Analysis of the phytochemical components of Prunella vulgaris using high-performance liquid chromatography quadrupole time-of-flight mass spectrometry combined with molecular networking and assessment of their antioxidant and anti-α-glucosidase activities.

Abstract

Prunella vulgaris has long been used in traditional medicine and is consumed as a tea in China. Here, the total phenolic and flavonoid concentrations of plants from different geographical regions were measured. It was found that the total phenolic acid concentration ranged from 4.15 to 8.82 g of gallic acid equivalent per 100 g of dry weight (DW), and the total flavonoid concentration was 4.67-7.33 g of rutin equivalent per 100 g DW. Antioxidant activities were measured using 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, and the results ranged from 73.47% to 94.43% and 74.54% to 93.39%, respectively, whereas α-glucosidase inhibition was between 75.31% and 95.49%. Correlation analysis showed that the total flavonoids in P. vulgaris had superior antioxidant and anti-α-glucosidase activities compared to the total phenolic compounds. The active components of P. vulgaris were analyzed using high-performance liquid chromatography quadrupole time-of-flight mass spectrometry combined with both classical molecular networking and feature-based molecular networking on the Global Natural Products Social platform, identifying 32 compounds, namely 14 flavonoids, 12 phenolic compounds, and 6 other chemical components. These results could provide useful information on the use of P. vulgaris as a functional tea.