, the significant bioactive potential of M. amoena as a natural source of antioxidants and cholinesterase inhibitors, supporting its prospective use in the prevention or management of neurodegenerative conditions.