Phytochemical analysis and biological activities of Leiotulus aureus extracts: Antioxidant, anticholinesterase, antidiabetic, and antidepressant properties

This study aimed to evaluate the antioxidant properties, phytochemical contents (LC-MS/MS), and inhibitory effects of Leiotulus aureus extracts on enzymes related to Alzheimer's disease, diabetes, and depression. This is the first L. aureus enzyme inhibition study. In the study, the ethanol extract exhibited the strongest antioxidant effect scavenging DPPH (IC₅₀: 43.76 mg/mL) and ABTS (IC₅₀: 22.41 mg/mL) radical and Fe⁺³-Fe⁺² reducing capacity. In the LC-MS/MS analysis, fumaric acid (1.262 mg/g) and quinic acid (1.074 mg/g) were identified as major components in the ethanol extract, which also exhibited high phenolic (32.69 mg GAE/g) and flavonoid (20.19 mg QE/g) contents. In contrast genistin (0.047 mg/g) was identified as the main component in the dichloromethane: methanol extract. The ethanol extract exhibited the highest inhibitory effect against AChE and BChE, while the dichloromethane: methanol extract showed the strongest effect against α-glycosidase and α-amylase. The inhibitory effect of the dichloromethane extract (IC₅₀: 6.54 mg/mL) on the MAO-B enzyme was found to be very close to that of the standard inhibitor pargyline HCl (IC₅₀: 5.06 mg/mL). These findings indicate that the plant may possess multifunctional pharmacological properties, such as antioxidant, antidiabetic, and antidepressant effects, and point to a potential natural agent, especially for neuropsychiatric disorders.