UHPLC-ESI-QTOF-Mass Spectrometric Assessment of the Polyphenolic Content of Salvia officinalis to Evaluate the Efficiency of Traditional Herbal Extraction Procedures

Abstract

The healing properties of Salvia officinalis L., Lamiaceae, sage are well known. The presence of high levels of polyphenols in S. officinalis leaves is responsible for many of the therapeutic benefits of the herb. This study used ultra-high-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry in conjunction with extensive mass spectral libraries to identify the polyphenols with high sensitivity. The study aimed to evaluate the effectiveness of six different traditional extraction procedures (fresh tissue homogenization, fresh and dry leaf decoction, and their respective fermentation) for efficient recovery of phytochemicals using data-independent acquisition in negative electrospray ionization mode. The concentrations of caffeic acid (477.57 ± 7.26 μg/g) and rosmarinic acid (13,694.13 ± 112.06 μg/g) in fermented dry leaf decoctions were found to be significantly higher than in other extracts. However, the dry leaf decoction yielded significantly higher levels of the flavonoid luteolin-7-O-glucoside (691.60 ± 9.81 μg/g) and the terpenoids carnosol, carnosic acid, and ursolic acid (215.61 ± 4.92 μg/g, 529.61 ± 9.61 μg/g, and 19.90 ± 0.22 μg/g, respectively). Two flavonoid compounds, diosmetin ([M-H]− m/z 299.0554) and pectolinarigenin ([M-H]− m/z 313.0715), were identified for the first time in S. officinalis. Among fifty-four identified polyphenols, gallocatechin, scutellarin, sagerinic acid, salvianolic acids, pectolinarigenin, rosmanol, rosmadial, and 12-methoxy carnosic acid were found in higher intensities. Dry leaf decoction and its fermentation were found to be the most efficient traditional extraction methods for polyphenols in S. officinalis.