Determination of phytochemical content by LC-MS/MS, investigation of antioxidant capacity, and enzyme inhibition effects of nettle (Urtica dioica).

Abstract

Urtica dioica L. Subsp. dioica is an annual or perennial herbaceous plant belonging to the Urticaceae family that has an important place in ethnobotany. This study aimed to investigate the phytochemical content and the inhibition effect on acetylcholinesterase (AChE), which interact with beta-amyloid to promote the deposition of amyloid plaques and paraoxonase (PON1). This plays a role in the regulation of HDL and LDL and an antiatherogenic, and antioxidant capacity of Urtica dioica. Phytochemical content was determined by the liquid chromatography/mass spectrometry (LC-MS/MS), and to assess the enzyme inhibition and antioxidant capacity the spectrophotometer technique was used. The antioxidant capacity of U. dioica extracts (methanol, hexane, and water) was determined by applying 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+), 2,2-diphenyl-1-picrylhydrazyl (DPPH•+), ferric reducing antioxidant power (FRAP), and cupric ion reducing antioxidant capacity (CUPRAC) methods. The methanol extract of the U. dioica exhibited significant inhibition on the AChE (IC50= 0.098 ± 0.011 mg/mL). However, methanol and water extracts of the U. dioica did not exhibit the inhibition effect on PON1. The highest activity for ABTS•+ was in the hexane extract (55.97%), and for DPPH•+ was in the methanol extract (62.42%). Compared to other solvents (hexane and water), the methanol extract of the U. dioica showed the highest activity for FRAP and CUPRAC methods. Results (as absorbance) were 0.302 for CUPRAC and 0.147 for FRAP in the methanol extract of the U. dioica. The acetohydroxamic acid, gallic acid, caffeic acid, ellagic acid, p-hydroxybenzoic acid, and quercetin were qualified and quantified in LC-MS/MS analyses of Urtica dioica extract. U. dioica, which has antioxidant, anti-atherosclerotic and neuroprotective effects, has a natural medicine potential if compared to synthetic drugs used in Alzheimer's patients.